1Excellence Research Laboratory on Natural Products, Department of Microbiology, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Thailand.
2Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, Thailand.
Foodborne Pathog Dis. 2019 Aug;16(8):581-589. doi: 10.1089/fpd.2019.2620. Epub 2019 Apr 18.
Consumer concerns toward chemical preservatives have resulted in increased search for healthy green alternative. In this study, the antioxidant activity and antibacterial effects of ethanolic leaf extract against a serious foodborne pathogen, was evaluated. Total phenolic and flavonoid contents of the extract were 11.10 mg garlic acid equivalent/mg extract and 15.05 mg quercetin equivalent/mg extract, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration of the extract was 64-128 μg/mL and 256-512 μg/mL, respectively. Time-kill assay revealed growth inhibitory effects after 4-h treatment of the bacteria with the extract. A reduction of ≈2-3 log colony-forming units per milliliter was observed against the tested food and environmental isolates after challenging the pathogens with the extract at MIC for 6 h. Sub-MICs of the extract significantly inhibited motility and listeriolysin O production up to 80%, with 60% inhibition of biofilm formation ( < 0.05). Antioxidant assay revealed free radical scavenging activity with 50% inhibitory concentration (IC) of 57.07 μg/mL for 2,2-diphenyl-1-picrylhydrazyl and 29.01 μg/mL for ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] assay. Ferric reducing antioxidant power assay further showed a total antioxidant power equivalent to 92.93 μM ascorbic acid equivalent/mg extract. As the extract exhibited profound antilisterial activity and good radical scavenging ability, it might serve as a potential alternative source of biopreservative agent against .
消费者对化学防腐剂的担忧促使人们越来越多地寻找健康的绿色替代品。在这项研究中，评估了乙醇叶提取物对一种严重食源性病原体的抗氧化活性和抗菌作用。提取物的总酚和类黄酮含量分别为 11.10 mg 大蒜酸当量/mg 提取物和 15.05 mg 槲皮素当量/mg 提取物。提取物的最小抑菌浓度（MIC）和最小杀菌浓度分别为 64-128 μg/mL 和 256-512 μg/mL。时间杀伤试验显示，细菌在 4 小时的提取物处理后显示出生长抑制作用。在用提取物在 MIC 下处理 6 小时后，对测试的食源性病原体和环境分离株进行挑战时，观察到每毫升减少约 2-3 个对数菌落形成单位。提取物的亚 MIC 显著抑制运动性和李斯特菌溶血素 O 的产生，高达 80%，生物膜形成抑制率为 60%（ < 0.05）。抗氧化剂测定显示自由基清除活性，2,2-二苯基-1-苦基肼（2,2-diphenyl-1-picrylhydrazyl）的 50%抑制浓度（IC）为 57.07 μg/mL，ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)]的 IC 为 29.01 μg/mL。铁还原抗氧化能力测定进一步显示总抗氧化能力相当于 92.93 μM 抗坏血酸当量/mg 提取物。由于提取物表现出明显的抗李斯特菌活性和良好的自由基清除能力，它可能成为一种潜在的生物防腐剂替代物，用于对抗 。
