Molecules

15 pages, 3256 KiB

Open AccessReview

Metal Nanoparticles as Sustainable Tools for C–N Bond Formation via C–H Activation

by Federica Valentini, Oriana Piermatti and Luigi Vaccaro

Molecules 2021, 26(13), 4106; https://doi.org/10.3390/molecules26134106 - 05 Jul 2021

Cited by 7 | Viewed by 2686

The design of highly active metal nanoparticles to be employed as efficient heterogeneous catalysts is a key tool for the construction of complex organic molecules and the minimization of their environmental costs. The formation of novel C–N bonds via C–H activation is an [...] Read more.

The design of highly active metal nanoparticles to be employed as efficient heterogeneous catalysts is a key tool for the construction of complex organic molecules and the minimization of their environmental costs. The formation of novel C–N bonds via C–H activation is an effective atom-economical strategy to access high value materials in pharmaceuticals, polymers, and natural product production. In this contribution, the literature of the last ten years on the use of metal nanoparticles in the processes involving direct C–N bond formation will be discussed. Where possible, a discussion on the role and influence of the support used for the immobilization and/or the metal chosen is reported. Particular attention was given to the description of the experiments performed to elucidate the active mechanism. Full article

(This article belongs to the Special Issue Review Papers in Green Chemistry)

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28 pages, 2709 KiB

Open AccessEditor’s ChoiceReview

Melatonin, Its Metabolites and Their Interference with Reactive Nitrogen Compounds

by Rüdiger Hardeland

Molecules 2021, 26(13), 4105; https://doi.org/10.3390/molecules26134105 - 05 Jul 2021

Cited by 19 | Viewed by 4432

Abstract

Melatonin and several of its metabolites are interfering with reactive nitrogen. With the notion of prevailing melatonin formation in tissues that exceeds by far the quantities in blood, metabolites come into focus that are poorly found in the circulation. Apart from their antioxidant [...] Read more.

Melatonin and several of its metabolites are interfering with reactive nitrogen. With the notion of prevailing melatonin formation in tissues that exceeds by far the quantities in blood, metabolites come into focus that are poorly found in the circulation. Apart from their antioxidant actions, both melatonin and N¹-acetyl-5-methoxykynuramine (AMK) downregulate inducible and inhibit neuronal NO synthases, and additionally scavenge NO. However, the NO adduct of melatonin redonates NO, whereas AMK forms with NO a stable product. Many other melatonin metabolites formed in oxidative processes also contain nitrosylatable sites. Moreover, AMK readily scavenges products of the CO₂-adduct of peroxynitrite such as carbonate radicals and NO₂. Protein AMKylation seems to be involved in protective actions. Full article

(This article belongs to the Special Issue Melatonin as an Antioxidant and a Functionally Pleiotropic Molecule: Synthesis, Metabolism and Activities in Organisms II)

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11 pages, 1390 KiB

Open AccessFeature PaperArticle

A Rapid Gas-Chromatography/Mass-Spectrometry Technique for Determining Odour Activity Values of Volatile Compounds in Plant Proteins: Soy, and Allergen-Free Pea and Brown Rice Protein

by Anika Singh, Yuan Shi, Perrine Magreault, David D. Kitts, Maciej Jarzębski, Przemysław Siejak and Anubhav Pratap-Singh

Molecules 2021, 26(13), 4104; https://doi.org/10.3390/molecules26134104 - 05 Jul 2021

Cited by 11 | Viewed by 4466

Abstract

Plant-based protein sources have a characteristic aroma that limits their usage in various meat-alternative formulations. Despite being the most popular plant-based protein, the allergenicity of soy protein severely restricts the potential adoption of soy protein as an animal substitute. Thereby, allergen-free plant-protein sources [...] Read more.

Plant-based protein sources have a characteristic aroma that limits their usage in various meat-alternative formulations. Despite being the most popular plant-based protein, the allergenicity of soy protein severely restricts the potential adoption of soy protein as an animal substitute. Thereby, allergen-free plant-protein sources need to be characterized. Herein, we demonstrate a rapid solid-phase-microextraction gas-chromatography/mass-spectrometry (SPME-GC/MS) technique for comparing the volatile aroma profile concentration of two different allergen-free plant-protein sources (brown rice and pea) and comparing them with soy protein. The extraction procedure consisted of making a 1:7 w/v aqueous plant protein slurry, and then absorbing the volatile compounds on an SPME fibre under agitation for 10 min at 40 °C, which was subsequently injected onto a GC column coupled to an MS system. Observed volatile concentrations were used in conjunction with odour threshold values to generate a Total Volatile Aroma Score for each protein sample. A total of 76 volatile compounds were identified. Aldehydes and furans were determined to be the most dominant volatiles present in the plant proteins. Both brown rice protein and pea protein contained 64% aldehydes and 18% furans, with minor contents of alcohols, ketones and other compounds. On the other hand, soy protein consisted of fewer aldehydes (46%), but a more significant proportion of furans (42%). However, in terms of total concentration, brown rice protein contained the highest intensity and number of volatile compounds. Based on the calculated odour activity values of the detected compounds, our study concludes that pea proteins could be used as a suitable alternative to soy proteins in applications for allergen-free vegan protein products without interfering with the taste or flavour of the product. Full article

(This article belongs to the Special Issue Analysis of Foods and Food Components on Molecular Level)

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28 pages, 9061 KiB

Open AccessReview

Classification, Toxicity and Bioactivity of Natural Diterpenoid Alkaloids

by Amin Mahmood Thawabteh, Alà Thawabteh, Filomena Lelario, Sabino Aurelio Bufo and Laura Scrano

Molecules 2021, 26(13), 4103; https://doi.org/10.3390/molecules26134103 - 05 Jul 2021

Cited by 27 | Viewed by 4774

Abstract

Diterpenoid alkaloids are natural compounds having complex structural features with many stereo-centres originating from the amination of natural tetracyclic diterpenes and produced primarily from plants in the Aconitum, Delphinium, Consolida genera. Corals, Xenia, Okinawan/Clavularia, Alcyonacea (soft corals) and [...] Read more.

