Quassinoids metabolism

Two major groups of metabolically altered tiiterpenes, the limonoids (tetranortriterpenoids) and the quassinoids (decanortriterpenoids) are derived from euphol (1) (Fig. 25.1) or tirucallol (2) (Fig. 25.2). To date, these compounds are restricted in distribution to the Rutaceae, Meliaceae, Cneora-ceae, Simaroubaceae, and, perhaps, the Burseraceae (Connolly and Hill, 1991), and occur variously in seeds, fruits, and wood of plants of these families. In general, the limonoid and quassinoid content of leaves has not been examined (Taylor, 1983). 

Liou YF, Hall IH, Okano M, Lee KH, Chaney SG (1982) Antitumor agents XLVIII Structure - activity relationships of quassinoids as in vitro protein synthesis inhibitors of P-388 lymphocytic leukemia tumor cell metabolism. J Pharm Sci 71 430-435... 

Studies of microbial transformations of bruceantin (53) led to the isolation of new analogs of this antitumor quassinoid (70). Thus, Streptomyces griseus (ATCC 10137) totally metabolized bruceantin (53) within 19 h, and a preparative scale incubation using bruceantin provided brucein C (51), bruceantin-4, 5 -epoxide and bruceantin-5 -ol. None of the metabolites were as active as bruceantin in the P388 test system (70). 

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