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3 pages, 446 KiB

Open AccessEditorial

Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation

by Federica Pollastro and Alberto Minassi

Plants 2021, 10(11), 2368; https://doi.org/10.3390/plants10112368 - 03 Nov 2021

Cited by 2 | Viewed by 1299

Abstract

Historically, plants have represented an invaluable source of compounds with complex structures and interesting pharmacological profiles [...] Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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Research

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9 pages, 1045 KiB

Open AccessArticle

Triterpenoids from Vitellaria paradoxa Stem Barks Reduce Nitrite Levels in LPS-Stimulated Macrophages

by Carmina Sirignano, Pascal Nadembega, Ferruccio Poli, Barbara Romano, Giuseppe Lucariello, Daniela Rigano and Orazio Taglialatela-Scafati

Plants 2021, 10(5), 1006; https://doi.org/10.3390/plants10051006 - 18 May 2021

Cited by 6 | Viewed by 2183

Abstract

Vitellaria paradoxa C. F. Gaertn is widely used in African traditional medicine as an anti-inflammatory remedy to treat rheumatism, gastric problems, diarrhea, and dysentery. The phytochemical investigation of the ethyl acetate extract of V. paradoxa stem bark collected in Burkina Faso led to [...] Read more.

Vitellaria paradoxa C. F. Gaertn is widely used in African traditional medicine as an anti-inflammatory remedy to treat rheumatism, gastric problems, diarrhea, and dysentery. The phytochemical investigation of the ethyl acetate extract of V. paradoxa stem bark collected in Burkina Faso led to the isolation of eight known and two triterpenes undescribed to date (7 and 10), in the free alcohol form or as acetyl and cinnamyl ester derivatives. The stereostructures of the new compounds were elucidated using HR-ESIMS and 1D and 2D NMR data. The isolated compounds were evaluated in vitro for their inhibitory effect on nitrite levels on murine macrophages J774 stimulated with the lipopolysaccharide (LPS). Among all the compounds tested, lupeol cinnamate (3) and betulinic acid (5) showed a beneficial effect in reducing nitrite levels produced after LPS stimulation. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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9 pages, 1628 KiB

Open AccessArticle

Metabolome-Wide, Phylogenetically Controlled Comparison Indicates Higher Phenolic Diversity in Tropical Tree Species

by Guille Peguero, Albert Gargallo-Garriga, Joan Maspons, Karel Klem, Otmar Urban, Jordi Sardans and Josep Peñuelas

Plants 2021, 10(3), 554; https://doi.org/10.3390/plants10030554 - 16 Mar 2021

Cited by 1 | Viewed by 1915

Abstract

Tropical plants are expected to have a higher variety of defensive traits, such as a more diverse array of secondary metabolic compounds in response to greater pressures of antagonistic interactions, than their temperate counterparts. We test this hypothesis using advanced metabolomics linked to [...] Read more.

Tropical plants are expected to have a higher variety of defensive traits, such as a more diverse array of secondary metabolic compounds in response to greater pressures of antagonistic interactions, than their temperate counterparts. We test this hypothesis using advanced metabolomics linked to a novel stoichiometric compound classification to analyze the complete foliar metabolomes of four tropical and four temperate tree species, which were selected so that each subset contained the same amount of phylogenetic diversity and evenness. We then built Bayesian phylogenetic multilevel models to test for tropical–temperate differences in metabolite diversity for the entire metabolome and for four major families of secondary compounds. We found strong evidence supporting that the leaves of tropical tree species have a higher phenolic diversity. The functionally closer group of polyphenolics also showed moderate evidence of higher diversity in tropical species, but there were no differences either for the entire metabolome or for the other major families of compounds analyzed. This supports the interpretation that this tropical–temperate contrast must be related to the functional role of phenolics and polyphenolics. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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14 pages, 1446 KiB

Open AccessArticle

Leaves of White Beetroot As a New Source of Antioxidant and Anti-Inflammatory Compounds

by Urszula Gawlik-Dziki, Laura Dziki, Jakub Anisiewicz, Ewa Habza-Kowalska, Małgorzata Sikora and Dariusz Dziki

Plants 2020, 9(8), 944; https://doi.org/10.3390/plants9080944 - 26 Jul 2020

Cited by 6 | Viewed by 2650

Abstract

The white beetroot cv. Śnieżna Kula is the first betanin-free beetroot registered in the European Union. The aim of this study was to compare the phenolic acids profile and antioxidant capacity of leaves of white (SK) and red (CC) beetroots and red (LC) [...] Read more.