Diterpenoid alkaloids are natural compounds having complex structural features with many stereo-centres originating from the amination of natural tetracyclic diterpenes and produced primarily from plants in the Aconitum, Delphinium, Consolida genera. Corals, Xenia, Okinawan/Clavularia, Alcyonacea (soft corals) and marine sponges are rich sources of diterpenoids, despite the difficulty to access them and the lack of availability. Researchers have long been concerned with the potential beneficial or harmful effects of diterpenoid alkaloids due to their structural complexity, which accounts for their use as pharmaceuticals as well as their lousy reputation as toxic substances. Compounds belonging to this unique and fascinating family of natural products exhibit a broad spectrum of biological activities. Some of these compounds are on the list of clinical drugs, while others act as incredibly potent neurotoxins. Despite numerous attempts to prepare synthetic products, this review only introduces the natural diterpenoid alkaloids, describing ‘compounds’ structures and classifications and their toxicity and bioactivity. The purpose of the review is to highlight some existing relationships between the presence of substituents in the structure of such molecules and their recognised bioactivity. Full article

(This article belongs to the Special Issue Natural Terpenoid Alkaloids Therapeutic Perspectives)

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14 pages, 1909 KiB

Open AccessArticle

Antioxidant, Anti-Inflammatory and Antithrombotic Effects of Ginsenoside Compound K Enriched Extract Derived from Ginseng Sprouts

by In-Hee Baik, Kyung-Hee Kim and Kyung-Ae Lee

Molecules 2021, 26(13), 4102; https://doi.org/10.3390/molecules26134102 - 05 Jul 2021

Cited by 18 | Viewed by 3218

Abstract

Partially purified ginsenoside extract (PGE) and compound K enriched extract (CKE) were prepared from ginseng sprouts, and their antioxidant, anti-inflammatory and antithrombotic effects were investigated. Compared to the 6-year-old ginseng roots, ginseng sprouts were found to have a higher content of phenolic compounds, [...] Read more.

Partially purified ginsenoside extract (PGE) and compound K enriched extract (CKE) were prepared from ginseng sprouts, and their antioxidant, anti-inflammatory and antithrombotic effects were investigated. Compared to the 6-year-old ginseng roots, ginseng sprouts were found to have a higher content of phenolic compounds, saponin and protopanaxadiol-type ginsenoside by about 56%, 36% and 43%, respectively. PGE was prepared using a macroporous adsorption resin, and compound K(CK) was converted and enriched from the PGE by enzymatic hydrolysis with a conversion rate of 75%. PGE showed higher effects than CKE on radical scavenging activity in antioxidant assays. On the other hand, CKE reduced nitric oxide levels more effectively than PGE in RAW 264.7 cells. CKE also reduced pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β and IL-6 than PGE. Tail bleeding time and volume were investigated after administration of CKE at 70–150 mg/kg/day to mice. CKE administered group showed a significant increase or increased tendency in bleeding time than the control group. Bleeding volume in the CKE group increased than the control group, but not as much as in the aspirin group. In conclusion, ginseng sprouts could be an efficient source of ginsenoside, and CKE converted from the ginsenosides showed antioxidant, anti-inflammatory and antithrombotic effects. However, it was estimated that the CKE might play an essential role in anti-inflammatory effects rather than antioxidant effects. Full article

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14 pages, 3396 KiB

Open AccessArticle

Assessment of the In Vivo Release and Biocompatibility of Novel Vesicles Containing Zinc in Rats

by Liliana Mititelu-Tartau, Maria Bogdan, Daniela Angelica Pricop, Beatrice Rozalina Buca, Ana-Maria Pauna, Lorena Anda Dijmarescu, Ana-Maria Pelin, Liliana Lacramioara Pavel and Gratiela Eliza Popa

Molecules 2021, 26(13), 4101; https://doi.org/10.3390/molecules26134101 - 05 Jul 2021

Cited by 1 | Viewed by 1823

Abstract

This paper is focused on the in vivo release and biocompatibility evaluation in rats of some novel systems entrapping zinc chloride in lipid vesicles. The particles were prepared by zinc chloride immobilization inside lipid vesicles made using phosphatidylcholine, stabilized with 0.5% chitosan solution, [...] Read more.

This paper is focused on the in vivo release and biocompatibility evaluation in rats of some novel systems entrapping zinc chloride in lipid vesicles. The particles were prepared by zinc chloride immobilization inside lipid vesicles made using phosphatidylcholine, stabilized with 0.5% chitosan solution, and dialyzed for 10 h to achieve a neutral pH. The submicrometric systems were physico-chemically characterized. White Wistar rats, assigned into four groups of six animals each, were treated orally with a single dose, as follows: Group I (control): deionized water 0.3 mL/100 g body weight; Group II (Zn): 2 mg/kg body weight (kbw) zinc chloride; Group III (LV-Zn): 2 mg/kbw zinc chloride in vesicles; Group IV (LVC-Zn): 2 mg/kbw zinc chloride in vesicles stabilized with chitosan. Haematological, biochemical, and immune parameters were assessed after 24 h and 7 days, and then liver fragments were collected for histopathological examination. The use of zinc submicrometric particles—especially those stabilized with chitosan—showed a delayed zinc release in rats. No substantial changes to blood parameters, plasma biochemical tests, serum complement activity, or peripheral neutrophils phagocytic capacity were noted; moreover, the tested substances did not induce liver architectural disturbances. The obtained systems provided a delayed release of zinc, and showed good biocompatibility in rats. Full article

(This article belongs to the Special Issue Preparation, Characterization, and Effect of Lipid Nanoparticles Used in Different Application Fields II)

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27 pages, 1630 KiB

Open AccessReview

Targeting the PI3K/AKT/mTOR Signaling Pathway in Lung Cancer: An Update Regarding Potential Drugs and Natural Products

by Iksen, Sutthaorn Pothongsrisit and Varisa Pongrakhananon

Molecules 2021, 26(13), 4100; https://doi.org/10.3390/molecules26134100 - 05 Jul 2021

Cited by 92 | Viewed by 14454

Abstract

Lung cancer is one of the most common cancers and has a high mortality rate. Due to its high incidence, the clinical management of the disease remains a major challenge. Several reports have documented a relationship between the phosphatidylinositol-3-kinase (PI3K)/ protein kinase B [...] Read more.

