Naseem Ullah

Antibacterial potentials of Quercus baloot Griff.

Quercus baloot fractions were subjected to antibacterial susceptibility evaluation that illustrated inhibition zones against Staphylococcus aureus , Micrococcus luteus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa . The active fractions were chromatographed by thin layer chromatography (TLC) and then contact bioautography was utilized as hyphenated bioassay, which showed inhibition zones at different Rf values against B. subtilis, M. luteus, E. coli, and S. aureus . The minimum inhibitory concentrations (MICs) of active fractions were found using a 96-well micro-titer plate method and the non-viability of the organisms was ascertained by determining the minimum bactericidal concentration (MBC) of the fractions. This is the first report of antibacterial activities for Q. baloot.

Impact of geographical locations on Mentha spicata antibacterial activities

Department of Pharmacy, Faculty of Life Sciences, Sarhad University of Science and Information Technology, Peshawar, Pakistan. Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan. Department of Pharmacology, Kohat Institute of Medical Sciences, Kohat, Pakistan. Department of Medicine, University of Toronto, Canada. Department of Oncology, Hayatabad Medical Complex, Peshawar, Pakistan.

Effects of Luteolin and Quercetin in Combination with Some Conventional Antibiotics against Methicillin-Resistant Staphylococcus aureus

The present study was designed to evaluate the effects of flavonoids luteolin (L) and quercetin + luteolin (Q + L) in combination with commonly used antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates and S. aureus (ATCC 43300). Minimum inhibitory concentrations (MICs) of L and Q + L, as well as the MICs of flavonoids in combination with antibiotics were determined and results showed an increased activity of flavonoids with antibiotics. The synergistic, additive, or antagonistic relationships between flavonoids (L and Q + L) and antibiotics were also evaluated, and additive and synergistic effects were observed for some antibiotic + flavonoid combinations. In addition, some combinations were also found to damage the bacterial cytoplasmic membrane, as assessed through potassium leakage assay. The effects of flavonoids and flavonoids + antibiotics on mecA gene mutations were also tested, and no functional variation was detected in the coding region.

Phytochemical screening and in vitro evaluation of anticandidal activity of Dodonaea viscosa (L.) Jaeq. (Sapindaceae)

The activity of fractions derived from hydroalcoholic extract of Dodonaea viscosa leaves against Candida albicans (Cl. I. 4043) was evaluated. The hydroalcoholic extract was sequentially fractionated to give n-hexane, dichloromethane, ethylacetate and n-butanol fractions that were subjected to qualitative phytochemical analyses. Disk diffusion assay was used in preliminary anticandidal screening with clotrimazole and chloroform serving as positive and negative controls, respectively. Optimized solvent systems were used for thin layer chromatography (TLC) that was followed by contact bioautography to evaluate the bioactivities of the fractions. Using broth microdilution technique, minimum inhibitory concentrations (MIC) of the individual fractions were established. With the exception of aqueous fraction all the fractions exhibited anticandidal activities (zone of inhibition � 10 mm) in preliminary screening against test yeast. However, n-hexane fraction showed two inhibition zones at Rf = 0.14 and 0.60 in contact bioautography, which indicates location of inhibitory compounds. The MIC of 62.5 µg/ml also supports the presence of anticandidal moieties in n-hexane fraction. Flavonoids, terpenoids, tannins and steroids were the main metabolites indicated in phytochemical screenings.

Evaluation of anticandidal potential of Quercus baloot Griff. using contact bioautography technique

The activities of fractions derived from hydroalcoholic extract of Quercus baloot leaves against a dimorphoic pathogenic yeast, Candida albicans (Cl. I. 4043) was evaluated. The hydroalcoholic extract was sequentially fractionated to give n-hexane, dichloromethane, ethylacetate, and n-butanol fractions, which were also subjected to qualitative phytochemical analyses. Preliminary anticandidal screening was carried out using disk diffusion assay with clotrimazole and chloroform serving as positive and negative controls, respectively. Using optimized solvent systems for each fraction, thin layer chromatography was done to separate the secondary metabolites that were evaluated for bioactivity using contact bioautography technique. Minimum inhibitory concentrations of the individual fractions were found using broth microdilution method. Preliminary screening showed all the fractions, apart from aqueous fraction, to have anticandidal potential (zone of inhibition ≥ 10 mm) against test yeast. However, contact bioautography revealed that only dichloromethane fraction was bioactive with inhibition zones at R f = 0.44 and 0.50, which showed location of inhibitory compound. The MIC of 125 µg/ml also support the presence of anticandidal moieties in this fraction. Phytochemical analyses indicated flavonoids, terpenoids, and steroids in the fractions.

Dexibuprofen nanocrystals with improved therapeutic performance: fabrication, characterization, in silico modeling, and in vivo evaluation

Background The aim of this study was to prepare and evaluate the impact of polymers on fabricating stable dexibuprofen (Dexi) nanocrystals with enhanced therapeutic potential, using a low energy, anti-solvent precipitation method coupled with molecular modelling approach. Methods Dexi nanocrystals were prepared using antisolvent precipitation with syringe pump. Crystallinity of the processed Dexi particles was confirmed using differential scanning calorimetry and powdered X-ray diffraction and transmission electron microscopy. Dissolution of Dexi nanocrystals was compared with raw Dexi and marketed tablets. Molecular modelling study was coupled with experimental studies to rationalise the appropriate polymers for stable Dexi nanocrystals. Antinociceptive study was carried out using balb mice. Results Combinations of hydroxypropyl methylcellulose (HPMC)–polyvinyl pyrrolidone (PVP) and HPMC–Eudragit (EUD) were shown to be very effective in producing stable Dexi nanocrystals with particle sizes of 85.0±2.5 nm and 90±3.0 nm, and polydispersity of 0.179±0.01, 0.182±0.02, respectively. The stability studies conducted for 90 days demonstrated that nanocrystals stored at 2°C–8°C and 25°C were more stable than those at 40°C. The maximum recovery of Dexi nanocrystals was observed from the formulations using the combination of HPMC–PVP and HPMC–EUD, which equated to 98% and 94% of the nominal active drug content respectively. The saturation solubility of the Dexi nanocrystals was substantially increased to 270.0±3.5 μg/mL compared to the raw Dexi in water (51.0±2.0 μg/mL) and stabilizer solution (92.0±3.0 μg/mL). Enhanced dissolution rate (P<0.05) was observed for the Dexi nanocrystals compared to the unprocessed drug substance and marketed tablets. Dexi nanocrystals produced the analgesic effect at much lower doses (5 mg/kg) than that of control standard, diclofenac sodium (20 mg/kg) and Dexi counterparts (40 mg/kg). Conclusion HPMC-PVP and HPMC-EUD were found the best polymer combination to stabilise Dexi nanocrystals. The Dexi nanocrystals exhibited significant dissolution, solubility and analgesic effect compared to the raw Dexi and the control standard diclofenac sodium.