Antioxidant, Anti-Inflammatory and Anti-Diabetic Activities of Tectona grandis Methanolic Extracts, Fractions, and Isolated Compounds.

is a traditional Dai medicine plant belonging to the Lamiaceae family, which can be used to treat malaria, inflammation, diabetes, liver disease, bronchitis, tumors, cholelithiasis, jaundice, skin disease and as an anti-helminthic. To find more novel therapeutic agents contained in this medicinal plant, the antioxidant, anti-inflammatory and anti-diabetic activities of methanolic extract, fractions and compounds were evaluated. In this study, 26 compounds were isolated from the leaves and branches of . Their structures were identified based on extensive spectral experiments, including NMR, ESI-MS and comparison with published spectral data. Among them, compounds -, -, - and - were reported for the first time for this plant. The antioxidant activity screening results showed that compounds , and had potent antioxidant capacities, with SC values from 0.32 to 9.92 µmol/L, 0.92 to 1.10 mmol Trolox/L and 1.02 to 1.22 mmol Trolox/L for DPPH, ABTS and FRAP, respectively. In addition, their anti-inflammatory effects were investigated by releasing TNF-, IL-1 and IL-6 through the use of mouse monocytic macrophages (RAW 264.7). Compounds , , and had the effects of reducing the expression of inflammatory factors. Compounds and were reported for the first time for their anti-inflammatory activities. Furthermore, the methanolic extract (ME), petroleum ether extract (PEE) and EtOAc extract (EAE) of showed significant glucose uptake activities; compounds and significantly promoted glucose uptake of 3T3-L1 adipocytes at 40 µM. Meanwhile, compounds , and showed significant inhibitory activities against α-glucosidase, with IC values of 14.16 ± 0.34 µmol/L, 19.29 ± 0.26 µmol/L and 3.04 ± 0.08 µmol/L, respectively. Compounds and were reported for the first time for their -glucosidase inhibitory activities. Our investigation explored the possible therapeutic material basis of to prevent oxidative stress and related diseases, especially inflammation and diabetes.