Anis Ahmad

Antimicrobial Activity of Five Herbal Extracts Against Multi Drug Resistant (MDR) Strains of Bacteria and Fungus of Clinical Origin

Antimicrobial activities of the crude ethanolic extracts of five plants were screened against multidrug resistant (MDR) strains of Escherichia coli, Klebsiella pneumoniae and Candida albicans. ATCC strains of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus bovis, Pseudimonas aeruginosa, Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae and Candida albicans were also tested. The strains that showed resistance against the maximum number of antibiotics tested were selected for an antibacterial assay. The MDR strains were sensitive to the antimicrobial activity of Acacia nilotica, Syzygium aromaticum and Cinnamum zeylanicum, whereas they exhibited strong resistance to the extracts of Terminalia arjuna and Eucalyptus globulus. Community-acquired infections showed higher sensitivity than the nosocomial infections against these extracts. The most potent antimicrobial plant was A. nilotica (MIC range 9.75-313µg/ml), whereas other crude plant extracts studied in this report were found to exhibit higher MIC values than A. nilotica against community acquired as well as nosocomial infection. This study concludes that A. nilotica, C. zeylanicum and S. aromaticum can be used against multidrug resistant microbes causing nosocomial and community acquired infections.

Prevalence of Candida species and potential risk factors for vulvovaginal candidiasis in Aligarh, India

OBJECTIVES The objectives were to determine the frequency of Candida species in women of different age groups as well as to suggest the criteria for the diagnosis of vulvovaginal candidiasis (VVC). STUDY DESIGN A prospective study of vulvovaginal candidiasis was carried out using laboratory diagnosis, with the estimation of vaginal pH and the direct microscopic and biochemical examination of vaginal discharge/secretions. Vaginal cultures for Candida species were collected from 1050 women with vulvovaginal symptoms. RESULTS Out of 1050 women, 215 (20.47%) were positive for Candida species. Of 215 women, 172 (80%) had pH within the normal range and 167 (77.67%) were showing yeast cells and mycelia on direct microscopic examination. Candida albicans accounted for 46.9% of cases, Candida glabrata 36.7%, Candida parapsilosis 10.2%, Candida tropicalis 2.8%, Candida krusei 1.4%, and Candida kiefer 1.9%. The frequency of culture positivity was related to pregnancy (P<0.001), an increase in parity (P<0.001), and use of oral contraceptives (P<0.001) and antibiotics (P<0.001). The most common signs and symptoms in 215 women with positive cultures were pruritus with or without vaginal discharge and vaginal erythema. CONCLUSION Our study suggests that vulvovaginal candidiasis can only be diagnosed by using clinical criteria in correlation with vulvovaginal symptoms and Candida cultures.

Synthesis, characterization, and in vitro antimicrobial activities of 5-alkenyl/hydroxyalkenyl-2-phenylamine-1,3,4-oxadiazoles and thiadiazoles

The long-chain alkenoic acid hydrazides (1a-d) on reaction with phenylisocyanate and phenylthiocyanate gave their corresponding semicarbazides (2a-d) and thiosemicarbazides (4a-d), which on further refluxing with POCl(3) and Ac(2)O yielded corresponding 1,3,4-oxadiazoles (3a-d) and thiadiazoles (5a-d), respectively. The structure elucidation of synthesized compounds is based on the elemental analysis and spectral data (IR, (1)H NMR, (13)C NMR and MS). The synthesized oxadiazoles and thiadiazoles have been screened for antibacterial and antifungal activities. The investigation of antimicrobial screening revealed that compounds 3c, 3d, 5c, 5d and compounds 3b, 5b, showed good antibacterial and antifungal activities, respectively.

Thermal solvent-free synthesis of novel pyrazolyl chalcones and pyrazolines as potential antimicrobial agents.

A novel approach was adopted for the synthesis of series of new pyrazolyl chalcones (3a-c) by the reaction of 5-chloro-3-methyl-1-phenylpyrazole-4-carboxaldehyde (1) with different 5-acetylbarbituric acid derivatives (2a-c) under thermal solvent-free condition. The chalcones were then converted to the corresponding pyrazolines (4a-c) under the same condition in excellent yields. All the synthesized compounds were characterized using elemental analysis and spectral data (IR, (1)H NMR, and mass spectrometry). The synthesized compounds were tested for their antimicrobial activity by disk diffusion assay with slight modifications against Gram-positive, Gram-negative strains of bacteria as well as fungal strains. The investigation of antimicrobial screening revealed that compounds (3a-4c) showed good antibacterial and antifungal activities, respectively. Among the screened compounds, 3b showed more potent inhibitory activity (MIC=12.5 μg/ml) nearly to that of standard antibiotics ciprofloxacin, griseofulvin and fluconazole.

