Editorial

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Open AccessEditorial

Coumarins, Xanthones and Related Compounds

by Pascal Richomme

Molecules 2016, 21(3), 341; https://doi.org/10.3390/molecules21030341 - 10 Mar 2016

Cited by 4 | Viewed by 4587

It has long been known that coumarins (γ-pyrones) and xanthones (α-pyrones) together form a large class of naturally occurring compounds exhibiting a wide range of biological activities.[...] Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

Research

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1542 KiB

Open AccessArticle

Synthesis and Characterization of Some New Coumarins with in Vitro Antitumor and Antioxidant Activity and High Protective Effects against DNA Damage

by Mounir A. I. Salem, Magda I. Marzouk and Azza M. El-Kazak

Molecules 2016, 21(2), 249; https://doi.org/10.3390/molecules21020249 - 22 Feb 2016

Cited by 81 | Viewed by 8154

Abstract

Coumarins are naturally occurring oxygen heterocyclic compounds having multifarious medicinal properties, hence used as lead compounds for designing new potent analogs. The chromene butenoic acid 3 and the benzochromene butenoic acid 4 which are derived from the reaction of glyoxalic acid with 3-acetylcoumarin [...] Read more.

Coumarins are naturally occurring oxygen heterocyclic compounds having multifarious medicinal properties, hence used as lead compounds for designing new potent analogs. The chromene butenoic acid 3 and the benzochromene butenoic acid 4 which are derived from the reaction of glyoxalic acid with 3-acetylcoumarin and 3-acetylbenzocoumarin, respectively, were reacted with different nitrogen and carbon nucleophiles to give new heterocyclic compounds. The structures of the prepared compounds were elucidated by IR, ¹H-NMR, and mass spectroscopy. Some of the newly prepared compounds were tested in vitro against a panel of four human tumor cell lines namely; hepatocellular carcinoma (liver) HepG2, colon cancer HCT-116, human prostate cancer PC3, and mammary gland breast MCF-7. Also they were tested as antioxidants. Almost all of the tested compounds showed satisfactory activity. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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1806 KiB

Open AccessArticle

Coumarin-Containing Polymers for High Density Non-Linear Optical Data Storage

by Denis Gindre, Konstantinos Iliopoulos, Oksana Krupka, Marie Evrard, Emilie Champigny and Marc Sallé

Molecules 2016, 21(2), 147; https://doi.org/10.3390/molecules21020147 - 26 Jan 2016

Cited by 36 | Viewed by 6971

Abstract

Optical data storage was performed with various thin polymer films containing coumarin-based derivatives and by using femtosecond laser pulses as well as two-photon absorption processes. Exploring the photodimerization attribute of coumarin derivatives and using appropriate irradiation wavelengths, recording/erasing processes could be carried out [...] Read more.

Optical data storage was performed with various thin polymer films containing coumarin-based derivatives and by using femtosecond laser pulses as well as two-photon absorption processes. Exploring the photodimerization attribute of coumarin derivatives and using appropriate irradiation wavelengths, recording/erasing processes could be carried out in the same area. Second harmonic generation microscopy was used to read the stored information. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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2530 KiB

Open AccessArticle

Nonprenylated Xanthones from Gentiana lutea, Frasera caroliniensis, and Centaurium erythraea as Novel Inhibitors of Vascular Smooth Muscle Cell Proliferation

by Birgit Waltenberger, Rongxia Liu, Atanas G. Atanasov, Stefan Schwaiger, Elke H. Heiss, Verena M. Dirsch and Hermann Stuppner

Molecules 2015, 20(11), 20381-20390; https://doi.org/10.3390/molecules201119703 - 13 Nov 2015

Cited by 20 | Viewed by 6896

Abstract

Aberrant proliferation of vascular smooth muscle cells (VSMC) plays a major role in restenosis, the pathological renarrowing of the blood vessel lumen after surgical treatment of stenosis. Since available anti-proliferative pharmaceuticals produce unfavorable side effects, there is high demand for the identification of [...] Read more.

