Comparative Chemical Profiling and Monacolins Quantification in Red Yeast Rice Dietary Supplements by 1H-NMR and UHPLC-DAD-MS

Abstract

Red yeast rice dietary supplements (RYR DS) are largely sold in Western countries for their cholesterol-lowering/regulating effect due to monacolins, mainly monacolin K (MK), which is, in fact, lovastatin, the first statin drug on the market. 1H-NMR was used as an easy, rapid and accurate method to establish the chemical profiles of 31 RYR DS and to quantify their monacolin contents. Among all the 1H resonances of the monacolins found in RYR, only those of the ethylenic protons of the hexahydronaphthalenic ring at 5.84 and 5.56 ppm are suitable for quantification because they show no overlap with the matrix signals. The total content in monacolins per capsule or tablet determined in 28 DS (the content in 3 DS being below the limit of quantification of the method, ≈ 0.25 mg per unit dose) was close to that measured by UHPLC, as shown by the good linear correlation between the two sets of values (slope 1.00, y-intercept 0.113, r2 0.986). Thirteen of the 31 RYR DS analyzed (i.e., 42%) did not provide label information on the concentration of monacolins and only nine of the 18 formulations with an indication (i.e., 50%) actually contained the declared amount of monacolins.

Analysis of Monacolins and Berberine in Food Supplements for Lipid Control: An Overview of Products Sold on the Italian Market

“…Furthermore, the lack of a strict control by food and drug regulatory organs can lead to the marketing of products that, especially in the case of herbal nutraceuticals, might have been scarcely characterized in terms of their contents of potential bioactive (and potentially harmful) components [26]. As already highlighted by other authors, these issues frequently occur for food supplements with lipid-reducing properties, such as those containing RYR and BBR as the main active ingredients [17,18]. Commercial RYR powders and extracts often present scarce standardization of MK and other potentially bioactive monacolins, whose bioactivity and safety have not been well-established yet [27].…”

“…Furthermore, natural extracts often lack standardization of the main bioactive compounds, and this leads to a large variability of their amounts per serving, which could cause a lack of efficacy of the dietary supplements or, even worse, to unpredictable side effects [12]. Regarding nutraceuticals with lipid-lowering activity, articles published in the last 10 years have confirmed the heterogeneity of the products available on the market and the lack of standardization of the bioactive ingredients, showing frequent discrepancies between the amounts of bioactives reported by the manufacturers and those detected by the analysis of the same products [13][14][15][16][17].…”

“…Since, to the best of our knowledge, analyses of the content of monacolins and BBR in marketed dietary supplements for lipid control have been conducted only for products available in the U.S. [14,16,18], China [13,15], and France [17], in this work we aimed at recollecting data about dietary supplements available on the Italian market by determining the content of MK in RYR-containing dietary supplements, as well as the content of BBR in products containing this alkaloid as main lipid-lowering agent, both as a pure compound or as constituent of natural extracts. Considering the previously published reports on RYR and BBR supplements showing high variability in the amounts of MK and BBR among different product brands, we expected to observe a dose heterogeneity also in products available on the Italian market.…”

Perspectives on Functional Red Mold Rice: Functional Ingredients, Production, and Application

“…At least 84 MLs have been identified, though not all of the MLs have been studied . MLs, for instance, monacolin L, monacolin J, dihydromonacolin L, monacolin X, and compactin, etc., in both the lactone and acid forms have attracted more attention, owing to their high contents in FRMR and their well-known beneficial bioactivities (Endo and Hasumi, 1985;Endo, 1985a,b;Endo et al, 1986;Dhale et al, 2007a,b;Zhu et al, 2012;Hachem et al, 2020). With the progress in research on these compounds, more and more MLs have been isolated and characterized.…”

Food and Drug Analysis

“…All these new analytical methods accelerate the research and make the potential targets available in the near future. Hachem et al [17] reported an easy, rapid and accurate 1 H-NMR analytical method to establish the chemical profiles of red yeast rice dietary supplements and to quantify their monacolin contents. The total content of monacolin was close to that measured by UHPLC, as shown by the good linear correlation between the two sets of values.…”