Chemistryhttp://hdl.handle.net/10311/512024-03-29T04:37:53Z2024-03-29T04:37:53ZGC-MS analysis and preliminary antimicrobial activity of albizia adianthifolia (Schumach) and pterocarpus angolensis (DC)Abubakar, Mustapha N.Majinda, Runner R.T.http://hdl.handle.net/10311/19412019-06-08T00:01:48Z2016-01-29T00:00:00ZGC-MS analysis and preliminary antimicrobial activity of albizia adianthifolia (Schumach) and pterocarpus angolensis (DC)
Abubakar, Mustapha N.; Majinda, Runner R.T.
The non-polar components of two leguminoceae species Albizia adianthifolia (Schumach), and Pterocarpus angolensis (DC) were investigated. GC-MS analysis of the crude n-hexane and chloroform extracts together with several chromatographic separation techniques led to the identification and characterization (using NMR) of sixteen known compounds from the heartwood and stem bark of Albizia adianthifolia and Pterocarpus angolensis respectively. These constituents include, n-hexadecanoic acid (palmitic acid) 1, oleic acid 2, chondrillasterol 3, stigmasterol 4, 24S 5α-stigmast-7-en-3β-ol 5, 9,12-octadecadienoic acid (Z,Z)-, methyl ester 6, trans-13-octadecanoic acid, methyl ester 7, tetradecanoic acid 8, hexadecanoic acid, methyl ester 9, octadecanoic acid 10, tetratriacontane 11, 7-dehydrodiosgenin 12, lupeol 13, stigmasta-3,5-diene-7-one 14, friedelan-3-one (friedelin) 15, and 1-octacosanol 16. Using agar over lay method, the preliminary antimicrobial assay for the extracts was carried out against bacterial (E. coli, P. aeruginosa, B. subtilis, S. aueus) and a fungus/yeast (C. albicans) strains. The n-hexane and chloroform extracts of A. adianthifolia showed the best activity against E. coli with minimum inhibition quantity (MIQ) of 1 µg each while the remaining exhibited moderate-to-weak activity against the test microorganisms.
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2016-01-29T00:00:00ZAntimicrobial Flavonoids from Bolusanthus speciosusBojase, GomotsangMajinda, Runner R.T.Gashe, Berhanu A.Wanjala, Cornelius C.W.http://hdl.handle.net/10311/19402019-06-08T00:01:36Z2002-01-01T00:00:00ZAntimicrobial Flavonoids from Bolusanthus speciosus
Bojase, Gomotsang; Majinda, Runner R.T.; Gashe, Berhanu A.; Wanjala, Cornelius C.W.
A new isoflavanone namely 3,5,7,2′,4′-pentahydroxy-8,3′-di(γ,γ-dimethylallyl)isoflavanone (bolusanthin II) and four new pterocarpans identified as 3-hydroxy-6′,6′-dimethylpyrano[2′,3′:1,2] [6aR,11aR]-8,9-methylenedioxypterocarpan (bolucarpan A), 3-hydroxy-6′,6′-dimethyl-4′,5′-dihydropyrano[2′,3′:1,2][6aR,11aR]- 8,9-methylenedioxypterocarpan (bolucarpan B), 3-hydroxy-9-methoxy-6′,6′-dimethylpyrano-[2′,3′:1,2][6aR,11aR]-pterocarpan (bolucarpan C) and 3-hydroxy-9-methoxy-6′,6′-dimethyl-4′,5′-dihydropyrano[2′,3′:1,2][6aR,11aR]-pterocarpan (bolucarpan D) and three known isoflavonoids were isolated from the methanolic extracts of the root bark, while eight known isoflavonoids were isolated from the stem bark of Bolusanthus speciosus. These compounds showed antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae and Candida mycoderma using the agar overlay technique.
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2002-01-01T00:00:00ZFatty acid composition and antimicrobial activity of Baphia massaiensis seed oilKeroletswe, NgonyeMazimba, OfentseMajinda, Runner R.T.Masesane, Ishmaelhttp://hdl.handle.net/10311/19392019-06-08T00:01:35Z2017-04-03T00:00:00ZFatty acid composition and antimicrobial activity of Baphia massaiensis seed oil
Keroletswe, Ngonye; Mazimba, Ofentse; Majinda, Runner R.T.; Masesane, Ishmael
Aims: The seed oil composition of Baphia massaiensis seeds was determined using 1H NMR and GC-MS techniques. The seed oil was also screened for antimicrobial activity.
Study Design: The study was designed to determine Baphia massaiensis seed oil fatty acid composition and antimicrobial activity.
Place and Duration of Study: Department of Chemistry, University of Botswana, between June 2012 and July 2014.
Methodology: The Baphia massaiensis seed cotyledons powder (29.2 g) were extracted by Soxhlet extraction using n-hexane/ 1-propanol. The seed oil (3.12 g) was esterified to FAMEs using dry methanol. The percentage composition of fatty acids methyl esters (FAMEs) in the seed oil of B. massaiensis was determined using 1H NMR and GC-MS techniques. The antimicrobial screening was carried out using agar well diffusion method.
Results: The 1H NMR method showed the oil composition to be 20% ω-3 fatty acids, 11% mono-unsaturated, 60% di-unsaturated and 9% saturated fatty acids. Based on GC-MC analysis, saturated fatty acids composition was 12.2% and unsaturated fatty acids were 87.8% of the total FAMEs. The major constituents of B. massaiensis seed oil FAMEs were linoleic acid (C18:2; 49.0%) and linolenic acid (C18:3; 36.7%) methyl esters. The FAMEs were active against E. coli, S. aureus and B. subtilis with 10-16 mm inhibition zones.
Conclusion: Linoleic acid (49.0%) and linolenic (36.7%) methyl esters were the major components of Baphia massaiensis FAMEs.
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2017-04-03T00:00:00ZPhenolic and antibacterial constituents of Vahlia capensisMajinda, Runner R.T.Motswaledi, ModisaWaigh, Roger D.Waterman, Peter G.http://hdl.handle.net/10311/19382019-06-08T00:01:41Z1997-01-01T00:00:00ZPhenolic and antibacterial constituents of Vahlia capensis
Majinda, Runner R.T.; Motswaledi, Modisa; Waigh, Roger D.; Waterman, Peter G.
The n-butanol fraction of Vahlia capensis yielded kaempferol, quercetin, afzelin, astragalin, quercitrin, iso-quercitrin, rutin, gallic acid, chiro-inositol, dulcitol, and a novel biflavonoid, VC-15B (vahlia biflavone). The compounds were identified using ID and 2D NMR techniques and FABMS. Vahlia biflavone and gallic acid were isolated, using bioassay-guided procedure and identified as the antibacterial components. Both compounds showed activity against Gram positive Staphylococcus aureus and Bacillus subtilis. Vahlia biflavone gave MIC values of 15.3 µg/ml and 30.6 µg/ml against S. aureus and B. subtilis, respectively while gallic acid gave a value of 71.3 µg/ml for both organisms.
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1997-01-01T00:00:00Z