Browsing by Author "Mgani, Quintino A."
Now showing 1 - 13 of 13
Results Per Page
Sort Options
Item Antimalarial Activity of Tanzanian Plants and Their Active Constituents: The Genus Uvaria 1(1991-08) Nkunya, Mayunga H.H.; Weenen, Hugo; Bray, Dorothy; Mgani, Quintino A.; Mwasumbi, L. B.Item Chemical compositions and mosquito repellency of essential oils from Artabotrys hexapetalus and Artabotrys rupestris(AJOL, 2015-05) Suleiman, R. A.; Mgani, Quintino A.; Nyandoro, Stephen S.The two Tanzanian Artabotrys species were investigated to establish the chemical composition and mosquito repellent properties of their essential oils. Hydrodistillation of leaves and stem bark of Artabotrys hexapetalus (L.f.) (Annonaceae) and stem bark of Artabotrys rupestris Diels (Annonaceae) gave essential oils which were analyzed by Gas Chromatography – Mass Spectrometry (GC-MS). While the oil from the stem bark of A. hexapetalus contained high amount of β-caryophyllene oxide, the oil from the leaves had both β- caryophyllene oxide and 11-hexadcyn-1-ol as the main components. The oil from the root barks of A. rupestris contained large amount of 6-(p-tolyl)-2-methyl-2-heptanol and (-)-spathulenol. β-Caryophyllene oxide, cadinol, cubenol, (-)-spathulenol and 7-methyl-4-methylene-1-(1-methylethyl)-naphthalene were identified as common constituents of the essential oils from the two plant species investigated. On evaluation for mosquito repellency, the essential oil from the leaves of A. hexapetalus was found to exhibit strong activity with RC50 = 1.81×10-5 mg/cm2 and 2.79×10-5 mg/cm2 for the first and the second fractions, respectively against female Anopheles gambiae s.s. mosquitoes. The repellency activity of essential oil from leaves were significantly higher than from stem bark, but less than that of the standard citronella oil used (RC50 = 4.1×10-6 mg/cm2). The observed high mosquito repellent activity for the essential oil fractions from A. hexapetalus could be attributed to the presence of β-caryophyllene oxide.Item Fatty Acid Profile and Physico-Chemical Parameters of Castor Oils In Tanzania(2014-12) Omari, Athumani; Mgani, Quintino A.; Mubofu, Egid B.This paper reports on the assessment of the quality and quantity of castor oil from castor seeds collected from different regions in Tanzania. The castor seeds from Arusha, Dar es Salaam, Dodo-ma, Iringa, Kagera and Morogoro regions in Tanzania were extracted by Soxhlet method using n-hexane and the oil yields were determined. The yields were 52.78%, 49.95%, 47.89%, 44.23%, 43.71% and 43.69% for Dodoma, Arusha, Iringa, Morogoro, Kagera and Dar es Salaam respectively. The physico-chemical parameters that were determined were refractive index (1.468-1.473), pH 5.7-6.3, viscosity (0.943-0.954), specific gravity (165.50-187.46 mg KOH/g Oil), saponification value (76.68-80 mg KOH/g Oil), iodine value (76.68-80.12 g I2/100 g Oil), acid value (0.44-1.97 mg NaOH/g Oil), free fatty acid (0.22-0.99) and peroxide value (10.79-13.73). Fatty acid profile of castor oil was analysed using Shimadzu GCMS and ricinoleic acid ranged from 83.5% to 92.3% of the total fatty acids in the castor oils.Item Fatty Acid Profile and Physico-Chemical Parameters of Castor Oils in Tanzania(Scientific Research, 2015) Omari, Athumani; Mgani, Quintino A.; Mubofu, Egid B.This paper reports on the assessment of the quality and quantity of castor oil from castor seeds collected from different regions in Tanzania. The castor seeds from Arusha, Dar es Salaam, Dodo-ma, Iringa, Kagera and Morogoro regions in Tanzania were extracted by Soxhlet method using n-hexane and the oil yields were determined. The yields were 52.78%, 49.95%, 47.89%, 44.23%, 43.71% and 43.69% for Dodoma, Arusha, Iringa, Morogoro, Kagera and Dar es Salaam respectively. The physico-chemical parameters that were determined were refractive index (1.468-1.473), pH 5.7-6.3, viscosity (0.943-0.954), specific gravity (165.50-187.46 mg KOH/g Oil), saponification value (76.68-80 mg KOH/g Oil), iodine value (76.68-80.12 g I2/100 g Oil), acid value (0.44-1.97 mg NaOH/g Oil), free fatty acid (0.22-0.99) and peroxide value (10.79-13.73). Fatty acid profile of castor oil was analysed using Shimadzu GCMS and ricinoleic acid ranged from 83.5% to 92.3% of the total fatty acids in the castor oilsItem Fatty Acid Profile And Physico-Chemical Parameters of Castor Oils in Tanzania(2014-12) Omari, Athumani.; Mgani, Quintino A.; Mubofu, Egid B.This paper reports on the assessment of the quality and quantity of castor oil from castor seeds collected