Cytotoxic constituents from collected in Vietnam.

Phytochemical study on the extract of Vietnamese medicinal plant Lour. has led to the isolation and structural elucidation of twelve secondary metabolites, 3-O--caffeoylbetulinic acid (), 3-benzoylbetulinic acid (), betulinic acid methyl ester (), betulinic acid (), lupeol (), 4-hydroxybenzoic acid (), 3,4-dihydroxybenzoic acid methyl ester (), 4-hydroxy-3,5-dimethoxybenzoic acid (), 5,8-dihydroxy-7,4'-dimethoxyflavone (), isoscutellarein 4'-methyl ether 8--glucopyranoside (), methyl caffeate () and stigmasterol (). Especially, compound was reported as a new natural product. Their structures were elucidated by a combination of 2D NMR and ESI-FT-ICR-MS spectroscopies. Furthermore, eight compounds were tested for their cytotoxicity against five cancer cell lines (Hela, HepG2, SK-LU-1, AGS and SK-MEL-2). The results showed that compounds (, -, ) have moderate activities. This is the first study on the chemical constituents and their cytotoxicity of the Vietnamese L.