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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.
1

Isolation Of A Bioactive Compound Hypericin From A Medicinal Plant Hyppericum Perforatum L. Using Basic Chromatography Methods

Duru, Betul 01 December 2003 (has links) (PDF)
Medicinal plants which have been widely used in folk medicine are known to contain important biologically active compounds. Most of today&rsquo / s synthetic drug raw materials are to be prepared by using plant originated compounds as the starting material. Hypericum Perforatum is one of the medicinal plants that grows in Europe, Western Asia and Northern Africa and is distinguished by its golden yellow flowers. The common name of the plant is St. John&rsquo / s wort. From the time of the ancient Greeks down through the middle Ages, the plant was considered to be imbued with magical powers and was used to ward off evil and protect against disease. As a practical folk-remedy, it has been used widely to heal wounds, remedy kidney troubles, and alleviate nervous disorders, even insanity. In the last thirty years, Hypericum perforatum has undergone extensive clinical and laboratory testing. The extract of the flower is a red liquid that contains many biologically active compounds such as: naphtodianthrones (hypericin, pseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, hyperoside, quercitrin, isoquercitrin, rutin, campferol, myricetin, amentofloavone), procyanidins (procyanidin, catechin, epicatechin polymers) , tannins (tannic acid), essential oils (terpenes, alcohols), amino acids (GABA, Cysteine, glutamine, leucine, lysine, ornithine, praline, threonine), phenyl propanes (caffeic acid, chlorogenic acid), xanthones (keilcorin, norathriol), organic acids peptides and polysaccharides (other water soluble compounds). These compounds have previously been isolated using HPLC method. The aim of this study is to isolate the main biologically active compound groups of Hypericum Perforatum and simply characterize the compounds with TLC, UV-VIS spectroscopy, NMR spectroscopy using standard compounds as references.
2

An investigation of the natural products composition of Porphyra capensis (a red seaweed)

Yalo, Masande Nicholas January 2017 (has links)
Magister Scientiae - MSc (Chemistry) / Plants have been widely used in traditional medicine for a number of ailments, among which may be included infectious diseases such as colds, influenza, chicken pox, TB, etc. as well as lifestyle diseases such as diabetes and cancer. Seaweeds have also been shown to contribute to the maintenance of health through their nutritional and medicinal properties and recently, a great deal of interest has developed towards the isolation of bioactive compounds from marine sources due to their numerous health benefits. Furthermore, marine algae are valuable sources of structurally diverse metabolites with scientifically proven therapeutic claims. Chemical constituents of red seaweed, Porphyra capensis was investigated in this present study along with subsequent brine shrimp lethality assay analysis of the crude extracts. The compounds isolated from the plant were from the hexane (6) and butanol (2) extracts. These compounds were all isolated and purified by various chromatographic techniques, namely silica gel chromatography, Sephadex LH-20 gel as well as C18 reversed phase silica gel. The structures of the isolated compounds were analysed and characterised by NMR, GC-MS, ESI MS and FTIR spectroscopy. Eight compounds were isolated and identified as phytol, desmosterol, 9-eicosenoic acid, 5,8,11,14,17-eicosapentanoic acid, palmitic acid, methyl (E)-hexadec-9-enoate, glycerol and compound 1 (novel compound). All the compounds were isolated from Porphyra capensis for the first time. The hexane, butanol and methanol extracts were found to be non-toxic with the brine shrimp test LC50 value at least two times greater than ?g/ml.

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