Aberrant proliferation of vascular smooth muscle cells (VSMC) plays a major role in restenosis, the pathological renarrowing of the blood vessel lumen after surgical treatment of stenosis. Since available anti-proliferative pharmaceuticals produce unfavorable side effects, there is high demand for the identification of novel VSMC proliferation inhibitors. A natural product screening approach using a resazurin conversion assay enabled the identification of gentisin (1) from Gentiana lutea as a novel inhibitor of VSMC proliferation with an IC₅₀ valueof 7.84 µM. Aiming to identify further anti-proliferative compounds, 13 additional nonprenylated xanthones, isolated from different plant species, were also tested. While some compounds showed no or moderate activity at 30 µM, 1-hydroxy-2,3,4,5-tetramethoxyxanthone (4), swerchirin (6), and methylswertianin (7) showed IC₅₀ values between 10.2 and 12.5 µM. The anti-proliferative effect of 1, 4, 6, and 7 was confirmed by the quantification of DNA synthesis (BrdU incorporation) in VSMC. Cell death quantification (determined by LDH release in the culture medium) revealed that the compounds are not cytotoxic in the investigated concentration range. In conclusion, nonprenylated xanthones are identified as novel, non-toxic VSMC proliferation inhibitors, which might contribute to the development of new therapeutic applications to combat restenosis. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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5841 KiB

Open AccessArticle

Auraptene Acts as an Anti-Inflammatory Agent in the Mouse Brain

by Satoshi Okuyama, Mayu Morita, Miki Kaji, Yoshiaki Amakura, Morio Yoshimura, Koji Shimamoto, Yu Ookido, Mitsunari Nakajima and Yoshiko Furukawa

Molecules 2015, 20(11), 20230-20239; https://doi.org/10.3390/molecules201119691 - 10 Nov 2015

Cited by 40 | Viewed by 5886

Abstract

The anti-inflammatory activity of auraptene (AUR), a citrus coumarin, in peripheral tissues is well-known, and we previously demonstrated that AUR exerts anti-inflammatory effects in the ischemic brain; the treatment of mice with AUR for eight days immediately after ischemic surgery suppressed demise and [...] Read more.

The anti-inflammatory activity of auraptene (AUR), a citrus coumarin, in peripheral tissues is well-known, and we previously demonstrated that AUR exerts anti-inflammatory effects in the ischemic brain; the treatment of mice with AUR for eight days immediately after ischemic surgery suppressed demise and neuronal cell death in the hippocampus, possibly through its anti-inflammatory effects in the brain. We suggested that these effects were at least partly mediated by the suppression of inflammatory mediators derived from astrocytes. The present study showed that (1) AUR, as a pretreatment for five days before and another three days after ischemic surgery, suppressed microglial activation, cyclooxygenase (COX)-2 expression in astrocytes, and COX-2 mRNA expression in the hippocampus; (2) AUR suppressed the lipopolysaccharide-induced expression of COX-2 mRNA and the mRNA of pro-inflammatory cytokines in cultured astrocytes; (3) AUR was still detectable in the brain 60 min after its intraperitoneal administration. These results support our previous suggestion that AUR directly exerts anti-inflammatory effects on the brain. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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3152 KiB

Open AccessArticle

Synergy and Other Interactions between Polymethoxyflavones from Citrus Byproducts

by Benito F. García, Ascensión Torres and Francisco A. Macías

Molecules 2015, 20(11), 20079-20106; https://doi.org/10.3390/molecules201119677 - 06 Nov 2015

Cited by 25 | Viewed by 11628

Abstract

The citrus by-products released from citrus processing plants may contain high levels of potentially bioactive compounds such as flavonoids, which are a widely distributed group of polyphenolic compounds with health-related properties based on their antioxidant activity. In the study reported here, the potential [...] Read more.

