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Biological Activity of Natural and Synthetic Compounds 2.0

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: closed (31 July 2023) | Viewed by 16177

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Guest Editor
Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
Interests: medicinal chemistry; drug discovery; chemical synthesis; PROTAC; anticancer agents; cancer metabolism; endocannabinoid system
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The drug discovery process is a challenging multi-step path towards the identification of potential new medicines. The driving force of this process is an unmet medical need: new drugs are needed to prevent disease, to fight pathology, or to diagnose medical conditions for which there are currently no suitable medical products. An intensive search is ongoing to find drug-like molecules which could be obtained by chemical synthesis from smaller chemical building blocks or isolated from natural sources such as plants. Currently, the drugs on the market are of both natural and synthetic origin, however there are also semi-synthetic drugs, which are generally obtained by converting starting materials from natural sources into final products by chemical reactions. The main aim of this Special Issue on the “Biological Activity of Natural and Synthetic Compounds” is to collect contributions, in the form of both original research and review articles, covering studies concerning the identification of natural and synthetic bioactive compounds with relevant biological activities.

Prof. Dr. Carlotta Granchi
Guest Editor

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Keywords

  • medicinal chemistry
  • drug discovery
  • natural compounds
  • synthetic compounds
  • bioactive compounds

Published Papers (11 papers)

