Free radical scavengers, anti-inflammatory and analgesic activity of Acaena magellanica.

Extracts of the whole plant Acaena magellanica (Rosaceae) were assessed for anti-inflammatory, antipyretic and analgesic activity in animal models. At 600 mg kg(-1), the global ethanolic extract (GEE), dichloromethane (DCM) and defatted methanol (MeOH) fractions showed a mild anti-inflammatory effect in the carrageenan-induced guinea-pig paw oedema. The GEE, DCM and defatted MeOH fractions significantly reduced inflammation by 43.2, 40.5 and 42.1%, respectively. The GEE did not showed any significant antipyretic activity in doses up to 600 mg kg(-1). A 20% w/v infusion administered orally at 16 mL kg(-1) presented analgesic effect in the acetic acid-induced abdominal constriction test in mice. The GEE and MeOH extract of A. magellanica showed free radical scavenging activity in the diphenylpicrylhydrazyl decolouration assay. Assay-guided isolation led to quercetin, Q-3-O-beta-glucoside, Q-3-O-beta-D-galactoside, ellagic acid and catechin as the free radical scavengers. The saponins tormentic acid 28-O-beta-D-galactopyranoside and 28-O-beta-D-glucopyranoside were isolated from the polar extract. The structures were determined by spectroscopic methods.