The citrus by-products released from citrus processing plants may contain high levels of potentially bioactive compounds such as flavonoids, which are a widely distributed group of polyphenolic compounds with health-related properties based on their antioxidant activity. In the study reported here, the potential bioactivities and antioxidant activities of extracts, fractions and compounds from citrus by-products were evaluated along with the chemical interactions of binary mixtures of compounds and complex mixtures. The bioactivities and interactions were evaluated in wheat coleoptile bioassays and the antioxidant activity was evaluated by the al DPPH (2,2-diphenyl-1-picrylhdrazyl radical) radical scavenging assay. The extracts, fractions and most of the isolated compounds (mainly polymethoxyflavones) showed high activity in the wheat coleoptile bioassay. However, the antioxidant activity was not consistently high, except in the acetone extract fractions. Moreover, a study of the interactions with binary mixtures of polymethoxyflavones showed the occurrence of synergistic effects. The complex mixtures of fractions composed mainly of polymethoxyflavones caused a synergistic effect when it was added to a bioactive compound such as anethole. The results reported here highlight a new application for the wheat coleoptile bioassay as a quick tool to detect potential synergistic effects in compounds or mixtures. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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1234 KiB

Open AccessArticle

Analysis of the Photophysical Behavior and Rotational-Relaxation Dynamics of Coumarin 6 in Nonionic Micellar Environments: The Effect of Temperature

by Cristóbal Carnero Ruiz, José Manuel Hierrezuelo and José Antonio Molina-Bolivar

Molecules 2015, 20(10), 19343-19360; https://doi.org/10.3390/molecules201019343 - 23 Oct 2015

Cited by 22 | Viewed by 6970

Abstract

The photodynamics of Coumarin 6 have been investigated in three nonionic micellar assemblies, i.e., n-dodecyl-β-d-maltoside (β-C₁₂G₂), p-tert-octyl-phenoxy polyethylene (9.5) ether (Triton X-100 or TX100) and n-dodecyl-hexaethylene-glycol (C₁₂E₆), to assess their potential [...] Read more.

The photodynamics of Coumarin 6 have been investigated in three nonionic micellar assemblies, i.e., n-dodecyl-β-d-maltoside (β-C₁₂G₂), p-tert-octyl-phenoxy polyethylene (9.5) ether (Triton X-100 or TX100) and n-dodecyl-hexaethylene-glycol (C₁₂E₆), to assess their potential use as encapsulation vehicles for hydrophobic drugs. To evaluate the effect of the micellar size and hydration, the study used a broad temperature range (293.15–323.15 K). The data presented here include steady-state absorption and emission spectra of the probe, dynamic light scattering, together with fluorescence lifetimes and both steady-state, as well as time-resolved fluorescence anisotropies. The time-resolved fluorescence anisotropy data were analyzed on the basis of the well-established two-step model. Our data reveal that the molecular probe in all of the cases is solubilized in the hydration layer of micelles, where it would sense a relatively polar environment. However, the probe was found to undergo a slower rotational reorientation when solubilized in the alkylpolyglycoside surfactant, as a result of a more compact microenvironment around the probe. The behavior of the parameters of the reorientation dynamics with temperature was analyzed on the basis of both micellar hydration and the head-group flexibility of the surfactants. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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1577 KiB

Open AccessArticle

Validated LC-MS/MS Method for the Determination of Scopoletin in Rat Plasma and Its Application to Pharmacokinetic Studies

by Yingchun Zeng, Sha Li, Xiaohong Wang, Tao Gong, Xun Sun and Zhirong Zhang

Molecules 2015, 20(10), 18988-19001; https://doi.org/10.3390/molecules201018988 - 19 Oct 2015

Cited by 34 | Viewed by 6978

Abstract

A rapid, sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed and validated for the quantification of scopoletin in rat plasma. After the addition of the internal standard xanthotoxin, plasma samples were pretreated by a simple one-step protein precipitation with acetonitrile-methanol [...] Read more.

