Browsing by Author "Magadula, Joseph Jangu"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Phenylpropanoids, aporphine and indole alkaloids from three species of annonaceae
    (University of Dar es Salaam, 2000) Magadula, Joseph Jangu
    The investigations reported in this Thesis were aimed at phytochemical analysis for biologically active and other natural products from three plants of the family Annonaceae, namely Friesodielsia obovata, Asteranthe lutea and Uvariodendron sp. (smelling). Phytochemical investigations of Friesodielsia obovata were carried out on the root and stem barks and fruits, which were collected from Ugowola Village, Tabora Region, Tanzania. The ethanol extract of the root bark yielded two known flavanones, 5,7-dihydroxy-6,8-dimethylflavanone and 5,7-dihydroxy-6-formyl-8- methylflavanone. Other compounds obtained from the root bark were (-)-crotepoxide and benzyl benzoate. In addition to the above compounds, the dichloromethane extract of the stem bark yielded a hitherto unreported aporphinoid, friesobovatine. The n-hexane extract of the fruits of F. obovata yielded the triglyceride of oleic acid as a major compound and a mixture of (3-sitosterol and stigmasterol. Phytochemical analysis of the ethanol extract of the root bark of Asteranthe lutea collected from Kwamngumi Forest Reserve in the East Usambara Mountains, Muheza District in Tanga region, yielded two diprenylated indoles, the asteranthine derivatives 2\3'-epoxyasteranthine and 2',3'-dihydroxyasteranthine together with a naphthoquinone, 7-methyljuglone. 7-Methyljuglone exhibited antifungal activity in the plate diffusion test against Candida albicans, with an inhibition zone of 15 mm at a concentration of 100 |Xg/ml. The two asteranthines were inactive against the above organisms when tested in vitro. Chemical analysis of the ethanol extract of the root bark of Uvariodendron sp. (smelling) which was collected from Kwamngumi Forest Reserve in the East Usambara Mountains in Muheza District, Tanga region, led to the isolation of two phenyl propene derivatives elemicin and 3',4',51 -tri^iethoxycinnamy 1 alcohol from the medium polar fractions. Besides the above compounds, a mixture of two catechin derivatives, cinchonain la and cinchonain lb were isolated from the polar fractions. An attempt to separate the cinchonains was not possible due to the small amount of the sample that was obtained. Elemicin was active against Candida albicans in vitro, with an inhibition zone of 17 mm at a concentration of 100 |ig/ml.