Nephroma laevigatum

Most of the previously identified 25 chlorinated anthraquinones are found in lichen and fungi (1). The newly discovered examples have a wider range of sources. Studies of the lichen Nephroma laevigatum from the British Columbia coast have identified the new anthraquinone, 7-chloro-l-O-methyl-co-hydroxy-emodin (2157), and the two novel hypericins, 7,7 -dichlorohypericin (2158) and 2,2, 7,7 -tetrachlorohypericin (2159) (1931), as well as 5-chloroemodin (2160), 5-c h I oro -1 - (9 - m e t h v I - o >- h yd ro x ye m od i n (2161), and 5-chloro-co-hydroxyemodin (2162) (1932). In addition to containing several known chlorinated anthraquinones, the Scandinavian fungus Dermocybe sanguinea has afforded the new 5,7-dichloroendocrocin (2163) (1933). The novel tetracyclic anthraquinones... 

StL Caloplaca xanthaspis (Krempelh.) Zahlbr., Nephroma laevigatum Ach. 

Deriv 6a,7a-Diacetoxyhopan-22-ol, mp 222 °C (EtOH-HjO), from hopan-6a,7a,22-triol with acetyl chloride and N,N-dimethylaniline in CHCI3 under reflux for 20 h StL Nephroma laevigatum Ach., Pseudo-cyphellaria crocata (L.) Vain. 

Bohman G (1968) Chemical studies on lichens. 11. An-thraquinones from Nephroma laevigatum. Ark Kemi 30 217-223... 

Cardarelli M, Serino G, Campanella L et al (1997) Antimitotic effects of usnic acid on different biological systems. Cell Mol Life Sci 53 667-672 Cheng B, Cao S, Vasquez V et al (2013) Identification of anziaic acid, a lichen depside from Hypotrachyna sp., as a new topoisomerase poison inhibitor. PLoS One 8(4) e60770 Cohen PA, Towers GHN (1995) Anthraquinones and phenanthroperylenequinones from Nephroma laevigatum. J Nat Prod 58 520-526... 

Nephroma laevigatum, Heterodermia obscurata Emodin, 7-chloroemodin, 7 -chloro-1 -0-methy lemodin, 5,7-dichloroemodin, 7,7 dichlorohypericin, and hypericin Herpes simplex virus type 1 (HSV-1) Cohen et al. (1996)... 

Cohen PA, Towers GHN (1995a) Anthraquinones and phenanthroperylenequinmies from Nephroma laevigatum. J Nat Prod 58 520... 

Nephroma laevigatum Emodin Anthraquinones APP Antifungal activity Manojlovic... 

Nephroma laevigatum, 343 Nephroma resupinatum, 41, 82, 396 Nephromiaceae, 616 Nephromopsis, 620 Neuropogon, 256, 620 Neuropogon acromelanus, 333, 334, 335, 359... 

Dichlorohypericin (537) and 2,2, 7,7 -tetrachlorohyperidn (538) are new phenanthroperylenequinones from Nephroma laevigatum and Heterodermia obscurata respectively. Both compounds were synthesized by chlorination of hypericin with A -chlorosuccinimide in dimethylform-amide (73, 74). 

Nephroma laevigatum from British Columbia contained the following anthraquinones emodin, 7-chloroemodin, 7-chloro-l-O-methylemodin, 7-chloro-1 -0-methylcitreorosein, 5-chloroemodin, 5-chloro-l-O-methyl-emodin, 5-chloro-l-O-methylcitreorosein and 5-chlorocitreorosein. Feeding experiments with Na[2-14C]-acetate and Na[l-13C]-acetate showed that these anthraquinones are biosynthesized via the polyketide pathway (75). 

The chlorination of emodin and 7-chloroemodin was studied by Cohen and Towers 76) with an enzyme from Nephroma laevigatum and a fungal chloroperoxidase. The lichen enzyme chlorinated emodin only at C-7 while the fungal enzyme converted emodin to a mixture of 5-chloro-, 7-chloro- and 5,7-dichloroemodin (see Scheme 186). 

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