Cytotoxic and anti-inflammatory activities of dihydroisocoumarin and xanthone derivatives from garcinia picrorhiza

Garcinia picrorhiza, a woody plant native to Sulawesi and Maluku Islands, Indonesia, has been traditionally used as a wound healing ointment. In our continuous search for bioactive compounds from this plant, 15 phenolic compounds were isolated from its stem bark, including a previously undescribed dihydroisocoumarin, 2^′-hydroxyannulatomarin, and two undescribed furanoxanthones, gerontoxanthone C hydrate and 3^′-hydroxycalothorexanthone. The structures of the new metabolites were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR and HRESIMS. Gerontoxanthone C hydrate possessed cytotoxicity against four cancer cells (KB, HeLa S3, MCF-7, and Hep G2) with IC₅₀ values ranging from 5.6 to 7.5 µM. Investigation on the anti-inflammatory activities showed that 3^′-hydroxycalothorexanthone inhibited NO production in RAW 264.7 and BV-2 cell lines with IC₅₀ values of 16.4 and 13.8 µM, respectively, whereas only (−)-annulatomarin possessed inhibition activity on COX-2 enzyme over 10% at 20 µM. This work describes the presence of 3,4-dihydroisocoumarin structures with a phenyl ring substituent at C-3, which are reported the first time in genus Garcinia. These findings also suggest the potential of furanx-anthone derivatives as cytotoxic and anti-inflammatory agents for further pharmacological studies.