A new naphthol from the twigs and leaves of Pterospermum yunnanense

A new naphthol, 7-hydroxy-6-methyl-1-naphthoic acid methyl ester (1), together with eight known compounds, 6-hydroxy-7-(hydroxymethyl)-1-isopropyl-4-methyl-naphthalene (2), α-hydroxyacetosyringone (3), hexadecyl ferulate (4), scoparone (5), (+)-syringaresinol (6), stigmast-1,5-dien-3β-ol (7), β-sitosterol (8) and daucosterol (9), were isolated from the twigs and leaves of Pterospermum yunnanense Hsue. Their structures were elucidated by using spectroscopic analysis. All the compounds were isolated for the first time from P. yunnanense Hsue. Compound 1 was assessed for its cytotoxicity against five human tumour lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), and the result showed that it has no activity.