7-Hydroxy-coumarin derivatives: synthesis, characterization and preliminary antimicrobial activities

A new series of 7-O-coumarinyl alkenoates were synthesized from 7-hydroxyl-coumarin and fatty acids using DCC and DMAP as catalyst. The synthesized compounds were characterized on the basis of their spectral data. All the target compounds were evaluated for their in vitro antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Streptococcus pyogene, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli and fungal cultures of Candida albicans, Candida krusei, Candida parapsilosis and Cryptococcus neoformans. The minimum inhibitory concentration (MIC) was determined for the test compounds as well as for reference standards. Among the tested compounds, 7-O-coumarinyl (9Z, 12R)-12-hydroxyoctadec-9-enoate and 7-O-coumarinyl (12Z, 9R)-9-hydroxyoctadec-12-enoate showed the most potent antifungal as well as antibacterial activities.

Designing and synthesis of novel antimicrobial heterocyclic analogs of fatty acids.

Novel series of long chain isoxazole derivatives were designed as inhibitors of Cytochrome P450-14DM14a-demethylase from Candida albicans and ribosomal subunit of S12 protein from Escherichia coli. The novel compounds (6-10) were synthesized through 1,3-dipolar cycloaddition of nitrile oxide to long chain alkynoic acid and alkenyl/hydroxyalkenyl esters and tested for their antimicrobial activity by disk diffusion assay and MIC by broth micro dilution method. After predicting the hidden potential and drug-likeness of compounds, ADMET-related descriptors were also calculated to predict pharmacokinetic properties. Molecular docking studies have been performed to evaluate possible mode of action of molecules in active site of receptor. Compounds (9 and 10) showed excellent antimicrobial activity nearly equivalent to the control compounds.

Synthesis of 4-Hydroxycoumarin Heteroarylhybrids as Potential Antimicrobial Agents

A new series of 4‐hydroxycoumarin derivatives 3a–d was synthesized by the reaction of 3‐bromo‐4‐hydroxy coumarin 1 with various heteroaldehydes 2a–d in good yields. The synthesized compounds were characterized on the basis of their elemental and spectral (IR, 1H‐NMR and mass spectrometry) analysis. All target compounds were evaluated for their in‐vitro antimicrobial activity against Streptococcus pyogenes, methicillin‐resistant Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli bacterial strains and fungal cultures of Candida albicans, Aspergillus fumigatus, Trichophyton mentagrophytes, and Penicillium marneffei by disk diffusion assay with slight modifications. The minimum inhibitory concentration (MIC) was determined for the test compounds as well as for reference standards. Among the tested compounds, 3a has shown the most potent antibacterial as well as antifungal activities.

Synthesis and characterization of novel fatty acid analogs of cholesterol: In vitro antimicrobial activity

In the present study we synthesized, characterized and checked the antimicrobial activity of fatty acid analogs of cholesterol. The synthesized compounds were characterized using IR, (1)H NMR, (13)C NMR and mass spectral data and tested for their antimicrobial activity by disk diffusion assay with slight modifications against Gram-positive, Gram-negative strains of bacteria as well as fungal strains. Minimum inhibitory concentration (MIC) of all the synthesized compounds was also determined. Compounds 7-14 showed inhibitory action against both the groups of bacteria and four strains of fungus. In vitro antimicrobial activity of the test compounds show that the compounds 10 and 13 are excellent antibacterial agents, where as compounds 13 and 14 are the excellent antifungal agents among the eight synthesized compounds.

Thermal solvent-free synthesis of chromonyl chalcones, pyrazolines and their in vitro antibacterial, antifungal activities

A facile and ecofriendly synthesis of new chromonyl chalcones 3a-b from 3-formylchromone 1 and active methyl compounds 2a-b is reported under thermal solvent-free heating condition in good yields. The chromonyl chalcones 3a-b were used as intermediates under green condition for the synthesis of new bioactive pyrazoline derivatives 4a-f. The compounds were tested for antimicrobial activity by disk diffusion assay with slight modifications against Gram-positive, Gram-negative strains of bacteria as well as fungal strains. The investigation of antimicrobial screening revealed that compounds 3a-b and 4a-f showed antibacterial and antifungal activities.

A facile, one-pot synthesis, characterization and antimicrobial activity of o-hydroxy anilide derivatives and 1-substituted-1,3-dicyclohexylurea analogs of long chain carboxylic acids.

A series of novel o-hydroxy anilide derivatives and 1-substituted-1,3-dicyclohexylurea analogs of long chain carboxylic acids have been synthesized. The structures of the synthesized compounds were elucidated by IR, (1)H NMR, (13)C NMR and mass spectral data. All the synthesized compounds were tested for their antimicrobial activity by disk diffusion assay with slight modifications against Gram-positive, Gram-negative strains of bacteria as well as fungal strains. After that minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs) and minimum fungicidal concentrations (MFCs) of all the synthesized compounds were determined. The investigation of antimicrobial screening data revealed that all the tested compounds showed moderate to good microbial inhibitions. Compounds 3e, 4e, 3f and 4f were found to be the most potent antimicrobial agents.