Fungus monascus-fermented red yeast rice (Ryr): Natural therapeutic statin source or mycotoxin?

Abstract

The kingdom fungi, including the genus Monascus, is a trove of potential pharmaceuticals. This mold Monascus holds paradoxical stature in the realm of healthcare. On one hand, it has been an ubiquitous ingredient of Oriental medication such as Traditional Chinese Medicine (TCM), since ages. Monascus-fermented product red yeast rice (RYR) is being used to ameliorate atherosclerosis, cancer, diabetes, bone ailments, and a gamut of other inflammations. On the other hand, it elaborates mycotoxins such as citrinin, which poses nephrotoxicity, hepatotoxicity, and teratogenicity risks. Also, the threat of the adverse interaction of RYR with chemotherapeutic antihypertensive drugs and the immunosuppressive effects loom over. With the unprecedented escalation in the instances of cardiovascular diseases, and the cognizance of side effects of the conventional statins, which includes myalgia, myositis, hepatic, and renal toxicities, the interest in the Monascus-fermented product RYR is growing. The advent in analytical techniques has characterized RYR to contain polyketides, unsaturated fatty acids, sterols, pigments, and statins. Monacolin K, which shares configurational similarity with commercial cholesterol-lowering drug lovastatin, has drawn worldwide attention. In vitro, in vivo, and clinical cohort studies have traced the biological mechanism of monacolin K to the crosstalk with human endogenous antioxidant coenzyme Q10 and the inhibition of HMG-CoA reductase, a crucial enzyme of the mevalonate pathway. As the purification of the statins from the hazardous mycotoxins of RYR, and dosage standardization, might provide with a natural source of antilipemic nutraceutical, this aspect holds relevance for exploration.