Standardization issues in botanicals: A metabolomic and in silico approach to Monascus purpureus food supplements

A metabolomic strategy was explored to profile 33 Monascus purpureus botanicals, revealing low standardization levels in terms of monacolins and Monascus pigments. A fast and highly accurate screening method was applied by means of UHPLC-TWIMS-QTOF, enabling the monitoring of 36 monacolins and 8 pigments. Evidence confirmed that very different fermentation processes are used for red yeast rice production, resulting in erratic profiles and large variability among samples. Remarkably, minor monacolins represented on average a 37% (range 8–54%) of the sum of monacolins and pigments. Dehydromonacolins and dihydromonacolins were spanning from 7 to 43% with as many as 26 products containing a relative percentage exceeding 20%. Total pigments average ranged between traces and 65%, with a percentage exceeding 20% in 12 occasions. In silico docking results showed that monacolins other than Monacolin K had lower but not negligeable inhibitory potential for 3-hydroxy-3-methylglutaryl coenzyme A reductase for precise structural limitations. Our results confirms that standardization of Monascus purpureus botanicals is dubious and strict quality control must be encouraged. At the same time, they reinforce the opportunity to take advantage of new metabolomic tools to properly describe raw materials or food supplements used in investigations and clinical trials, suggesting extensive phytochemical analysis beyond the mere quantification of Monacolin K.