A new neolignan, 3,4-dimethoxy-3′,4′-methylenedioxy-2,9-epoxy-6,7-cyclo-
1,8-neolign-11-en-5(5H)-one, which has been named (+)-kunstlerone (1), together with six
known alkaloids: (+)-norboldine (2), (+)-N-methylisococlaurine (3), (+)-cassythicine (4),
(+)-laurotetanine (5), (+)-boldine (6) and (-)-pallidine (7), were isolated from the leaves of
Beilschmiedia kunstleri. The structures were established through various spectroscopic
methods notably 1D- and 2D-NMR, UV, IR and LCMS-IT-TOF. (+)-Kunstlerone (1)
showed a strong antioxidant activity, with an SC50 of 20.0 μg/mL.
