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Assessment of Dihydro[1,3]oxazine‐Fused Isoflavone and 4‐Thionoisoflavone Hybrids as Antibacterials
Author(s) -
Lathwal Ankit,
Ali Asghar,
Uddin Amad,
Khan Nashra Shareef,
Sheehan Gerard,
Kavanagh Kevin,
Haq Qazi Mohd. Rizwanul,
Abid Mohammad,
Nath Mahendra
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202101364
Subject(s) - bacillus subtilis , antibacterial activity , ampicillin , minimum inhibitory concentration , escherichia coli , chemistry , microbiology and biotechnology , staphylococcus aureus , pseudomonas aeruginosa , cytotoxicity , agar diffusion test , galleria mellonella , in vivo , antibiotics , bacteria , in vitro , biology , biochemistry , genetics , gene , virulence
A series of isoflavone functionalized 3,4‐dihydro‐1,3‐oxazine hybrids was synthesized in good to excellent yields through a Mannich‐type condensation cyclization reaction of 6‐chloro‐7‐hydroxy‐3‐(2‐methoxy‐phenyl)‐chromen‐4‐one or 6‐chloro‐7‐hydroxy‐3‐(2‐methoxy‐phenyl)‐chromene‐4‐thione with formaldehyde and primary amines. After spectroscopic characterization, these newly prepared hybrids were evaluated for their antibacterial activities against two of each Gram positive ( Staphylococcus aureus and Bacillus subtilis ) and Gram negative ( Escherichia coli and Pseudomonas aeruginosa ) bacterial strains. Among the screened compounds, dihydro[1,3]oxazine‐fused 4‐thionoisoflavones( 9 b and 9 c ) exhibited potent inhibitory activity against all the tested bacterial species. Moreover, compound 9 b possessed most promising antibacterial activity against P. aeruginosa and B. subtilis with MIC 16 μg/mL and S. aureus and E. coli with MIC 32 μg/mL. Further, 9 b demonstrated better efficacy (MIC=16 μg/mL) than the standard drug ampicillin (MIC=32 μg/mL) against P. aeruginosa and it also found to be equipotent (MIC=16 μg/mL) as ampicillin against B. subtilis . Considering the disk diffusion and synergistic studies, 9 b emerged asmost active compound showing potent activity against all the tested bacterial strains. In addition, no significant hemolysis or cytotoxicity was observed towards human embryonic kidney (HEK293)cells as well as Galleria mellonella larvae (in vivo). Hence, compound 9 b has potential to be further explored alone and in combination with ampicillin as a next generation antibacterial agent.