Amarisolide A and pedalitin as bioactive compounds in the antinociceptive effects of Salvia circinata (Lamiaceae)

Abstract

Background: Salvia circinata is an endemic species of Mexico used in the folk medicine of Santiago Huauclilla, Oaxaca, mainly as remedy for gastrointestinal diseases. Hypothesis: If the extracts of Salvia circinata have secondary metabolites with antinociceptive activity, then the behavior of nociception in the model of "whriting" in mice will decrease. Specie studied: Salvia circinata Cav. (Lamiaceae). Study site and years of study: Salvia circinata was collected in Santiago Huauclilla, Oaxaca, in July 2014. Methods: Firstly, the acute toxicity of S. circinata extracts was evaluated to calculate the LD50 with OECD method. Then, dose-response curves of the antinociceptive effect of S. circinata organic and aqueous extracts (1, 10, 30, 100, and 300 mg/kg) were obtained in the writhing test in mice. Furthermore, chromatographic techniques were applied to isolate the compounds and were identified by comparison of the values of 1H NMR, 13C NMR and ESIMS reported in the literature. Results: Our data showed significant antinociceptive activity in all the tested extracts. Amarisolide A and pedalitin were isolated in the ethyl acetate and methanol extracts, respectively and assayed at doses of 1, 5 and 10 mg/kg, i.p. All the compounds decreased nociception in mice in at least 50 % from a minimal dosage of 1 mg/kg, i.p. and in a similar manner than the reference drug ketorolac (1 mg/kg, i.p.). Conclusions: Our findings give evidence that Salvia circinata possesses antinociceptive activity depending on the presence of several known bioactive constituents, reinforcing its use in the Mexican traditional medicine to alleviate abdominal pain.