Discovery of novel arylethenesulfonyl fluorides as potential candidates against methicillin-resistant of Staphylococcus aureus (MRSA) for overcoming multidrug resistance of bacterial infections.

The multidrug-resistant Staphylococcus aureus (MRSA) is one of the most prevalent human pathogens involved in many minor to major disease burdens throughout the world. Inhibition of biofilm formation is an attractive strategy to treat diseases associated with MRSA infection. In the present investigation, a series of functional group diverse (hetero)aryl fluorosulfonyl analogs were designed, synthesized and tested as antibacterial agents against Staphylococcal spp., and as anti-biofilm candidates. Compounds 8, 15, and 67 were found to possess potent in vitro antibacterial activity among this class of sulfonyl fluorides (MIC = 0.818 ±â€¯0.42, 0.840 ±â€¯0.37 and 0.811 ±â€¯0.37 µg/mL respectively). The analogs 8, 15, 36, and 67 exhibited outstanding anti-biofilm properties compared to other available synthetic antibiotics. The efficacy of synthetic analogs displayed membrane-damaging effect and they are also validated by cellular content release assay. The insight physiological changes were explored by studying the intracellular redox activities through changing cyclic voltammetric (CV) method. The compounds 8, 15, 22, 32, 36, 51, and 67 were found to participate in the interfering in the electron transport chain (ETC) of MRSA. The analogs 8, 15, and 67 possess great potentiality for discovery and development of anti-staphylococcal drugs to treat the MRSA infections.

Aryl fluorosulfate analogues as potent antimicrobial agents: SAR, cytotoxicity and docking studies.

A series of aryl fluorosulfate analogues (1-37) were synthesized and tested for in vitro antibacterial and antifungal studies, and validated by docking studies. The compounds 9, 12, 14, 19, 25, 26, 35, 36 and 37 exhibited superior antibacterial potency against tested bacterial strains, while compounds 2, 4, 5, 15, 35, 36 and 37 were found to have better antifungal activity against tested fungal strains, compared to standard antibiotic gentamicin and ketoconazole respectively. Among all the synthesized 37 analogs, compounds 25, 26, 35, 36 and 37 displayed excellent anti-biofilm property against Staphylococcus aureus. The structure-activity relationship (SAR) revealed that the antimicrobial activity depends upon the presence of -OSO2F group and slender effect of different substituent's on the phenyl rings. The electron donating (OCH3) groups in analogs increase the antibacterial activity, and interestingly the electron withdrawing (Cl, NO2, F and Br) groups increase the antifungal activity (except compound 35, 36 and 37). The mechanism of potent compounds showed membrane damage on bacteria confirmed by SEM. Compounds 35, 36 and 37 exhibited highest glide g-scores in molecular docking studies and validated the biocidal property.

Synthesis, SAR and molecular docking studies of benzo[d]thiazole-hydrazones as potential antibacterial and antifungal agents.

A series of new benzo[d]thiazole-hydrazones analogues were synthesized and screened for their in vitro antibacterial and antifungal activities. The results revealed that compounds 13, 14, 15, 19, 20, 28 and 30 exhibited superior antibacterial potency compared to the reference drug chloramphenicol and rifampicin. Compounds 5, 9, 10, 11, 12, 28 and 30 were found to be good antifungal activity compared to the standard drug ketoconazole. A preliminary study of the structure-activity relationship (SAR) revealed that the antimicrobial activity depended on the effect of different substituents on the phenyl ring. The electron donating (OH and OCH3) groups presented in the analogues, increase the antibacterial activity (except compound 12), interestingly, while the electron withdrawing (Cl, NO2, F and Br) groups increase the antifungal activity (except compound 19 and 20). In addition, analogues containing thiophene (28) and indole (30) showed good antimicrobial activities. Whereas, aliphatic analogues (24-26) shown no activities in both bacterial and fungal stains even in high concentrations (100µg/mL). Molecular docking studies were performed for all the synthesized compounds of which compounds 11, 19 and 20 showed the highest glide G-score.

Synthesis of benzo[d]thiazole-hydrazone analogues: molecular docking and SAR studies of potential H+/K+ ATPase inhibitors and anti-inflammatory agents.

A series of new benzo[d]thiazole-hydrazones were synthesized and characterized by analytical and spectroscopic techniques. All the compounds were screened for their in vitro inhibition of H+/K+ ATPase and anti-inflammatory effects. The results revealed that compounds 6-8, 13-15, 18-20, 22, 23 and 27-30 displayed excellent inhibitory activity against H+/K+ ATPase, and their IC50 values were lower than those of the standard compound omeprazole. Compounds 2-5, 9-12, 28 and 30 exhibited better anti-inflammatory activity in comparison to the standard compound indomethacin. Studies of the structure-activity relationship (SAR) showed that electron-donating groups (OH and OCH3) favored inhibitory activity against H+/K+ ATPase, whereas electron-withdrawing groups (F, Cl, Br and NO2) favored anti-inflammatory activity, and derivatives with both electron-donating (OH and OCH3) and electron-withdrawing (Br) groups (16-18) displayed reasonable activity, whereas aliphatic analogues (24-26) exhibited less activity and heterocyclic analogues (27-30) displayed moderate activity in both biological studies. Molecular docking studies were performed for all the synthesized compounds, among which compounds 19 and 20 exhibited the highest docking scores for inhibitory activity against H+/K+ ATPase, whereas compounds 10 and 12 displayed the highest docking scores for anti-inflammatory activity.

Synthesis and molecular docking studies of xanthone attached amino acids as potential antimicrobial and anti-inflammatory agents.

A series of novel xanthone conjugated amino acids were synthesised and characterised by analytical and spectroscopic methods. All the synthesized analogues (2-23) were screened for their in vitro antimicrobial and anti-inflammatory activities. Compounds 7, 8, 9, 12, 18, 19, 20, 21 and 23 showed excellent antimicrobial activities compared to antibacterial and antifungal reference drugs gentamicin and bavistin, respectively. Compounds 7-12 and 18-23 showed good anti-inflammatory activity compared to a standard drug, indomethacin. The preliminary structure-activity relationship revealed that tryptophan, tyrosine, phenylalanine, proline and cysteine conjugated compounds showed excellent antimicrobial and anti-inflammatory activities. This may be explained by the contribution of aromaticity and hydrophobicity of amino acids. Molecular docking studies were performed for all the synthesised compounds, among which compounds 20, 21 and 23 showed the highest docking scores for antimicrobial activity while compounds 9, 20 and 22 showed the highest docking scores for anti-inflammatory activity. Different amino acids conjugated xanthone derivatives were synthesized and evaluated for their in vitro biological activities. The conjugation was found to play a major role in improving the biological activities of those compounds.