Picraquanines A－C, three new phenolic derivatives from the stems of Picrasma quassioides
Three new phenolic derivatives, picraquanines A–C (1–3), along with 6 known ones 4–9 were obtained from the stems of Picrasma quassioides (D. Don) Benn. The new structures were determined by extensive spectroscopic data analysis, including IR, HRESIMS, 1H-NMR, 13C-NMR, HSQC, HMBC, 1H-1H COSY experiments. The absolute configuration of 1 was determined by comparison of its experimental and calculated ECD spectra. Furthermore, all the compounds were tested for their nitric oxide (NO) inhibitory effects against LPS-stimulated RAW 264.7 cells, however, none of them exhibited inhibitory effects (IC50 >100 μM).