Flavonoid glycosides and phenolic compounds from Potentilla supina

Potentilla supina L., which belongs to the family Rosaceae, grows as a perennial herb, and is distributed in temperate regions of northern hemisphere. Its whole plants have been used as a Chinese herbal drug for the treatment of various bleeding, diarrhea, dysentery, enteritis and uterine cervical cancer. In our continuing studies to find bioactive compounds from natural products, we have found that the MeOH extract of P. supina whole plants has cytotoxic effects against human tumor cell lines. The MeOH extract was consecutively partitioned with organic solvents to give n-hexane, CH₂Cl₂, EtOAc, n-BuOH and H₂O fractions. Among these fractions, the EtOAc soluble which showed comparatively higher cytotoxic effects (IC₅₀: 17.0µg/ml for SK-MEL-2) than the other fractions was subjected to column chromatographic separation. A new and twelve known compounds were isolated from the EtOAc fraction. Twelve known compounds were identified as protocatechuic acid, gallic acid, methyl gallate, astragalin, kaempferol 3-glucuronide, kaempferol 3-glucuronide 6”-methyl ester, tiliroside, isoquercitrin, quercetin 3-glucuronide 6”-methyl ester, luteolin 7-glucuronide 6”-methyl ester, 2-O-(trans-caffeoyl) malic acid 4-methyl ester, and ellagic acid by comparison of their spectral data with literature values, The structure of a new compound was established as 2-O-(trans-caffeoyl) malic acid 1,4-dimethyl ester by spectroscopic evidence. Cytotoxicity for isolated compounds were evaluated by the sulforhodamin B (SRB) assay against human tumor cell lines (A549, SK-OV-3, SK-MEL-2, HCT15).