Objective Toxicodendron succedaneum (Vietnamese lacquer tree) and T. vernicifluum (Korean lacquer tree) have attracted scientific interest due to their rich polyphenolic content and therapeutic potential. This study aimed to isolate methyl gallate (MG) from T. succedaneum and quantify MG, gallic acid (GA), and fisetin in both species. Additionally, the antioxidant, anti-inflammatory, and hepatoprotective activities of MG and GA were assessed to explore the pharmacological potential of T. succedaneum as a source of bioactive phenolics. Methods MG was isolated from the bark of T. succedaneum and structurally confirmed via NMR and mass spectrometry. Quantitative analysis of MG, GA, and fisetin in various plant parts of both T. succedaneum and T. vernicifluum were performed using a validated HPLC/PDA method. Antioxidant activity was evaluated using DPPH and MDA assays; anti-inflammatory activity was assessed via nitric oxide (NO) inhibition in LPS-stimulated RAW 264.7 cells; and hepatoprotective effects were examined using an APAP-induced HepG2 cell injury model. Results MG was isolated from T. succedaneum bark with a yield of 0.2% (w/w). Both MG and GA were detected in all tested plant parts, whereas fisetin was confined to the stem, bark, and branch of T. vernicifluum and the stem of T. succedaneum . MG content was highest in the stem of T. succedaneum (5.82 mg/g). MG exhibited stronger lipid peroxidation inhibition than GA in antioxidant assays (corresponding IC 50 values of 40.12 µM and 230.55 µM), while GA was more effective in NO inhibition. Both compounds showed dose-dependent hepatoprotective effects, with MG offering greater efficacy at lower concentrations. At 100 µM, a reversal of protective activity was observed–consistent with the hormesis phenomenon. Conclusion T. succedaneum , traditionally exploited for lacquer but rarely studied for its phytochemicals, was identified as a rich and underutilized source of bioactive phenolics, particularly MG. The compound demonstrated promising antioxidant, anti-inflammatory, and hepatoprotective effects.
Le et al. (Thu,) studied this question.