Studies on immunomodulatory activity of Withania somnifera (Ashwagandha) extracts in experimental immune inflammation

Abstract

The immunomodulatory activities of an Indian Ayurvedic medicinal preparation, i.e. extracts from Ashwagandha, Withania somnifera (L.) Dunal (Solanaceae), namely WST and WS2, were studied in mice for immune inflammation: active paw anaphylaxis and delayed type hypersensitivity (DTH). Immunomodulatory effect was assessed in If IgE-mediated anaphylaxis as reduction of ovalbumin-induced paw edema, in animals treated with WS2 at doses of 150 and 300 mg/kg, and the results were compared with the standard drug disodium chromoglycate. In the DTH model, the modulatory effect was assessed as potentiation or suppression of the reaction, revealing an increase or decrease in mean foot pad thickness, respectively. Potentiation of the DTH reaction was observed in animals treated with cyclophosphamide at a dose of 20 mg/kg, WST at a dose of 1000 mg/kg and WS2 at a dose of 300 mg/kg. On the other hand, cyclophosphamide-induced potentiation of DTH reaction was suppressed in animals treated with WST and WS2. A significant increase in white blood cell counts and platelet counts was observed in animals treated with WST. A protective effect in cyclophosphamide-induced myelosuppression was observed in animals treated with WST and WS2, revealing a significant increase in white blood cell counts and platelet counts. Cyclophosphamide-induced immunosuppression was counteracted by treatment with WS2, revealing significant increase in hemagglutinating antibody responses and hemolytic antibody responses towards sheep red blood cells.