Attallah Nashwah G M, Al-Fakhrany Omnia Momtaz, Elekhnawy Engy, Hussein Ismail A, Shaldam Moataz A, Altwaijry Najla, Alqahtani Moneerah J, Negm Walaa A
Department of Pharmaceutical Science, College of Pharmacy, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt.
Antibiotics (Basel). 2022 Jul 24;11(8):993. doi: 10.3390/antibiotics11080993.
Enterococcus species possess many virulence factors that have an essential role in exacerbating the infections caused by them. The current study aimed to evaluate the effect of the secondary metabolites ginkgetin (GINK) and sotetsuflavone (SOTE), isolated from Cycas media R. Br dichloromethane fraction, on Enterococcus faecalis (E. faecalis) isolates for the first time. The antibacterial and antivirulence activities of the isolated compounds were investigated using docking studies and in vitro by determination of the minimum inhibitory concentrations (MICs). Additionally, flow cytometry and scanning electron microscope (SEM) were utilized to assess the effect of SOTE on the tested bacteria. Moreover, crystal violet assay and qRT-PCR were used to test the effect of SOTE on the biofilm-forming ability of E. faecalis isolates. In addition, a systemic infection model was utilized in vivo to investigate the antibacterial activity of SOTE. We found that both GINK and SOTE showed a good affinity for the five proteins enrolled in the virulence of E. faecalis, with SOTE being the highest, suggesting the possible mechanisms for the antivirulence activity of both ligands. In addition, SOTE exhibited a higher antibacterial activity than GINK, as the values of the MICs of SOTE were lower than those of GINK. Thus, we performed the in vitro and in vivo assays on SOTE. However, they did not exhibit any significant variations (p > 0.05) in the membrane depolarization of E. faecalis isolates. Moreover, as evaluated by SEM, SOTE caused distortion and deformation in the treated cells. Regarding its impact on the biofilm formation, it inhibited the biofilm-forming ability of the tested isolates, as determined by crystal violet assay and qRT-PCR. The in vivo experiment revealed that SOTE resulted in a reduction of the inflammation of the liver and spleen with an increase in the survival rate. SOTE also improved the liver-function tests and decreased tumor necrosis factor-alpha using immunostaining and the inflammation markers, interleukins (IL-1β and IL-6), using ELISA. Thus, we can conclude that SOTE could be a promising compound that should be investigated in future preclinical and clinical studies.
肠球菌属拥有许多毒力因子，这些毒力因子在加剧由它们引起的感染方面起着至关重要的作用。本研究旨在首次评估从苏铁中二氯甲烷馏分中分离出的次生代谢产物银杏素（GINK）和苏铁黄酮（SOTE）对粪肠球菌（E. faecalis）分离株的影响。通过对接研究和体外测定最低抑菌浓度（MICs）来研究分离化合物的抗菌和抗毒力活性。此外，利用流式细胞术和扫描电子显微镜（SEM）评估SOTE对受试细菌的影响。而且，采用结晶紫测定法和qRT-PCR来检测SOTE对粪肠球菌分离株生物膜形成能力的影响。另外，在体内利用全身感染模型来研究SOTE的抗菌活性。我们发现GINK和SOTE对参与粪肠球菌毒力的五种蛋白质都表现出良好的亲和力，其中SOTE的亲和力最高，这提示了两种配体抗毒力活性的可能机制。此外，SOTE表现出比GINK更高的抗菌活性，因为SOTE的MIC值低于GINK。因此，我们对SOTE进行了体外和体内试验。然而，它们在粪肠球菌分离株的膜去极化方面没有表现出任何显著差异（p > 0.05）。而且，通过SEM评估，SOTE导致处理后的细胞出现扭曲和变形。关于其对生物膜形成的影响，通过结晶紫测定法和qRT-PCR确定，它抑制了受试分离株的生物膜形成能力。体内实验表明，SOTE导致肝脏和脾脏炎症减轻，存活率提高。SOTE还通过免疫染色改善了肝功能测试，并使用ELISA降低了肿瘤坏死因子-α以及炎症标志物白细胞介素（IL-1β和IL-6）。因此，我们可以得出结论，SOTE可能是一种有前途的化合物，未来应在临床前和临床研究中进行研究。