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Research

Jump to: Review

14 pages, 1932 KiB  
Article
Cell-Penetrating Milk-Derived Peptides with a Non-Inflammatory Profile
by Clement Agoni, Ilias Stavropoulos, Anna Kirwan, Margharitha M. Mysior, Therese Holton, Tilen Kranjc, Jeremy C. Simpson, Helen M. Roche and Denis C. Shields
Molecules 2023, 28(19), 6999; https://doi.org/10.3390/molecules28196999 - 09 Oct 2023
Cited by 1 | Viewed by 1137
Abstract
Milk-derived peptides are known to confer anti-inflammatory effects. We hypothesised that milk-derived cell-penetrating peptides might modulate inflammation in useful ways. Using computational techniques, we identified and synthesised peptides from the milk protein Alpha-S1-casein that were predicted to be cell-penetrating using a machine learning [...] Read more.
Milk-derived peptides are known to confer anti-inflammatory effects. We hypothesised that milk-derived cell-penetrating peptides might modulate inflammation in useful ways. Using computational techniques, we identified and synthesised peptides from the milk protein Alpha-S1-casein that were predicted to be cell-penetrating using a machine learning predictor. We modified the interpretation of the prediction results to consider the effects of histidine. Peptides were then selected for testing to determine their cell penetrability and anti-inflammatory effects using HeLa cells and J774.2 mouse macrophage cell lines. The selected peptides all showed cell penetrating behaviour, as judged using confocal microscopy of fluorescently labelled peptides. None of the peptides had an effect on either the NF-κB transcription factor or TNFα and IL-1β secretion. Thus, the identified milk-derived sequences have the ability to be internalised into the cell without affecting cell homeostatic mechanisms such as NF-κB activation. These peptides are worthy of further investigation for other potential bioactivities or as a naturally derived carrier to promote the cellular internalisation of other active peptides. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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16 pages, 7394 KiB  
Article
Myrcene: A Natural Compound Showing Anticancer Activity in HeLa Cells
by Luca Pincigher, Francesca Valenti, Christian Bergamini, Cecilia Prata, Romana Fato, Riccardo Amorati, Zongxin Jin, Giovanna Farruggia, Diana Fiorentini, Natalia Calonghi and Chiara Zalambani
Molecules 2023, 28(18), 6728; https://doi.org/10.3390/molecules28186728 - 21 Sep 2023
Cited by 1 | Viewed by 1178
Abstract
γ-terpinene, α-terpinene, p-cymene, and myrcene are monoterpenes found in many essential oils extracted from a variety of plants and spices. Myrcene also occurs naturally in plants such as hops, cannabis, lemongrass, and verbena and is used as a flavoring agent in food and [...] Read more.
γ-terpinene, α-terpinene, p-cymene, and myrcene are monoterpenes found in many essential oils extracted from a variety of plants and spices. Myrcene also occurs naturally in plants such as hops, cannabis, lemongrass, and verbena and is used as a flavoring agent in food and beverage manufacturing. In this research, the biological efficacy of γ-terpinene, α-terpinene, p-cymene, and myrcene was studied in human cell lines (HeLa, SH-SY5Y, and HDFa). Cytotoxicity, cell proliferation, cell migration, and morphology assays were performed to obtain detailed information on the anticancer properties. Our results show that myrcene has potential biological activity, especially in HeLa cells. In this cell line, it leads to an arrest of proliferation, a decrease in motility and morphological changes with loss of sphericity and thickness, and DNA damage. In addition, the interaction of γ-terpinene, α-terpinene, p-terpinene, and myrcene with calf thymus DNA (ct-DNA) was studied by UV-visible spectrophotometry. DNA binding experiments show that only myrcene can interact with DNA with an apparent dissociation constant (Kd) of 29 × 10−6 M. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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14 pages, 1927 KiB  
Article
In Vitro Effects of Combining Genistein with Aromatase Inhibitors: Concerns Regarding Its Consumption during Breast Cancer Treatment
by Patrícia H. A. Bezerra, Cristina Amaral, Cristina F. Almeida, Georgina Correia-da-Silva, Maria Regina Torqueti and Natércia Teixeira
Molecules 2023, 28(13), 4893; https://doi.org/10.3390/molecules28134893 - 21 Jun 2023
Cited by 2 | Viewed by 1461
Abstract
Introduction: The third-generation of aromatase inhibitors (AIs)—Exemestane (Exe), Letrozole (Let), and Anastrozole (Ana)—is the main therapeutic approach applied for estrogen receptor-positive (ER+) breast cancer (BC), the most common neoplasm in women worldwide. Despite their success, the development of resistance limits their efficacy. Genistein [...] Read more.
Introduction: The third-generation of aromatase inhibitors (AIs)—Exemestane (Exe), Letrozole (Let), and Anastrozole (Ana)—is the main therapeutic approach applied for estrogen receptor-positive (ER+) breast cancer (BC), the most common neoplasm in women worldwide. Despite their success, the development of resistance limits their efficacy. Genistein (G), a phytoestrogen present in soybean, has promising anticancer properties in ER+ BC cells, even when combined with anticancer drugs. Thus, the potential beneficial effects of combining G with AIs were investigated in sensitive (MCF7-aro) and resistant (LTEDaro) BC cells. Methods: The effects on cell proliferation and expression of aromatase, ERα/ERβ, and AR receptors were evaluated. Results: Unlike the combination of G with Ana or Let, which negatively affects the Ais’ therapeutic efficacy, G enhanced the anticancer properties of the steroidal AI Exe, increasing the antiproliferative effect and apoptosis relative to Exe. The hormone targets studied were not affected by this combination when compared with Exe. Conclusions: This is the first in vitro study that highlights the potential benefit of G as an adjuvant therapy with Exe, emphasizing, however, that soy derivatives widely used in the diet or applied as auxiliary medicines may increase the risk of adverse interactions with nonsteroidal AIs used in therapy. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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24 pages, 3010 KiB  