from different regions in Tanzania. The castor seeds from Arusha, Dar es Salaam, Dodo-ma, Iringa, Kagera and Morogoro regions in Tanzania were extracted by Soxhlet method using n-hexane and the oil yields were determined. The yields were 52.78%, 49.95%, 47.89%, 44.23%, 43.71% and 43.69% for Dodoma, Arusha, Iringa, Morogoro, Kagera and Dar es Salaam respectively. The physico-chemical parameters that were determined were refractive index (1.468-1.473), pH 5.7-6.3, viscosity (0.943-0.954), specific gravity (165.50-187.46 mg KOH/g Oil), saponification value (76.68-80 mg KOH/g Oil), iodine value (76.68-80.12 g I2/100 g Oil), acid value (0.44-1.97 mg NaOH/g Oil), free fatty acid (0.22-0.99) and peroxide value (10.79-13.73). Fatty acid profile of castor oil was analysed using Shimadzu GCMS and ricinoleic acid ranged from 83.5% to 92.3% of the total fatty acids in the castor oils.Item Isomerization of Anacardic Acid: A Possible Route to the Synthesis of an Unsaturated Benzolactone and a Kairomone(Wiley, 2014-09) Mgaya, James E.; Mubofu, Egid B.; Mgani, Quintino A.; Cordes, David B.; Slawin, Alexandra M. Z.; Cole‐Hamilton, David J.Crystalline unsaturated lactone, 8-hydroxy-3-tridecyl-1H-isochromen-1-one (6) has been synthesized by isomerization of anacardic acid having heterogeneous alkyl side chains (a mixture of mono-, di-, and tri-unsaturated anacardic acid) (1). Hydrogenation of 8-hydroxy-3-tridecyl-1H-isochromen-1-one produced a saturated lactone, 8-hydroxy-3-tridecyl-3,4-dihydroisochromen-1-one (7). Isomerization of monoene anacardic acid resulted in a crystalline isoanacardic acid, (E)-2-hydroxy-6-(pentadec-1-enyl)benzoic acid (8) as a major product. This was then metathesized with 2-butene to give 3-prop-1-enylphenol (10). Both isomerization reactions used a 1,2-bis(ditertiarybutylphosphinomethyl)benzene modified palladium catalyst. The two products, 8-hydroxy-3-tridecyl-1H-isochromen-1-one and (E)-2-hydroxy-6-(pentadec-1-enyl)benzoic acid have been crystallographically characterized.Item Isomerization Of Anacardic Acid: A Possible Route To The Synthesis Of An Unsaturated Benzolactone And A Kairomone(Wiley, 2014-08) Mgaya, James E.; Mubofu, Egid B.; Mgani, Quintino A.; Cordes, David B.; Slawin, Alexandra M. Z.; Cole‐Hamilton, David J.Item Isomerization of Anacardic acid: A Possible Route to the Synthesis of an Unsaturated Benzolactone and a Kairomone(2014-08) Mgaya, James E.; Mubofu, Egid B.; Mgani, Quintino A.; Cordes, David B.; Slawin, Alexandra M. Z.; Cole‐Hamilton, David J.Item Stereoselective total syntheses of conduritols-F and -A from tricyclo[6.2.1.0 2 , 7 ]undeca-4,9-dien-3,6-dione(1995-06) Mgani, Quintino A.; Klunder, Antonius J.H.; Nkunya, Mayunga H.H.; Zwanenburg, BinneItem Synthesis of A Kairomone and Other Chemicals From Cardanol, A Renewable Resource(Wiley, 2012-09) Mmongoyo, Juma A.; Mgani, Quintino A.; Mdachi, Stephen J. M.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.Item Synthesis of a kairomone and other chemicals from cardanol, a renewable resource(2012-06-05) Mmongoyo, Juma A.; Mgani, Quintino A.; Mdachi, Stephen J. M.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.Synthesis of a tsetse fly kairomone component (3-propylphenol), a detergent [sodium 2-(dec-8-enyl)-6hydroxybenzenesulfonate], a polymer additive (1-octene), and a detergent precursor [3-(non-8enyl)phenol] using cardanol [3-(pentadec-8-enyl)phenol], has been accomplished. Both carbon– carbon double bond isomerization and metathesis methodologies were employed in the syntheses of these target molecules. The kairomone component was obtained, albeit in low yield, in three steps starting with cardanol. Synthesis of a new detergent, sodium 2-(dec-8-enyl)-6-hydroxybenzenesulfonate, was achieved by direct metathesis of cardanol with cis-2-butene followed by sulfonation and basification. Finally, synthesis of 1-octene and 3-(non-8-enyl)phenol was accomplished in one pot by direct metathesis of cardanol with ethylene. These products have been characterized spectroscopically, especially using 1H and 13C NMR.Item Synthesis Of Benzyl-Substituted Naphthalenes From Benzylidene Tetralones.(2012-04) Deck, Lorraine M.; Mgani, Quintino A.; Martinez, Andrea; Martinic, Alice; Whalen, Lisa J.; Vander Jagt, David L.; Royer, Robert E.Item Synthesis of Bifunctional Monomers by The Palladium-Catalyzed Carbonylation Of Cardanol And Its Derivatives(2016-02) Mgaya, James E.; Bartlett, Stuart A.; Mubofu, Egid B.; Mgani, Quintino A.; Slawin, Alexandra M. Z.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.