A rapid, sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed and validated for the quantification of scopoletin in rat plasma. After the addition of the internal standard xanthotoxin, plasma samples were pretreated by a simple one-step protein precipitation with acetonitrile-methanol (2:1, v/v). Chromatographic separation was achieved on a Diamonsil ODS chromatography column using gradient elution with the mobile phase consisting of acetonitrile and 0.1% formic acid. The determination was performed by positive ion electrospray ionization in multiple reaction monitoring mode. The calibration curve was linear over the concentration range of 5–1000 ng/mL (r = 0.9996). The intra- and inter-day precision (RSD%) was less than 6.1%, and the accuracy (RE%) was from −3.0%–2.5%. This method was successfully applied to the pharmacokinetic research of scopoletin in rats after intravenous (5 mg/kg) or oral (5, 10 and 20 mg/kg) administration. The result showed that oral bioavailability with a dose of 5 mg/kg was 6.62% ± 1.72%, 10 mg/kg, 5.59% ± 1.16%, and 20 mg/kg, 5.65% ± 0.75%. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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758 KiB

Open AccessArticle

Quantification of Coumarins in Aqueous Extract of Pterocaulon balansae (Asteraceae) and Characterization of a New Compound

by Bruna Medeiros-Neves, Francisco Maikon Corrêa De Barros, Gilsane Lino Von Poser and Helder Ferreira Teixeira

Molecules 2015, 20(10), 18083-18094; https://doi.org/10.3390/molecules201018083 - 02 Oct 2015

Cited by 15 | Viewed by 5780

Abstract

Plants from the genus Pterocaulon are popularly used as antifungal and wound-healing agents. Such activities have been related to coumarins, which are abundant in those plants. Coumarins are soluble in organic solvents, such as hexane and dichloromethane, and some of them are also [...] Read more.

Plants from the genus Pterocaulon are popularly used as antifungal and wound-healing agents. Such activities have been related to coumarins, which are abundant in those plants. Coumarins are soluble in organic solvents, such as hexane and dichloromethane, and some of them are also soluble in hot water. Considering that infusion and decoctions of these plants are used in traditional medicine, the aim of this study was to identify and quantify the coumarins in the aqueous extract of Pterocaulon balansae. The aqueous extract was obtained by dynamic maceration and the compounds were characterized by UPLC-UV-MS analysis. A new coumarin and 5-methoxy-6,7-methylenedioxycoumarin, used for validation of the analytical HPLC method were obtained by partition of the aqueous extract with n-hexane. The HPLC method validated was linear, specific, and precise. Seven coumarins were characterized in the aqueous extract in a range of 0.584–54 mg/g of dry plant material. The main compound, 5,6-dimethoxy-7-(3′-methyl-2′,3′-dihydroxybutyloxy)coumarin, is described for the first time in P. balansae together with a new compound, 5,6-dimethoxy-7-(2′,3′-epoxy-3′-methylbutyloxy)coumarin. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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3377 KiB

Open AccessArticle

Phytotoxic Potential and Biological Activity of Three Synthetic Coumarin Derivatives as New Natural-Like Herbicides

by Fabrizio Araniti, Raffaella Mancuso, Antonio Lupini, Salvatore V. Giofrè, Francesco Sunseri, Bartolo Gabriele and Maria Rosa Abenavoli

Molecules 2015, 20(10), 17883-17902; https://doi.org/10.3390/molecules201017883 - 29 Sep 2015

Cited by 38 | Viewed by 6784

Abstract

Coumarin is a natural compound well known for its phytotoxic potential. In the search for new herbicidal compounds to manage weeds, three synthetic derivatives bearing the coumarin scaffold (1–3), synthesized by a carbonylative organometallic approach, were in vitro assayed [...] Read more.

Coumarin is a natural compound well known for its phytotoxic potential. In the search for new herbicidal compounds to manage weeds, three synthetic derivatives bearing the coumarin scaffold (1–3), synthesized by a carbonylative organometallic approach, were in vitro assayed on germination and root growth of two noxious weeds, Amaranthus retroflexus and Echinochloa crus-galli. Moreover, the synthetic coumarins 1–3 were also in vitro assayed on seedlings growth of the model species Arabidopsis thaliana to identify the possible physiological targets. All molecules strongly affected seed germination and root growth of both weeds. Interestingly, the effects of synthetic coumarins on weed germination were higher than template natural coumarin, pointing out ED₅₀ values ranging from 50–115 µM. Moreover, all synthetic coumarins showed a strong phytotoxic potential on both Arabidopsis shoot and root growth, causing a strong reduction in shoot fresh weight (ED₅₀ values ≤ 60 µM), accompanied by leaf development and a decrease in pigment content. Furthermore, they caused a strong alteration in root growth (ED₅₀ values ≤ 170 µM) and morphology with evident alterations in root tip anatomy. Taken together, our results highlight the promising potential herbicidal activity of these compounds. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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Open AccessCommunication

