Lichen constituents

Letcher, R.M. Chemistry of Lichen Constituents VII Mass Spectra of Some Pulvic Acid Derivatives. Org. Mass Spectrom. 1, 805 (1968). 

Letcher, R.M., and S.H. Eggers Chemistry of Lichen Constituents IV. Tetrahedron Letters 1967, 3541. 

Particularly good colour differentiation is obtained with the anisaldehyde-sulphuric acid reagent (No. 11). The following hJ /-values and colours have been obtained under the conditions mentioned above vulpinic acid, hBf 80, yellow usnic acid, 65, violet evemic acid, 11, red and the decomposition product orcinol, 3, red. Further details about lichen constituents are given by Ntjno [159] and Ramaut [174]. 

Lichen constituents, phenols, terpenes, sugars and steroids yield violet, blue, red, grey or green products, depending on the compound. 

Foo LY, Gwyn SA (1978) The identification of norlobariol, a new lichen constituent from Xanthoparmelia scabrosa (Tayl.) Hale. Experientia 34 970-971 Fox CH, Huneck S (1969) The formation of roccellic acid, eugenitol, eugenitin, and rupicolon by the mycobiont Lecanora rupicola. Phytochemistry 8 1301-1304... 

Lenton JR, Goad LJ, Goodwin TW (1973a) Sterols of the mycobiont and phycobiont isolated from the lichen Xanthoria parietina. Phytochemistry 12 2249-2253 Lenton JR, Goad LJ, Goodwin TW (1973b) Sterols of Xanthoria parietina evidence for two sterol pools and the identification of a novel Qs triene, ergosta-5,8,22-trien-3-P-ol. Phytochemistry 12 1135-1140 Letcher RM (1968) Chemistry of lichen constituents VII mass spectra of some pulvic acid derivatives. Org Mass Spectrom 1 805-817... 

Seshadri TR, Venkatasubramanian GB (1959) A new synthesis of diploschistesic acid. J Chem Soc 1658-1659 Shibamoto T, Wei C-I (1984) Mutagenicity of lichen constituents. Environmental Mutagenesis 6 757-762 Shibata S (1973) Polysaccharides of lichens. J Natl Sci Counc Sri Lanka 1 183-188... 

Shibamoto T, Wei Cl (1984) Mutagenicity of lichen constituents. Environ Mutagen 6(5) 757-762 Singh NP, McCoy MT, Tice RR et al (1988) A simple technique for quantitation of low levels of DNA damage in individual cells. Exp Cell Res 175 184-191 Speit G, Vasquez M, Hartmann A (2009) The comet assay as an indicatra- test for germ cell genotoxicity. Mutat Res 681 3-12... 

Culberson and Elix 100) in Harborne s Methods in Plant Biochemistry treated lichen constituents. Several minor reviews were published in 1984 382), 1991 385) and 1994 386). Volume III of Galun s Handbook of Lichenology 311) contains a chapter on chemical constituents of lichens including secondary metabohc products, storage products of lichens, carotenoids and phycobihproteins. 

Ichinose T, Miller M, Shibamoto T (1994) Inhibition of Malondialdehyde Formation from Liver Microsomes by a Lichen Constituent. Food Chem Toxicol 32 1167... 

Shibamoto T, Wei C-I (1984) Mutagenicity of Lichen Constituents. Environmental Mutagenesis 6 757... 

Of the terpenoid antibiotics so far discovered, grifolin (I) presents the fewest biosynthetic problems. The last step in its biogenesis apparently consists of the alkylation of orcinol (II), a well-known lichen constituent, with trans-trans-farnesyl pyrophosphate. Orcinol (II) is one of the simplest acetate condensation products, and is derived as shown by decarboxylation of orseUinic acid (III), a fungus and lichen constituent whose biogenesis from acetate has been exten-... 

The next several entries feature examples from the lichen literature. Study of chemical constituents of lichens has proved an invaluable source of information on relationships within this widespread group of organisms. The first example, Pseudevernia furfuracea (= Parmelia furfuracea) involves a disjunction across the Atlantic Ocean, bnt other examples in this set enjoy mnch wider—and often unusual—disjunctions. This example is inclnded here in order to keep the lichen material in one place. 

Alkal. azoxv elaiomycin Streptomyces hepaticus, Actincm., Bact. from Ontario MI) (ycein-class wcein, constituent of litmus dye (Roccella tinctoria DC. (1805), Lecanora tartarea (L.) Ach., lichens from Scandinavian tundra, and also lichens from temperate and trc ical land MI). 

Tar preparations are used mainly in the treatment of psoriasis, dermatitis, and lichen simplex chronicus. The phenolic constituents endow these compounds with antipruritic properties, making them particularly valuable in the treatment of chronic lichenified dermatitis. Acute dermatitis with vesiculation and oozing may be irritated by even weak tar preparations, which should be avoided. However, in the subacute and chronic stages of dermatitis and psoriasis, these preparations are quite useful and offer an alternative to the use of topical corticosteroids. 

In 1907, Collie proposed that polymers of ketene (CH2=C=O) might be precursors of such compounds as orsellinic acid, a common constituent of lichens. The hypothesis was modernized in 1953 by Birch and Donovan, who proposed that several molecules of acetyl-CoA are condensed (Eq. 21-19) but without the two reduction steps required in biosynthesis of fatty acids (Fig. 17-12).329 As we now know they were correct in assuming that the condensation occurs via malonyl-CoA and an acyl carrier group of an enzyme. The resulting p-polyketone can react in various ways to give the large group of compounds known as polyketides. 

Elix JA, Lumbsch HT, Lucking R (1995) The Chemistry of Foliicolous Lichens 2. Constituents of Some Byssoloma and Sporopodium Species. Bibl Lichenol 58 81... 

Jayaprakasha, G.K. Rao, L.J. Singh, R.P. Sakariah, K.K. 1998. Improved chro-matographie method for the purification of phenolic constituents of the lichen parmotrema tinctorum (Nyl.) Hale. J. Chromatogr. Sci. 36 8-10. 

A further hopane constituent of the lichen Peltigera aphthosa is phlebic acid B (125). " Woodwardic acid, from Woodwardia orientalis, is 3jff-hydroxy-21y5H-hop-22(29)-ene-23-carboxylic acid (126). Mollugogenol E (127), from Mollugo hirta, has been correlated with niollugogenol A. 

CAS 125-46-2. C18H1607. A tricyclic compound. A constituent of many lichens. Known in d, l, and dl forms. 

ICELAND MOSS, Lichen islandicus consists of the dried thallus of Cetraria islandica (L.) Acharius sensu latiore, family Parmeliaceae. Characteristic constituents include bitter-tasting lichen acids usnic acid gives the bitter-taste and has antibacterial effects. It also contains polysaccharides, which form a mucilage Lichenin, a linear cellulose-like polymer of D-glucose, is soluble in hot water, and on cooling it forms a gel. The other polysaccharide is isolichenin, a linear starch-like polymer of D-glucose, soluble in cold water. 

Prsellinic acid, a common constituent of lichens, is synthesized from the condensation of acetyl thioester and malonyl thioester. If a lichen were grown on a medium containing acetate that was radioactively labeled with at the carbonyl carbon, which carbons would be labeled in orsellinic acid ... 

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