Development of a quick neutralization therapy for the diseases caused by bacterial toxins

本研究对霍乱弧菌的霍乱毒素(CT)、肠出血性大肠杆菌的Vero毒素(VT)和肉毒杆菌的肉毒杆菌毒素(Bt)的活性成分进行了化学合成鉴定和验证。Kampo制剂Dio-kanzo-to抑制CT活性(即ADP-核糖化、中国仓鼠卵巢细胞伸长)；在daio-kanzo-to中，Dio(大黄)负责这一作用。大黄提取物中的几种有效成分中，大黄没食子酸单宁(RG-单宁)是最有效的，它具有多没食子酸酯结构。为了确定活性成分，合成了类似于RG-单宁的没食子酸酯类似物。这些没食子酸酯化合物抑制所有的CT活性，包括ADP-核糖化，中国仓鼠卵巢细胞的伸长，以及重要的回肠回肠积液。在苹果多酚Pur…中也发现了类似的抑制CT的作用从含有高分子量儿茶素的啤酒花苞片中提纯的多酚(HBT)在体外和体内均能抑制VT活性，且呈浓度依赖关系。几种尚未纯化的植物多酚在动物实验中对Bt有抑制作用。幽门螺杆菌的空泡毒素(VacA)是幽门螺杆菌重要的毒力因子之一，与幽门螺杆菌引起的胃炎和溃疡有关。我们在此报告了几种天然多酚在体外和体内对VacA活性的抑制。其中，啤酒花苞单宁(HBT)的抑制活性最强。HBT以浓度依赖的方式抑制VacA与其受体RPTPA和RPTPB的结合，抑制其摄取，并抑制敏感细胞的空泡化。此外，VacA与HBT联合经口给药，48h可减轻VacA引起的胃损伤，HBT与VacA直接相互作用形成复合体。综上所述，这些观察结果表明，HBT可以抑制幽门螺杆菌VacA引起的炎症和溃疡的发展，提示HBT可能是一种新型的预防VacA引起的胃溃疡和炎症的药物。因此，包括水果多酚在内的几种天然多酚可能是口服补液液和中和治疗这些细菌毒素引起的疾病的有效辅助治疗。

Our studies were undertaken to identify and verify by chemical synthesis the active components that inhibited cholera toxin(CT) of Vibrio cholerae, vero toxin(VT) of enterohaemorragic Escherichia coli and botulinum toxin(BT) of Clostridium botulinum, the virulence factors secreted by these bacteria. The Kampo formulation, Dio-kanzo-to, inhibited CT activities (i.e., ADP-ribosylation, Chinese hamster ovary cell elongation) ; in Daio-kanzo-to, Dio(Rhei rhizoma) was responsible for this effect. Among several components purified from Dio extract, rhubarb galloyl-tannin(RG-tannin), a compound characterized by a polygallate structure, was the most effective. To define the active component, gallate analogues similar to RG-tannin were synthesized. These gallate compounds inhibited all CT activities including ADP-ribosylation, elongation of Chinese hamster ovary cells, and importantly, fluid accumulation in ileal loops. The similar inhibitory effect on CT was also found in apple polyphenols pur … More ified from immature apples.The polyphenols (HBT) purified from hop bract containing high molecular weight of polymerized catechin, inhibited VT activities in a concentration-dependent manner in vitro and in vivo. And several plant polyphenols which were not be purified yet inhibited BT in animal studies. Vacuolating cytotoxin, (VacA) of H.pylori is one of the important virulence factors and is responsible for H.pylori-induced gastritis and ulcer. We report here that several natural-occurring polyphenols inhibited VacA activity in vitro and in vivo. Especially, hop bract tannin(HBT) had the strongest inhibitory activity among the other polyphenols investigated. In a concentration-dependent manner HBT inhibited VacA binding to its receptors, RPTPa and RPTPb, its uptake, and vacuolation in susceptible cells. In addition, oral administration of VacA with HBT to mice, reduced VacA-induced gastric damage at 48 h. HBT and VacA interacted directly and formed a complex. Taken together, these observations indicate that HBT may suppress the development of inflammation and ulceration by H.pylori VacA, suggesting that HBT may be useful as a new type of agent for the prevention of gastric ulcer and inflammation caused by VacA.Thus, several natural-occurring polyphenols including fruit polyphenols might be effective adjunctive therapy with oral rehydration solution and neutralization therapy forthe diseases caused by these bacterial toxins Less