Genus Hypericum hypericin from

Naphtodianthrones isolated from the genus Hypericum include hypericin (C3oHi6Og, 10,11 -dimethyl-1,3,4,6,8,13-hexahydroxynaphtodianthrone), pseudohypericin, Fig. (3), and isohypericin [2,3,9,10,22]. Those metabolites are powerful photosensitizers and they are believed to be responsible for hypericism, a photodermatosis which affects cattle grazing on Hypericum plants. 

Hypericin, Fig. (13) is a polycyclic quinone obtained from plants of Hypericum genus, which exhibits strong photodynamic antitumor effects. 

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