Chemical-constituent diversity of Tridax procumbens

Three new phytochemicals, a polyacetylene, 1,2-dihydrodendroarboreol B (1), an ionone derivative, (3S,5R,6S,7E)-3-tetradecanoate-5,6-epoxy-beta-ionone (4), and a flavonol diglycoside, quercetagetin-3,6.4'-trimethoxy-7-O-neohesperidoside (38), along with 35 known compounds with diverse structures, were isolated from the EtOH extract Of the aerial parts of Tridax procumbens. The structures of 1, 4, and 38 were determined on the basis of comprehensive methods including UV, IR, NMR, HR-ESI-MS, and CD, and by comparison of the spectroscopic data with those reported for structurally related compounds. Compounds 4, (3S,5R,6S,7E)-5,6-epoxy-3-hydroxy-7-megastigmene-9-one (5) and icariside B, (12) were tested for their abilities to inhibit SGC-7901 and HL-60 cells. The antioxidant activities of quercetagetin-3,6,4'-trimethoxyl-7-O-beta-D-glucopyranoside (36). quercetin-3-methoxyl-4'-O-beta-D-glucoside (37), and 38 were evaluated by measuring their free-radical-scavenging effects, using the DPPH free-radical method.