Lung cancer is one of the most common cancers and has a high mortality rate. Due to its high incidence, the clinical management of the disease remains a major challenge. Several reports have documented a relationship between the phosphatidylinositol-3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway and lung cancer. The recognition of this pathway as a notable therapeutic target in lung cancer is mainly due to its central involvement in the initiation and progression of the disease. Interest in using natural and synthetic medications to target these signaling pathways has increased in recent years, with promising results in vitro, in vivo, and in clinical trials. In this review, we focus on the current understanding of PI3K/AKT/mTOR signaling in tumor development. In addition to the signaling pathway, we highlighted the therapeutic potential of recently developed PI3K/AKT/mTOR inhibitors based on preclinical and clinical trials. Full article

(This article belongs to the Special Issue Natural Products in Cancer Research: From Isolation to Mechanisms of Action)

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20 pages, 2102 KiB

Open AccessReview

Plants and Natural Products with Activity against Various Types of Coronaviruses: A Review with Focus on SARS-CoV-2

by Susana A. Llivisaca-Contreras, Jaime Naranjo-Morán, Andrea Pino-Acosta, Luc Pieters, Wim Vanden Berghe, Patricia Manzano, Jeffrey Vargas-Pérez, Fabian León-Tamariz and Juan M. Cevallos-Cevallos

Molecules 2021, 26(13), 4099; https://doi.org/10.3390/molecules26134099 - 05 Jul 2021

Cited by 23 | Viewed by 7304

Abstract

COVID-19 is a pandemic disease caused by the SARS-CoV-2 virus, which is potentially fatal for vulnerable individuals. Disease management represents a challenge for many countries, given the shortage of medicines and hospital resources. The objective of this work was to review the medicinal [...] Read more.

COVID-19 is a pandemic disease caused by the SARS-CoV-2 virus, which is potentially fatal for vulnerable individuals. Disease management represents a challenge for many countries, given the shortage of medicines and hospital resources. The objective of this work was to review the medicinal plants, foods and natural products showing scientific evidence for host protection against various types of coronaviruses, with a focus on SARS-CoV-2. Natural products that mitigate the symptoms caused by various coronaviruses are also presented. Particular attention was placed on natural products that stabilize the Renin–Angiotensin–Aldosterone System (RAAS), which has been associated with the entry of the SARS-CoV-2 into human cells. Full article

(This article belongs to the Special Issue Antiviral Properties of Natural Products)

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9 pages, 22468 KiB

Open AccessFeature PaperArticle

Photodegradation of Brilliant Green Dye by a Zinc bioMOF and Crystallographic Visualization of Resulting CO₂

by Paula Escamilla, Marta Viciano-Chumillas, Rosaria Bruno, Donatella Armentano, Emilio Pardo and Jesús Ferrando-Soria

Molecules 2021, 26(13), 4098; https://doi.org/10.3390/molecules26134098 - 05 Jul 2021

Cited by 5 | Viewed by 2342

Abstract

We present a novel bio-friendly water-stable Zn-based MOF (1), derived from the natural amino acid L-serine, which was able to efficiently photodegrade water solutions of brilliant green dye in only 120 min. The total degradation was followed by UV-Vis spectroscopy [...] Read more.

We present a novel bio-friendly water-stable Zn-based MOF (1), derived from the natural amino acid L-serine, which was able to efficiently photodegrade water solutions of brilliant green dye in only 120 min. The total degradation was followed by UV-Vis spectroscopy and further confirmed by single-crystal X-ray crystallography, revealing the presence of CO₂ within its channels. Reusability studies further demonstrate the structural and performance robustness of 1. Full article

(This article belongs to the Special Issue Emerging Applications of Metal-Organic Frameworks and Related Porous Materials)

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9 pages, 2241 KiB

Open AccessCommunication

Self-Assembled Bimetallic Aluminum-Salen Catalyst for the Cyclic Carbonates Synthesis

by Wooyong Seong, Hyungwoo Hahm, Seyong Kim, Jongwoo Park, Khalil A. Abboud and Sukwon Hong

Molecules 2021, 26(13), 4097; https://doi.org/10.3390/molecules26134097 - 05 Jul 2021

Cited by 4 | Viewed by 2958

Abstract

Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO₂. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) [...] Read more.

Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO₂. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) of the bis-urea salen Al catalyst is three times higher than that of a μ-oxo-bridged catalyst, and 13 times higher than that of a monomeric salen aluminum catalyst. The bimetallic reaction pathway is suggested based on urea additive studies and kinetic studies. Additionally, the X-ray crystal structure of a bis-urea salen Ni complex supports the self-assembly of the bis-urea salen metal complex through hydrogen bonding. Full article

(This article belongs to the Special Issue Ligands in Catalysis)

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10 pages, 3830 KiB

Open AccessArticle

Additive Effects of Lithium Salts with Various Anionic Species in Poly (Methyl Methacrylate)

by Asae Ito and Koh-hei Nitta

Molecules 2021, 26(13), 4096; https://doi.org/10.3390/molecules26134096 - 05 Jul 2021

Cited by 5 | Viewed by 2766

Abstract

We report that lithium salts in lithium-ion batteries effectively modify the physical properties of poly (methyl methacrylate) (PMMA). The glass transition temperature (T_g) is an indicator of the heat resistance of amorphous polymers. The anionic species of the salts strongly [...] Read more.

We report that lithium salts in lithium-ion batteries effectively modify the physical properties of poly (methyl methacrylate) (PMMA). The glass transition temperature (T_g) is an indicator of the heat resistance of amorphous polymers. The anionic species of the salts strongly affected the glass transition behavior of PMMA. We focused on the additive effects of various lithium salts, such as LiCF₃SO₃, LiCOOCF₃, LiClO₄, and LiBr, on the T_g of PMMA. The large anions of the former three salts caused them to form macroscopic aggregates that acted as fillers in the PMMA matrix and to combine the PMMA domains, increasing T_g. On the other hand, LiBr salts dispersed microscopically in the PMMA matrix at the molecular scale, leading to the linking of the PMMA chains. Thus, the addition of LiBr to PMMA increased T_g as well as the relaxation time in the range of glass to rubber transition. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Macromolecular Chemistry Section of Molecules 2021)

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28 pages, 2237 KiB

Open AccessReview

Pharmacological Efficacy of Ginseng against Respiratory Tract Infections

by Abdulrhman Alsayari, Abdullatif Bin Muhsinah, Dalia Almaghaslah, Sivakumar Annadurai and Shadma Wahab

Molecules 2021, 26(13), 4095; https://doi.org/10.3390/molecules26134095 - 05 Jul 2021

Cited by 25 | Viewed by 7938

Abstract

Respiratory tract infections are underestimated, as they are mild and generally not incapacitating. In clinical medicine, however, these infections are considered a prevalent problem. By 2030, the third most comprehensive reason for death worldwide will be chronic obstructive pulmonary disease (COPD), according to [...] Read more.

