Bioassay-guided evaluation of anti-inflammatory and antinociceptive activities of pistachio, Pistacia vera L.

The ethanolic and aqueous extracts prepared from different parts of Pistacia vera L. (Anacardiaceae) as well as its oleoresin were evaluated for their in vivo anti-inflammatory and antinociceptive activities. Among the extracts screened, only the oleoresin was shown to possess a marked anti-inflammatory activity against carrageenan-induced hind paw edema model in mice without inducing any gastric damage at both 250 and 500 mg/kg doses whereas the rest of the extracts were totally inactive. While the oleoresin was found to display significant antinociceptive activity at 500 mg/kg dose, the ethanolic and aqueous extracts belonging to fruit, leaf, branch and peduncle of Pistacia vera did not exhibit any noticeable antinociception in p-benzoquinone-induced abdominal contractions in mice. Fractionation of the oleoresin indicated the n-hexane fraction to be active, which further led to recognition of some monoterpenes, mainly alpha-pinene (77.5%) by capillary gas chromatography-mass spectrometry (GC-MS) as well as the oleoresin itself. alpha-Pinene was also assessed for its antinociceptive and anti-inflammatory activities in the same manner and exerted a moderate anti-inflammatory effect at 500 mg/kg dose.