الفهرس 
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Abstract
The present study aimed to evaluate the antifungal effect of some medicinal plant extracts against phytopathogenic fungi isolated from potato tubers and tomato fruits in the post-harvest period before arrival to the consumer to find out a natural and safe biological control method as alternative for chemical pesticides.
The infected potato tubers and tomato fruits showing symptoms of rotten were collected randomly. After isolating the associated fungi, four phytopathogenic fungi were identified as follow Alternaria alternata, Mucor hiemalis, Geotrichum candidum and Fusarium oxysporum.
Twelve kinds of wild or cultivated plants were collected: Azadirachta indica, Cakile maritima, Calligonum comosum, Capparis sinaica, Chenopodium polygonoids, Eucalyptus citriodora, Malva parviflora, Mesembryanthemum, Moringa oleifera, Ricinus communis, Ziziphus spina-christi, Zygophyllum aegyptium in addition to 3 plants purchased from a local market: Cinnamomum zeylanicum, Syzygium aromaticum, and Zingeber officinale. The ethanolic extracts of these plants were prepared using ethanol 95% to evaluate their antifungal activity against isolated fungi.
Only two extracts showed antifungal activity, the ethanolic extract of S. aromaticum recorded the highest value of inhibition, while the E. citriodora extract showed little antifungal activity and showed no
effect against Alternaria alternata. On the other hand, the fungal isolates showed different degrees of response and Mucor hiemalis was the most sensitive to the extract when compared to other fungi.
Determination of MIC showed that lowest concentration S. aromaticum extract was 2.5% for Mucor hiemalis, Alternaria alternata, Geotrichum candidum and 12.5% for Fuarium oxysporum.
Qualitative and quantitative preliminary phytochemical screening for S. aromaticum was carried out to determine the bioactive compounds of the secondary metabolites. Results showed the presence of chemical constituents like of phenols, alkaloids, saponins, flavonoids, and tannins in addition to protein, carbohydrate and oil contents.
Chemical profile for ethanolic crude extract of clove was predicted by GC/MS which exhibited the crude extract contained 18 different chemicals such as hexadecenoic and octadecanoic esters, eugenol, trans-caryophyllene, humulene, anthracenedione, Lucenin 2 Cedran-diol, and Citroflex A.
TLC technique succeeded in separating three fractions. All detected bands on TLC plate were screened for antifungal activity against all isolated fungi. Only one fraction (Rf = 0.87) showed an antifungal activity but less effective than the crude extract.
The ratio of total protein and total carbohydrate were determined in both extract and separated fraction. The values belong to the fraction were too much little than those belong to the original crude extract due to lose of large quantities of carbohydrates and protein during partial purification process on TLC plate.
The components of the separated fraction was also analyzed using (GC/MS) which exhibited the presence of only one peak as an indication for high purity of the fraction, the compound predicted to be glucoside β-sitosterol.