Antinociceptive and anti-inflammatory effects of triterpenes from Pluchea quitoc DC. aerial parts

Background: Pluchea quitoc DC. (Asteraceae), a medicinal plant known as “quitoco,” “caculucage,” “tabacarana” and “madre-cravo,” is indicated for inflammatory conditions such as bronchitis, arthritis, and inflammation in the uterus and digestive system. Objective: This study evaluated the analgesic and anti-inflammatory activities of the triterpenes compounds obtained from P. quitoc aerial parts. Materials and Methods: The triterpenes compounds β-amyrin, taraxasterol and pseudo-taraxasterol in a mixture (T); β-amyrin, taraxasterol and pseudo-taraxasterol acetates in a mixture (Ta); β-amyrin, taraxasterol, pseudo-taraxasterol acetates in a mixture with β-amyrin, taraxasterol and pseudo-taraxasterol myristates (Tafe) were analyzed in the models of nociception and inflammation. The evaluation of antinociceptive activity was carried out by the acetic acid-induced writhing and tail-flick tests while leukocyte migration to the peritoneal cavity was used for anti-inflammatory profile. Results: The oral administration of T or Tafe (40 mg/kg and 70 mg/kg) and Ta (70 mg/kg) to mice reduced acetic acid-induced writhing. The tail-flick response of mice was not affected by T or Tafe (40 mg/kg). T or Tafe (40 mg/kg) and Ta (70 mg/kg) also inhibited peritoneal leukocyte infiltration following the injection of carrageenan. Conclusion: The results demonstrate the anti-inflammatory and peripheral antinociceptive activity of the triterpenes β-amyrin, taraxasterol, and pseudo-taraxasterol that were decreased when these were acetylated; while the acetylated triterpenes in mixture with myristyloxy triterpenes improved this activity. These compounds seem, at least in part, to be related to the plant's reported activity.