The white beetroot cv. Śnieżna Kula is the first betanin-free beetroot registered in the European Union. The aim of this study was to compare the phenolic acids profile and antioxidant capacity of leaves of white (SK) and red (CC) beetroots and red (LC) and white (BL) Swiss chard growing in Poland. LC leaves were the richest source of total phenolics (16.55 mg GAE/g FW) and phenolic acids (1.81 mg/g FW), while the highest content of flavonoids was determined in CC leaves (1.6 mg QE/g FW). The highest antiradical activity was observed for LC, whereas CC extract exhibited the highest chelating power. BL and CC leaf extracts demonstrated high LOX inhibitory potential (EC₅₀ = 53.23 and 56.97 mg FW/mL, respectively). An uncompetitive type of LOX inhibition was obtained for all extracts. SK extracts demonstrated the highest XO inhibitory activity (EC₅₀ = 81.04 mg FW/mL). A noncompetitive type of XO inhibition was obtained in both extracts from red leaves (CC and LC), whereas an uncompetitive mode of inhibition was observed in the case of white leaf (SK and LC) extracts. Thus, it can be assumed that the presence of betanin influences the XO inhibition mechanism. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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13 pages, 529 KiB

Open AccessArticle

The Essential Oil of Salvia rosmarinus Spenn. from Italy as a Source of Health-Promoting Compounds: Chemical Profile and Antioxidant and Cholinesterase Inhibitory Activity

by Mariarosaria Leporini, Marco Bonesi, Monica Rosa Loizzo, Nicodemo Giuseppe Passalacqua and Rosa Tundis

Plants 2020, 9(6), 798; https://doi.org/10.3390/plants9060798 - 26 Jun 2020

Cited by 29 | Viewed by 4137

Abstract

The chemical composition of the essential oil from Salvia rosmarinus Spenn. collected in Calabrian Ionian (R1) and Tyrrhenian (R2) coast (Southern Italy) was examined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Essential oils are mainly characterized by monoterpene hydrocarbons (39.32–40.70%) and [...] Read more.

The chemical composition of the essential oil from Salvia rosmarinus Spenn. collected in Calabrian Ionian (R1) and Tyrrhenian (R2) coast (Southern Italy) was examined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Essential oils are mainly characterized by monoterpene hydrocarbons (39.32–40.70%) and oxygenated monoterpenes (36.08-39.47%). The 1,8-cineole, α-pinene, camphor, and trans-caryophyllene are the most representative compounds. S. rosmarinus essential oils were investigated for their antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing ability power (FRAP), and β-carotene bleaching tests. Additionally, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays were used to screen the neuroprotective effects of S. rosmarinus. R2 showed the highest antioxidant potential as confirmed by relative antioxidant capacity index (RACI) and exhibited a selective activity against AChE (half maximal inhibitory concentration, IC₅₀, value of 41.86 μg/mL). These results suggest S. rosmarinus essential oil as a potential source of bioactive compounds. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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10 pages, 2554 KiB

Open AccessArticle

Insecticidal Activity of Hyoscyamus niger L. on Lucilia sericata Causing Myiasis

by Esra Küpeli Akkol, Mert Ilhan, Esma Kozan, Fatma Tuğçe Gürağaç Dereli, Mustafa Sak and Eduardo Sobarzo-Sánchez

Plants 2020, 9(5), 655; https://doi.org/10.3390/plants9050655 - 22 May 2020

Cited by 11 | Viewed by 4283

Abstract

Background: Hyoscyamus niger L. (Solanaceae) generally known as henbane, is commonly distributed in Europe and Asia. In Turkey, henbane seeds have been used in folk medicine to remove worms from the eyes. The present study aimed to investigate the insecticidal activity of H. [...] Read more.

Background: Hyoscyamus niger L. (Solanaceae) generally known as henbane, is commonly distributed in Europe and Asia. In Turkey, henbane seeds have been used in folk medicine to remove worms from the eyes. The present study aimed to investigate the insecticidal activity of H. niger seeds. Methods: n-hexane, ethyl acetate, methanol and alkaloid extracts were prepared from the seeds of the plant and their insecticidal activities on Lucilia sericata larvae were evaluated. EC₅₀ and EC₉₀ values of the alkaloid extract were calculated and morphological abnormalities were investigated. Results: Alkaloid extract prepared from the seeds of this plant displayed significant insecticidal activity. EC₅₀ values of H. niger seeds alkaloid extract were found to be 8.04, 8.49, 7.96 μg/mL against first, second and third instar, respectively. It was determined that malformations of larvae included damaged larvae with small size, contraction and weak cuticle. Furthermore, HPLC analysis was performed on alkaloid extract of H. niger seeds and main components of the extract were determined. It was determined that alkaloid extract mainly contain hyoscyamine and scopolamine. Conclusions: These results confirm the folkloric usage of the plant and suggest that the alkaloid content of the plant could be responsible for the insecticidal activity. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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Review

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31 pages, 4970 KiB

Open AccessFeature PaperReview

Biomimetic Approaches to the Synthesis of Natural Disesquiterpenoids: An Update

by Diego Caprioglio, Stefano Salamone, Federica Pollastro and Alberto Minassi

Plants 2021, 10(4), 677; https://doi.org/10.3390/plants10040677 - 01 Apr 2021

Cited by 9 | Viewed by 2655

Abstract

Natural disesquiterpenoids represent a small group of secondary metabolites characterized by complex molecular scaffolds and interesting pharmacological profiles. In the last decade, more than 400 new disesquiterpenoids have been discovered and fully characterized, pointing out once more the “magic touch” of [...] Read more.

