Ya-Hok-Sing: bioactive substance components, in vitro toxicity, and a case series

Background: Ya-Hok-Sing is a traditional Thai polyherbal medicine used by Singhanakhon healers, Thailand. This study aimed to provide scientific evidence supporting the traditional use of Ya-Hok-Sing as an anti-fever remedy. Methods: The chemical fingerprinting and in vitro toxicity of Ya-Hok-Sing were investigated using the Liquid Chromatography-Quadrupole time-of-flight-Mass spectrometry (LC-QTOF-MS) method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The clinical efficacy of Ya-Hok-Sing for fever relief was examined using a case series of five patients following treatment from a traditional Thai healer. Results: The mass-spectrometry-total ion chromatogram (MS‑TIC) for Ya-Hok-Sing revealed the presence of thirty-six compounds, including twenty-one phenolics and fifteen organic acids. Ya-Hok-Sing was non-toxic at the highest tested concentration of 80 µg/mL in vero cells and mouse fibroblast cells. The results of the case series indicated that three patients out of five tested positive for COVID-19. The two remaining patients were diagnosed with influenza by a traditional healer. For the first two days, each patient took 90 mL of Ya-Hok-Sing every three hours. Starting on day 3, each patient took Ya-Hok-Sing three times daily (90 mL each) before meals for one week. All patients improved clinically after three to five days and recovered from fever and co-morbidities by six to nine days. Quality of life assessment showed that the patients had better mean quality of life scores after treatment (106.40 ± 7.90), compared to before treatment (62.00 ± 5.34). Conclusion: Our findings supported the folk medicinal properties of Ya-Hok-Sing for the treatment of fever. Keywords: Ya-Hok-Sing, Chemical fingerprinting, Toxicity, Thailand