Bioactive compounds from the bark of beilschmiedia palembanica (MIQ.) kosterm
A dienamide, named (-) kunstleramide (1), were isolated from the bark of Beilschmiedia Palembanica (Miq.) Kosterm together with one flavanone: pinocembrin (2), one phenanthrenol: perakensol (3) and 12 known alkaloids: sebiferine (4), reticuline (5), norisoboldine (6), norboldine (7), norisodomesticine (8), crychine (9), cassythicine (10), argentinine (11), isoboldine (12), o-methylnorflavinantine (13), nornantenine (14), and milonine (15). Their structures were established from spectroscopic techniques, most notably 1D- and 2D-NMR, UV, IR, OR, circular dichroism (CD) spectra and LCMS-IT-TOF. (-)-Kunstleramide (1) exhibited very poor dose-dependent inhibition of DPPH activity, with an IC50 value of 179.5 ± 4.4 μg/mL, but showed a moderate cytotoxic effect on MTT assays of A375, A549, HT-29, PC-3 and WRL-68 with EC50 values of 64.65, 44.74, 55.94, 73.87 and 70.95 µg/mL, respectively.