Erding Formula in hyperuricaemia treatment: unfolding traditional Chinese herbal compatibility using modern pharmaceutical approaches.

OBJECTIVES: Traditional Chinese herbal formulas are difficult to be understood because of complex compositions and specific therapeutic principles. To better understand herbal compatibility in Traditional Chinese medicine (TCM), this study was conducted to investigate the effects of a Chinese pharmacopoeia-listed formula, Erding Formula (EF) and its constituent herbs for a new indication, hyperuricaemia. METHODS: A hypoxanthine and potassium oxonate-induced hyperuricemic mouse model, a xylene-induced inflammatory mouse model and an acetic acid-induced pain model were used to test the effects of EF and its constituent herbs. In addition, we investigated whether EF and/or its relevant herbs had an impact on the expression of URAT1 and OAT3 mRNA. KEY FINDINGS: The results showed EF and individual herbs had pharmacological effects on selected targets. Only Viola yedoensis Makino (Viola) lowered uric acid levels, while all four herbs had anti-inflammatory and analgesic effects. The EF may lower the uric acid level through inhibiting the expression of URAT1 mRNA and enhancing the expression of OAT3 mRNA. CONCLUSIONS: These findings provide pharmacological insights into the effects of EF and individual herbs on UA excretion. This study suggests that Viola is the main herb in EF. This study facilitates better understanding of TCM principles and theories using modern pharmaceutical approaches.

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

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 time-of-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.