Heterotheca inuloides: Anti-inflammatory and analgesic effect

Abstract

Heterotheca inuloides Cass. (Asteraceae) is used in the traditional medicine of Mexico. The aqueous extract obtained from the flowers of H. inuloides was assessed for anti-inflammatory activity by carrageenan-induced edema test. At 100 mg/kg, i.p, it produced 29% inhibition of inflammation. Ethyl ether (HI-1), butanol (HI-2) and aqueous fraction (HI-3) were obtained from the aqueous extract. The biological assay, by carrageenan-induced edema test, gave the following values (% inhibition): HI-1, 19.9; HI-2, 58.0 and HI-3, 30.0. HI-2 was significantly more effective than HI-1 and HI-3. The dose-effect curve of HI-2 was obtained and the calculated ED 50 was 29.7 (22.5–39.2) mg/kg. The peritoneal examination after the treatment with HI-2 showed that the anti-inflammatory action of H. inuloides was not due to an irritating effect at the injection site. At 50–100 mg/kg, i.p., HI-2 inhibited inflammation induced by dextran (38.9–68.1% inhibition) and arachidonic acid (0–33.9 %). No effect was observed at the same doses for zymosan or C 16-paf-induced edema. In addition, HI-2 reduced abdominal constrictions in mice following injection of acetic acid: at 50–100 mg/kg, it gave 73.8–78.2% inhibition. The ulcerogenic assay showed that ulcer indices after HI-2 i.p. treatment were 0.5±0.5 at 50 mg/kg and 1.2±0.4 at 100 mg/kg. The results showed related anti-inflammatory activity and the analgesic effect of HI-2.