Respiratory tract infections are underestimated, as they are mild and generally not incapacitating. In clinical medicine, however, these infections are considered a prevalent problem. By 2030, the third most comprehensive reason for death worldwide will be chronic obstructive pulmonary disease (COPD), according to the World Health Organization. The current arsenal of anti-inflammatory drugs shows little or no benefits against COPD. For thousands of years, herbal drugs have been used to cure numerous illnesses; they exhibit promising results and enhance physical performance. Ginseng is one such herbal medicine, known to alleviate pro-inflammatory chemokines and cytokines (IL-2, IL-4, IFN-γ, TNF-α, IL-5, IL-6, IL-8) formed by macrophages and epithelial cells. Furthermore, the mechanisms of action of ginsenoside are still not fully understood. Various clinical trials of ginseng have exhibited a reduction of repeated colds and the flu. In this review, ginseng’s structural features, the pathogenicity of microbial infections, and the immunomodulatory, antiviral, and anti-bacterial effects of ginseng were discussed. The focus was on the latest animal studies and human clinical trials that corroborate ginseng’s role as a therapy for treating respiratory tract infections. The article concluded with future directions and significant challenges. This review would be a valuable addition to the knowledge base for researchers in understanding the promising role of ginseng in treating respiratory tract infections. Further analysis needs to be re-focused on clinical trials to study ginseng’s efficacy and safety in treating pathogenic infections and in determining ginseng-drug interactions. Full article

(This article belongs to the Special Issue Biomolecules from Plant and Animal Wastes: From Processing to Application in Food and Medicine)

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15 pages, 3349 KiB

Open AccessArticle

Effects of Graphene Nanoplatelets on Mechanical and Fire Performance of Flax Polypropylene Composites with Intumescent Flame Retardant

by Imran Ali, Nam Kyeun Kim and Debes Bhattacharyya

Molecules 2021, 26(13), 4094; https://doi.org/10.3390/molecules26134094 - 05 Jul 2021

Cited by 18 | Viewed by 2635

Abstract

The integration of intumescent flame-retardant (IFR) additives in natural fiber-based polymer composites enhances the fire-retardant properties, but it generally has a detrimental effect on the mechanical properties, such as tensile and flexural strengths. In this work, the feasibility of graphene as a reinforcement [...] Read more.

The integration of intumescent flame-retardant (IFR) additives in natural fiber-based polymer composites enhances the fire-retardant properties, but it generally has a detrimental effect on the mechanical properties, such as tensile and flexural strengths. In this work, the feasibility of graphene as a reinforcement additive and as an effective synergist for IFR-based flax-polypropylene (PP) composites was investigated. Noticeable improvements in tensile and flexural properties were achieved with the addition of graphene nanoplatelets (GNP) in the composites. Furthermore, better char-forming ability of GNP in combination with IFR was observed, suppressing HRR curves and thus, lowering the total heat release (THR). Thermogravimetric analysis (TGA) detected a reduction in the decomposition rate due to strong interfacial bonding between GNP and PP, whereas the maximum decomposition rate was observed to occur at a higher temperature. The saturation point for the IFR additive along with GNP has also been highlighted in this study. A safe and effective method of graphene encapsulation within PP using the fume-hood set-up was achieved. Finally, the effect of flame retardant on the flax–PP composite has been simulated using Fire Dynamics Simulator. Full article

(This article belongs to the Special Issue Recent Advances in Flame-Retardant Polymers and Composites)

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14 pages, 1066 KiB

Open AccessArticle

Synthesis and Evaluation of Chalcone-Quinoline Based Molecular Hybrids as Potential Anti-Malarial Agents

by Bonani Vinindwa, Godwin Akpeko Dziwornu and Wayiza Masamba

Molecules 2021, 26(13), 4093; https://doi.org/10.3390/molecules26134093 - 05 Jul 2021

Cited by 14 | Viewed by 2815

Abstract

Molecular hybridization is a drug discovery strategy that involves the rational design of new chemical entities by the fusion (usually via a covalent linker) of two or more drugs, both active compounds and/or pharmacophoric units recognized and derived from known bioactive molecules. The [...] Read more.

Molecular hybridization is a drug discovery strategy that involves the rational design of new chemical entities by the fusion (usually via a covalent linker) of two or more drugs, both active compounds and/or pharmacophoric units recognized and derived from known bioactive molecules. The expected outcome of this chemical modification is to produce a new hybrid compound with improved affinity and efficacy compared to the parent drugs. Additionally, this strategy can result in compounds presenting modified selectivity profiles, different and/or dual modes of action, reduced undesired side effects and ultimately lead to new therapies. In this study, molecular hybridization was used to generate new molecular hybrids which were tested against the chloroquine sensitive (NF54) strain of P. falciparum. To prepare the new molecular hybrids, the quinoline nucleus, one of the privileged scaffolds, was coupled with various chalcone derivatives via an appropriate linker to produce a total of twenty-two molecular hybrids in 11%–96% yield. The synthesized compounds displayed good antiplasmodial activity with IC₅₀ values ranging at 0.10–4.45 μM. Full article

(This article belongs to the Special Issue Quinolones: Chemistry and Biological Activities)

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23 pages, 2279 KiB

Open AccessArticle

Regioselective Mercury(I)/Palladium(II)-Catalyzed Single-Step Approach for the Synthesis of Imines and 2-Substituted Indoles

by Rsuini U. Gutiérrez, Mayra Hernández-Montes, Aarón Mendieta-Moctezuma, Francisco Delgado and Joaquín Tamariz

Molecules 2021, 26(13), 4092; https://doi.org/10.3390/molecules26134092 - 05 Jul 2021

Cited by 2 | Viewed by 2955

Abstract

An efficient synthesis of ketimines was achieved through a regioselective Hg(I)-catalyzed hydroamination of terminal acetylenes in the presence of anilines. The Pd(II)-catalyzed cyclization of these imines into the 2-substituted indoles was satisfactorily carried out by a C-H activation. In a single-step approach, a [...] Read more.

