Objective: To study chemical constituents in nutshell of Trapa acornis and in vitro inhibitory activity against alpha-glucosidase.
Method: EtOAC and n-butanol extractive fractions were separated by chromatography and their structures were identified by multiple spectroscopic techniques.
Result: Nine compounds were separated, they were 4,23,24-trimethylcholest-22-en-3-ol (1), stigmasterol (2), alpha-amyrin (3), (+)-nyasol (4), oleanolic acid (5), ursolic acid (6), hederagenin (7), 3,23-dihydroxy-12-ursen-28-oic acid (8) and beta-daucosterol (9). Total extracts from T. acornis nutshells, petroleum ether fractions, acetic ether fractions and normal butanol fractions showed inhibitory activity against alpha-glucosidase. Compound 5 (IC50 2.88 mg x L(-1)) and 6 (IC50 4.42 mg L(-1)) showed stronger inhibitory activity against alpha-glucosidase.
Conclusion: All compounds except compound 2 were separated from the genus for the first time, and compound 1-9 were separated from this plant for the first time.