Article
Novel Tryptanthrin Derivatives with Selectivity as c–Jun N–Terminal Kinase (JNK) 3 Inhibitors
by Igor A. Schepetkin, Oleksander S. Karpenko, Anastasia R. Kovrizhina, Liliya N. Kirpotina, Andrei I. Khlebnikov, Stepan I. Chekal, Alevtyna V. Radudik, Maryna O. Shybinska and Mark T. Quinn
Molecules 2023, 28(12), 4806; https://doi.org/10.3390/molecules28124806 - 16 Jun 2023
Cited by 1 | Viewed by 1455
Abstract
The c-Jun N-terminal kinase (JNK) family includes three proteins (JNK1-3) that regulate many physiological processes, including cell proliferation and differentiation, cell survival, and inflammation. Because of emerging data suggesting that JNK3 may play an important role in neurodegenerative diseases, such as Alzheimer’s [...] Read more.
The c-Jun N-terminal kinase (JNK) family includes three proteins (JNK1-3) that regulate many physiological processes, including cell proliferation and differentiation, cell survival, and inflammation. Because of emerging data suggesting that JNK3 may play an important role in neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease, as well as cancer pathogenesis, we sought to identify JNK inhibitors with increased selectivity for JNK3. A panel of 26 novel tryptanthrin-6-oxime analogs was synthesized and evaluated for JNK1-3 binding (Kd) and inhibition of cellular inflammatory responses. Compounds 4d (8-methoxyindolo[2,1-b]quinazolin-6,12-dione oxime) and 4e (8-phenylindolo[2,1-b]quinazolin-6,12-dione oxime) had high selectivity for JNK3 versus JNK1 and JNK2 and inhibited lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 (NF-κB/AP-1) transcriptional activity in THP-1Blue cells and interleukin-6 (IL-6) production by MonoMac-6 monocytic cells in the low micromolar range. Likewise, compounds 4d, 4e, and pan-JNK inhibitor 4h (9-methylindolo[2,1-b]quinazolin-6,12-dione oxime) decreased LPS-induced c-Jun phosphorylation in MonoMac-6 cells, directly confirming JNK inhibition. Molecular modeling suggested modes of binding interaction of these compounds in the JNK3 catalytic site that were in agreement with the experimental data on JNK3 binding. Our results demonstrate the potential for developing anti-inflammatory drugs based on these nitrogen-containing heterocyclic systems with selectivity for JNK3. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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15 pages, 3087 KiB  
Article
Anti-Inflammatory Potential of Seasonal Sonoran Propolis Extracts and Some of Their Main Constituents
by Mayra A. Mendez-Encinas, Dora Valencia, Jesús Ortega-García, Elizabeth Carvajal-Millan, José C. Díaz-Ríos, Pablo Mendez-Pfeiffer, Cinthia M. Soto-Bracamontes, Adriana Garibay-Escobar, Efrain Alday and Carlos Velazquez
Molecules 2023, 28(11), 4496; https://doi.org/10.3390/molecules28114496 - 01 Jun 2023
Cited by 3 | Viewed by 1669
Abstract
Biological properties of Sonoran propolis (SP) are influenced by harvest time. Caborca propolis showed cellular protective capacity against reactive oxygen species, which might be implicated in anti-inflammatory effects. However, the anti-inflammatory activity of SP has not been investigated so far. This study investigated [...] Read more.
Biological properties of Sonoran propolis (SP) are influenced by harvest time. Caborca propolis showed cellular protective capacity against reactive oxygen species, which might be implicated in anti-inflammatory effects. However, the anti-inflammatory activity of SP has not been investigated so far. This study investigated the anti-inflammatory activity of previously characterized seasonal SP extracts (SPE) and some of their main constituents (SPC). The anti-inflammatory activity of SPE and SPC was evaluated by measuring nitric oxide (NO) production, protein denaturation inhibition, heat-induced hemolysis inhibition, and hypotonicity-induced hemolysis inhibition. SPE from spring, autumn, and winter showed a higher cytotoxic effect on RAW 264.7 cells (IC50: 26.6 to 30.2 µg/mL) compared with summer extract (IC50: 49.4 µg/mL). SPE from spring reduced the NO secretion to basal levels at the lowest concentration tested (5 µg/mL). SPE inhibited the protein denaturation by 79% to 100%, and autumn showed the highest inhibitory activity. SPE stabilized erythrocyte membrane against heat-induced and hypotonicity-induced hemolysis in a concentration-dependent manner. Results indicate that the flavonoids chrysin, galangin, and pinocembrin could contribute to the anti-inflammatory activity of SPE and that the harvest time influences such a property. This study presents evidence of SPE pharmacological potential and some of their constituents. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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10 pages, 3385 KiB  
Communication
Hydroxide-Mediated SNAr Rearrangement for Synthesis of Novel Depside Derivatives Containing Diaryl Ether Skeleton as Antitumor Agents
by Xiang Yu, Yinkai Xi, Yi Sui, Yang Liu, Guifen Chen, Minjie Zhang, Yan Zhang, Guoyong Luo, Yi Long and Wude Yang