An efficient synthesis of ketimines was achieved through a regioselective Hg(I)-catalyzed hydroamination of terminal acetylenes in the presence of anilines. The Pd(II)-catalyzed cyclization of these imines into the 2-substituted indoles was satisfactorily carried out by a C-H activation. In a single-step approach, a variety of 2-substituted indoles were also generated via a Hg(I)/Pd(II)-catalyzed, one-pot, two-step process, starting from anilines and terminal acetylenes. The arylacetylenes proved to be more effective than the alkyl derivatives. Full article

(This article belongs to the Special Issue Applications of Palladium-Catalyzed in Organic Chemistry)

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29 pages, 7129 KiB

Open AccessReview

Plasma and Polymers: Recent Progress and Trends

by Igor Levchenko, Shuyan Xu, Oleg Baranov, Olha Bazaka, Elena P. Ivanova and Kateryna Bazaka

Molecules 2021, 26(13), 4091; https://doi.org/10.3390/molecules26134091 - 05 Jul 2021

Cited by 43 | Viewed by 4848

Abstract

Plasma-enhanced synthesis and modification of polymers is a field that continues to expand and become increasingly more sophisticated. The highly reactive processing environments afforded by the inherently dynamic nature of plasma media are often superior to ambient or thermal environments, offering substantial advantages [...] Read more.

Plasma-enhanced synthesis and modification of polymers is a field that continues to expand and become increasingly more sophisticated. The highly reactive processing environments afforded by the inherently dynamic nature of plasma media are often superior to ambient or thermal environments, offering substantial advantages over other processing methods. The fluxes of energy and matter toward the surface enable rapid and efficient processing, whereas the charged nature of plasma-generated particles provides a means for their control. The range of materials that can be treated by plasmas is incredibly broad, spanning pure polymers, polymer-metal, polymer-wood, polymer-nanocarbon composites, and others. In this review, we briefly outline some of the recent examples of the state-of-the-art in the plasma-based polymer treatment and functionalization techniques. Full article

(This article belongs to the Special Issue Plasma Polymers for Advanced Material Design)

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20 pages, 3870 KiB

Open AccessArticle

Salt Stress Mitigation via the Foliar Application of Chitosan-Functionalized Selenium and Anatase Titanium Dioxide Nanoparticles in Stevia (Stevia rebaudiana Bertoni)

by Morteza Sheikhalipour, Behrooz Esmaielpour, Gholamreza Gohari, Maryam Haghighi, Hessam Jafari, Habib Farhadi, Muhittin Kulak and Andrzej Kalisz

Molecules 2021, 26(13), 4090; https://doi.org/10.3390/molecules26134090 - 05 Jul 2021

Cited by 36 | Viewed by 3850

Abstract

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of [...] Read more.

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs, titanium dioxide nanoparticles (TiO₂ NPs) and selenium functionalized using chitosan nanoparticles (Cs–Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A). For this reason, the current study was designed to investigate the potential of TiO₂ NPs (0, 100 and 200 mg L⁻¹) and Cs–Se NPs (0, 10 and 20 mg L⁻¹) to alleviate salt stress (0, 50 and 100 mM NaCl) in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic traits but resulted in substantial cell damage through increasing H₂O₂ and MDA content, as well as electrolyte leakage (EL). However, the application of TiO₂ NPs (100 mg L⁻¹) and Cs–Se NPs (20 mg L⁻¹) increased the growth, photosynthetic performance and activity of antioxidant enzymes, and decreased the contents of H₂O₂, MDA and EL under the saline conditions. In addition to the enhanced growth and physiological performance of the plant, the essential oil content was also increased with the treatments of TiO₂ (100 mg L⁻¹) and Cs–Se NPs (20 mg L⁻¹). In addition, the tested NPs treatments increased the concentration of stevioside (in the non-saline condition and under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall, the current findings suggest that especially 100 mg L⁻¹ TiO₂ NPs and 20 mg L⁻¹ Cs–Se could be considered as promising agents in combating high levels of salinity in the case of stevia. Full article

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21 pages, 5825 KiB

Open AccessArticle

Comprehensive Characterisation of the Ketoprofen-β-Cyclodextrin Inclusion Complex Using X-ray Techniques and NMR Spectroscopy

by Katarzyna Betlejewska-Kielak, Elżbieta Bednarek, Armand Budzianowski, Katarzyna Michalska and Jan K. Maurin

Molecules 2021, 26(13), 4089; https://doi.org/10.3390/molecules26134089 - 05 Jul 2021

Cited by 4 | Viewed by 2449

Abstract

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an [...] Read more.

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an aqueous solution, it was found that in the samples obtained by methods 1 and 2, there were large excesses of β-CD in relation to KP, 10 and 75 times, respectively, while the sample obtained by method 3 contained equimolar amounts of β-CD and KP. NMR results indicated that KP/β-CD inclusion complexes were formed and the estimated binding constants were approximately 2400 M⁻¹, showing that KP is quite strongly associated with β-CD. On the other hand, the X-ray single-crystal technique in the solid state revealed that the (S)-KP/β-CD inclusion complex with a stoichiometry of 2:2 was obtained as a result of heating-under-reflux, for which the crystal and molecular structure were examined. Among the methods used for the preparation of the KP/β-CD complex, only method 3 is suitable. Full article

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10 pages, 697 KiB

Open AccessArticle

Natural and Conventional Cosmetics—Mercury Exposure Assessment

by Aleksandra Podgórska, Anna Puścion-Jakubik, Anita Grodzka, Sylwia K. Naliwajko, Renata Markiewicz-Żukowska and Katarzyna Socha

Molecules 2021, 26(13), 4088; https://doi.org/10.3390/molecules26134088 - 05 Jul 2021

Cited by 15 | Viewed by 3564

Abstract

Mercury (Hg) can enter the human body through the respiratory tract and digestive system, but also through the skin. Sources of Hg in the environment can be natural processes, but also human activities, including agriculture, chemical, and pharmaceutical industries. Hg can also enter [...] Read more.

