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Titre : Phytochemical Analysis of Lantana and Nerium leaves and the Antifungal Effects of their Extracts on Potato Dry Rot Disease Caused by Fusarium solani

Auteur : Omyma Algamer Ahmed, Abdalgabar

Université de soutenance : University of Gezira

Grade : Doctor of Philosophy in Pesticides and Toxicology (Pesticides) 2021

Résumé partiel
Plant secondary metabolites derived from weeds, medicinal and aromatic plants have been found to be aprotective bio-pesticidal agent, cost effective and safe to ecosystem and public health. In the present investigation, the ethanol extracts of Lantana camara and Nerium oleander L have proven to be interesting source of terpenoid and alkaloid derivatives for their bio-pesticidal properties. The broad objective of this study was to evaluate the antifungal activity effects of the Lantana camara and Nerium oleander L. Leaf extracts against the dry rot disease of potato crop caused by the fungus Fusarium solani which is an important disease of potato crop causing significant reduction in yield. The objective was achieved through different methodologies ; the Powdered leaves extract of N. oleander L. and L. camara were screened for detection of saponins, glycosides, terpenes, flavonoids, tannins, alkaloids, cardiac glycosides, and cyanogenic glycosides. The results of the qualitative analysis and phytochemical screening profiles indicated that, most of the natural products tested for are present in the N. oleander L leave extracts, regarding L. camara, most of the natural products tested for are present except saponins and glycosides. The chemical compositions of the leaf ethanol extract of N. oleander and L. camara were investigated using Gas Chromatography–Mass Spectroscopy (GC-MS). GC-MS analysis of N.oleander leaf ethanol extract revealed the existence of twenty two components identified, of them 4-0-Methylmannose, Squalene, n-hexadecanoic acid, Vitamin E ; 3,5-Dimethoxyacetophenone ; 9,12,15-octadecatrienoic acid and Benzofuran-2, 3-dihydro, represent 35.92%, 14.72%, 11.10%, 7,57%, 7.13%, 6.84 %, 3.19%, respectively, the other components were in the range from 1.3- 1.97 %. While L. camara major chemical component identified by GC-MS were found to be forty two of them, caryophyllene bicycle (3, 1, 0) hexane, 4-methylene-1-(1-methyl-lhumulene, bicycle (3, 1, 0) hexane-6-methanol,2-hydro, eucalyptol, caryophyllene oxide, represent 21.47%,11.68 %,10.93 %,9.75% 8.97%, 8..03%, respectively, the other components were in the range of,1.1- 3.53%. In this study the pathogenic fungus was isolated from infected Potato tubers showing Symptoms of dry rot disease which were collected from Port-sudan market and identified based on morphological and cultural characters as Fusarium solani f.sp.eumaartii. N. oleander L. and L. camara were screened in vitro for antifungal activity against Fusarium solani using poison food bioassay. Aqueous and ethanolic leaves extracts and fungicide Tillnour 25% Ec as standard control were prepared with differnt concentration (25, 50 and100 %) and evaluated under laboratory conditions.

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