Bioactive biphenyl derivatives from Garcinia nujiangensis and structural revision

Twelve biphenyl derivatives, including ten previously undescribed (1-10) and two known analogues (11 and 12), were isolated from the twigs and leaves of Garcinia nujiangensis. Two previously reported compounds, nujiangbiphenyls B and A were revised to garcinudiran I and J (9 and 10), respectively. Their structures were elucidated through comprehensive spectroscopic analysis, quantum chemical calculations, and X-ray crystallography. Subsequent α-glucosidase inhibitory effect revealed that five compounds (2, 6, 9, 10, and 11) exhibited more potential inhibitory effects than the positive control, with IC₅₀ values of 37.80 ± 1.43 to 147.70 ± 7.36 μg·mL^-1. Notably, compound 10 (IC₅₀ = 37.80 ± 1.43 μg·mL^-1) was identified as the most potent α-glucosidase inhibitor, which was approximately 7 times stronger than the positive control (acarbose). Additionally, six compounds (1, 2, 6, 7, 9, and 10) exhibited stronger lipid-lowering effects than the positive control (atorvastatin) in OA-induced HepG2 cells. This study expands the structural diversity of biphenyl derivatives from the genus Garcinia. It also provides promising anti-diabetic and lipid-lowering candidates for further investigation.