The occurrence of taxonomically informative types of compounds in the family Gentianaceae, namely iridoids, xanthones, mangiferin, and C-glucoflavones, has been recorded. The iridoids (mainly secoiridoid glucosides) appear to be present in all species investigated, with a predominance of swertiamarin and/or gentiopicroside; about 90 different compounds have been reported from 127 species in 24 genera. Xanthones are not universally present in Gentianaceae, but about 100 different compounds have been reported from 121 species in 21 genera (Jensen and Schripsema, 2002). Secoiridoids have been isolated from several members of this family, e.g. Centaurium spp., Gentiana spp. and Swertia spp.
The roots of Canscora decussata has been shown to contain sixteen xanthones (e.g. mangiferin and others) (Rizk, 1986). Four xanthones viz. 1,3,5-trihydroxy-8-methoxyxanthone, 3,5-dihydroxy-8-methoxy-1-O-β-D-glucopyranosylxanthone, 1,7-dihydroxy-3,8-dimethoxyxanthone and 1-hydroxy-3,7,8-trimethoxyxanthone were isolated from Gentiana azurium Bunge (Purev et al., 2002)…