Document Details
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Document Type |
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Thesis |
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Document Title |
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CHEMICAL STUDIES ON THE CONSTITUENTS OF SOME SAUDI MARINE ORGANISMS دراسات كيميائية على مكونات بعض اللافقاريات البحرية السعودية |
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Subject |
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Faculty of Sciences |
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Document Language |
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Arabic |
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Abstract |
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The objective of this thesis is to investigate and isolate the secondary metabolites content of some selected Red Sea marine invertebrates (red algae and soft coral), then evaluation of their biological activity. Thus, extracts of two marine organisms, red alga (Laurencia obtusa) and soft coral (Sarcophyton glaucum) were processed.
The Red Alga Laurencia obtusa collected from Salman Gulf, north of Jeddah, offered 17 pure metabolites represented different structural subclasses within the C15-acetogenines and sesquiterpenes derivatives; nine of them were previously undescribed compounds include two maneonenes, Jeddahenyne A (330) and B (331); an isomaneonene 12-debromo-12-methoxy isomaneonene A (332); two hexahydrofuro[3,2-b]furan-based C15-acetogenin, isolaurenidificin (333) and bromlaurenidificin (334); a cuparane-type sesquiterpenoid, 10-hydroxycuparaldehyde (335); two new nor-cuparanes, 3-hydroxy-15-nor-cuparan-10β-ol (336) and 2-bromo-3-hydroxy-15-nor-cuparan-10β-ol (337); as well as an eudesmanes-type sesquiterpenoid, eudesma-4(15),11-diene-5,7-diol (339). The eight known compounds include, cis-maneonene-A (54) and E (61), cuparene-3-ol (338), α-isobromocuparene (144), 4,10-dibromo-3-chloro-7(14)-chamigrene (85), 4,10-dibromo-3-chloro-7-chamigrene (95) teuhetenone A (147), and chabrolidione B (148).
Chemical investigation of the Saudi Red Sea soft coral Sarcophyton glaucum yielded four previously undescribed pyran-based cembranoidal diterpenes (340-343). Sarcoglauphine A (340) and B (341) could be viewed as conformers differ in the dihedral angle between H-7 and the pair of H-6a, 6b; sarcotrocheliol-B acetate (342) and sarcotrochelione (343) are bicyclic cembranoids. The chemical structures of all isolated metabolites were characterized employing spectroscopic methods (1D and 2D NMR, IR, UV and MS) and single crystal X-ray analysis.
The biologecal activity of all isolated compounds were studied. Compounds 330, 331, and 332 were isolated from Laurencia obtusa may be involved in the regulation of programmed death in the initiation and propagation of inflammatory responses. Compounds 333 and 334 showed weak cytotoxicity against A549, HepG-2, HCT116, MCF-7, and PC-3 cells. However, they exhibited a relatively potent cytotoxic effects against peripheral blood neutrophils with IC50 14 µM for 333, and 11µM for 334 versus dexamethasone 0.9 µM at 24 h of exposure. Compound 339 showed a relatively anticandidal activity, whereas 335 exhibited reasonable antibacterial activity against multidrug-resistant bacteria, especially towards Gram-positive ones. The cytotoxicity of isolated compounds from Sarcophyton glucum on viability of HepG2, MCF-7, and HCT116 cell lines was assessed. The obtained results showed that most of the activity was observed for compound 340 and compound 341 |
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Supervisor |
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Prof. Khalid Omar Al-Footy |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1439 AH
2017 AD |
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Co-Supervisor |
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Dr. Walied Mohamed Alarif |
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Added Date |
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Thursday, December 28, 2017 |
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Researchers
| ناهد عبيد باواكد | Bawakid, Nahed Obaid | Researcher | Doctorate | |
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