Xanthones from the latex and twig extracts ofGarcinia nigrolineataPlanch. 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 µM), 16 (IC₅₀ value of 124.8 ± 0.7 µM), and 17 (IC₅₀ value of 44.4 ± 1.1 µM) exhibited the highest α-glucosidase inhibitory, α-amylase inhibitory, and glycation inhibition activities, respectively. Compound 11 showed glucose consumption and glucose uptake with IC₅₀ values of 14.2 ± 0.8 µM and 3.1-fold. Compound 10 displayed cytotoxic activity against colon cancer (SW480) with an IC₅₀ value of 4.3 ± 0.1 µM), while compound 2 showed cytotoxicity against leukemic cancer (K562) with IC₅₀ value of 4.4 ± 0.3 µM.