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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Synthesis and Study of Bioactive Compounds: I. Pyrethroids; II. Glutathione Derivatives

Chyan, Ming-Kuan 05 1900 (has links)
Part I: In the first study of pyrethroids, twenty-one novel pyrethroid esters bearing strong electron-withdrawing groups (e.g., halomethylketo and nitro groups) in the double bond side chain of the cyclopropane acid moiety have been synthesized and evaluated for insect toxicity. Rather than the usually employed Wittig reaction for these syntheses, the novel pyrethroid acid moieties were prepared by amino acidcatalyzed Knoevenagel condensations under mild conditions. In the second study of pyrethroids, fourteen pyrethroid-like carbonates were synthesized by condensation of a variety of alcohols and the chloroformates of the corresponding known pyrethroid alcohols.

Effects manufacturing method on surface mineralization of bioactive glasses

Pirayesh, Hamidreza Unknown Date
No description available.

A rapid techniques for the detection of actinophage and their putative hosts

Williams, Nicholas Jon January 1998 (has links)
No description available.

Sphingosine 1-phosphate signalling in guinea pig airway smooth muscle

Kong, Kok Choi January 2002 (has links)
No description available.

Novel solid-phase synthesis strategies for the preparation of heterocycles and guanidines

Kilburn, John Paul January 2002 (has links)
No description available.

Synthetic and metabolic studies on centrally acting amines /

Zhao, Zhiyang, January 1991 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 196-207). Also available via the Internet.

The isolation, structure elucidation and biological testing of compounds from Plectranthus hadiensis.

Dukhea, Shiksha. January 2010 (has links)
Three diterpenes of the abietane class, 7b-acetoxy-6b-hydroxyroyleanone (I), 6b,7b- dihydroxyroyleanone (II) and ent-pimara-8(14),15-diene-3b,11a-diol (III) and three triterpenes, 2a,3a,19 -trihydroxyurs-12-en-28-oic acid (IV), stigmasterol (V) and lupeol (VI) were isolated from the stem and leaf material of Plectranthus hadiensis. The structures of the compounds were elucidated using 2D NMR spectroscopy and Mass spectrometry. All six compounds have been isolated previously, but this is the first occurrence of compounds III-VI in Plectranthus hadiensis. This is also the first report of the isolation of a pimarene from Plectranthus, which provides a biochemical link to other genera in the family Lamiaceae where this class of compounds exist. Compounds I to IV were tested for their antibacterial activity against Enterococcus faecalis and Pseudomonas aeruginosa as well as their anticancer activity against breast (MCF-7), renal (TK- 10) and melanoma (UACC-62) cell lines. Compounds I and II exhibited good antibacterial activity against Enterococcus faecalis and Pseudomonas aeruginosa and although the entpimara- 8(14),15-diene-3 ,11 -diol (III), was inactive against E. faecalis, it was very active against P. aeruginosa. Compound IV, the triterpenoid, was structurally different to I-III and did not show any anti-bacterial activity. Compounds I-III were weakly active toward the cancerous renal (TK-10), melanoma (UACC-62) and breast (MCF-7) cell lines, while IV was inactive in all of the cell lines. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

Study of metallothionein-1 mRNA and its interaction with elongation factor 1 alpha

Fan, Kunbo January 2008 (has links)
Metallothioneins (MT) are small metal-binding proteins. Metallothionein isoform MT-1 alters localization from cytoplasm to nucleus as cells enter S phase. The perinuclear localization of MT-1 mRNA is essential for this nuclear localization. The localization of the MT-1 mRNA requires a signal in the 3'untranslated region (3'UTR). This thesis describes studies of the localization signal in the MT-1 3'UTR and its binding to transacting cellular proteins.

Targeting molecules to mitochondria

Finichiu, Peter György January 2015 (has links)
No description available.

