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The chemical composition, antimicrobial and antioxidant properties of the essential oils of Tulbaghia violacea Harv and Eucalyptus grandis W.Hill ex Maiden.

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dc.contributor.advisor Opoku, A.R.
dc.contributor.advisor Oyedeji, A.O.
dc.contributor.author Sewanu, Soyingbe Oluwagbemiga
dc.date.accessioned 2012-06-05T12:17:29Z
dc.date.available 2012-06-05T12:17:29Z
dc.date.issued 2012
dc.identifier.uri http://hdl.handle.net/10530/1057
dc.description A dissertation submitted in fulfilment of the requirement for the Degree of Master of Science in the Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, South Africa, 2012. en_US
dc.description.abstract Tulbaghia violacea Harv. and Eucalyptus grandis W. Hill ex Maidan are medicinal plants used by Zulu traditional healers for managing respiratory track diseases such as asthma and bronchitis. This study was designed to evaluate the chemical composition, antioxidant and antibacterial activities of the essential oils hydrodistilled separately from the rhizomes of Tulbaghia violacea and the leaves of Eucalyptus grandis. Chemical profile of the oils were carried out using GC and GC-MS. The main constituents of the essential oils of Tulbaghia violacea, were found to be 2,4- Dithiapentane (51.04%), p- Xylene (4.43%),Chloromethylmethyl sulfide (8.62%), O- Xylene (6.08%), Thiodiglycol (6.17%), and p- xylol (5.88%); these together constituted 82.22% of the extracted oil. The main constituents (81.44%) of the essential oils of Eucalyptus grandis were m- Xylene (33.04%), Ethylbenzene (11.59%), Eucalyptol (15.50%), p- Xylene (9.61%), Limonene (3.48%), Operea 1(3.30%), p-cymene (2.75%) and Toluene (2.17%). While the oils of Tulbaghia violacea showed very weak activity (≤ 50%) in the scavenging of DPPH and ABTS radicals, they strongly (63% and 61%) scavenged nitric oxide and chelated Fe2+ ions respectively. The essential oils of Eucalyptus grandis, on the other hand, had a better scavenging activity for DPPH and ABTS, and the other free radicals tested (≥ 50%), but poorly chelated Fe2+ ions. The antimicrobial activity of the essential oils carried out on both Gram positive and Gram negative bacteria showed that the oils of Tulbaghia violacea were affective against 8 of the 16 microorganisms tested with minimum inhibitory concentration (MIC) values ranging from 2.5 mg/ml - 5.0 mg/ml; the oils of Eucalyptus grandis were active against 13 of the 16 organisms tested with the MIC‘s ranging from 0.625 mg/ml – 5.0 mg/ml, and the minimum bactericidal concentration (MBC) value determined for 4 of the bacteria used, ranging from 2.5 mg/ml – 10 mg/ml. The essential oils of Eucalyptus grandis were also tested against 8 bacteria that were resistant to antibiotics (CIPRO: Levo, Clindamycin, Gentimicin, Penicillin, OxaClox, Oxameth, Cotrimoxazole and Ampicillin) and were seen to show high activity against 7 of the 8 with MIC ranging from 5 mg/ml – 10 mg/ml. The studies on the effect of the essential oils on the DNA of the susceptible microorganisms revealed that the oils could not damage the microbial DNA. The cytotoxicity levels of the T. Violacea essential oils against HEK293 and HepG2 cell lines were low (IC50values of 1218 μM and 1641 μM respectively). It is apparent that the bioactivity of the essential oils of T. violacea and E. grandis contribute to the use of these plants in folk medicine. en_US
dc.description.sponsorship University of Zululand en_US
dc.language.iso en en_US
dc.subject Tulbaghia violacea Harv en_US
dc.subject Eucalyptus grandis W.Hill ex Maiden en_US
dc.title The chemical composition, antimicrobial and antioxidant properties of the essential oils of Tulbaghia violacea Harv and Eucalyptus grandis W.Hill ex Maiden. en_US
dc.type Thesis en_US


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