CYTOTOXIC PRINCIPLES OF SECURINEGA VIROSA : VIROSECURININE AND VIROALLOSECURININE AND RELATED DERIVATIVES

Virosecurinine (1) and viroallosecurinine (2) were isolated as two cytotoxic alkaloids from the leaves of Securinega virosa. A comparison of the cytotoxicity of 1 and several of its derivatives indicates that an α,β- and a γ,δ-unsaturated lactone located in a strained ring system, such as rings -B, -C, and -D of 1, is structurally required for significant cytotoxicity.