Chemical investigations of the cytotoxic plants: Lettowianthus stellatus and secamone parvifolia
| dc.contributor.author | Makangara, John Joseph | |
| dc.date.accessioned | 2020-12-08T10:20:00Z | |
| dc.date.available | 2020-12-08T10:20:00Z | |
| dc.date.issued | 1995 | |
| dc.description | Available in print form, East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF QK861.M3) | en_US |
| dc.description.abstract | This Thesis reports on phytochemical investigations of the root barks of two cytotoxic plants. Lettowianthus stellatus of the family Annonaceae and Secamone parvifolia of the family Asclepiadaceae. Chemical investigations on L. stellatus yielded two new compounds, a sesquiterpenoid 10-hydroxyhimachalen-1-one (53), and a dioxoaporphine alkaloid (55). These compounds were isolated from the chloroform and chanol extracts, respectively. Compound 53 was found to be mildly active when tested against shrimp larvae in the brine shrimp test whereas compound 55 was not tested due to the small amount of this compound as obtained during these investigations. The plant also yielded two known methyl esters of farnesoic acid derivatives, namely methyl 10, 11-epoxy-3,7,11-trimethyl- 10,11 –dihydroxy -3, 7, 11 –trimethyl- 2, 6 –dodecadienoate (28). The compounds were isolated from the chloroform and ethanol extracts, respectively. Compound 27 exhibited a mild toxicity against shrimp larvae in the brine shrimp test. Furthermore, two known compounds, liriodenine (7) and 3,4,5-trimethoxyphonol (52), together with a C18 acetylenic fatty acid 29 were isolated from the ethanol extract. Compound 29 was also isolated from the pet ether extract and it was found to have a mild toxicity against shrimp larvae and a mild antimalarial activity, having IC50 value of 29 and 28 µg/ml respectively against the multidrug resistance strain K1 and chloroquine sensitive strain NF54 of Plasmodium falciparum malaria parasites. The rest of the compounds were not tested for their lethality in the brine shrimp test. They were also not evaluated for their antimalarial activities. Plant materials of L. stellatus were collected from both the Udzungwa mountains (Morogoro region) and from Easter Usambara mountains (Tanga region). Plant materials collected from both localities were found to be containing the same constituents as revealed by TLC analysis and the compounds isolatedduring these investigations. Although Verdcourt had suggested that the plant materials growing from the two localities belong to two Lettowianthus species, the phytochemical results obtainedduring investigations reported in this thesis strongly suggest that the plant materials belong to one and the same plant species, viz. L. stellatus. Phytochemical studies on S.parvifolia afforded one tetracyelic triterpenoid. Namely cupha-7, 24,-dien-3β-o1 (butyrospermol) (56). The compound was isolated from the pet ether. Dichloromethane and water extracts. The compound was inactive in the brine shrimp test. It was also inactive against P. falciparum malaria parasite strains. | en_US |
| dc.identifier.citation | Makangara, J.J. (1995) Chemical investigations of the cytotoxic plants: Lettowianthus stellatus and secamone parvifolia, Master dissertation, University of Dar es Salaam | en_US |
| dc.identifier.uri | http://41.86.178.5:8080/xmlui/handle/123456789/13697 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of Dar es Salaam | en_US |
| dc.subject | Botanical chemistry | en_US |
| dc.subject | Annonaceae (Pawpaw) | en_US |
| dc.subject | Asdepiadaceae (Milkweed) | en_US |
| dc.title | Chemical investigations of the cytotoxic plants: Lettowianthus stellatus and secamone parvifolia | en_US |
| dc.type | Thesis | en_US |