The antinociceptive and anti-inflammatory effects of the crude extract of Jatropha isabellei in a rat gout model.

BACKGROUND

Jatropha isabellei Müll Arg. (Euphorbiaceae) is a medicinal plant that has been used in South American folk medicine for the treatment of arthritic diseases, particularly gout.

OBJECTIVE

This study was designed to verify the antinociceptive, anti-inflammatory and hypouricemic potential of Jatropha isabellei.

METHODS

Rats were orally administered with the crude extract (100-300 mg/kg) or a fraction that is rich in alkaloids (0.15 mg/kg) of Jatropha isabellei. An intra-articular (i.a.) injection of 50 μl of monosodium urate (MSU) crystals (1.25mg/site) was used to generate the gout model to assess the effect of the treatment on nociception (thermal and mechanical hyperalgesia) and inflammation (oedema and neutrophil infiltration). The effect of Jatropha isabellei on the serum levels of uric acid was evaluated in a model of hyperuricaemia induced by the intraperitoneal injection of potassium oxonate (250 mg/kg). The side effects were analysed using an open-field test, gastric lesion assessment and by measuring the levels of the ALT and AST enzymes.

RESULTS

Our study demonstrated that the crude extract of Jatropha isabellei and a fraction rich in alkaloids were able to prevent the thermal hyperalgesia, mechanical allodynia, oedema and neutrophil infiltration induced by intra-articular MSU injection in rats. On the other hand, treatment with Jatropha isabellei did not alter the uric acid levels increased by potassium oxonate in the hyperuricaemia model. In addition, Jatropha isabellei did not induce gastric lesions or liver damage and did not alter spontaneous locomotor activity.

CONCLUSIONS

The crude extract of Jatropha isabellei and its fraction rich in alkaloid presents antinociceptive and anti-inflammatory effects in a rat gout model, similar to that observed after treatment with colchicine, supporting the traditional use of this plant in gouty patients.