The in vitro and in vivo anti-flammatory properties and cytotoxicity of extracts of Euphorbia hirta

Abstract

Asthma is considered one of the most common respiratory complaints in the world today but a medical cure for this condition is currently not available. The use of herbal medicines to treat asthma has however been reported and Euphorbia hirtais one such herb. The alkaloids, flavonoids, glycosides, sterols, tannins and triterpenoids in E. hirta appear to exert the anti-asthma effects reported. In the first part of this study, the aqueous, acetone, dichloromethane and hexane extracts of E. hirta were evaluated for their effects on the lysosomal membrane integrity, cell viability and cell number of MRC-5 cell-line using the NR/MTT/CV assay. Hydrocortisone was used as a pharmaceutical control. The differences between the effects of the different extracts were investigated and the effects of the extracts were compared with hydrocortisone. Results obtained showed that hydrocortisone was relatively toxic to the MRC-5 cells whereas all four extracts studied showed very limited cytotoxic effects, with the aqueous extracts generally exhibiting the least effects. In the second part of this study, the effects of the aqueous E. hirta extract on the blood coagulation system and general airway wall microstructure and ultrastructure were investigated using the BALB/c mouse asthma model. Hydrocortisone was also used as a pharmaceutical control. Parameters studied included inflammatory cell population in peripheral blood and their migration into the lung parenchyma; platelet aggregation and fibrin fibre morphology; fibroblast and mucous cell proliferation; alveolar cell numbers, lamellar body formation as well as filopodia formation. The animal weights were continuously being monitored throughout the study. Results from the animal studies showed that the aqueous extract of E. hirta had limited effects on changes in the animal weights and did not cause fragility of blood fibrin fibres nor change the integrity and morphology of the platelets in the mice as seen in those treated with hydrocortisone. E. hirta extracts also significantly reduced the number of active inflammatory cells (especially neutrophils, eosinophils and basophils); restored the histological alterations observed in respiratory structures studied and had diverse, dose-dependent beneficial ultrastructural effects like reduction of smooth muscle hypertrophy, inhibition of macrophages into the airway parenchyma, among others. The final judgment and conclusion of this study was that the aqueous E. hirta extract did not show cytotoxic effects and could be used for the treatment of asthma in the BALB/c mice at doses ranging 25-62.5mg/kg. Further research leading to clinical trials is recommended after testing the potency of equivalent doses of this extract in other animal asthma models.