Immunosuppressive and hepatoprotective potential of Sarcococca saligna and its biomarker components

Sarcococca saligna methanolic extract, fractions and isolated pure compounds saracocine (1), saracodine (2), pachyximine-A (3) and terminaline (4) were found to possess potent immunosuppressive activities. The fractions and compounds were tested in-vitro for their effects on human T-cell proliferation, and cytokine (IL-2) production. All the fractions, sub-fractions and purified compounds showed significant suppressive effect on IL-2 production in a dose-dependent manner. They also exhibited a suppressive effect on the phytohemagglutinin-stimulated T-cell proliferation. None of the extracts and purified compounds showed any cytotoxicity effects on the 3T3 mice fibroblast cell line. The crude extract, DCM fraction (pH9), DCM fractions (pH7) and one of the steroidal alkaloids (terminaline) were checked in-vivo for their hepato-protective potential against CCl4-induced liver injury. In in-vivo experiments, the basic and neutral DCM fractions and terminaline (4) significantly reduced inflammation in the liver. DCM fraction (pH9), DCM fractions (pH7) and compound 4 reduced the serum enzyme levels (ALT, AST, and ALP) down to control levels despite CCl4 treatment. They also reduced the CCl4-induced damaged area to almost zero as assessed by histopathology. The pale necrotic areas and mixed inflammatory infiltrate which are seen after CCl4 treatment were absent in the cases of basic, neutral fractions and terminaline treatment. These hepato-protective effects were better than the positive control silymarin. Our results suggest the therapeutic effect of S. saligna extract, fractions and bioactive steroidal alkaloids against CCl4-induced liver injury in vivo and their immunosuppressive function in vitro.