[Chemical constituents from Polygonum capitatum and their antioxidation activities in vitro].

Objective: To study the chemical constituents from Polygonum capitatum and their antioxidation activties in vitro.

Methods: Compounds were isolated and purified by silica, polyamide and Sephadex LH-20 column chromatography. Their structures were identified by physicochemical properties and spectral analyses. The isolated compounds were screened with three antioxidation models in vitro.

Results: Ten compounds were isolated and identified as galic acid (1), protocatechuic acid (2), progallin A (3), nimbecetin (4), quercetin (5), quercitroside (6), tetracosylferulate (7), quercetin-3-O-beta-D-glucoside (8), beta-deucosterol and beta-sitosterol (10). Compounds 1-6 from this plant showed antioxidation activities.

Conclusion: Compound 3 and 7 are isolated from this genus for the first time, compound 2, 4 and 9 are isolated from this plant for the first time, the pharmacological activities of the pure compounds from this plant are also reported firstly.