Four Unidentified Compounds Isolated from the Stem Barks of Aphanamixis polystachya and Their NO Production Inhibition in LPS Activated RAW 264.7 Cells

Phytochemical study on the methanol extract of the stem barks of Aphanamixis polystachya led to the isolation of four previously undescribed (1‐4) and ten known compounds (5‐14). Their chemical structures were elucidated to be 11‐methoxysawaranospiroride C (1), 6α,9S,10,13‐tetrahydroxymegastigmane‐3‐one (2), 11‐hydroxyaphanamixin B (3), (2Z,6E,13E)‐2,6,13‐triene‐11,15‐dihydroxyphytanic acid (4), cinnacasside D (5), cinnacasside E (6), vilsonol F (7), (3S,5R,6S,7E,9R)‐3,5,6,9‐tetrahydroxy‐7‐en‐megastigmane (8), (3S,5R,6R,7E,9R)‐3,6,9,10‐tetrahydroxy‐7‐en‐megastigmane (9), citroside A (10), threo‐1‐(3,4,5‐trimethoxyphenyl)‐1,2,3‐propanetriol (11), 3,4,5‐trimethoxyphenyl‐1‐O‐β‐D‐glucopyranoside (12), p‐coumaric acid (13), ferulic acid (14) by HR‐ESI‐MS, ECD, 1D‐, and 2D‐NMR spectra. Compounds 1, 3, 4, and 9 showed NO production inhibitory activity in LPS activated RAW 264.7 cells with IC50 values of 42.0, 67.9, 20.5, and 78.6 μM, respectively, while the remaining compounds were inactive with IC50 values over 100 μM.