Quassinoids from seeds of Brucea Javanica and their anticomplement activities.

An investigation on seeds of Brucea javanica led to the acquisition of a new quassinoid, 20-hydroxyyadanzigan (1), along with five known quassinoids (2–6). The structure of the new compound was elucidated on the basis of extensive spectral analysis. All of the compounds were assayed for their anticomplement activities through classical and alternative pathways. Compounds 1–6 exhibited potent anticomplement activity with CH₅₀ and AP₅₀ values of 0.032–0.075 mg/mL and 0.061–0.118 mg/mL, respectively. Moreover, the structure-activity relationships of these compounds are discussed. [ABSTRACT FROM AUTHOR]