A New Lignan from the Leaves of Piper sarmentosum

A new lignan, named 4'-methoxy-neotaiwanensol (1), together with five known compounds (2-6) were isolated from the leaves of the plant Piper sarmentosum. The known compounds consist of a phenylpropanoid (2), a flavonoid (3), two acyclic monoterpenoids (4 and 5), and a phenylacetic acid derivative (6). Structure elucidation of these compounds was conducted by detailed interpretation of the spectral data including NMR and HRESIMS data. Compounds 4 and 5 are new natural products and the NMR data in methanol-d(4) were reported for the first time. The other known compounds were elucidated to be hydroxychavicol (2), hispidulin (3), 4-hydroxy-benzeneacetic acid (6). In vitro, compounds 1 and 3 showed better inhibitory effects on alpha-glucosidase than the reference acarbose, and compound 1 and 2 exhibited moderate antioxidant effects.