Ozone-Mediated Modulation of Green Tea Extract Enhances Bioactive Compounds and Therapeutic Potential Relevant to...

Background: Ozonation is a non-thermal process that can remodel the chemistry and bioactivity of plant extracts. We evaluated whether ozonating green tea extract enhances its phenolic composition and in vitro bioactivity in relation to nutrition and food applications, with potential clinical applications. Methods: Ethanolic green tea extract (GTE) was exposed to ozone (0-7 L/min, 5 h) to yield an ozonated extract (GTOE). Phenolics were quantified by the HPLC. Bioactivities included antimicrobial testing (agar diffusion; MIC/MBC/MFC), antibiofilm formation, time-kill kinetics (0-180 min), bacteria-induced hemolysis in human RBCs, DPPH radical scavenging, pancreatic lipase inhibition, and scratch-wound closure in human fibroblasts. Data from n = 3 independent experiments were analyzed by one-way ANOVA with Tukey's post hoc test (α = 0.05). Results: Ozonation increased gallic acid (3150.92 to 3229.69 µg/g) and ellagic acid (2470.66 to 2789.40 µg/g), while catechin decreased slightly (2634.09 to 2535.09 µg/g). Compared with GTE, GTOE produced larger inhibition zones and lower MIC/MBC/MFC against Candida albicans, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, and Salmonella typhi; Aspergillus niger remained unsusceptible. For example, inhibition zones for S. aureus and K. pneumoniae increased by 2-4 mm and MIC/MBC values were 2-8-fold lower. Candida albicans showed marked sensitivity (MFC 500 to 125 µg/mL). GTOE exhibited superior, dose-dependent antibiofilm activity across all tested strains, reaching up to 97.82% inhibition, (highest for S. aureus and S. typhi, at 75% MBC). GTOE reduced bacterial counts more rapidly than GTE across all tested strains, achieving full eradication within 150 min. Bacteria-induced hemolysis was inhibited by 97% at 75% MIC with GTOE, versus 93-96% with GTE. Antioxidant capacity improved (DPPH IC₅₀ 3.31 vs. 5.54 μg/mL), as did lipase inhibition IC₅₀ 6.06 vs. 17.69 μg/mL). Wound closure at 48 h increased (GTOE 61.1%; GTE 56.8%; control 50.8%). Conclusions: Controlled ozonation of green tea extract remodeled phenolics and consistently enhanced antimicrobial, antibiofilm, antioxidant, potential anti-obesity, and wound-healing activities in vitro. These results support food-grade optimization and safety/by-product profiling, followed by in vivo validation at diet-relevant doses, to enable nutrition, food, and potential clinical applications.