Abstract
Otteacumienes G-K (1-5), five pairs of enantiomeric diarylheptanoids, along with one undescribed diarylheptanoid glycoside and one new lignan, were isolated from Ottelia acuminata var. acuminata. Compounds 1-5 were identified as five pairs of enantiomers and their structural configurations were determined through a combination of spectroscopic analysis, X-ray crystallography, and ECD calculation. Notably, compound 6 was the first diarylheptanoid glycoside isolated from this aquatic species, and its absolute configuration was unequivocally established through semi-synthesis. Biological evaluation demonstrated that compound 1 exhibited α-glucosidase inhibitory activity, with an inhibition ratio of 38.97% (acarbose as the positive control, inhibition ratio = 13.52%).