Syk - GTP RAC-1 mediated immune-stimulatory effect of Cuscuta epithymum, Ipomoea batata and Euphorbia hirta plant extracts.

Polymorphonuclear neutrophils (PMNn) are the pivotal mediators of phagocytosis. In addition to neutropenia, impaired neutrophilic function is associated with pathological conditions and immuno-deficiencies. Henceforth, Immuno-stimulatory strategies targeting neutrophilic function are indeed powerful tools in combating obstinate infections. In appreciation towards the usefulness of herbal medicines in therapeutic scenario, the present study was carried out to analyse the immuno-stimulatory effect of Cuscuta epithymum, Ipomoea batata and Euphorbia hirta using in-vitro and in-vivo rodent experimental models. Throughout the experimentation, phagocytosis was studied and expressed as phagocytotic index and percentage phagocytosis. Different extracts of these plants were initially screened for their potency to induce phagocytosis in PMNn and the methanolic fractions, which are effective, were considered for further experimentation.The phagocytosis stimulation by the methanolic extracts was compared with the standard Granulocyte Macrophage - Colony Stimulating Factor (GM-CSF) at a dose of 65ng/ml. Immunoblotting analysis shown that the methanolic extracts induce the phosphorylation of Syk which in turn phosphorylates GDP-RAC-1, hinting the possible mechanism of action. Following these in vitro investigations, the potency of methanolic extracts was assessed using rat model by performing carbon clearance assay, Delayed Type Hypersensitivity and antibody titre.The phosphorylation status of Syk and GDP-RAC-1 was also assessed in the edematous fluid collected from the right hind paw. In vivo findings were in agreement with the in vitro findings by presenting an improved immune response and increased phosphorylation of Syk and GDP-RAC-1. Conclusively, this study provides the initial insights into the therapeutic implications of the tropical plants in inducing phagocytosis.