Cytotoxic and antioxidant constituents from Garcinia subelliptica.

Two new triterpenoids, garcinielliptones Q (1) and S (3), and a new phloroglucinol, garcinielliptone R (2), were isolated from the seed of Garcinia subelliptica. Their structures were established by analysis of their spectroscopic data. Phloroglucinol, garcinielliptone FC (4) from this plant exhibited a significant increase of antiproliferative effect, while 4 combined with cisplatin significantly caused decrease of cell inhibition induced by cisplatin in NTUB1. Exposure of NTUB1 cells to 4 cotreated with cisplatin for significantly decreased the amount of reactive oxygen species (ROS) than that of the total amount generated by 4 and cisplatin. These results suggested that 4 could protect the cisplatin toxicity through reduction of ROS in NTUB1. Phloroglucinols, garcinielliptones, A (5) and F (7), and garsubelline A (6), from this plant, revealed ABTS radical cation scavenging activity and 5 displayed an inhibitory effect on xanthine oxidase. These finding showed that 5-7 may be used as antioxidants.