Preliminary Phytochemical Analysis and Antimicrobial Properties of Crude Extract of Combretodendron macrocarpum Stem Bark

The antimicrobial properties of the tree bark extract of Combretodendron macrocarpum using different solvents were investigated. Extracts of C. macrocarpum were prepared using hot water, cold water, diethyl ether and dilute hydrochloric acid (0.02M). The extracts were tested against Staphylococcus aureus, Escherichia coli, Pseudomonas and Klebsiella pnuemoniae using well-diffusion method. The plant extracts of dilute HCl and diethyl ether exerted the highest zone of inhibition against all the test microorganisms with S. aureus (29.9 mm) and K. pneumoniae (27.5 mm). The diethyl ether extract exerted the highest effect against P. aeruginosa (21.9 mm) and K. pneumoniae (21.8 mm) with no effect on E. coli. The cold water extract was not active on any of the bacterial pathogens tested at any of the concentrations of the extract used. The Minimum Inhibitory Concentration (MIC) value of the hot water extract was lowest for E. coli (31.25mg/ml) and K. pneumoniae ( 62.5 mg/ml), and the dil. HCl extract also showed a low MIC against P. aeruginosa (31.25mg/ml). Preliminary phytochemical screening revealed the presence of alkaloids, saponin, steroids, tannins and terpenoids. These results therefore support and encourage the use of C. macrocarpum stem bark for the treatment of conditions that may be of bacterial etiology.Keywords: Combretodendron macrocarpum, phytochemicals, etiology, minimum inhibitory concentration,antimicrobials

Phytochemical and Antimicrobial Evaluation of Aqueous and Organic Extracts of Calotropis procera Ait Leaf and Latex

The aqueous and ethanol extract of Calotropis procera leaf and latex were investigated. The leaves and latex from the plant were tested for antimicrobial activities. The bioactive constituents extracted from the leaf and latex were tested against pathogenic organisms (Eschericia coli, Salmonella typhi, Bacillius subtilis, Candida albicans, Aspergillus niger) using the Agar well diffusion method. The ethanolic latex extract showed  significant activity against all the test organisms. The results revealed that ethanol is a more effective extractive solvent for antimicrobial activity of leaf and latex of C. procera. The ethanol extract of the latex gave the widest zone of inhibition (21mm) against B. subtilis. All the extracts inhibit the growth of all the organisms except B. subtilis of which the aqueous extract has no effect. The Minimum Inhibitory Concentration (MIC) for the latex extract was between 3 and 7.5 mg/ml for bacteria, and 5.0 to 7.0 mg/ ml for fungi. For the leaf extract the MIC for bacteria was between 5.0 and 10.5 mg/ml and 11 and 15 mg/ml for fungi. The results also showed an increase in antimicrobial activity with increase in temperature. This  study therefore revealed that C. procera latex extract demonstrated strong and better inhibitory activity on the test organisms than the leaf extract. These findings therefore provide an explanation for the traditional  medicinal use of C. procera extracts.Keywords: Calotropis procera, latex, bioactive, antimicrobial activity, minimum inhibitory concentration

Production and partial purification of glucoamylase from Aspergillus niger isolated from cassava peel soil in Nigeria

Glucoamylase is an enzyme that hydrolyses 1,4α and 1,6β-glucosidic linkages in polysaccharides yielding glucose. Aspergillus niger strains 1, 2 and 3 were locally isolated from cassava peel dumpsite for the production of glucoamylase enzyme. A. niger strains 1, 2 and 3 were screened for their hyper producing ability on potato dextrose agar using plate assay method fortified with starch agar, and showed zone of clearance of 17.0, 23.0 and 8.0 mm, respectively. The glucoamylase activity for A. niger strains 1 and 2 were 13 000.0 and 11 740.0, respectively. These values were however higher than the activity as obtained from the commercial enzyme with 2 500.0. Investigations on the protein (mg/ml), and specific activity (units/mg) on glucoamylase produced by A. niger strains 1 and 2 was 24.20, 537.19, 23.13 and 507.57, respectively. Fractionation of the enzyme ammonium sulphate (% w/v) using 60, 80 and 100% showed that the enzyme activities were 33 179.86, 47 985.86 and 19 167.65 units/ml, respectively. Protein concentrations were 16.29, 16.29 and 21.55 units/mg, respectively, while specific activities were 2 036.82, 2 945.725 and 889.45 units/mg, respectively. The production, packaging, and commercialization of glucoamylase in Nigeria will save a lot of foreign exchange earnings, and boost the economy of Nigeria.Keywords: Glucoamylase, specific activity, Aspergillus niger, fractionation, cassava peel.African Journal of Biotechnology, Vol 13(21) 2154-215