Bufadienolides from the venom of bufo bufo gargarizans and their enzyme inhibition activities and brine shrimp lethality

Abstract

A new bufadienolide named dyscinobufotalin (1), along with twenty known bufadienolides (2-21) were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidated by spectroscopic analysis. The absolute configuration of the new natural product 2 was determined by X-ray single crystal diffraction and the complete NMR data for 3 was delivered for the first time. Both compounds 4 and 8 showed comparable α-glucosidase inhibitory activity (IC50 values of 0.25 and 0.26 μM, respectively) to the positive control acarbose (IC50 value of 0.42 μM), and 5 displayed potent inhibitory activity on acetylcholinesterase with an IC50 value of 0.12 μM. Moreover, 5, 8 and 13 presented moderate toxicity against brine shrimp.