Mercury (Hg) can enter the human body through the respiratory tract and digestive system, but also through the skin. Sources of Hg in the environment can be natural processes, but also human activities, including agriculture, chemical, and pharmaceutical industries. Hg can also enter the body through food, but also with cosmetics that are used for a long time. Therefore, the aim of this study was to evaluate the Hg content in 268 randomly selected cosmetics: Natural and conventional, for face and body. Hg content was determined using an atomic absorption spectrometer (AMA 254, Leco, Prague, Czech Republic). It was shown that the face preparations were characterized by a significantly higher Hg content than the body preparations. No differences in the content of the tested element were found between natural and conventional preparations. Hg could be detected in all samples with concentrations measured from 0.348 to 37.768 µg/kg. Full article

(This article belongs to the Special Issue Natural Products and Skin Diseases)

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17 pages, 749 KiB

Open AccessReview

The Diversity of the Mitochondrial Outer Membrane Protein Import Channels: Emerging Targets for Modulation

by Monika Mazur, Hanna Kmita and Małgorzata Wojtkowska

Molecules 2021, 26(13), 4087; https://doi.org/10.3390/molecules26134087 - 04 Jul 2021

Cited by 6 | Viewed by 3344

Abstract

The functioning of mitochondria and their biogenesis are largely based on the proper function of the mitochondrial outer membrane channels, which selectively recognise and import proteins but also transport a wide range of other molecules, including metabolites, inorganic ions and nucleic acids. To [...] Read more.

The functioning of mitochondria and their biogenesis are largely based on the proper function of the mitochondrial outer membrane channels, which selectively recognise and import proteins but also transport a wide range of other molecules, including metabolites, inorganic ions and nucleic acids. To date, nine channels have been identified in the mitochondrial outer membrane of which at least half represent the mitochondrial protein import apparatus. When compared to the mitochondrial inner membrane, the presented channels are mostly constitutively open and consequently may participate in transport of different molecules and contribute to relevant changes in the outer membrane permeability based on the channel conductance. In this review, we focus on the channel structure, properties and transported molecules as well as aspects important to their modulation. This information could be used for future studies of the cellular processes mediated by these channels, mitochondrial functioning and therapies for mitochondria-linked diseases. Full article

(This article belongs to the Special Issue Compounds Modulating Mitochondrial Ion Channels)

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22 pages, 4559 KiB

Open AccessArticle

The Effect of Simulated In Vitro Digestion on Biological Activity of Viburnum opulus Fruit Juices

by Nina Pietrzyk, Małgorzata Zakłos-Szyda, Małgorzata Redzynia and Anna Podsędek

Molecules 2021, 26(13), 4086; https://doi.org/10.3390/molecules26134086 - 04 Jul 2021

Cited by 1 | Viewed by 3508

Abstract

In the present study, an in vitro digestion method has been used to assay the influence of the physiological conditions in the mouth, stomach, and intestine on the stability and activity in different cell models of the main phenolic compounds from Viburnum opulus [...] Read more.

In the present study, an in vitro digestion method has been used to assay the influence of the physiological conditions in the mouth, stomach, and intestine on the stability and activity in different cell models of the main phenolic compounds from Viburnum opulus fresh juice (FJ), phenolic-rich juice (PJ), and the bioavailable fractions (DFJ and DPJ). The data obtained indicate that the V. opulus samples achieved after in vitro digestion had an influence on cellular glucose and lipid metabolism. The bioavailable fraction of both digested juices stimulated glucose uptake and decreased lipid accumulation by L6 myoblasts and HepG2 hepatocytes. Both DFJ and DPJ reduced the secretion of inflammatory cytokines by 3T3-L1 adipocytes: interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Simultaneously, DFJ and DPJ enhanced oxidative stress in MIN6 cells and decreased glucose-stimulated insulin secretion (GSIS). UPLC–MS analysis revealed qualitative and quantitative changes in hydroxycinnamic acids. In particular, the content of chlorogenic acid decreased drastically; its content in the bioavailable fraction was almost 7 times and 30 times lower than in the FJ and PJ, respectively. Our results suggested that although the phenolic compounds of V. opulus juices undergo transformation during digestion, they are still potent antioxidant agents with biological activity. Full article

(This article belongs to the Special Issue Biosynthesis and Biological Activities of Flavonoids)

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8 pages, 444 KiB

Open AccessArticle

Hypocholesterolemic Effect of Blackcurrant (Ribes nigrum) Extract in Healthy Female Subjects: A Pilot Study

by Naoki Nanashima, Kayo Horie, Maiko Kitajima, Shizuka Takamagi, Kasumi Mikami, Naoya In and Toshiko Tomisawa

Molecules 2021, 26(13), 4085; https://doi.org/10.3390/molecules26134085 - 04 Jul 2021

Cited by 5 | Viewed by 2769

Abstract

Blackcurrant extract (BCE) ameliorates dyslipidemia in menopausal model animals and in elderly women at a risk of dyslipidemia. However, it is unknown whether the daily intake of BCE can prevent lipid abnormalities in healthy individuals. Lipids are essential for the body, but they [...] Read more.

Blackcurrant extract (BCE) ameliorates dyslipidemia in menopausal model animals and in elderly women at a risk of dyslipidemia. However, it is unknown whether the daily intake of BCE can prevent lipid abnormalities in healthy individuals. Lipids are essential for the body, but they also cause arteriosclerosis. In this noncomparative pilot study, we examined the effects of BCE administered for 29 days on serum lipids in young healthy women. Blood samples were collected before and on days 4 and 29 after BCE intake, and 20 lipoprotein fractions in the serum were separated using a gel-permeation high-performance liquid chromatography method to measure the triacylglycerol and cholesterol levels in lipoproteins. There were no effects on lipids on day 4 of BCE intake, but the total cholesterol level decreased on day 29. Furthermore, the levels of total very-low-density lipoprotein (VLDL) cholesterol, small VLDL cholesterol, and large low-density lipoprotein cholesterol were significantly decreased. These results suggest that the daily intake of BCE has a hypocholesterolemic effect in healthy women, and that it is effective in preventing atherosclerosis. Full article

(This article belongs to the Special Issue Dietary Bioactive Compounds and Their Health Implications)

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21 pages, 5099 KiB

Open AccessReview

Self-Assembling Peptides and Carbon Nanomaterials Join Forces for Innovative Biomedical Applications

by Petr Rozhin, Costas Charitidis and Silvia Marchesan

Molecules 2021, 26(13), 4084; https://doi.org/10.3390/molecules26134084 - 04 Jul 2021

Cited by 16 | Viewed by 6444

Abstract

Self-assembling peptides and carbon nanomaterials have attracted great interest for their respective potential to bring innovation in the biomedical field. Combination of these two types of building blocks is not trivial in light of their very different physico-chemical properties, yet great progress has [...] Read more.

