Journal of natural medicines
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In the present study, siaresinolic acid (siaresinol, SA) was isolated from the leaves of Sabicea grisea and studied to evaluate its antinociceptive and anti-inflammatory activity. The antinociceptive effect of SA was investigated in mice using different animal models to study pain. In the acetic acid-induced writhing test, intraperitoneal (i.p.) injection of SA (0.1, 1, and 10 mg/kg, i.p.) 1 h before a pain stimulus significantly reduced the nociceptive response (by 42.3, 68.2, and 70.9 %, respectively). ⋯ In the pleurisy model, induced by carrageenan, treatment with SA inhibited important events involved in inflammatory responses, namely leukocyte influx, plasma leakage, and increased inflammatory mediators (TNF-α, IL-1β, and chemokine CXCL1), in the pleural exudate. Additionally, SA itself was not cytotoxic when evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in macrophages cultured for 24 h at concentrations ranging from 1 to 200 μg/mL. These results suggest, for the first time, that SA attenuates nociceptive behavior through mechanisms involving receptors for ATP-dependent potassium channels, in addition to suppressing acute inflammatory responses.