Chemical and Biological Stability of Thai Traditional Pain Relief Remedy named “Yaa-Thaa-Phra-Sen” Under Forced Degradation and Accelerated Storage Conditions

Abstract

Yaa-Thaa-Phra-Sen (YTPS) is a traditional Thai remedy composed of 13 herbs, with Drypetes roxburghii Wall. as the main ingredient. It has long been used in Thai traditional medicine (TTM) to alleviate pain and inflammation in osteoarthritis. This study aimed to evaluate the stability of YTPS extract under forced degradation and accelerated storage conditions. Forced degradation was performed under thermal, moisture, acid, alkaline, and oxidative conditions. The extract was also stored under accelerated conditions (40 ± 2ºC, 75 ± 5% RH) for 6 months. Stability was assessed by measuring ellagic acid content using high-performance liquid chromatography (HPLC), anti-inflammatory activity via nitric oxide (NO) inhibition, and antioxidant activity via DPPH assay. The results showed that acid hydrolysis and oxidation significantly reduced ellagic acid content, as well as anti-inflammatory and antioxidant activities. In contrast, alkaline hydrolysis increased ellagic acid content. Under accelerated storage conditions, ellagic acid and antioxidant activity remained stable, whereas anti-inflammatory activity declined. The conclusion is crucial to avoid acidic conditions during preparation to preserve the efficacy of the YTPS extract, and the inclusion of an antioxidant agent is recommended to prevent degradation. Both hot and cold preparation methods were found to be effective. Based on accelerated stability data, the extract is estimated to have a tentative shelf life of one year.