Phenolic Constituents of Platanus Orientalis L. Leaves

A new flavonoid glycoside, 5,7,4′-trihydroxy-3,6-dimethoxyflavone-3′-O-β-D-xylopyranoside (axillarin-3′-O-β-D-xylopyranoside), was isolated from the ethyl acetate fraction of the ethanolic extract of Platanus orientalis L. leaves, along with nine known flavonoid aglycones and glycosides, a phenolic acid and a phenolic acid derivative. Their structures were established on the basis of detailed spectral analysis. The total ethanolic, aqueous and ethyl acetate extracts of the leaves were tested for antihepatotoxic, antioxidant and cytotoxic activities. The extracts were found to be effective in protection against CCl4 liver injury by significantly lowering alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) levels. The extracts also significantly restored depleted levels of glutathione, indicating a strong antioxidant activity, while they showed variable cytotoxic activity.