Ethanol Extract of <I>Jatropha curcas (Euphorbiaceae)</I> Leaves Ameliorates Allergic Airway Inflammatory Responses in Wistar Rats

Abstract

Jatropha curcas (J. curcas), a member of the Euphorbiaceae family, is a tropical medicinal plant that has been used in African Traditional Medicine for the treatment of asthma and related allergic airway diseases. This study investigated the ameliorative effects of Jatropha curcas leaf extract on ovalbumin-induced allergic airway inflammation in Wistar rats. Preliminary phytochemical screening of the extract was carried out using standard procedures, and oral median lethal dose (LD50) was determined using Lorke’s method. Allergic airway inflammation was induced in Wistar rats via ovalbumin sensitization and challenge over 28 days. Rats were divided into six groups: normal control, ovalbumin control, three groups treated with J. curcas extract at 35, 70, and 140 mg/kg, and a positive control receiving prednisolone (10 mg/kg). Post-treatment, bronchoalveolar lavage fluid (BALF) was analyzed for leukocytes and cytokines, and lung tissues were examined histologically. Phytochemical analysis identified flavonoids, alkaloids, terpenes, saponins, glycosides, steroids, and anthraquinones. Acute oral toxicity test revealed an LD50 exceeding 5000 mg/kg, indicating that the extract is relatively safe. Anti-inflammatory activity evaluation showed that J. curcas at 140 mg/kg dose significantly (p ≤ 0.05) reduced eosinophil counts and IL-13 levels, which was comparable to that of prednisolone group. the extract also showed a dose-dependent reduction in IL-4 and IL-5 levels. Histopathological examination revealed protection against alveolar necrosis and tracheal hyperplasia at higher doses. Overall, the extract demonstrated notable anti-inflammatory and airway-protective effects, suggesting its potential as a complementary therapy for allergic airway diseases. Further clinical studies are warranted to confirm these findings.