Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Kenya → 2005 → Ethnobotany, tissue culture, seed oil extraction and characterisation of Thevetia peruviana Schum.(orange and yellow flowering varieties) in Kenya

Jomo Kenyatta University of Agriculture and Technology (2005)

Ethnobotany, tissue culture, seed oil extraction and characterisation of Thevetia peruviana Schum.(orange and yellow flowering varieties) in Kenya

Odhiambo, Peter Onyango

Titre : Ethnobotany, tissue culture, seed oil extraction and characterisation of Thevetia peruviana Schum.(orange and yellow flowering varieties) in Kenya

Auteur : Odhiambo, Peter Onyango

Université de soutenance : Jomo Kenyatta University of Agriculture and Technology, Kenya

Grade : Master of Science (MS) 2005

Résumé
Plants are known to be the primary source of food and medicine for humans and animals since time immemorial. Nature has always provided numerous plant species, some with multipurpose endowment as food and source of medicine amongst other uses. Thevetia peruviana appears to be one of the plants that nature has endowed with the dual purposes for food and medicine that should be harnessed for human welfare. The present study involved ethnobotany, tissue culture, seed oil extraction and characterization of T. peruviana Schum. with a broad objective of finding its economic significance as an alternative source of edible vegetable oil and proteins in Kenya. A monocultural ethnobotanical survey of the two varieties, orange and yellow flowering varieties of Thevetia peruviana was conducted among the Luos living along the Lake Victoria basin region, where the plant has naturalized and is used by 47% of the respondents as ornamental, 17% as hedge, 10% as shade, 9% as source of medicine and 5% as wood fuel amongst other minor uses. This was done by practical field visits to the Luo community and administration of questionnaires. Tissue culture on modified Murashige and Skoog (MS) culture media resulted in regeneration of whole plantlets from leaf discs of the orange flowering variety via callus, embryogenesis, shooting, and rooting in vitro. Callus was initiated in a fortnight in modified MS culture media supplemented with 0.3 mg/l of 2, 4-dichlorophenoxyacetic acid (2,4-0) and 0.1 mg/l of kinetin. Callus maturation into embryogenic calli was attained in MS media supplemented with 0.3 mg/l of 6, benzylaminopurine (BAP) and 0.1 mg/l of kinetin in two months. Shooting was also attained in MS media supplemented with 0.3 mg/l of BAP and 0.1 mg/l of kinetin in two to three months period. Rooting was attained in modified MS media supplemented with 0.2 g/l of biotin, 1 g/l of glycine and 0.3 mg/l of indole-S-butyric acid (IBA). Of the three conventional methods for oil extraction, solvent system using nhexane in a soxleht apparatus yielded the highest of 62% of glycoside free oil, followed by 21 % from mechanical extraction using a ram press, and 20% from wet rendering oil extraction method. Fatty acid analysis of the oil samples using Gas Chromatography (GC) showed that the oil contains, myristic 8.8%, oleic 52.1%, linoleic 16.3%, palmitic 18.5%, and stearic acids 7.5%. The oil had saponification value (S.V) of 171.603, iodine value (I. V) of 71.235, acid value (FFA) of 0.982, and peroxide value (Pe.V) of 14.016. The refractive index and density was found to be 1.4649,0.9108 respectively. The screening for glycosides was done by acid hydrolysis method using O.1M hydrochloric acid, and Thin Layer Chromatography (TLC), which indicated absence of the glycosides in the n-hexane extracted, wet rendered, mechanically extracted and filtered oil samples, as well as the ethanol deglucosylated seed kernel samples. The crude protein content of the de-fatted, ethanol de-glucosylated cake was determined by Micro-Kjeldahl method and was found to contain 65.75% of proteins. The species is recommended for domestication for vegetable oil and seed protein production in Kenya especially in the arid to semi arid lands (ASAL).

Mots clés : Thevetia peruviana / Plants / Ethnobotany

Présentation (Research Kenya)

Page publiée le 22 septembre 2010, mise à jour le 24 février 2018