Abstract: Cucurbitacin B (CUB) is a major active principle contained in the calyx melo of Cucumis melo L. The immunopotentiating effects of CuB (im, qd×5) were studied.At lower doses, CuB increased the number of peripheral blood T lymphocytes (0.1 mg/kg), the rate of PHA-induced lymphocyte transformation (0.2 mg/kg), the number of plaque forming cells(PFC)of the spleen(0.2 mg/kg) and the level of serum hemolysin (0.4 mg/kg). The phagocytosis of macrophages and the clearance rate of charcoal particles were enhanced only by a large dose(0.8 mg/kg). The results indicate that CuB can potentiate both cellular and humoral immune function.

Key words: Cucurbitacin B, Macrophage, Hemolysin, Plaque forming cell, Lymphocyte transformation, T lymphocyte