A New Lignan from the Leaves of Styrax annamensis

Phytochemical investigation of the ethyl acetate extract of Styrax annamensis leaves has led to the isolation and determination of a new lignan, 7R,8S,7′S,8′R-3,4,3′-trimethoxy-9,4′,7′-trihydroxy-8.8′,7.O.9′-lignan ( 1 ), together with a known compound, 4-ketopinoresinol ( 2 ). Compound 2 was isolated from the genus Styrax for the first time, and showed moderate activity to capture the DPPH radical with the IC 50 value of 56.74 ± 0.79 μg/mL.