Antiproliferative Constituents in Plants 10. Flavones from the Leaves of Lantana montevidensis BRIQ. and Consideration of Structure–Activity Relationship

Abstract

The flavonoid fraction from the leaves of Lantana montevidensis BRIQ. (Verbenaceae) showed antiproliferative activity against human gastric adenocarcinoma (MK-1, GI₅₀: 12 μg/ml), human uterus carcinoma (HeLa, 5 μg/ml), and murine melanoma (B16F10, 5 μg/ml) cells in vitro. Bioactivity-guided chemical investigation of the fraction has resulted in the isolation of apigenin (10) and ten 5,6,7-oxygenated flavones: cirsilineol (1), eupatorin (2), 5,4′-dihydroxy-6,7,3′,5′-tetramethoxyflavone (3), 5,6-dihydroxy-7,3′,4′-trimethoxyflavone (4), 5,6,4′-trihydroxy-7,3′,5′-trimethoxyflavone (5), 5,6,3′-trihydroxy-7,4′-dimethoxyflavone (6), 5,3′,4′-trihydroxy-6,7,5′-trimethoxyflavone (7), cirsiliol (8), hispidulin (9), and eupafolin (11). Antiproliferative activity of the isolated flavones, some other related flavones (luteolin, baicalein, 6-hydroxyluteolin, pectolinarigenin, jaceosidin, desmethoxycentaureidin, eupatilin, and chrysin) from other plant materials, and synthetic 6- and 7-methoxyflavones was evaluated, and the structure–activity relationships were examined.