Patra Jayanta Kumar, Das Gitishree, Baek Kwang-Hyun
School of Biotechnology, Yeungnam University, Gyeongsan, 712-749, Gyeongbuk, Republic of Korea.
Bot Stud. 2015 Dec;56(1):13. doi: 10.1186/s40529-015-0093-7. Epub 2015 May 23.
Identification of natural antibacterial agents from various sources that can act effectively against disease causing foodborne bacteria is one of the major concerns throughout the world. However, the natural antibacterial agents identified to date are primarily effective against Gram positive bacteria, but less effective against Gram negative bacteria. In the present study, Enteromorpha linza L. essential oil (EEO) was evaluated for antibacterial activity against Escherichia coli and Salmonella Typhimurium along with the mode of their antibacterial action.
The chemical composition of EEO revealed high amounts of acids (54.6 %) and alkenes (21.1 %). EEO was effective against both E. coli and S. Typhimurium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of EEO for both pathogens were 12.5 mg/ml and 25.0 mg/mL, respectively. EEO at the MIC acted on the loss in viability of E. coli ATCC 43890, which was used as the model system for evaluation of the antibacterial mode of action of EEO against Gram negative bacteria. Significant increase in relative electrical conductivity and K concentration were recorded with respect to time, indicating the disruption of tested E. coli cells owing to the controlling effect of EEO. Alternation of the morphology of the cell surface, increase in the release of 260 nm absorbing materials and loss of high salt tolerance were observed.
The results suggest that EEO induced a bactericidal effect via structural membrane damage caused by deposition of EEO in the cytosol or through enzymatic degradation of bacterial intracellular enzymes that resulted in cellular lysis. Accordingly, EEO can be used as a strong natural antibacterial agent against Gram negative foodborne pathogens such as E. coli and S. Typhimurium.
从各种来源鉴定出能够有效对抗引起疾病的食源细菌的天然抗菌剂是全世界主要关注的问题之一。然而，迄今为止鉴定出的天然抗菌剂主要对革兰氏阳性菌有效，但对革兰氏阴性菌效果较差。在本研究中，对肠浒苔精油（EEO）针对大肠杆菌和鼠伤寒沙门氏菌的抗菌活性及其抗菌作用方式进行了评估。
EEO的化学成分显示含有大量的酸（54.6%）和烯烃（21.1%）。EEO对大肠杆菌和鼠伤寒沙门氏菌均有效。EEO对两种病原体的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）值分别为12.5mg/ml和25.0mg/mL。MIC浓度的EEO作用于用作评估EEO对革兰氏阴性菌抗菌作用模式的模型系统的大肠杆菌ATCC 43890的活力丧失。随着时间的推移，相对电导率和钾浓度显著增加，表明由于EEO的控制作用，受试大肠杆菌细胞受到破坏。观察到细胞表面形态改变、260nm吸收物质释放增加以及高盐耐受性丧失。
结果表明，EEO通过EEO在细胞质中的沉积导致的结构膜损伤或通过细菌细胞内酶的酶促降解导致细胞裂解，从而诱导杀菌作用。因此，EEO可作为一种强大的天然抗菌剂，对抗革兰氏阴性食源性病原体，如大肠杆菌和鼠伤寒沙门氏菌。
