Evaluation of Agrimonia eupatoria l. as analgesic and anti-inflammatory on in vivo models

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

Introduction: Agrimonia eupatoria L. is a plant found on clay soils, namely in Portugal. In popular medicine, Agrimonia eupatoria L. is used for the treatment of several disorders including inflammations (1). Previous studies indicate that the aqueous extract of agrimony presents a prevalence of several phenolic compounds and that its ethyl acetate fraction shows anti-oxidant activity and lower toxicity levels (2). Objectives: Evaluate the analgesic and anti-inflammatory activities of the aqueous extract of agrimony and its ethyl acetate fraction and to assess their toxicities in animal models. Methods: The samples were obtained by infusion of the aerial parts of the plant (aqueous extract), followed by the extraction with ethyl acetate. The hot-plate test and the writhing test – male mice 25-30g, n=6-8/group, fasted for 18 h – were used to study, respectively, the central and peripheral analgesic activities (3), whereas the formalin test – also using mice – was used to complement these results. The carrageenan induced paw oedema test – male Wistar rats 160-250g, n=6-8/group, with free access to water but fasted for 24 h prior to experiments – was used to evaluate the anti-inflammatory activity (3). Test groups were used with two concentrations (single dose and double dose) of the sample. For the aqueous extract, the single doses were 199.18 mg/kg (mice) and 99.59 mg/kg (rats); for the fraction, single doses were 36.24 mg/kg (mice) and 18.12 mg/kg (rats). There was no sign of toxicity in the liver or kidneys tissues, when comparing the histopathological images of the tissues obtained from the control animals and the ones treated with the samples. The data was expressed as means ± S.E.M. The differences between the control and treatment groups were tested by one-way analyses of variance (ANOVA). The probability of P<0.05 was considered to show significant differences for all comparisons made. Results: No central analgesia was detected. In the writhing test, the percentage of inhibition of the number of abdominal constrictions was 43.5% – single dose – and 49.8% – double dose – for the extract and 29.2% – single dose – and 46.8% – double dose – for the ethyl acetate fraction. The form alin test confirmed these results. The paw oedema test showed that both doses of the extract and its fraction have anti-inflammatory properties, with 43.2% and 52.2% – extract – and 34.6% and 35.4% – fraction - of oedema reduction. The histologic analysis did not shown differences between control and test tissues. Discussion: These results confirm the peripheral analgesic and anti-inflammatory properties of agrimony, revealing a probable consequence of the activity of the phenolic compounds of agrimony. No signals of hepatic or renal toxicities were detected.

1 – Correia, H et al. Biomedical Chromatography. 2006; 20: 88–94; 2 – Correia, H et al. BioFactors. 2007; 29: 91-104; 3 – Silva, L et al. Biol Pharm Bull. 2010; 33(5): 830-835.