Bioactivity of extracts and components of Pteleopsis myrtifolia

Rabie, Annelie 08 May 2008 (has links)
Combretaceae contain several species with bioactive properties - especially the genera Combretum and Terminalia. Pteleopsis myrtifolia and Quisqualis littorea belong to this family and have not previously been thoroughly investigated for their bioactivity. Leaf and fruit extracts of P. myrtifolia and leaf extracts of Q. littorea were separated by three different thin layer chromatography eluent systems. For all leaf and fruit material, the largest amount of acetone soluble material was extracted with extractants of intermediate polarity. Antibacterial activity of 30 extracts was investigated using a microplate serial dilution method and bioautography. The four most important nosocomial pathogens that are used worldwide namely two Gram-positive: Staphylococcus aureus and Enterococcus faecalis, and two Gram-negative bacteria: Pseudomonas aeruginosa and Escherichia coli were used as test organisms. Areas of growth inhibition were best defined after an eluent system that separates compounds of intermediate polarity had been used. The Gram-positive bacteria were most sensitive to some extracts of P. myrtifolia leaves. Fruit extracts exhibited minimum inhibitory concentrations (MIC) values as low as 0.04 mg/ml, less than that of the allopathic antibiotics, ampicillin and chloramphenicol. Q.littorea leaf extracts had an average MIC value of 0.32 mg/ml for Gram-negative bacteria. The average antibacterial activity expressed as total activity for each bacterium was higher in the leaves than in the fruit of P. myrtifolia. After considering the amount of antibacterial compounds extracted, toxicity of extractants to test organisms and miscibility of several extractants, acetone was eventually chosen as the best extractant for future extractions. Results obtained in this investigation showed clearly that P. myrtifolia leaves, fruit, and Q. littorea leaves contain several antibacterial compounds. Five different extracts of P. myrtifolia leaves were tested for growth inhibitory effects on different human cell lines (MCF-12, MCF-7, H157, WHCO3, HeLa). The non-cancerous MCF-12A cell line’s growth was not inhibited extensively, and the cancer cell lines - MCF-7, H157, WHCO3 and HeLa, differed in their sensitivity to the plant extracts. This indicated that the plant extracts’ effects were selective and not due to general toxicity. The effect of some extracts on certain cell lines, especially WHCO3, was growth inhibitory but not lethal. This is the desired effect – to inhibit growth of cancer cells, but not to be toxic to cells in general. The presence of tannin in extracts either promoted or inhibited growth inhibition of different cell lines. The same extractants that were used for cytotoxic tests were investigated for their antioxidant activity. All extracts gave positive scavenging capacity with the 1,2-diphenyl-2-picrylhydrazyl assay. The cold water, methanol and hot water extracts had vitamin C equivalents of 0.34, 0.20 and 0.147 mg/g respectively, all more than that of black tea. The solvent-solvent separation of P. myrtifolia leaves was started with acetone as an initial extractant. Separation was undertaken with immiscible solvents of different polarities. All fractions had antibacterial activity against the Gram-positive bacteria. The chloroform fraction was antibacterial to all bacteria tested, and had the largest amount of antibacterial compounds. Pure compounds were isolated from the chloroform fraction by column chromatography. One pure compound’s structure was elucidated as a pentacyclic triterpenoid, taraxerol (C30H50O). Taraxerol had MIC values of 0.04, 0.016, 0.63 and 0.31 mg/ml for the bacteria S. aureus, E. faecalis, P. aeruginosa and E. coli respectively. It significantly inhibited growth of the human lung cancer cell line H157 and did not display free radical scavenger activity. This is the first report of the antibacterial activity of several extracts from P. myrtifolia and Q. littorea, growth inhibition effects of several P. myrtifolia leaf extracts on the human cell lines MCF-12, MCF-7, H157 and WHCO3, the isolation of taraxerol from P. myrtifolia leaves, taraxerol’s antibacterial activity for above-mentioned test organisms, and growth inhibition effects on human cancer cell lines MCF-7, H157, WHCO3 and HeLa. / Thesis (PhD (Pharmacology))--University of Pretoria, 2008. / Pharmacology / unrestricted

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