Comprehensive investigation into the interconversion of C-2 diastereomers of naringin.

Naringin is a flavanone that widely presents on daily diet and traditional medicinal materials. The ratios of naringin C-2 diastereomers are found different in reported samples, thus suspiciously leading to various functions. In this study, we measured the interconversion of C-2 diastereomers intensively with ultimate high-performance liquid chromatography and circular dichroism spectra. We examined the diastereomeric naringins in fresh citrus fruit, Huajuhong decoction pieces, and naringin tablet; evaluated the impact of tablet production procedures in factory; and monitored the rapid racemization in incubation. The results not only confirmed that enzyme, temperature, and pH condition could influence the interconversion but also demonstrated that diverse ratios of diastereomers showed limited influence on metabolic behaviors of naringin in the blood, which consequently cause comparable bioactivities. This study could provide comprehensive understanding of diastereomeric interconversion and provide useful reference for drug development.