Identification of Minor Benzoylated 4-Phenylcoumarins from a Mammea neurophylla Bark Extract

by Bach Tai Dang, Caroline Rouger, Marc Litaudon, Pascal Richomme, Denis Séraphin and Séverine Derbré

Molecules 2015, 20(10), 17735-17746; https://doi.org/10.3390/molecules201017735 - 25 Sep 2015

Cited by 7 | Viewed by 6849

Abstract

Through dereplication analysis, seven known Mammea coumarins were identified in a fraction obtained from Mammea neurophylla dichloromethane bark extract selected for its ability to prevent advanced glycation end-product (AGE) formation. Among them, a careful examination of the NMR dataset of pedilanthocoumarin B led [...] Read more.

Through dereplication analysis, seven known Mammea coumarins were identified in a fraction obtained from Mammea neurophylla dichloromethane bark extract selected for its ability to prevent advanced glycation end-product (AGE) formation. Among them, a careful examination of the NMR dataset of pedilanthocoumarin B led to a structural revision. Inspection of LC-DAD-MSⁿ chromatograms allowed us to predict the presence of four new compounds, which were further isolated. Using spectroscopic methods (¹H-, ¹³C- and 2D-NMR, HRMS, UV), these compounds were identified as new benzoyl substituted 4-phenylcoumarins (iso-pedilanthocoumarin B and neurophyllol C) and 4-(1-acetoxypropyl)coumarins cyclo F (ochrocarpins H and I). Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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Transport of Twelve Coumarins from Angelicae Pubescentis Radix across a MDCK-pHaMDR Cell Monolayer—An in Vitro Model for Blood-Brain Barrier Permeability

by Yan-Fang Yang, Wei Xu, Wei Song, Min Ye and Xiu-Wei Yang

Molecules 2015, 20(7), 11719-11732; https://doi.org/10.3390/molecules200711719 - 25 Jun 2015

Cited by 39 | Viewed by 6794

Abstract

Angelicae Pubescentis Radix (APR), a widely used traditional Chinese medicine, is reported to have central nervous system activities. The purpose of this study was to characterize the blood-brain barrier permeability of twelve coumarins from APR including umbelliferone (1), osthol (2 [...] Read more.

Angelicae Pubescentis Radix (APR), a widely used traditional Chinese medicine, is reported to have central nervous system activities. The purpose of this study was to characterize the blood-brain barrier permeability of twelve coumarins from APR including umbelliferone (1), osthol (2), scopoletin (3), peucedanol (4), ulopterol (5), angepubebisin (6), psoralen (7), xanthotoxin (8), bergapten (9), isoimperatorin (10), columbianadin (11), and columbianetin acetate (12) with an in vitro model using a MDCK-pHaMDR cell monolayer. The cell monolayer was validated to be suitable for the permeation experiments. The samples’ transports were analyzed by high performance liquid chromatography and their apparent permeability coefficients (P_app) were calculated. According to the P_app value, most coumarins could be characterized as well-absorbed compounds except for 4, 10 and 11 which were moderately absorbed ones, in concentration-dependent and time-dependent manners. The results of P-glycoprotein (P-gp) inhibitor (verapamil) experiments showed that the transport of coumarin 4 was affected by the transport protein P-gp. Sigmoid functions between permeability log(P_app_AP_-_BL*MW^0.5) and log D (at pH 7.4) were established to analyze the structure-activity relationship of coumarins. The results provide useful information for discovering the substance basis for the central nervous system activities of APR, and predicting the permeability of other coumarins through BBB. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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3086 KiB

Open AccessArticle

Xanthones from the Leaves of Garcinia cowa Induce Cell Cycle Arrest, Apoptosis, and Autophagy in Cancer Cells

by Zhengxiang Xia, Hong Zhang, Danqing Xu, Yuanzhi Lao, Wenwei Fu, Hongsheng Tan, Peng Cao, Ling Yang and Hongxi Xu

Molecules 2015, 20(6), 11387-11399; https://doi.org/10.3390/molecules200611387 - 19 Jun 2015

Cited by 30 | Viewed by 8092

Abstract

Two new xanthones, cowaxanthones G (1) and H (2), and 23 known analogues were isolated from an acetone extract of the leaves of Garcinia cowa. The isolated compounds were evaluated for cytotoxicity against three cancer cell lines and [...] Read more.