Natural disesquiterpenoids represent a small group of secondary metabolites characterized by complex molecular scaffolds and interesting pharmacological profiles. In the last decade, more than 400 new disesquiterpenoids have been discovered and fully characterized, pointing out once more the “magic touch” of nature in the design of new compounds. The perfect blend of complex and unique architectures and biological activity has made sesquiterpene dimers an attractive and challenging synthetic target, inspiring organic chemists to find new and biomimetic approaches to replicate the efficiency and the selectivity of natural processes under laboratory conditions. In this work, we present a review covering the literature from 2010 to 2020 reporting all the efforts made in the total synthesis of complex natural disesquiterpenoids. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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34 pages, 3143 KiB

Open AccessReview

Current Perspectives on Taxanes: Focus on Their Bioactivity, Delivery and Combination Therapy

by Jan Škubník, Vladimíra Pavlíčková, Tomáš Ruml and Silvie Rimpelová

Plants 2021, 10(3), 569; https://doi.org/10.3390/plants10030569 - 17 Mar 2021

Cited by 46 | Viewed by 6846

Abstract

Taxanes, mainly paclitaxel and docetaxel, the microtubule stabilizers, have been well known for being the first-line therapy for breast cancer for more than the last thirty years. Moreover, they have been also used for the treatment of ovarian, hormone-refractory prostate, head and neck, [...] Read more.

Taxanes, mainly paclitaxel and docetaxel, the microtubule stabilizers, have been well known for being the first-line therapy for breast cancer for more than the last thirty years. Moreover, they have been also used for the treatment of ovarian, hormone-refractory prostate, head and neck, and non-small cell lung carcinomas. Even though paclitaxel and docetaxel significantly enhance the overall survival rate of cancer patients, there are some limitations of their use, such as very poor water solubility and the occurrence of severe side effects. However, this is what pushes the research on these microtubule-stabilizing agents further and yields novel taxane derivatives with significantly improved properties. Therefore, this review article brings recent advances reported in taxane research mainly in the last two years. We focused especially on recent methods of taxane isolation, their mechanism of action, development of their novel derivatives, formulations, and improved tumor-targeted drug delivery. Since cancer cell chemoresistance can be an unsurpassable hurdle in taxane administration, a significant part of this review article has been also devoted to combination therapy of taxanes in cancer treatment. Last but not least, we summarize ongoing clinical trials on these compounds and bring a perspective of advancements in this field. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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26 pages, 5602 KiB

Open AccessReview

Progress in the Chemistry of Macrocyclic Meroterpenoids

by Dmitriy N. Shurpik, Alan A. Akhmedov, Peter J. Cragg, Vitaliy V. Plemenkov and Ivan I. Stoikov

Plants 2020, 9(11), 1582; https://doi.org/10.3390/plants9111582 - 15 Nov 2020

Cited by 9 | Viewed by 2841

Abstract

In the last decade, the chemistry of meroterpenoids—conjugated molecules formed from isoprenyl fragments through biosynthetic pathways—has developed rapidly. The class includes some natural metabolites and fully synthetic fragments formed through nonbiological synthesis. In the field of synthetic receptors, a range of structures can [...] Read more.

In the last decade, the chemistry of meroterpenoids—conjugated molecules formed from isoprenyl fragments through biosynthetic pathways—has developed rapidly. The class includes some natural metabolites and fully synthetic fragments formed through nonbiological synthesis. In the field of synthetic receptors, a range of structures can be achieved by combining fragments of different classes of organic compounds into one hybrid macrocyclic platform which retains the properties of these fragments. This review discusses the successes in the synthesis and practical application of both natural and synthetic macrocycles. Among the natural macrocyclic meroterpenoids, special attention is paid to isoprenylated flavonoids and phenols, isoprenoid lipids, prenylated amino acids and alkaloids, and isoprenylpolyketides. Among the synthetic macrocyclic meroterpenoids obtained by combining the “classical” macrocyclic platforms, those based on cyclodextrins, together with meta- and paracyclophanes incorporating terpenoid fragments, and meroterpenoids obtained by macrocyclization of several terpene derivatives are considered. In addition, issues related to biomedical activity, processes of self-association and aggregation, and the formation of host–guest complexes of various classes of macrocyclic merotenoids are discussed in detail. Full article

(This article belongs to the Special Issue Exploring the Universe of Natural Products: Recent Advances in Synthesis, Isolation and Structural Elucidation)

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