Development of a new highly standardized and granulated extract from Monascus purpureus with a high content of monacolin K and KA and free of inactive secondary monacolins and citrinin

Abstract

Monacolins, well-known natural statins obtained from rice fermentation with Monascus purpureus (red yeast), are a class of fungal secondary metabolites able to inhibit HMG-CoA reductase. Interest in using fermented products as natural sources of monacolins, instead of chemically synthesized statins, has increased enormously in recent years mainly because these substances are perceived as ‘natural’. This perception has also increased the demand for them. In this study we first analyzed the composition of several Chinese red yeast-fermented dried extracts commonly available on the market. Fifht percent of them (16 out of 32) did result to be likely adulterated products whilst the other 50% did not. Anyway, the not adulterated products did show 1) high variability in terms monacolin K and KA (considered to be the active monacolins), 2) relevant content in terms of inactive, or poorly active, secondary monacolins, 3) detectable content in terms of citrinin, a nephrotoxic compound and secondary metabolite yealded by fermentation process and 4) a total titre, expressed as monacolin K, correspondent instead to the sum of all monacolins present in the extract. We have therefore developed a method for purifying not adulterated red yeast fermented products in order to produce a highly purified, standardized extract (MonaKoPure-K20) characterized by a constant, high content of monacolin K+KA (≥20%), no detectable citrinin (<50 ppb) and very few secondary monacolins, where the global titre, expressed as monacolin K, exactly corresponds to the combined content of the two monacolins K and KA.