Molecules 2023, 28(11), 4303; https://doi.org/10.3390/molecules28114303 - 24 May 2023
Cited by 2 | Viewed by 1071
Abstract
A simple and efficient hydroxide-mediated SNAr rearrangement was reported to synthesize new depside derivatives containing the diaryl ether skeleton from the natural product barbatic acid. The prepared compounds were determined using 1H NMR, 13C NMR, HRMS, and X-ray crystallographic [...] Read more.
A simple and efficient hydroxide-mediated SNAr rearrangement was reported to synthesize new depside derivatives containing the diaryl ether skeleton from the natural product barbatic acid. The prepared compounds were determined using 1H NMR, 13C NMR, HRMS, and X-ray crystallographic analysis and were also screened in vitro for cytotoxicity against three cancer cell lines and one normal cell line. The evaluation results showed that compound 3b possessed the best antiproliferative activity against liver cancer HepG2 cell line and low toxicity, which made it worth further study. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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25 pages, 3767 KiB  
Article
Novel Thiazolylketenyl Quinazolinones as Potential Anti-MRSA Agents and Allosteric Modulator for PBP2a
by Jie Dai, Narsaiah Battini, Zhonglin Zang, Yan Luo and Chenghe Zhou
Molecules 2023, 28(10), 4240; https://doi.org/10.3390/molecules28104240 - 22 May 2023
Cited by 7 | Viewed by 1375
Abstract
Bacterial infections caused by methicillin-resistant Staphylococcus aureus have seriously threatened public health. There is an urgent need to propose an existing regimen to overcome multidrug resistance of MRSA. A unique class of novel anti-MRSA thiazolylketenyl quinazolinones (TQs) and their analogs were developed. Some synthesized [...] Read more.
Bacterial infections caused by methicillin-resistant Staphylococcus aureus have seriously threatened public health. There is an urgent need to propose an existing regimen to overcome multidrug resistance of MRSA. A unique class of novel anti-MRSA thiazolylketenyl quinazolinones (TQs) and their analogs were developed. Some synthesized compounds showed good bacteriostatic potency. Especially TQ 4 was found to exhibit excellent inhibition against MRSA with a low MIC of 0.5 μg/mL, which was 8-fold more effective than norfloxacin. The combination of TQ 4 with cefdinir showed stronger antibacterial potency. Further investigation revealed that TQ 4, with low hemolytic toxicity and low drug resistance, was not only able to inhibit biofilm formation but also could reduce MRSA metabolic activity and showed good drug-likeness. Mechanistic explorations revealed that TQ 4 could cause leakage of proteins by disrupting membrane integrity and block DNA replication by intercalated DNA. Furthermore, the synergistic antibacterial effect with cefdinir might be attributed to TQ 4 with the ability to induce PBP2a allosteric regulation of MRSA and further trigger the opening of the active site to promote the binding of cefdinir to the active site, thus inhibiting the expression of PBP2a, thereby overcoming MRSA resistance and significantly enhancing the anti-MRSA activity of cefdinir. A new strategy provided by these findings was that TQ 4, possessing both excellent anti-MRSA activity and allosteric effect of PBP2a, merited further development as a novel class of antibacterial agents to overcome increasingly severe MRSA infections. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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15 pages, 4964 KiB  
Article
Inhibition of Acetylcholinesterase by Novel Lupinine Derivatives
by Igor A. Schepetkin, Zhangeldy S. Nurmaganbetov, Serik D. Fazylov, Oralgazy A. Nurkenov, Andrei I. Khlebnikov, Tulegen M. Seilkhanov, Anarkul S. Kishkentaeva, Elvira E. Shults and Mark T. Quinn
Molecules 2023, 28(8), 3357; https://doi.org/10.3390/molecules28083357 - 11 Apr 2023
Viewed by 1423
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive memory loss and cognitive impairment due in part to a severe loss of cholinergic neurons in specific brain areas. AD is the most common type of dementia in the aging population. Although several [...] Read more.
Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive memory loss and cognitive impairment due in part to a severe loss of cholinergic neurons in specific brain areas. AD is the most common type of dementia in the aging population. Although several acetylcholinesterase (AChE) inhibitors are currently available, their performance sometimes yields unexpected results. Thus, research is ongoing to find potentially therapeutic AChE inhibitory agents, both from natural and synthetic sources. Here, we synthesized 13 new lupinine triazole derivatives and evaluated them, along with 50 commercial lupinine-based esters of different carboxylic acids, for AChE inhibitory activity. The triazole derivative 15 [1S,9aR)-1-((4-(4-(benzyloxy)-3-methoxyphenyl)-1H-1,2,3-triazol-1-yl)methyl)octahydro-2H-quinolizine)] exhibited the most potent AChE inhibitory activity among all 63 lupinine derivatives, and kinetic analysis demonstrated that compound 15 was a mixed-type AChE inhibitor. Molecular docking studies were performed to visualize interaction between this triazole derivative and AChE. In addition, a structure-activity relationship (SAR) model developed using linear discriminant analysis (LDA) of 11 SwissADME descriptors from the 50 lupinine esters revealed 5 key physicochemical features that allowed us to distinguish active versus non-active compounds. Thus, this SAR model could be applied for design of more potent lupinine ester-based AChE inhibitors. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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Review

