Anti-inflammatory and anti-hypersensitive effects of the crude extract, fractions and triterpenes obtained from Chrysophyllum cainito leaves in mice.

Ethnopharmacological Relevance: Chrysophyllum cainito, popularly known as "star apple", caimito, "abiu-roxo" or "abiu-do-Pará", is a tree of about 25m in height. Besides its culinary use, it is also used in folk medicine for the treatment of diabetes mellitus and several inflammatory diseases.

Materials And Methods: The crude methanolic extract (CME) was submitted to phytochemical studies for obtaining fractions and isolated compounds. They were monitored by thin-layer-chromatography (TLC). The biological activity was evaluated in mice using the carrageenan-induced mechanical hypersensitivity and paw oedema. Biochemical assays, such as myeloperoxidase (MPO) and activity and cytokines levels quantification, were carried out to analyse the involvement of neutrophil migration and IL-1β and TNFα production. Some adverse effects were investigated using the open-field and rota-rod tests, and it was also measured the rectal temperature.

Results: This study demonstrates, for the first time, the anti-hypersensitivity and anti-inflammatory effects of CME, fractions and two isolated triterpenes obtained from the leaves of Chrysophyllum cainito on carrageenan-induced hypersensitivity and paw-oedema. The mice treated with CME or chloroform fraction (CHCl3) presented reduction in mechanical hypersensitivity. The effect of the CME seemed to be partially related to the anti-inflammatory activity, as the paw-oedema and MPO activity were also significantly inhibited. The isolated compound Lup-20(29)-en-3β-O-hexanoate demonstrated more reduction of the hypersensitivity than 3β-Lup-20(29)-en-3-yl acetate, suggesting that this molecule might be partially responsible for the biological effects obtained with CME and CHCl3 fractions. Finally, animals treated with CME and CHCl3 did not present changes in locomotor activity, motor performance or body temperature.

Conclusions: Our data demonstrates, for the first time, that the crude extract, fractions and pure compounds obtained from the Chrysophyllum cainito leaves possess important anti-hypersensitive properties against inflammatory pain in mice. The mechanisms through which Chrysophyllum cainito exerts its anti-hypersensitive actions are still unclear, and require further investigation; however, this could well constitute a new and attractive alternative for the management of persistent inflammatory and neuropathic pain in humans.