ABSTRACT
To evaluate phytochemical content and biological activities of Hypotrigona squamuligera honey. Study Design: Standard chemical tests, DPPH antiradical activity assay and agar diffusion methods. Place and Duration of Study: Department of Chemistry (Natural product section) and Biological Science Department November 2011 and March 2012. Methodology: Standard chemical tests, DPPH antiradical activity and agar diffusion methods were adopted to determine phytochemical compounds present, antioxidant and antibacterial activity respectively. The following bacterial strains were employed in the screening studies: Staphylococcus aureus and Escherichia coli, all from stock cultures of Bindura University Biological Sciences Department. Results: Phytochemical screening revealed presence of tannins, alkaloids, flavonoids, terpenoids, anthraquinones and cardiac glycosides. H. Squamuligera honey exhibited marked antioxidant and antibacterial activity. Its antiradical activity was lower than that of ascorbic acid and quercetin at low concentrations 0,0125 and 0,025mg/ml however as from 0,05mg/ml methanolic extract exhibited significantly higher antioxidant activity. H. squamuligera honey (100%) produced a greater inhibition (24 ± 0,09 mm) than amoxicillin (19±0,01mm) for S. aureus. For E. coli amoxicillin produced greater inhibition than H. squamuligera honey. Compared to Apis mellifera honey at a concentration of 100%, H. squamuligera honey revealed better inhibitory activity. Minimum inhibitory values ranged from 10 - 25 μg/ml. The lowest MIC value (15μg/ml) for H. squamuligera honey was recorded for S. aureus. Conclusion: The results suggest that H. squamuligera honey could potentially be used as an alternative pharmaceutical agent against certain microorganisms and source of natural antioxidants for promotion of health however there is a need to perform structural elucidation to identify the structures of phytochemical compounds present in the honey.
ABSTRACT
Aims: The study was conducted to determine antimicrobial activity of Temnocalyx obovatus mature root extracts popularly used in folk medicine to treat diarrhoea in chickens, stomach disorders in turkeys, goats and cows, snakebites, asthma, ulcers and whooping cough in humans. Study Design: Agar disk diffusion method and determining MIC. Place and Duration of Study: Department of Chemistry (Natural product section) June 2011 and July 2011. Methodology: Two methods were employed for the determination of antimicrobial activities; an agar paper disc diffusion method and determination of minimal inhibitory concentration (MIC). Methanol and ethanol extracts were assayed for antimicrobial activities. The following bacterial strains were employed in the screening studies: Staphylococcus aureus, Escherichia coli, Clostridium perfringens and fungi: Aspergillus niger, Candida albicans all from stock cultures of Bindura University department. Results: Methanol extract exhibited the greatest extraction efficiency; 136,1g/Kg as compared to ethanol; 124,8 g/Kg. Both methanol and ethanol extracts showed significant antibacterial and antifungal activity. Sensitivity to the extracts was not similar for the chosen strains. The highest antibacterial activity of plant extract was 37,0 mm for methanol and 28,0 for ethanol extracts for diameter of zone inhibition found against Clostridium perfringens followed by 35,0 mm and 26,3 diameter of zone inhibition against Escherichia coli at a concentration of 100%. Antifungal activity was highest for Aspergillus niger at a concentration of 100%. The minimum inhibitory concentration (MIC) values against these bacteria ranged from 10 - 60 μg/ml. In comparison to reference standards Gentamicin, and miconazole, methanolic extracts showed significant antimicrobial activity, student t-test, p = 0,05. Conclusion: The present results support the use of aqueous extracts of Temnocalyx obovatus roots in folk medicine for the treatment of conditions such as diarrhoea and stomach disorders. These results encourage follow-ups through bioassay-directed isolation of the phytocompounds responsible for the potency.
ABSTRACT
Total demand for ethanol due to fear of crude oil depletion and the need to mitigate global warming due to green house gas emissions is increasing year after year. The present study was undertaken to investigate optimum parameters for ethanol production from Ziziphus mauritiana by Saccharomyces cerevisiae (NA33) strain. Various parameters, yeast concentration, pH and temperature were considered. A control experiment (without Saccharomyces cerevisiae (NA33) strain) was also set up for results comparison. The optimized conditions for ethanol production were established as pH 6, temperature 30ºC and yeast concentration of 8.0g per 20g fruit pulp. Under these conditions an ethanol concentration of 63 g/L was achieved. The control vessel showed not much rate of fermentation and hence it was shown that addition of Saccharomyces cerevisiae (NA33) was necessary to increase the rate and yield.