Self-assembling peptides and carbon nanomaterials have attracted great interest for their respective potential to bring innovation in the biomedical field. Combination of these two types of building blocks is not trivial in light of their very different physico-chemical properties, yet great progress has been made over the years at the interface between these two research areas. This concise review will analyze the latest developments at the forefront of research that combines self-assembling peptides with carbon nanostructures for biological use. Applications span from tissue regeneration, to biosensing and imaging, and bioelectronics. Full article

(This article belongs to the Special Issue Peptide Aggregates as Up-and-Coming Multivalent Biotechonogical Tools)

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9 pages, 3550 KiB

Open AccessCommunication

The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

by Heming Jiang and Tian-Yu Sun

Molecules 2021, 26(13), 4083; https://doi.org/10.3390/molecules26134083 - 04 Jul 2021

Cited by 4 | Viewed by 3028

Abstract

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly [...] Read more.

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation. Full article

(This article belongs to the Collection Recent Advances in Organocatalysis)

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10 pages, 2969 KiB

Open AccessArticle

Argon Adsorption on Cationic Gold Clusters Au_n⁺ (n ≤ 20)

by Piero Ferrari and Ewald Janssens

Molecules 2021, 26(13), 4082; https://doi.org/10.3390/molecules26134082 - 04 Jul 2021

Cited by 3 | Viewed by 2164

Abstract

The interaction of Au_n⁺ (n ≤ 20) clusters with Ar is investigated by combining mass spectrometric experiments and density functional theory calculations. We show that the inert Ar atom forms relatively strong bonds with Au_n⁺. The strength [...] Read more.

The interaction of Au_n⁺ (n ≤ 20) clusters with Ar is investigated by combining mass spectrometric experiments and density functional theory calculations. We show that the inert Ar atom forms relatively strong bonds with Au_n⁺. The strength of the bond strongly varies with the cluster size and is governed by a fine interplay between geometry and electronic structure. The chemical bond between Au_n⁺ and Ar involves electron transfer from Ar to Au, and a stronger interaction is found when the Au adsorption site has a higher positive partial charge, which depends on the cluster geometry. Au₁₅⁺ is a peculiar cluster size, which stands out for its much stronger interaction with Ar than its neighbors, signaled by a higher abundance in mass spectra and a larger Ar adsorption energy. This is shown to be a consequence of a low-coordinated Au adsorption site in Au₁₅⁺, which possesses a large positive partial charge. Full article

(This article belongs to the Special Issue Gold Coordination Chemistry and Applications)

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11 pages, 5563 KiB

Open AccessArticle

The Fruits of Paris polyphylla Inhibit Colorectal Cancer Cell Migration Induced by Fusobacterium nucleatum-Derived Extracellular Vesicles

by Liang-Tzung Lin, Yeu-Ching Shi, Chen-Yen Choong and Chen-Jei Tai

Molecules 2021, 26(13), 4081; https://doi.org/10.3390/molecules26134081 - 04 Jul 2021

Cited by 22 | Viewed by 3395

Abstract

Colorectal cancer (CRC) is one of the most common cancers worldwide. Gut microbiota are highly associated with CRC, and Fusobacterium nucleatum was found to be enriched in CRC lesions and correlated with CRC carcinogenesis and metastases. Paris polyphylla is a well-known herbal medicine [...] Read more.

Colorectal cancer (CRC) is one of the most common cancers worldwide. Gut microbiota are highly associated with CRC, and Fusobacterium nucleatum was found to be enriched in CRC lesions and correlated with CRC carcinogenesis and metastases. Paris polyphylla is a well-known herbal medicine that showed anticancer activity. The present study demonstrates that P. polyphylla inhibited the growth of CRC cells. In addition, treating with active compounds pennogenin 3-O-beta-chacotrioside and polyphyllin VI isolated from P. polyphylla inhibited the growth of F. nucleatum. We also found that extracellular vesicles (EVs) released from F. nucleatum could promote mitochondrial fusion and cell invasion in CRC cells, whereas active components from P. polyphylla could dampen such an impact. The data suggest that P. polyphylla and its active ingredients could be further explored as potential candidates for developing complementary chemotherapy for the treatment of CRC. Full article

(This article belongs to the Special Issue Antitumoral Properties of Natural Products Ⅱ)

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22 pages, 1177 KiB

Open AccessArticle

Essential Oil of Cannabis sativa L: Comparison of Yield and Chemical Composition of 11 Hemp Genotypes

by Ylenia Pieracci, Roberta Ascrizzi, Valentina Terreni, Luisa Pistelli, Guido Flamini, Laura Bassolino, Flavia Fulvio, Massimo Montanari and Roberta Paris

Molecules 2021, 26(13), 4080; https://doi.org/10.3390/molecules26134080 - 03 Jul 2021

Cited by 23 | Viewed by 4700

Abstract

Cannabis sativa L. is an annual species cultivated since antiquity for different purposes. While, in the past, hemp inflorescences were considered crop residues, at present, they are regarded as valuable raw materials with different applications, among which extraction of the essential oil (EO) [...] Read more.

Cannabis sativa L. is an annual species cultivated since antiquity for different purposes. While, in the past, hemp inflorescences were considered crop residues, at present, they are regarded as valuable raw materials with different applications, among which extraction of the essential oil (EO) has gained increasing interest in many fields. The aim of the present study is the evaluation of the yield and the chemical composition of the EO obtained by hydrodistillation from eleven hemp genotypes, cultivated in the same location for two consecutive growing seasons. The composition of the EOs was analyzed by GC–MS, and then subjected to multivariate statistical analysis. Sesquiterpenes represented the main class of compounds in all the EOs, both in their hydrocarbon and oxygenated forms, with relative abundances ranging from 47.1 to 78.5%; the only exception was the Felina 32 sample collected in 2019, in which cannabinoids predominated. Cannabinoids were the second most abundant class of compounds, of which cannabidiol was the main one, with relative abundances between 11.8 and 51.5%. The statistical distribution of the samples, performed on the complete chemical composition of the EOs, evidenced a partition based on the year of cultivation, rather than on the genotype, with the exception of Uso-31. Regarding the extraction yield, a significant variation was evidenced among both the genotypes and the years of cultivation. Full article

(This article belongs to the Special Issue Extraction, Characterization, and Potential Applications of Bioactive Molecules from Natural Sources)

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12 pages, 2704 KiB

Open AccessArticle

Phosphine Sulfide-Based Bipolar Host Materials for Blue Phosphorescent Organic Light-Emitting Diodes

by Gaozhan Xie, Jiangchao Wang, Yang Cao, Xudong Xue, Xiao Zhang, Chang Liu, Huanhuan Li, Ye Tao and Runfeng Chen

Molecules 2021, 26(13), 4079; https://doi.org/10.3390/molecules26134079 - 03 Jul 2021

Cited by 1 | Viewed by 2441

Abstract

Three phosphine sulfide-based bipolar host materials, viz CzPhPS, DCzPhPS, and TCzPhPS, were facilely prepared through a one-pot synthesis in excellent yields. The developed hosts exhibit superior thermal stabilities with the decomposition temperatures (T_d) all exceeding 350 °C [...] Read more.

