Antinociceptive activity of aqueous extract of Psychotriasarmentosa leaves

Abstract

BACKGROUND: Adverse side effects caused by NSAIDS and other existing allopathic analgesic agents have made these drugs unwelcoming to many. The search for alternative therapies has intensified over the years. Consequently, the investigations on the efficacy of plant based drugs used in traditional medicine has been seen as a fruitful research strategy in the search for new analgesic drugs due to possibly lesser side effects as well as the low cost. Indigenous healers in Sri Lanka prescribe an aqueous extract of leaves of Psychotriasarmentosa (named “Gonica” in Sinhala; Family: Rubiaceae) for individuals who have been physically assaulted, indicating that it may possess potent analgesic and/or anti-inflammatory activity. OBJECTIVES: Previous studies have shown that aqueous extract of P. sarmentosa has significant anti-inflammatory activity and the general objective of the present study was to determine the antinociceptive activity of this preparation. METHODS: Acetic acid induced writhing method was conducted to evaluate the analgesic activity on male Wistar rats. Data analysis was carried out using one-way analysis variance (ANOVA) and results with p <0.05 were considered as statistically significant. RESULTS: The results showed that the treatment with 100 mg/kg of freeze dried aqueous extract of P. sarmentosa leaves significantly reduced the abdominal contractions induced by the intra-peritoneal administration of acetic acid solution when compared to the control. The percentage inhibition of it was found to be 44.4 % whereas it was 50.8 % for acetyl salicylic acid. CONCLUSIONS: These preliminary observations provide evidence for the antinociceptive properties of leaves of P. sarmentosa as claimed in folk medicine.