Esculetin as bioactive marker: towards a rational scientific approach for the treatment of hyperuricemia using Traditional Chinese Medicine

Abstract

Traditional Chinese Herbal Medicine has been used to prevent and cure disease in China for thousands of years and has gained global interest in recent decades. The Erding formula is a Chinese Pharmacopeia (ChP)-listed herbal preparation used for treating sore throat, carbuncles and boils. Esculetin is a ChP quality control (QC) marker for these indications. A previous study found that a new indication, hyperuricemia, can be added to the Erding formula. Therefore, this study aimed to evaluate whether the traditionally used marker, esculetin, still has bioactivity for hyperuricemia, which is substantially different from the original indications. The study analyzed the quantity of esculetin by high-performance liquid chromatography, assessed the therapeutic effect of esculetin using animal model, and then characterized esculetin and its metabolites in serum via ultra-performance liquid chromatography-quadrupole timeof-flight mass spectrometry. The results showed that the esculetin content in the aqueous Erding extract was 0.26±0.05% (w/w). Both the Erding extract and esculetin significantly reduced uric acid levels. Six metabolites of esculetin were identified in mice serum. This study revealed a rational scientific approach to prove esculetin is a reliable bioactive and QC marker for Erding formula in hyperuricemia treatment which contributed to ensure product quality and therapeutic efficacy.