Three phosphine sulfide-based bipolar host materials, viz CzPhPS, DCzPhPS, and TCzPhPS, were facilely prepared through a one-pot synthesis in excellent yields. The developed hosts exhibit superior thermal stabilities with the decomposition temperatures (T_d) all exceeding 350 °C and the melting temperatures (T_m) over 200 °C. In addition, their triplet energy (E_T) levels are estimated to be higher than 3.0 eV, illustrating that they are applicable to serve as hosts for blue phosphorescent organic light-emitting diodes (PhOLEDs). The maxima luminance, current efficiency (CE), power efficiency (PE), and external quantum efficiency (EQE) of 17,223 cd m⁻², 36.7 cd A⁻¹, 37.5 lm W⁻¹, and 17.5% are achieved for the blue PhOLEDs hosted by CzPhPS. The PhOLEDs based on DCzPhPS and TCzPhPS show inferior device performance than that of CzPhPS, which might be ascribed to the deteriorated charge transporting balance as the increased number of the constructed carbazole units in DCzPhPS and TCzPhPS molecules would enhance the hole-transporting ability of the devices to a large extent. Our study demonstrates that the bipolar hosts derived from phosphine sulfide have enormous potential applications in blue PhOLEDs, and the quantity of donors should be well controlled to exploit highly efficient phosphine sulfide-based hosts. Full article

(This article belongs to the Special Issue Opportunities and Challenges in Organic Optoelectronic Materials and Devices)

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19 pages, 3286 KiB

Open AccessArticle

Thermodynamic Characteristics of Phenacetin in Solid State and Saturated Solutions in Several Neat and Binary Solvents

by Maciej Przybyłek, Anna Kowalska, Natalia Tymorek, Tomasz Dziaman and Piotr Cysewski

Molecules 2021, 26(13), 4078; https://doi.org/10.3390/molecules26134078 - 03 Jul 2021

Cited by 11 | Viewed by 3168

Abstract

The thermodynamic properties of phenacetin in solid state and in saturated conditions in neat and binary solvents were characterized based on differential scanning calorimetry and spectroscopic solubility measurements. The temperature-related heat capacity values measured for both the solid and melt states were provided [...] Read more.

The thermodynamic properties of phenacetin in solid state and in saturated conditions in neat and binary solvents were characterized based on differential scanning calorimetry and spectroscopic solubility measurements. The temperature-related heat capacity values measured for both the solid and melt states were provided and used for precise determination of the values for ideal solubility, fusion thermodynamic functions, and activity coefficients in the studied solutions. Factors affecting the accuracy of these values were discussed in terms of various models of specific heat capacity difference for phenacetin in crystal and super-cooled liquid states. It was concluded that different properties have varying sensitivity in relation to the accuracy of heat capacity values. The values of temperature-related excess solubility in aqueous binary mixtures were interpreted using the Jouyban–Acree solubility equation for aqueous binary mixtures of methanol, DMSO, DMF, 1,4-dioxane, and acetonitrile. All binary solvent systems studied exhibited strong positive non-ideal deviations from an algebraic rule of mixing. Additionally, an interesting co-solvency phenomenon was observed with phenacetin solubility in aqueous mixtures with acetonitrile or 1,4-dioxane. The remaining three solvents acted as strong co-solvents. Full article

(This article belongs to the Special Issue New Insights into Thermodynamics of Solutes in Neat and Complex Solvents)

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15 pages, 1237 KiB

Open AccessArticle

Efficacy of a Covalent Microtubule Stabilizer in Taxane-Resistant Ovarian Cancer Models

by Samantha S. Yee and April L. Risinger

Molecules 2021, 26(13), 4077; https://doi.org/10.3390/molecules26134077 - 03 Jul 2021

Cited by 3 | Viewed by 2884

Abstract

Ovarian cancer often has a poor clinical prognosis because of late detection, frequently after metastatic progression, as well as acquired resistance to taxane-based therapy. Herein, we evaluate a novel class of covalent microtubule stabilizers, the C-22,23-epoxytaccalonolides, for their efficacy against taxane-resistant ovarian cancer [...] Read more.

Ovarian cancer often has a poor clinical prognosis because of late detection, frequently after metastatic progression, as well as acquired resistance to taxane-based therapy. Herein, we evaluate a novel class of covalent microtubule stabilizers, the C-22,23-epoxytaccalonolides, for their efficacy against taxane-resistant ovarian cancer models in vitro and in vivo. Taccalonolide AF, which covalently binds β-tubulin through its C-22,23-epoxide moiety, demonstrates efficacy against taxane-resistant models and shows superior persistence in clonogenic assays after drug washout due to irreversible target engagement. In vivo, intraperitoneal administration of taccalonolide AF demonstrated efficacy against the taxane-resistant NCI/ADR-RES ovarian cancer model both as a flank xenograft, as well as in a disseminated orthotopic disease model representing localized metastasis. Taccalonolide-treated animals had a significant decrease in micrometastasis of NCI/ADR-RES cells to the spleen, as detected by quantitative RT-PCR, without any evidence of systemic toxicity. Together, these findings demonstrate that taccalonolide AF retains efficacy in taxane-resistant ovarian cancer models in vitro and in vivo and that its irreversible mechanism of microtubule stabilization has the unique potential for intraperitoneal treatment of locally disseminated taxane-resistant disease, which represents a significant unmet clinical need in the treatment of ovarian cancer patients. Full article

(This article belongs to the Special Issue Natural Products in Cancer Research: From Isolation to Mechanisms of Action)

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