Data_Sheet_1_Pharmacodynamic Functions of Synthetic Derivatives for Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) and Mycobacterium tuberculosis.docx

Drug resistant bacteria have emerged, so robust methods are needed to evaluate combined activities of known antibiotics as well as new synthetic compounds as novel antimicrobial agents to treatment efficacy in severe bacterial infections. Marine natural products (MNPs) have become new strong leads in the drug discovery endeavor and an effective alternative to control infections. Herein, we report the bioassay guided fractionation of marine extracts from the sponges Lendenfeldia, Ircinia, and Dysidea that led us to identify novel compounds with antimicrobial properties. Chemical synthesis of predicted compounds and their analogs has confirmed that the proposed structures may encode novel chemical structures with promising antimicrobial activity against the medically important pathogens. Several of the synthetic analogs exhibited potent and broad spectrum in vitro antibacterial activity, especially against the Methicillin-resistant Staphylococcus aureus (MRSA) (MICs to 12.5 μM), Mycobacterium tuberculosis (MICs to 0.02 μM), uropathogenic Escherichia coli (MIC o 6.2 μM), and Pseudomonas aeruginosa (MIC to 3.1 μM). Checkerboard assay (CA) and time-kill studies (TKS) experiments analyzed with the a pharmacodynamic model, have potentials for in vitro evaluation of new and existing antimicrobials. In this study, CA and TKS were used to identify the potential benefits of an antibiotic combination (i.e., synthetic compounds, vancomycin, and rifampicin) for the treatment of MRSA and M. tuberculosis infections. CA experiments indicated that the association of compounds 1a and 2a with vancomycin and compound 3 with rifampicin combination have a synergistic effect against a MRSA and M. tuberculosis infections, respectively. Furthermore, the analysis of TKS uncovered bactericidal and time-dependent properties of the synthetic compounds that may be due to variations in hydrophobicity and mechanisms of action of the molecules tested. The results of cross-referencing antimicrobial activity, and toxicity, CA, and Time-Kill experiments establish that these synthetic compounds are promising potential leads, with a favorable therapeutic index for antimicrobial drug development.

耐药细菌的涌现，迫切需要采用稳健的方法来评估已知抗生素以及新型合成化合物作为新型抗菌剂的联合活性，以治疗严重细菌感染的治疗效果。海洋天然产物（MNPs）已成为药物发现领域的新兴强有力线索，并成为控制感染的有效替代品。本研究中，我们对来源于海绵Lendenfeldia、Ircinia和Dysidea的海洋提取物进行了生物活性指导下的分离，从而鉴定出具有抗菌特性的新型化合物。预测化合物的化学合成及其类似物的合成证实，所提出的结构可能编码具有潜在抗菌活性的新型化学结构，针对具有重要医学意义的病原体。其中一些合成类似物在体外表现出强大的广谱抗菌活性，尤其是对耐甲氧西林金黄色葡萄球菌（MRSA）（最低抑菌浓度至12.5 μM）、结核分枝杆菌（最低抑菌浓度至0.02 μM）、尿路致病性大肠杆菌（最低抑菌浓度至6.2 μM）和铜绿假单胞菌（最低抑菌浓度至3.1 μM）。通过药代动力学模型分析的棋盘格试验（CA）和时间-杀灭研究（TKS）实验，具有在体外评估新型和现有抗菌剂的潜力。在本研究中，CA和TKS被用于识别抗生素组合（即合成化合物、万古霉素和利福平）治疗MRSA和M. tuberculosis感染的潜在益处。CA实验表明，化合物1a和2a与万古霉素、化合物3与利福平的组合对MRSA和M. tuberculosis感染分别具有协同作用。此外，TKS分析揭示了合成化合物的杀菌性和时间依赖性特性，这可能是由于测试分子疏水性和作用机制的变化。抗菌活性、毒性、CA和时间-杀灭实验的结果交叉验证表明，这些合成化合物是具有良好治疗指数的潜在先导化合物，具有抗菌药物开发的巨大潜力。