Chemical constituents from Taraxacum officinale and their α-glucosidase inhibitory activities.

Three novel butyrolactones (1-3) and butanoates (4-6), namely taraxiroside A-F, were isolated from Taraxacum officinale along with twenty-two known compounds (7-28). Their chemical structures were elucidated by interpretation of spectroscopic data and comparison with those of literatures. All isolates were evaluated for their α-glucosidase inhibitory activities. Novel compounds 1-6 (IC50 145.3-181.3 μM) showed inhibitory activities similar to that of acarbose (IC50 179.9 μM). Compound 7 and 12 were the most potent inhibitor with IC50 values of 61.2 and 39.8 μM respectively. Compounds 2 and 12 showed as mixed-type inhibition, whereas compound 7 and acarbose showed competitive inhibition.