This invention provides a compound comprising a triterpenoidal saponin, triterpenoid, triterpenoidal compound or sapongenin, comprising at least two side groups selected from the group consisting of: angeloyl groups, tigloyl groups and senecioyl groups, wherein the side groups are attached to carbon 21, 22 or/and 28 of triterpenoidal saponin, triterpenoid, triterpenoidal compound or sapongenin backbone. This invention provides a composition for inhibiting tumor cell growth, comprising an appropriate amount of a triterpenoidal saponin, triterpenoid, triterpenoidal compound or sapongenin, wherein the triterpenoidal saponin, triterpenoid, triterpenoidal compound or sapongenin comprises any two side groups selected from the group consisting of: angeloyl groups, tigloyl groups and senecioyl groups, wherein the side groups are attached to carbon 21, 22 or/and 28 of triterpenoidal saponin, triterpenoid, triterpenoidal compound or sapongenin backbone.