Monographs of fragrance chemicals and extracts that have caused contact allergy / allergic contact dermatitis
Anton C. de Groot in Monographs in Contact Allergy, 2021
The chemical composition of commercial oakmoss extracts is strongly dependent on the mode of production (type of solvent, temperature, duration and number of contacts) and possible intentional or unintentional adulteration with lichens other than Evernia prunastri or biomass (50). In oakmoss of various origins, some 175 constituents have been identified, including 15 depsides, 19 mono-aromatic compounds, 9 chlorinated mono-aromatic compounds, 5 divarinol-derivatives, 26 triterpenes and steroids, 51 terpenoids and 48 other compounds (50). Selected chemicals (the depsides and the terpenoids which are known to have caused contact allergy [from any source]) identified in oakmoss extracts of various origin are shown in table 3.67.2 (adapted from refs. 50,51). The (chlorinated) mono-aromatic compounds and divarinol-derivatives are degradation products of the depsides through hydrolysis or decarboxyla-tion. These include the main sensitizers atranol and chloroatranol, which are derived from the depsides atranorin and chloroatranorin (50).
Anti-microbial and Anti-oxidant Properties of Solvent Extract of Lichen Species Collected from Kodaikanal Hills, Western Ghats of Tamil Nadu
Parimelazhagan Thangaraj in Phytomedicine, 2020
Fungi in association with algae form an autotrophic, one single thallus with two different organisms, or lichens. They are able to grow on rock (saxicolous), soil (terricolous), and bark (corticolous). Because of its small size, the contribution of lichen to pharmaceutical industry has been ignored for several years. A total population of about 22,000 species are widespread in the world. It was estimated that about 2714 species occur in India. Five hundred and fifty-seven species of lichen were recognized as endemic in India. Lichens are known for unique secondary metabolites of about 1050 total compounds. Over 550 compounds are unique to lichens. The derivatives of lichen compounds are fatty acids, macrolytic lactones, zeorins, pulvic acid derivatives, cumarone derivatives, dibenzofurans, depsides, depsidones, terpenoids, anthroquinone derivatives, steroids, carotenoids, and diphenyl ethers. All lichen compounds have generally poor solubility in water. The amount of lichen substances in the lichen species are quite variable. The thallus of Pamotrema tinctorum had 23.5% lecanoric acid. The thallus of wolf lichen showed 10.5% vulpinic acid. Atranorin, parietin, usnic acid, and fungal melanins are some of the lichen substances found in the cortex. The lichen extracts with protocetratic acid, physodalic acid, and physodic acid are organized in the medullary layer. The lichen substances are identified by spot test and thin layer chromatography or high pressure liquid chromatography. Lichens are used to cure dyspepsia, bleeding piles, bronchitis, scabies, stomach disorders, and other disorders of the blood and heart. Cetrarin accelerated peristalsis and the substance was recommended for anemia and lack of appetite, and the usnic acid extracted from lichens rendered wide applications as analgesics and anti-pyretics to treat psoriasis and parasitic infections and skin diseases in the pharmaceutical industry.
Protective effects of extracts of lichen Dirinaria consimilis (Stirton) D.D. Awasthi in bifenthrin- and diazinon-induced oxidative stress in rat erythrocytes in vitro
Published in Drug and Chemical Toxicology, 2022
Vinay Bharadwaj Tatipamula, Biljana Kukavica
Dirinaria (foliose lichen) is the sole genus of the tropical family Caliciaceae, widely distributed in tropical regions. Dirinaria genus comprises about 29 species across the globe, most of them reported existing in the flora of India. Among these, Dirinaria consimilis (Stirton) D.D. Awasthi has mostly been identified on the barks of mangrove plants of estuaries of Andhra Pradesh, India (Bharadwaj et al.2018). Biologically, the lichen D. consimilis has been reported for its antioxidant, anti-inflammatory, and anticancer activities. Chemical examination of D. consimilis leads to the identification of polyhydroxy aromatic compounds, namely 2′-O-methyl divaricatic acid, atranorin, antarvediside A-B, divaricatic acid, and sekikaic acid. All these metabolites are possessed to have better inhibitory profiles against free radicals, inflammation, and cancer due to the presence of more oxygenated groups (Tatipamula et al.2019).
Lichenochemicals: extraction, purification, characterization, and application as potential anticancer agents
Published in Expert Opinion on Drug Discovery, 2020
Mahshid Mohammadi, Vasudeo Zambare, Ladislav Malek, Christine Gottardo, Zacharias Suntres, Lew Christopher
Cell viability of human neuroblastoma cells SH-SY5Y challenged with 20 µg/mL of usnic acid has been reduced in 24 h [170]. In another study, a concentration-dependent growth inhibition effect was seen on this cell line following challenge with atranorin isolated from the lichen Cladina kalbii (Table 8).
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