Two new phenylbutenoids from the rhizomes of cassumunar ginger and their α -glucosidase inhibitory activity.

An extract from the rhizomes of Cassumunar ginger ( Zingiber purpureum Roscoe). was found to have significant α -glucosidase inhibitory activity with an IC 50 value of 6.3  µ g/mL. Two new phenylbutenoids, cassudimin A ( 1 ) and cassumunol N ( 2 ), and seven known compounds ( 3 - 9 ) were isolated. Their structures and relative configurations of two new compounds were elucidated based on spectra interpretation. Compounds 1 - 3 , 6 - 9 showed more potent α -glucosidase inhibitory activity than a positive control, acarbose (IC 50 = 168.0  µ M). Dehydrozingerone ( 6 ) exhibited the most potent α -glucosidase inhibition with an IC 50 value of 8.3  μ M. Compounds 7 and 9 were found in Z. purpureum rhizomes for the first time.