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Monographs of fragrance chemicals and extracts that have caused contact allergy / allergic contact dermatitis
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Freshly harvested oakmoss has substantially no scent. The moss contains various types of depsides, which are non-volatile, odorless, polyfunctional diaryl derivatives, including lecanoric acid, evernic acid, divaricatic acid, barbatic acid, atranorin, chloroatranorin and thamnolic acid (see the section ‘Chemical composition’ below). The characteristic oakmoss fragrance is only developed after cleavage of the depsides during treatment of the oakmoss resinoid with alcohols to give volatile, scented, monoaryl derivatives (73). Resorcinol derivatives such as methyl-β-orcinol carboxylate and orcinol monomethyl ether are mainly responsible for the characteristic earthy-moss-like odor of the oakmoss products (74).
Anti-microbial and Anti-oxidant Properties of Solvent Extract of Lichen Species Collected from Kodaikanal Hills, Western Ghats of Tamil Nadu
Published in Parimelazhagan Thangaraj, Phytomedicine, 2020
R. Kalidoss, M. Mariraj, M. Shenbagam, J. Merlin Seles, K. Arun Prasath, N. Rajaprabu, P. Ponmurugan
A bioprospection study was carried out in four species of foliose and two fruticose lichens. With an exception of Usnea stigmatoides, the methanolic extract of all lichens exhibited moderate anti-bacterial activity against clinical pathogens. The Parmotrema nilgherrense lichen extract revealed higher phenolic content. The methanolic extract of Usnea stigmatoides showed good anti-oxidant properties. The lichen substances identified in the present study were lecanoric acid, salazinic acid, and usnic acid. Drug resistance of all known microorganisms to all existing anti-microbial agents is fully established. It is necessary to identify the new anti-microbial agents and to determine which of the potential compound is more effective against unidentified microorganisms. Therefore, this work will provide the baseline information for the future pharmacological studies.
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
Lichenochemicals as potential anticancer agents represent a diverse group of compounds with different physicochemical properties and concentrations [26–28] The bioactive lichenochemicals represent an array of different chemical structures (Figure 1) [19,29–31]. These structures vary with the lichen species and environmental factors including light, temperature [10,31,32], UV expose [33,34], altitude [35,36] and seasonality[37,38]. Lichenochemicals include but are not limited to chemical families, such as flavonoids [39] and terpenoids [40], tridepsides [12,13,41,], orsinol tridepsides, orcinol tetradepsides, aphthosin [18], and phenolic compounds [36]. The structural identification of lichenochemicals is carried out using analytical methods such as TLC, HPLC, UV, IR, NMR, MS, and X-ray crystallography [42]. For example, lichen compounds reported for Umbilicaria species include compounds with different aromatic, aliphatic and cyclic structures, such as lecanoric acid, gyrophoric acid, umbilicaric acid, and norstictic acid [43], parietin [44], myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid and linolenic acid [45], just to mention a few.