Abstract The aim of this study was to investigate the extraction of antibacterial substances from Galla chinensis (ASGC) that act against the aquatic pathogen Vibrio harveyi, to identify the chemical composition and explore the mechanism of action. The optimal extraction process was as follows: anhydrous methanol, liquid/material ratio (mL/g) 26:1, extraction temperature 98 °C and extraction time 157 min. The diameter of the inhibition zones (21.31 ± 0.51 mm) under the optimal conditions agreed with the predicted value by experimental rechecking. The yield of ASGC was 39.39% ± 0.69%, and two compounds including gallic acid (GA) and penta-O-galloyl-β-d-glucose (5GG) were identified in ASGC. The minimal inhibitory concentration (MIC) values of ASGC and GA were 0.50 and 0.25 mg/mL, respectively. Meanwhile, 5GG and other chemical constituents did not exert antibacterial activities against V. harveyi (MICs > 1 mg/mL). Further investigation of the mechanisms of action of ASGC and GA against V. harveyi revealed their strong destructive effects on the growth of bacterial cells, the integrity and permeability of the cell membrane, and morphological alterations. The report provides a favorable prospect of GA as a potential control agent against V. harveyi in aquaculture.

中文翻译：

---

五倍子对哈氏弧菌抗菌物质的提取、鉴定及作用机制

摘要 本研究旨在研究从五倍子中提取对水生病原体哈氏弧菌起作用的抗菌物质，鉴定其化学成分并探讨其作用机制。最佳提取工艺为：无水甲醇，液料比（mL/g）26:1，提取温度98℃，提取时间157 min。最佳条件下抑菌圈直径(21.31±0.51 mm)与实验复核预测值一致。ASGC的产率为39.39%±0.69%，在ASGC中鉴定出没食子酸(GA)和五-O-没食子酰-β-d-葡萄糖(5GG)两种化合物。ASGC 和 GA 的最小抑菌浓度 (MIC) 值分别为 0.50 和 0.25 mg/mL。同时，5GG 和其他化学成分对哈维伊弧菌（MIC > 1 mg/mL）没有抗菌活性。进一步研究 ASGC 和 GA 对 V. harveyi 的作用机制表明它们对细菌细胞的生长、细胞膜的完整性和渗透性以及形态学改变具有强烈的破坏作用。该报告为 GA 作为水产养殖中哈维伊氏菌的潜在控制剂提供了良好的前景。