COUPLING THE CHOLESTEROL-SUPPRESSIVE AND TUMOR-SUPPRESSIVE ACTIONS OFPALM-OIL TO THE IMPACT OF ITS MINOR CONSTITUENTS ON 3-HYDROXY-3-METHYLGLUTARYL COENZYME-A REDUCTASE-ACTIVITY

The impact of palm oil on cardiovascular disease and cancer may be exp lained by the mevalonate-suppressive action of constituent isoprenoid end products of plant secondary metabolism. Assorted monoterpenes, ses quiterpenes, carotenoids and tocotrienols down regulate, post-transcri ptionally, 3-hydroxy-3-methylglutaryl coenzyme A reductase activity th ereby modestly decreasing cholesterol synthesis and concomitantly decr easing LDL cholesterol, The reductase activity in tumor tissues differ s from that of liver in being resistant to sterol feedback regulation, Tumor reductase activity retains sensitivity to the post-transcriptio nal regulation, As a consequence, the isoprenoid-mediated suppression of mevalonate synthesis depletes tumor tissues of two intermediate pro ducts, farnesyl pyrophosphate and geranylgeranyl pyrophosphate, which are incorporated post-translationally into growth control-associated p roteins.