Black tea ( Camellia sinensis ) extract as an immunomodulator against immunocompetent and immunodeficient experimental rodents

Aim of the study was to evaluate the immunomodulatory activity of black tea extract (BTE) through immunocompetent and immunodeficient rodents. Black tea (Camellia sinensis) leaves (Assam, CTC, India) were collected commercially from authenticated tea supplier. Black tea extract (BTE) was prepared freshly with MilliQ water and expressed in terms of dry weight. BTE (250 & 500 mg/kg, p.o) was treated in male albino mice for 7, 15, 45 days. BTE induced changes were observed through hematological profile, immunopotentiating cells (peritoneal macrophage, spleenic and thymus lymphocyte, lung macrophage count), carbon clearance assay, chemotaxis of leucocyte, cellular response in spleenectomised mice, adjuvant effects, humoral and cellular response in immunodeficient mice (UV, cyclosporine, cyclophosphamide), immunoprophylactic effects (in E.coli induced peritonitis and S. aureus induced sepsis in male albino mice). BTE significantly increased blood leucocyte, lymphocyte count at day 15. BTE significantly increased peritoneal macrophages, spleen and thymic lymphocytes count and lung macrophages count. BTE induced high phagocytic activity (>1.5) observed through carbon clearance assay. In in vitro studies, BTE did not altered leucocyte chemotaxis. In spleenectomised mice, BTE significantly increased the blood lymphocyte, peritoneal macrophage, spleenic and thymic lymphocyte and lung macrophage count. The anti-SRBC hemagglutination titre was increased by BTE. BTE significantly increased the anti-SRBC hemagglutination titre, blood leucocytes and lymphocytes, peritoneal macrophage, thymic and spleenic lymphocycte count in UV, cyclosporine, cyclophosphamide induced immunodeficient mice. BTE showed significant protection against E. coli induced peritonitis and S. aureus induced sepsis in mice. It may be concluded that BTE possess significant immunomodulatory activity through cellular and humoral immune response in immunocompetent and immunodeficient animal models.