University of Münster, Institute of Pharmaceutical Biology and Phytochemistry, Corrensstraße 48, D-48149 Münster, Germany.
University of Münster, Institute of Pharmaceutical Biology and Phytochemistry, Corrensstraße 48, D-48149 Münster, Germany.
Fitoterapia. 2019 Nov;139:104387. doi: 10.1016/j.fitote.2019.104387. Epub 2019 Nov 1.
Aqueous and acetone extracts of O. stamineus leaves reduce the adhesion of uropathogenic E. coli (UPEC, strain UTI89) to T24 bladder cells significantly (IC ~ 524 mg/mL, resp. 40 μg/mL). The acteonic extract had no cytotoxic effects against UPEC in concentrations that inhibited the bacterial adhesion. The extract significantly reduced the gene expression of fimH, fimC, fimD, csgA and focG, which are strongly involved in the formation of bacterial adhesins. The antiadhesive effect was due to the presence of polymethoxylated flavones, enriched in the acetonic extract. Five flavones have been isolated by fast centrifugal partition chromatography, followed by preparative HPLC. Eupatorin, ladanein, salvigenin, sinensetin, 5,6,7,4'-tetramethoxyflavone and 5-hydroxy-6,7,3',4'-tetramethoxyflavone were identified as the main polymethoxylated flavones. With the exception of eupatorin, all of these flavones reduced the bacterial adhesion in a concentration depending manner, indicating that B-ring hydroxylation and methoxylation seems to have a major impact on the antiadhesive activity. In addition, this was confirmed by investigation of the flavones chrysoeriol and diosmetin, which had only very weak antiadhesive activity. From these data, Orthosiphon extracts can be assessed to have a pronounced antiadhesive activity against UPEC, based on a variety of polymethoxylated flavones.
糯米条叶的水提物和丙酮提物显著降低了尿路致病性大肠杆菌（UPEC，UTI89 株）对 T24 膀胱细胞的黏附作用（IC 50 分别为 24mg/mL 和 40μg/mL）。在抑制细菌黏附的浓度下，丙酮提取物对 UPEC 没有细胞毒性作用。该提取物显著降低了 fimH、fimC、fimD、csgA 和 focG 的基因表达，这些基因在细菌黏附素的形成中起着重要作用。这种抗黏附作用是由于存在于丙酮提取物中的多甲氧基黄酮。通过快速离心分配色谱法分离出 5 种黄酮类化合物，然后通过制备 HPLC 进行分离。艾杜素、劳丹素、圣草素、橙皮素、5,6,7,4'-四甲氧基黄酮和 5-羟基-6,7,3',4'-四甲氧基黄酮被鉴定为主要的多甲氧基黄酮。除了艾杜素外，所有这些黄酮类化合物都以浓度依赖的方式降低了细菌的黏附作用，这表明 B 环的羟化和甲氧基化似乎对其抗黏附活性有重大影响。此外，通过对黄酮类化合物 chrysoeriol 和 diosmetin 的研究也证实了这一点，这两种黄酮类化合物只有非常弱的抗黏附活性。基于多种多甲氧基黄酮，糯米条提取物可被评估为对 UPEC 具有显著的抗黏附活性。
