BackgroundMedicinal plants have long been used as dietary supplements to reduce the risk of chronic diseases, inflammation, cancer, and metabolic syndromes. Traditional remedies possess therapeutic properties, making them promising candidates for further investigation and potential pharmaceutical development. Aim of the studyThis study aimed to evaluate the efficacy of Belog Plus (BP), a polyherbal product containing five Thai medicinal plants: Citrus aurantifolia, Cannabis sativa, Tiliacora triandra, Alpinia galanga, and Piper nigrum, combined with safflower seed oil. This study focused on quantifying the total phenolic content (TPC) and total flavonoid content (TFC), and identifying key herbal biomarkers that contribute to its therapeutic properties. In addition to assessing the antioxidant and anti-inflammatory potential of the plant extracts, the study explored the molecular mechanisms underlying their anti-inflammatory activity, offering a comprehensive understanding of BP's efficacy. MethodsThe ethanolic extract of BP and its components were assessed for antioxidant potential using DPPH, FRAP, and H2O2 induced oxidative stress. The anti-inflammatory activity was evaluated using the Griess reaction assay, and the mechanisms were explored through mRNA and protein expression analysis. The TPC and TFC were measured using the Folin–Ciocalteu (F–C) assay and the aluminium chloride colorimetric assay, respectively, while herbal biomarkers were identified using LC-MS/MS analysis. ResultsThe results revealed that the ethanolic extract of BP (6.25-100 µg/ml) exhibited a potent anti-inflammatory effect through nitric oxide inhibition (IC50 24.4 μg/ml) and significantly reducing the expression of inflammatory genes iNOS, COX-2, IL-6, and TNF-α. Additionally, it significantly reduced the expression of inflammatory proteins iNOS and COX-2 at concentrations of 6.25-25 µg/ml. Among the individual components, C. aurantifolia, A. galanga, and P. nigrum showed potent anti-inflammatory effects with IC50 values of 35.7, 6.5, and 23.3 μg/ml, respectively. The TPC and TFC results demonstrated significant levels of phenolic (80.6 µg GAE/mg) and flavonoid (47.4 µg catechin/mg) compounds. Additionally, the LC-MS/MS analysis identified a variety of bioactive compounds known for their anti-inflammatory properties. ConclusionThese findings support BP's potential use as a dietary supplement to mitigate the risk of chronic inflammatory diseases, with its ethanolic extract containing bioactive phenolic and flavonoid compounds that significantly suppress iNOS and COX-2 protein expressions.