Jump to: Research

23 pages, 10733 KiB  
Review
Progress in Lewis-Acid-Templated Diels–Alder Reactions
by Jun Ishihara
Molecules 2024, 29(5), 1187; https://doi.org/10.3390/molecules29051187 - 06 Mar 2024
Viewed by 792
Abstract
The synthesis of natural products with complicated architectures often requires the use of segments with functional groups that can be structurally transformed with the desired stereogenic centers. Bicyclic 𝛾-lactones have great potential as a suitable segment for natural product synthesis. However, the stereoselective [...] Read more.
The synthesis of natural products with complicated architectures often requires the use of segments with functional groups that can be structurally transformed with the desired stereogenic centers. Bicyclic 𝛾-lactones have great potential as a suitable segment for natural product synthesis. However, the stereoselective construction of such functionalized bicyclic 𝛾-lactones is not as straightforward as one might expect. The template-mediated Diels–Alder reaction is one of the most powerful and versatile methods for providing bicyclic 𝛾-lactones with high regioselectivity and stereoselectivity. In this reaction, the diene is linked to the dienophile by a temporary tether, allowing the reaction to proceed efficiently, yielding a product that can be used for natural product synthesis. This review describes some important instances of the template-mediated Diels–Alder reaction and its application to the synthesis of biologically active compounds. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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28 pages, 6255 KiB  
Review
Aromatase Inhibitors as a Promising Direction for the Search for New Anticancer Drugs
by Sara Janowska, Serhii Holota, Roman Lesyk and Monika Wujec
Molecules 2024, 29(2), 346; https://doi.org/10.3390/molecules29020346 - 10 Jan 2024
Viewed by 1737
Abstract
Aromatase is an enzyme that plays a crucial role in the biosynthesis of estrogens, which are hormones that contribute to the growth of certain types of breast cancer. In particular, aromatase catalyzes the conversion of androgens (male hormones) into estrogens (female hormones) in [...] Read more.
Aromatase is an enzyme that plays a crucial role in the biosynthesis of estrogens, which are hormones that contribute to the growth of certain types of breast cancer. In particular, aromatase catalyzes the conversion of androgens (male hormones) into estrogens (female hormones) in various tissues, including the adrenal glands, ovaries, and adipose tissue. Given the role of estrogen in promoting the growth of hormone-receptor-positive breast cancers, aromatase has become an important molecular target for the development of anticancer agents. Aromatase inhibitors can be classified into two main groups based on their chemical structure: steroidal and non-steroidal inhibitors. This work presents a review of the literature from the last ten years regarding the search for new aromatase inhibitors. We present the directions of search, taking into account the impact of structure modifications on anticancer activity. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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26 pages, 1379 KiB  
Review
Natural and Synthetic Anticancer Epidrugs Targeting the Epigenetic Integrator UHRF1
by Waseem Ashraf, Tanveer Ahmad, Nicolas Reynoird, Ali Hamiche, Yves Mély, Christian Bronner and Marc Mousli
Molecules 2023, 28(16), 5997; https://doi.org/10.3390/molecules28165997 - 10 Aug 2023
Cited by 1 | Viewed by 2305
Abstract
Cancer is one of the leading causes of death worldwide, and its incidence and mortality are increasing each year. Improved therapeutic strategies against cancer have progressed, but remain insufficient to invert this trend. Along with several other risk factors, abnormal genetic and epigenetic [...] Read more.
Cancer is one of the leading causes of death worldwide, and its incidence and mortality are increasing each year. Improved therapeutic strategies against cancer have progressed, but remain insufficient to invert this trend. Along with several other risk factors, abnormal genetic and epigenetic regulations play a critical role in the initiation of cellular transformation, as well as tumorigenesis. The epigenetic regulator UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) is a multidomain protein with oncogenic abilities overexpressed in most cancers. Through the coordination of its multiple domains and other epigenetic key players, UHRF1 regulates DNA methylation and histone modifications. This well-coordinated dialogue leads to the silencing of tumor-suppressor genes (TSGs) and facilitates tumor cells’ resistance toward anticancer drugs, ultimately promoting apoptosis escape and uncontrolled proliferation. Several studies have shown that the downregulation of UHRF1 with natural compounds in tumor cells induces the reactivation of various TSGs, inhibits cell growth, and promotes apoptosis. In this review, we discuss the underlying mechanisms and the potential of various natural and synthetic compounds that can inhibit/minimize UHRF1’s oncogenic activities and/or its expression. Full article
(This article belongs to the Special Issue Biological Activity of Natural and Synthetic Compounds 2.0)
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