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Two new styryl lactone derivatives, goniothapic acids A ( 1 ) and B ( 2 ), and 18 known compounds, were isolated from the twig and leaf extracts of Goniothalamus tapis Miq. The structures of new compounds were characterised by spectroscopic methods and HRESITOFMS. Their absolute configuration was established by comparing the experimental and calculated ECD spectra. Eleven compounds were evaluated for their α-glucosidase inhibitory activity. Of these, (-)-goniothalamin ( 5 ) and oldhamactam ( 16 ) showed the best α-glucosidase inhibitory activity with IC 50 values of 54.8 and 57.9 µM, respectively.

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 (IC 50 value of 25.8 ± 0.2 µM), 16 (IC 50 value of 124.8 ± 0.7 µM), and 17 (IC 50 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 IC 50 values of 14.2 ± 0.8 µM and 3.1-fold. Compound 10 displayed cytotoxic activity against colon cancer (SW480) with an IC 50 value of 4.3 ± 0.1 µM), while compound 2 showed cytotoxicity against leukemic cancer (K562) with IC 50 value of 4.4 ± 0.3 µM.

A new C -benzylated flavone, uvariaruflavone ( 1 ), along with 13 known compounds ( 2 - 14 ) were isolated from the twig and leaf extracts of Uvaria rufa Blume. Their structures were established by extensive spectroscopic methods. Flavones ( 5 - 8 ) and cyclohexene ( 10 ) were isolated from U. rufa for the first time. Most of the isolated compounds were evaluated for their α -glucosidase and α -amylase inhibitory activities. Of these, uvariaruflavone ( 1 ) showed the highest α -glucosidase inhibitory activity with an IC 50 value of 44.3 µM, while ferrudiol ( 12 ) displayed the highest α -amylase inhibitory activity with an IC 50 value of 73.5 µM.

A new clerodane diterpene, 2 β -methoxyhardwickiic acid ( 1 ), and four known compounds ( 2-5 ) were isolated from the twigs of Monoon membranifolium. The structure of the new compound was determined by extensive spectroscopic methods and ESITOFMS data. The absolute configuration of 1 was established by a comparison of its ECD spectrum and specific rotation with those of related previously reported compounds. All compounds were evaluated for their nitric oxide (NO) production inhibitory activities in RAW264.7 macrophage cells. Compounds 3 and 5 inhibited NO production with IC 50 values of 16.1 and 28.9 μM, respectively, which were better than that of standard compound, indomethacin (IC 50 = 32.2 μM).