Two new xanthones, cowaxanthones G (1) and H (2), and 23 known analogues were isolated from an acetone extract of the leaves of Garcinia cowa. The isolated compounds were evaluated for cytotoxicity against three cancer cell lines and immortalized HL7702 normal liver cells, whereby compounds 1, 5, 8, and 15–17 exhibited significant cytotoxicity. Cell cycle analysis using flow cytometry showed that 5 induced cell cycle arrest at the S phase in a dose-dependent manner, 1 and 16 at the G2/M phase, and 17 at the G1 phase, while 16 and 17 induced apoptosis. Moreover, autophagy analysis by GFP-LC3 puncta formation and western blotting suggested that 17 induced autophagy. Taken together, our results suggest that these xanthones possess anticancer activities targeting cell cycle, apoptosis, and autophagy signaling pathways. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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779 KiB

Open AccessArticle

Protein Tyrosine Phosphatase 1B Inhibitors from the Roots of Cudrania tricuspidata

by Tran Hong Quang, Nguyen Thi Thanh Ngan, Chi-Su Yoon, Kwang-Ho Cho, Dae Gill Kang, Ho Sub Lee, Youn-Chul Kim and Hyuncheol Oh

Molecules 2015, 20(6), 11173-11183; https://doi.org/10.3390/molecules200611173 - 17 Jun 2015

Cited by 42 | Viewed by 7134

Abstract

A chemical investigation of the methanol extract from the roots of Cudrania tricuspidata resulted in the isolation of 16 compounds, including prenylated xanthones 1–9 and flavonoids 10–16. Their structures were identified by NMR spectroscopy and mass spectrometry and [...] Read more.

A chemical investigation of the methanol extract from the roots of Cudrania tricuspidata resulted in the isolation of 16 compounds, including prenylated xanthones 1–9 and flavonoids 10–16. Their structures were identified by NMR spectroscopy and mass spectrometry and comparisons with published data. Compounds 1–9 and 13–16 significantly inhibited PTP1B activity in a dose dependent manner, with IC₅₀ values ranging from 1.9–13.6 μM. Prenylated xanthones showed stronger PTP1B inhibitory effects than the flavonoids, suggesting that they may be promising targets for the future discovery of novel PTP1B inhibitors. Furthermore, kinetic analyses indicated that compounds 1 and 13 inhibited PTP1B in a noncompetitive manner; therefore, they may be potential lead compounds in the development of anti-obesity and -diabetic agents. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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Review

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Open AccessReview

Xanthones of Lichen Source: A 2016 Update

by Pierre Le Pogam and Joël Boustie

Molecules 2016, 21(3), 294; https://doi.org/10.3390/molecules21030294 - 02 Mar 2016

Cited by 43 | Viewed by 8924

Abstract

An update of xanthones encountered in lichens is proposed as more than 20 new xanthones have been described since the publication of the compendium of lichen metabolites by Huneck and Yoshimura in 1996. The last decades witnessed major advances regarding the elucidation of [...] Read more.

An update of xanthones encountered in lichens is proposed as more than 20 new xanthones have been described since the publication of the compendium of lichen metabolites by Huneck and Yoshimura in 1996. The last decades witnessed major advances regarding the elucidation of biosynthetic schemes leading to these fascinating compounds, accounting for the unique substitution patterns of a very vast majority of lichen xanthones. Besides a comprehensive analysis of the structures of xanthones described in lichens, their bioactivities and the emerging analytical strategies used to pinpoint them within lichens are presented here together with physico-chemical properties (including NMR data) as reported since 1996. Full article

(This article belongs to the Special Issue Coumarins, Xanthones and Related Compounds)

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