Characterization of Red Yeast Rice Products and Raw Materials Using Accurate-Mass Q-TOF LC/MS and Principal Component Analysis Authors

Rice fermented with the mold Monascus purpureus, also known as the red yeast rice (RYR) used in traditional Chinese medicine, contains pharmacologically important monacolins. The prescription statin, lovastatin, is identical to monacolin K, and there is a suspicion of spiking RYR products with lovastatin. Profiling authentic and raw RYR samples has the potential to distinguish the spiked from natural product. Monascus purpureus is also known to produce the mycotoxin citrinin. Sudan red G, considered possibly genotoxic or carcinogenic by the European Food Safety Authority (EFSA), is a RYR adulterant. Pigments produced by Monascus spp. are used as coloring agents. To address regulatory requirements, and assess product and raw material quality, origin, and safety, a robust method for characterizing and quantitating monacolins, pigments, and contaminants such as citrinin is needed. This application note presents a method that uses the Agilent Accurate-Mass Q-TOF LC/MS system and Agilent MassHunter Workstation software with principal component analysis (PCA) to characterize three authentic (AU) RYR samples, 31 RYR raw materials (CR), and 14 dietary supplements (DS). Quantitation was performed using UHPLC DAD. The method uncovered notable variation among RYR samples and raw materials. High mass accuracy Q-TOF LC/MS data enabled determination of compound identities, including identities of isobaric compounds. PCA showed that monacolin and pigment type could be used to classify RYR samples to determine the authenticity and quality of other RYR samples.