Scalemic Caged Xanthones Isolated from the Stem Bark Extract of Garcinia propinqua
journal contributionposted on 10.05.2017, 16:15 by Teerayut Sriyatep, Raymond J. Andersen, Brian O. Patrick, Stephen G. Pyne, Chatchai Muanprasat, Sawinee Seemakhan, Suparerk Borwornpinyo, Surat Laphookhieo
Seven new caged xanthones, doitunggarcinones E–K (1–7), all as scalemic mixtures and 10 known compounds (8–17), were isolated from the stem bark extract of Garcinia propinqua. The structures were elucidated on the basis of spectroscopic methods. The separation of the enantiomers of 1–6 was achieved by semipreparative chiral HPLC. The absolute configuration of compound (+)-1 was determined by single-crystal X-ray crystallographic analysis using Cu Kα radiation. The absolute configurations of the other related compounds were determined from comparisons of their ECD spectra with that of compound (+)-1. Compounds (−)-6 and 7 showed cytotoxicity against a colon cancer cell line with IC50 values of 14.23 and 23.95 μM, respectively.