Supplementation with aqueous leaf extract of Morinda lucida enhances immunorestoration and upregulates the expression of cytokines and immunostimulatory markers

Abstract

Morinda lucida Benth (Rubiaceae) is a versatile plant used in traditional medicine of many countries for the treatment of a variety of ailments and the claims of efficacy are particularly remarkable in the treatment of infections and immuno-inflammatory disorders. In this study, we investigated the immunostimulatory and immunorestorative properties of the aqueous leaf extract of Morinda lucida (AML) in cultures of murine splenic lymphocytes and in cyclophosphamide-induced immunosupression models, respectively. Administration of AML (100 and 250 mg/kg; per os) in alternate days significantly (P < 0.05) increased specific total IgG, IgG1, and IgG2a responses to ovalbumin by as much as 2-10 fold when compared to untreated controls. In cyclophophamide treated mice, the rate of wound healing, leukopoiesis , and body weight recovery were all enhanced by oral supplementation with AML (100 and 250 mg/kg) in a dose-dependent manner. In vitro cultures of BALB/C splenocytes treated with AML (12.5 and 50 μg/ml) for 24 h resulted in 5-10 fold increase in IFNγ and IL-4 measured by cytokine capture ELISA. Surface expression of immunostimulatory markers, CD69 and CD25, measured flow cytometrically by FACS analyis, were also significantly (P < 0.05) upregulated on splenic T and B cells by as much as 8-20 fold. Taken together, the results of these studies show the potent immunostimulatory and immunorestorative properties of the aqueous leaf extract of Morinda lucida, which may explain some of the beneficial effects of the plant in the treatment of infections and immuno-inflammatory disorders.