Xanthones from the latex and twig extracts of Garcinia nigrolineata Planch. ex T. Anderson (Clusiaceae) and their antidiabetic and cytotoxic activities

A new geranylated xanthone, nigrolineaxanthone AA (1) together with 18 known compounds (2-19) were isolated from latex and twig extracts of Garcinia nigrolineata Planch. ex T. Anderson. Some of the isolated compounds were assessed for their antidiabetic activities and cytotoxicity against three cancer cell lines. Of these, compounds 12 (IC50 value of 25.8 +/- 0.2 mu M), 16 (IC50 value of 124.8 +/- 0.7 mu M), and 17 (IC50 value of 44.4 +/- 1.1 mu M) exhibited the highest alpha-glucosidase inhibitory, alpha-amylase inhibitory, and glycation inhibition activities, respectively. Compound 11 showed glucose consumption and glucose uptake with IC50 values of 14.2 +/- 0.8 mu M and 3.1-fold. Compound 10 displayed cytotoxic activity against colon cancer (SW480) with an IC50 value of 4.3 +/- 0.1 mu M), while compound 2 showed cytotoxicity against leukemic cancer (K562) with IC50 value of 4.4 +/- 0.3 mu M.