Two New Xanthones from the Root Bark of Garcinia Subelliptica

Abstract

From the root bark of Garcinia subelliptica, two new xanthones named subelliptenones C (1) and D (2) were isolated in addition to two known xanthones [12h-hydroxy-des-D-garcigerin (3) and globuxanthone (4)).The structures were determined by analysis of nmr spectral data including 2D techniques.In continuation of our works'-3 oriented to reach for xanthone derivatives with bioactive potency in Guttifaamus plants, we now report the isolation and characterization of two new xanthones from the root bark of G. subelliptica Merr.(= S. spicuta Hook.f.) (Clusiaceae) along with two known xanthones.The root bark of G. subelliptica collected in Okinawa, Japan was dried and ground, and successively extracted with n-hexane, benzene, acetone and 70%MeOH.The acetone extract suspended in water was partitioned with EtOAc.The EtOAc layer was repeatedly chromatographed on silica gel and Sephadex LH-20 to give four xanthones (1-4).Compound (I), subelliptenone C, obtained as a yellow amorphous, reacted positively to Gibbs and FeC13 reactions.The [Mtl at m/z 352.0971 in the HRms corresponds to C20HL606.The uv and their spectrum were suggestive 1 to be a xanthone derivative.In the 'H-nmr spectrum, a chelated hydroxyl (8 13.01) and two aromatic singlet signals (8 7.33 and 8.04) were observed in addition to two aromatic hydroxyl groups 18 8.90 (2H, br s)].The spectrum further showed the presence of a 1,l-dimethylallyl chain [8 1.55 (6H, s, Me x 2),