Phenolic compounds from Trigonostemon honbaensis and their cytotoxic activity

Abstract Seven phenolic compounds including (±)‐ erythro ‐1‐(3′,4′,5′‐trimethoxyphenyl)propane‐1,2‐diol ( 1 ), (±)‐ threo ‐1‐(3′,4′,5′‐trimethoxyphenyl)propane‐1,2‐diol ( 2 ), ( R )‐3‐3‐(3′,4′‐dimethoxyphenyl)propane‐1,2‐diol ( 3 ), (±)‐3‐(3′,4′,5′‐trimethoxyphenyl)propane‐1,2‐diol ( 4 ), (+)‐syringaresinol ( 5 ), (7 S ,8 R ,8′ R )‐5,5′‐dimethoxylariciresinol ( 6 ), juniperoside ( 7 ) were isolated from the leaves of Trigonostemon honbaensis . Their chemical structures were determined using ESI‐MS, 1D NMR, and 2D NMR spectra and in comparison with the reported literature. Compounds 1 ‐ 7 were reported from Trigonostemon genus for the first time. At concentration of 30 μM, compounds 1 ‐ 7 exhibited weak cytotoxic activity with cell viability percentages as low as 73.3±0.87 % and 79.5±0.23 % on CAL‐27 and MDA‐MB231 cell lines, respectively.