Browsing by Author "Joseph, C. C."

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    Composition of Non Volatile Oils and Antimicrobial Activities of Extracts from Monanthotaxis Discolor, and an Undescribed Uvariondedron Species
    (2012) Sumary, Dominic; Mgina, Clarence A.; Joseph, C. C.
    The chemical compositions of non volatile oil extracts from two Annoneceous plant species Monanthotaxis discolor and an undescribed Uvariodendron species which are endemic to Eastern Arc Mountains, Tanzania were determined by GC-MS. The biological activities of extracts and fractionated samples were also determined. Both methanol and dichloromethane extracts of the root bark of M. discolor showed mild antimicrobial activity and had positive brine shrimp test (BST). The BST test for dichloromethane extract of M. discolor root bark were LC50 41.794 µg/ml and that of methanol extract showed LC50 13.560 µg/ml. The petroleum ether and dichloromethane extracts of root bark of Uvariodendron species showed cytotoxicity of LC50 33.06 µg/ml and LC50 35.35 µg/ml, respectively. Twelve major constituents were identified from the dichloromethane extract of M. discolor root bark of which the following compounds were in high composition; α- cadinol (42.85%), (-)-alloaromadendrene (11.7%) aristolone (10.57 %), γ-cadinene (8.72%), δ- cadinene (3.44%) and cubenene (2.28%). The Second fraction of the third repeated column chromatography from the VLC fraction of dichloromethane extract and the first fraction of the VLC of methanol extract root bark revealed, among others 23 components of which the most abundant were; (-)-alloaromadendrene (15.1%), T-cadinol (8.08%), chamigren (5.3%) and γ- Cadinene (5.1%). Other components were also identified from other methanol fractions; (+)- aromadendrene, (18.2%), (-)-alloaromadendrene (12.8%), 4,9-muurodiene (5.3%), T-cadinol (83%), ς-himachelene (0.63%) and ledol (0.3%). The ethanol:dichloromethane (1:1) extract of the leaves of M. discolor showed four different components from those identified from root bark extracts among which heptacosane and tributylamine had percentage composition of (3.42%) and (0.34%),.respectively. The petroleum ether extract of the root bark of the undescribed Uvariodendron species revealed seven components of which the most abundant were methyl eugenol (38.7%) and elemicin (18.2%). For the ethanol extract of stem bark oil mixtures the most abundant components were δ-cadinol (0.25%), methyl eugenol (0.12%), isoelemecene (0.04%), and diisooctyphthalate (0.02%).
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    In Vitro Cytotoxicity of Some Medicinal Plants Used in Traditional Medicine in Tanzania
    (2011) Kisangau, Daniel P.; Lyaruu, Herbert V. M.; Hosea, Ken M.; Joseph, C. C.; Bruno, L. N.; Devkota, Krishna P.; Bogner, T.; Sewald, Norbert
    Plants used in traditional medicine in Tanzania were screened for their cytotoxicity using the brine shrimp and CellTiter-BlueTM cell viability assays. Dichloromethane extracts of Capparis erythrocarpos, Cussonia arborea, Dracaena steudneri, Lannea schimperi, Pseudospondias microcarpa, Rauvolfia vomitoria, Sapium ellipticum and Zehneria scabra exhibited various cytotoxic activities against brine shrimp larvae. Only semi-purified fractions of C. erythrocarpos, C. arborea, D. steudneri, Lannea schimperi and S. ellipticum and one pure compound Lup-20(29)-en-3-one (1) from S.ellipticum were tested against K562 Leukaemia cell line using the CellTiter-BlueTM cell viability assay method. In the brine shrimp lethality assay, P. microcarpa was the most toxic plant with an LC50 value of 1.9 μg/ml (95%CI, 1.6-2.2 μg/ml) , while Z. scabra was the least toxic plant with LC50 value of 179.4 μg/ml (95%CI, 156.1-213.9 μg/ml). In the CellTiter-BlueTM cell viability assay, the mean % cell vitality growth for the fractions of each of the five plant species C. arborea, C. erythrocarpos, D. steudneri, L. schimperi and S. ellipticum were 43.1%, 67.2%, 82.1%, 52.3% and 87.6% respectively, with P<0.0001 and 95% confidence intervals (CI) of 54.746-81.082 μg/ml. The IC50 concentration for compound Lup-20(29)-en-3-one (1) was 1.747x10-6 μM with 95% confidence intervals (CI) of 3.019x10-7 to 1.011x10-4 μM. Results indicate that most of the extracts tested were relatively non-toxic hence supporting the inherent use of these plants in traditional medicine.