|Keywords (Extracted from title, table of contents and abstract of thesis)
green algae, chaeiophora elegans (roth) agardh, chara contraria a braun ex kutzing, chlorococcum numicolum(nageli) rabenhorst, hydrodictyon reticulatum (linnaeus) lagerheim, rhizoclonium hieroglyphicum (ca agardh) kutzing, spirogyra hyaline cleve, tetraspora cylindrica( wahlenberg) agardh, tetraspora gelatinosa (voucher) desvaux, zygnema czurdae randhawa, zygnema stellinum(voucher) ca agardh, zygnema tenue kutzing
Eleven species of freshwater green algae i.e. Chaeiophora elegans (Roth) Agardh, Chara contraria A Braun ex Kutzing, Chlorococcum numicolum(Nageli) Rabenhorst, Hydrodictyon reticulatum (Linnaeus) Lagerheim, Rhizoclonium hieroglyphicum (CA Agardh) Kutzing, Spirogyra hyaline Cleve, Tetraspora cylindrica( Wahlenberg) Agardh, Tetraspora gelatinosa (voucher) Desvaux, Zygnema czurdae Randhawa, Zygnema stellinum(voucher) CA Agardh, Zygnema tenue Kutzing, have been collected from different areas of Hydrabad, Tando Muhammad Khan, Dadu and Jamshoro in the province of Sindh, Pakistan. These algae which belong to 2 Kingdoms, 3 phyla, 6 classes, 6 orders, 7 families and 8 genera have been taxonomically determined. All the them were found to be taxonomically known species. Their methanolic extracts were investigated for the fist time phycochemically as well as from the viewpoint of their bioactivity and the following major results obtained.
A variety of saturated and unsaturated fatty acids (FAs) were detected in the methanolic extract of these algal species and analysed as methyl esters qualitatively as well as quantitatively through GLC and GC-MS techniques. A few sterols and terpense have also been isolated and purified from them. Their structures were chemically elucidated through IR & UV, EI-, FAB-, FD-, GC-& HR-MS and 1H-& 13C-NMR spectroscopy. All natural products are being reported for the fist time from the corresponding algal species.
Altogether 42 different FAs have been detected including 14 saturated fatty acids (SFAs), 27 unsaturated fatty acids(UFAs) and one steroidal FA which was identified as D-norandrostane-16-carbosylic acid. The UFAs comprised of 13 monounsaturated fatty acids (MUFAs), 5 diunsaturated fatty acids(DUFAS), 5 triunsturated fatty acids (TUFAs) and 4 polyunsaturated fatty acids (PUFAs), indicating that UFAs of the investigated species exhibited greater diversity than that of SFAs. Practically in all the investigated species UFAs were found in a larger proportion (54-94%) than the SFAs(6-40%). Only in Rhizoclonium hieroglyphicum the SFAs were detected in a lager amount(66.29%), while in Tetraspora cylindrical (44.868 & 44.882%) and Zygnema czurdae (50.46 & 49.54%) and Zygnema czurdae (50.46 & 49.54%) both the categories of FAs were almost in equal quantity.
Pentadecylic (C15:0) and palmitic(C 16:0) acids were the most commonly occurring FAs, as they were detected in eight out to the nine investigated species. They were followed by oleic (C18:1) and nonadecylenic (C19:1)acids, which were detected in seven species. Pentadecatrienoic(C15:1) and haxadecatrienoic (C17:3) acids were observed in six investigated species. Tetraspora cylindrica exhibited the largest diversity as it contained 24 different FAs, and Zygnema stellinum appeared to be the least diverse species with 9 FAs. The FA-composition of the investigated freshwater algae, varied not only from order to order or family to family or genus but also from species to species, and no generalization may be made in this Member of the phylum Charophyta possessed only β-sitosterol and lacked transphytol.
Methanolic extract of the investigated algal species have been tested for their biological activities. While studying antibacterial activity, Shigellu boydii appeared to he the most sensitive bacterium, four of the nine investigated extracts displayed a positive activity against it by showing decrease in the bacterial population per unit area. This was followed by Klebsiella pneumoniae which was affected by the extracts of four algal species, All the tested algae of the phylum Volvocophy1a exhibited antibacterial activity, while most of the members of the phyla Chlorophyta and Charophyta were inactive. Among fungi one of the three facultative parasites. four of the six plant parasites and one tested saprophyte were affected by all the algae extracts. When antifungal activity was tested by food poisoning method, uniformly similar results were obtained against all the tested fungal organisms. The phytotoxic activity against Lemna aequinoctialis was observed to be 14 to 1110 % significant while that against L minor varied from 7 to13 % only. All the results of cytotoxic and insecticidal activities were non-significant. Chara col1lraria exhibited an appreciable amount of antitumour activity which enhanced with increasing concentration of the extract.