Antimicrobial Activity of New 2-Thioxo-benzo[g]quinazolin-4(3H)-one Derivatives.
BACKGROUND
The antimicrobial activity of a synthesized series of 28 2-thioxobenzo[ g]quinazolin-4(3H)-one derivatives was evaluated in vitro against five Gram-positive bacteria, including Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pyogenes. The antibacterial activity was extended to include five Gramnegative bacteria: Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Klebsiella oxytoca and Enterobacter cloacae. Furthermore, the antifungal activity was evaluated against 10 fungal strains, including Aspergillus fumigatus, Syncephalastrum racemosum, Geotricum candidum, Candida albicans, Aspergillus niger, Cryptococcus neoformans, Candida tropicalis, Penicillium expansum, Microsporum canis and Trichophyton mentagrophytes.


METHODS
The agar well diffusion method was adopted against Gram-positive and Gram-negative bacteria and fungi, using ampicillin, gentamicin and amphotericin B as reference drugs, respectively.


RESULTS
The findings of the antibacterial studies revealed that most of the tested compounds possess strong activity against both bacterial species. Compounds 8 and 23 were the most active on Grampositive bacteria, while several compounds demonstrated significant antibacterial activity on Gramnegative bacteria, especially Escherichia coli. Furthermore, several compounds showed strong antifungal activity against many of the investigated fungi. The obtained results were reinforced by determination of the minimum inhibitory concentration for the active compounds against Grampositive and Gram-negative bacteria, as well as fungi, compared to the reference drugs.


CONCLUSIONS
Many of the investigated compounds showed potent activity against all tested microbial species. The discovery has provided a foundation for the synthesized compounds to serve as a platform for further design and development of more potent antimicrobial agents.
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.. Saudi Arabia.
Rashad
R
Al-Salahi
Hatem A
HA
Abuelizz
Rabab El
RE
Dib
Mohamed
M
Marzouk
Mohammed B
MB
Alshammari
D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005658:Fungi / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D011799:Quinazolines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D011799:Quinazolines
Antimicrobial; amphotericin B.; ampicillin; benzo[g]quinazoline; gentamicin