Four new neolignans isolated from Eleutherococcus senticosus and their protein tyrosine phosphatase 1B inhibitory activity (PTP1B)

Abstract Four new compounds, erythro -7′ E -4-hydroxy-3,3′-dimethoxy-8,5′-oxyneoligna-7′-ene-7,9-diol-9′-al ( 1 ), (7 S ,8 S )-4-hydroxy-3,1′,3′-trimethoxy-4′,7-epoxy-8,5′-neolign-9-ol ( 5 ), (7 S ,8 S ,7′ E )-5-hydroxy-3,3′-dimethoxy-4′,7-epoxy-8,5′-neolign-7′-ene-9,9′-diol ( 6 ) and (7 S ,8 S ,7′ E )-5-hydroxy-3,3′,9′-trimethoxy-4′-7-epoxy-8,5′-neolign-7′-ene-9-ol ( 7 ). Along with four known compounds ( 2 – 4 , 8 ) were isolated from the EtOAc-soluble extract of Eleutherococcus senticosus . Their structures were elucidated on the basis of spectroscopic and physicochemical analyses. All the compounds were evaluated for in vitro inhibitory activity against PTP1B, VHR and PP1. Among them, compounds 1 – 4 and 6 – 8 were found to exhibit selective inhibitory activity on PTP1B with IC 50 values ranging from 17.2 ± 1.6 to 32.7 ± 1.2 μM.