Abstract：
At present, consumers increasingly favored the natural food preservatives with fewer side-effects on health. The green tea catechins and black tea theaflavins attracted considerable interest, and their antibacterial effects were extensively reported in the literature. Epicatechin (EC), a green tea catechin without a gallate moiety, showed no bactericidal activity, whereas the theaflavin (TF), also lacking a gallate moiety, exhibited potent bactericidal activity, and the antibacterial effects of green tea catechins and black tea theaflavins were closely correlated with their abilities to disrupt the bacterial cell membrane. In our present study, the mechanisms of membrane interaction modes and behaviors of TF and EC were explored by molecular dynamics simulations. It was demonstrated that TF exhibited markedly stronger affinity for the POPG bilayer compared to EC. Additionally, the hydrophobic interactions of tropolone/catechol rings with the acyl chain part could significantly contribute to the penetration of TF into the POPG bilayer. It was also found that the resorcinol/pyran rings were the key functional groups in TF for forming hydrogen bonds with the POPG bilayer. We believed that the findings from our current study could offer useful insights to better understand the stronger antibacterial effects of TF compared to EC.
摘要：
目前,消费者越来越青睐对健康副作用较小的天然食品防腐剂。绿茶儿茶素和红茶茶黄素引起了相当大的兴趣，它们的抗菌作用在文献中被广泛报道。表儿茶素(EC)，没有没食子酸酯部分的绿茶儿茶素，显示无杀菌活性，而茶黄素(TF)，也缺乏没食子酸酯部分，表现出有效的杀菌活性，绿茶儿茶素和红茶茶黄素的抗菌作用与其破坏细菌细胞膜的能力密切相关。在我们目前的研究中，通过分子动力学模拟，探讨了TF和EC的膜相互作用模式和行为机制。已证明，与EC相比，TF对POPG双层表现出明显更强的亲和力。此外,托罗酮/儿茶酚环与酰基链部分的疏水相互作用可以显着促进TF渗透到POPG双层中。还发现间苯二酚/吡喃环是TF中与POPG双层形成氢键的关键官能团。我们相信，我们目前的研究结果可以提供有用的见解，以更好地了解TF与EC相比更强的抗菌作用。
