Immune-mediated Anti-inflammatory Activity of Root Bark Extracts of Calotropis Procera (Ait) R.Br. In Rodents

Background: The root bark of Calotropis procera has been reported to be a part of herbal remedies for the management of allergic diseases like asthma. However, there is paucity of data on its anti-inflammatory activity in allergic disorders. Objectives: This study is aimed to investigate the immune mediated anti-inflammatory activity of root bark extracts of Calotropis procera in rats. Materials and Methods: Aqueous and methanol root bark extracts of Calotropis Procera were subjected to preliminary phytochemical screening and their oral median lethal doses were estimated in rats. The aqueous and methanol root bark extracts were investigated for anti-allergic activity using carageenan-induced leucocytosis (100 and 200 mg/kg doses) and egg albumin induced passive paw anaphylaxis (250 and 350 mg/kg doses) test in rats. Results: The oral median lethal doses of both extracts were found to be greater than 5000 mg/kg in wistar rats. Both extracts were found to contain alkaloids, flavonoids, tannins, saponins, cardiac glycosides, and triterpenes. Both extracts significantly (p˂0.001) decreased leucocyte count in carrageenan induced leucocytosis test at the dose of 100 and 200 mg/kg, with both aqueous and methanol extracts exhibiting the same level of decrease in leucocyte count. Equally, there was a statistically significant decrease (p<0.05) in paw size at 250 mg/kg and 350 mg/kg in egg albumin-induced passive paw anaphylaxis compared to the peak increase for both standard and test groups, but with the aqueous extract exhibiting a greater level of decrease in paw size than methanol extract. Conclusion: The aqueous and methanol root bark extracts of Calotropis procera possesses Anti-inflammatory activity in in vivo anti-allergic tests on animal models, thus support the folkloric use of the plant in inflammatory and allergic conditions including asthma.