Novel compounds isolated from health food products containing beni-koji (red yeast rice) with adverse event reports

Recently, health hazards, such as kidney damage, have been reported owing to the ingestion of a health food product, so-called “foods with functional claims (FFC)’’, containing beni-koji (red yeast rice). Although not an expected compound in the FFC, the detection of puberulic acid has also been reported. Further investigations of these health food products, such as the identification of other unintended compounds and clarifying the health impacts of puberulic acid, are required. To clarify the causes of these health issues, we investigated the presence of unintended compounds in the FFC containing beni-koji using comprehensive instrumental analyses. Using differential analysis, novel compounds 1 and 2 were detected as unexpected components between the samples with and without adverse event reports. Although limited to the samples available for analyses in this study, both compounds 1 and 2 were detected in all the samples that also contained puberulic acid. Compounds 1 and 2, with molecular formulas of C₂₃H₃₄O₇ and C₂₈H₄₂O₈, respectively, may be lovastatin derivatives. Their structures were confirmed using NMR analyses and are novel natural compounds. For definitive confirmation, we are in the process of synthesizing compounds 1 and 2 from lovastatin. The route of contamination of these compounds are currently under investigation. The findings of this study could be used to address the growing health hazards associated with health food products.

Graphical abstract