The emergence of drug-resistant bacteria has impacted the outcome of current therapeutics as a threat to global healthcare; novel medicines are urgently needed. Thirteen medicinal plants were collected in Northeastern Thailand, and their crude ethanolic extracts were evaluated for antibacterial activities against Staphylococcus aureus ATCC25923 and Escherichia coli ATCC25922 using the broth micro-dilution method. Piper betle leaf ethanolic extract showed optimal activity against both representative bacterial strains. Activity was also observed against clinical isolates of methicillin-resistant S. aureus (MRSA) and E. coli, with minimal inhibitory concentration (MIC) ranging from 0.31 mg/mL to 2.5 mg/mL and minimal bactericidal concentration (MBC) ranging from 0.62 mg/mL to 2.5 mg/mL. A time-kill study revealed that the extract activity was time- and dose-dependent, and also bactericidal on the tested bacteria. P. betle extract inhibited biofilm formation and promoted biofilm eradication in both S. aureus and E. coli. 4-Allyl-1,2-diacetoxybenzene and eugenol were identified as the most abundant compounds in the extract and may play major roles in the anti-bacterial and anti-biofilm activity. Results suggest that ethanolic P. betle leaf extract shows promise as an alternative method for the prevention of bacterial diseases.

中文翻译：

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泰国植物提取物对病原菌的抗菌和抗生物膜活性的功效

耐药细菌的出现影响了当前疗法的结果，成为对全球医疗保健的威胁；迫切需要新药。在泰国东北部收集了 13 种药用植物，并使用肉汤微量稀释法评估了其粗乙醇提取物对金黄色葡萄球菌ATCC25923 和大肠杆菌ATCC25922 的抗菌活性。蒺藜叶乙醇提取物对两种代表性细菌菌株均表现出最佳活性。还观察到对耐甲氧西林金黄色葡萄球菌(MRSA) 和大肠杆菌的临床分离株的活性，最小抑菌浓度 (MIC) 范围为 0.31 mg/mL 至 2.5 mg/mL，最小杀菌浓度 (MBC) 范围为 0.62 mg/mL 至 2.5 mg/mL。一项时间杀灭研究表明，提取物的活性与时间和剂量有关，而且对测试的细菌也具有杀菌作用。P. betle提取物抑制了金黄色葡萄球菌和大肠杆菌中生物膜的形成并促进了生物膜的根除。4-Allyl-1,2-diacetoxybenzo 和丁香酚被确定为提取物中最丰富的化合物，可能在抗菌和抗生物膜活性中起主要作用。结果表明，乙醇化的P. betle叶提取物有望作为预防细菌疾病的替代方法。