Flavonoid, stilbene and diarylheptanoid constituents of Persicaria maculosa Gray and cytotoxic activity of the isolated compounds

Persicaria maculosa (Polygonaceae) has been used as edible and as medicinal plant since ancient times. As a result of multistep chromatographic purifications, chalcones [2'-hydroxy-3',4',6'-trimethoxychalcone (1), pashanone (2), pinostrobin chalcone (3)], flavanones [6-hydroxy-5,7-dimethoxyflavanone (4), pinostrobin (5), onysilin (6), 5-hydroxy-7,8-dimethoxyflavanone (7)], flavonol [3-O-methylgalangin (8)], stilbene [persilben (9)], diarylheptanoids [1,7-diphenylhept-4-en-3-one (10), dihydroyashabushiketol (12), yashabushidiol B (13)] and 3oxo-alpha-ionol-glucoside (11) were isolated from P. maculosa. The present paper reports for the first time the occurrence of diarylheptanoid-type constituents in the family Polygonaceae. Cytotoxicity of 1-5, 7 and 9-11 on 4 T1 mouse triple negative breast cancer cells was assayed by MTT test. None of the tested compounds reduced the cell viability to less than 80% of the control. On non-tumorigenic D3 human brain endothelial cells the decrease of cell viability was observed in case of 1 and 2. Further impedance measurements on 4 T1 and D3 cells a concentration-dependent decrease in the cell index of both cell types was demonstrated for 1, while 2 proved to be toxic only on endothelial cells.