IN VIVO EVALUATION OF ANTI-INFLAMMATORY AND ANALGESIC ACTIVITIES OF A PROANTHOCYANIDINS RICH FRACTION OF UNCARIA TOMENTOSA (WILLD.) DC.

J Pinto Ferreira1,3, T Santos1,3, G Costa2,3, M Caramona1,3, T Batista2,3, M Castel-Branco1,3, I Vitória1,3. 1Faculdade de Farmácia, Universidade de Coimbra, Laboratório de Farmacologia e Cuidados Farmacêuticos, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal, 2Faculdade de Farmácia, Universidade de Coimbra, Laboratório de Farmacognosia, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal, 3Universidade de Coimbra, Centro de Estudos Farmacêuticos, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal

Introduction: Uncaria tomentosa (Willd.) DC. (Rubiaceae), commonly known as cat´s claw, is an amazonian vine widely used in traditional peruvian medicine to the treatment of several ailments such as viral infections, cancer, gastric illnesses (gastric ulcers), arthritis, inflammation and other inflammatory disorders (1,2). Previous in vivo studies confirm the anti-inflammatory and analgesic properties of U. tomentosa bark decoctions (2,3). It was proved that a proanthocyanidins (PACs) free decoction does not present anti-oxidant properties, unlike the brute decoction, suggesting that their activity may be related to the anti-inflammatory and analgesic properties of U. tomentosa (4). Objectives: Evaluate the anti-inflammatory and analgesic activities of a PACs rich fraction of U. tomentosa decoction in animal models of inflammation and pain and to evaluate their hepatic and renal toxicities. Methods: U. tomentosa bark decoction was prepared according to the traditional peruvian medicine, as previous described (4). The PACs rich fraction was obtained by gel chromatography in a Sephadex LH-20 column according to their behavior under UV light and the presence of PACs was confirmed by HPLC analysis. The carrageenan-induced paw edema test - using male Wistar rats 160-250g, (n=6-8/group), with free access to water but fasted for 24h prior to experiments - was used to assess the effect of the PACs rich fraction (D1 – 4,81 mg/kg and D2 – 9,62 mg/kg) on in vivo acute inflammatory processes (5), using diclofenac as reference drug (10 mg/kg). In the analgesic activities tests were used male mice, 25-30g, n=6-8/group, fasted for 18 hours. The hot-plate test was used to evaluate the in vivo central analgesic activity (morphine as reference drug – 10 mg/kg) and the writhing test was used to evaluate the in vivo peripheral analgesic activity (diclofenac as reference drug – 10 mg/kg) (3) In these tests, the doses administrated were: D1 9,62 mg/kg – and D2 – 19,24 mg/kg. Data obtained was expressed as mean±S.E.M. Variance analysis (ANOVA) followed by the Bonferroni’s test was used to compare means. Values of p<0.05 were considered to be statistically significant. The hepatic and renal toxicities were evaluated by histological analysis. Results: The results obtained for edema reduction from the acute inflammatory model were 31% for D1, 49% for D2 and 84% for positive control. The results obtained for pain reduction from the peripheral analgesic model were 9% for D1, 51% for D2 and 72% for positive control. Moreover, results showed that this fraction does not present central analgesic activity. No hepatic or renal toxicities were detected. Conclusions: These results confirm the anti-inflammatory activity of PACs of U. tomentosa without significant toxicity suggesting that the analgesic activity is related to the nociception mechanism of pain, likely associated with the inflammatory process. References: 1 - Keplinger K. et al., J. Ethnopharmacol. 1999; 64: 23-34; 2 - Aguilar J. et al., J. Ethnopharmacol. 2002; 81: 271-276; 3 - Jürgensen S. et al., Pharmacol. Biochem. and Behavior 2005; 81: 466-477 4 - Gonçalves C. et al., Phytochemistry 2005; 66: 89-98; 5 - Winter et al., Proc. Soc. Exp. Biol. Med. 1962; 111: 544-547.