الفهرس 
Chapter 1 Literature ReviewOnly 14 pages are availabe for public view
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Abstract
C. sempervirens (lam.) is a medicinal plant known as Mediterranean cypress that possess a number of biological activities desired for human health This has enforced this study to clarify the chemical composition and the biological activities of this plant regarding antioxidant, antimicrobial and allelopathic activities of C. sempervirens. The biochemical determination of primary metabolites in C. sempervirens revealed that the moisture content, crude ash and crud fiber were within the acceptable limits of vegetable drugs. The plant contained crude lipid, crude protein as well as higher total carbohydrates. On the basis of the above-mentioned parameters, the aerial parts of C. sempervirens found to contain appreciable nutritive content with nutritional value of 268.56 kcal/100 g dry weight. The phytochemical screening of water, methanol and ethanol extracts of C. sempervirens revealed many active metabolites including tannins, phenolics and flavonoids. These active compounds were quantitatively analyzed during different seasons. The present study showed significant seasons-related variations in secondary metabolites content including flavonoids, phenolics and tannins in agreement with the previous studies reported that the accumulation of plant secondary metabolites varies substantially across seasons due to seasonal fluctuations in the environmental factors such as temperature, water availability and photoperiod, and to what extent they are synchronized with all abiotic stress factors. All the studied metabolites showed increase during summer periods and decrease in fall then in spring while the lowest levels were in winter. Regarding water extract, the phenolic content during different periods of the year expressed as mg gallic acid equivalent per gram dried extract could be descending ordered as July 2022 (182.34), October 2021(170.86), April 2022 (161.26) and January 2022 (158.55), the flavonoids content during different periods of the year expressed as mg catechine acid equivalent per gram dried extract could be descending ordered as July 2022 (88.16), October 2021(85.76), April 2022 (75.90) and January 2022 (72.78) and tannins content during different periods of the year expressed as mg tannic acid equivalent per gram dried extract could be descending ordered as July 2022 (11.22), October 2021(8.87), April 2022 (7.68) and January 2022 (7.17), respectively. Regarding ethanol extract, the phenolic content during different periods of the year expressed as mg gallic acid equivalent per gram dried extract could be descending ordered as July 2022 (226.11), October 2021(206.29), April 2022 (191.08) and January 2022 (180.22), the flavonoids content during different periods of the year expressed as mg catechine acid equivalent per gram dried extract could be descending ordered as July 2022 (41.55), October 2021(36.33), April 2022 (31.03) and January 2022 (28.83), the tannin content during different periods of the year expressed as mg catechine acid equivalent per gram dried extract could be descending ordered as July 2022 (15.02), October 2021(12.82), April 2022 (10.92) and January 2022 (9.56), respectively. phenolics and flavonoids present in the prepared extracts in variable quantities are well known for their potential as antioxidant components and antioxidant activity could be attributed to them. The free radical scavenging activity was estimated using diphenyl picryl hydrazyl (DPPH) assay. In this respect, the concentration of an antioxidant needed to diminish the initial concentration DPPH radical by 50% (IC50%) was used as a parameter for estimating the antioxidant activity. IC50%, is inversely proportional to the antioxidant activity. The obtained results in our investigation showed that Water, 80% methanol and 80% ethanol expressed high free radical scavenging activity with IC50 values of 0.034, 0.064 and 0.067 mg antioxidant /ml and AE values of 29.41, 14.93 and 15.63, respectively. The extracts could be descendingly ordered according to their antioxidant scavenging activity as water, 80% methanol and 80% ethanol, respectively.
The strongest activity was detected in water extract that was higher in its antioxidant activity than the ethanol. This antioxidant activity might be attributed to the presence of many active metabolites including phenolics, flavonoids, and tannins.
Microbial susceptibility test (well diffusion assay) was used to study the effect of C. sempervirens extracts against several pathogenic species of antibiotic resistant bacteria including three-Gram positive species (Staphylococcus aureus, Bacillus cereus and Staphylococcus epidermidis), four-Gram negative species (Escherichia coli, Enterobacter cloacae, Salmonella typhi and Pseudomonas aeruginosa) and one pathogenic fungus (Candida albican). Mthanol extract exhibited the broadest antimicrobial spectrum against the tested pathogenic microorganisms followed by ethanol while water showed no activity against any of the tested strains. The allelopathic bioassay of C. sempervirens illustrated by studying the phytotoxic effects of water extracts on seed germination and seedling growth of the targeted Echinocholae crusgalli and Oryza sativa grains. In our results, Echinocholae crusgalli seeds germination inhibited by all of the tested concentration of the water extract while the germination of Oryza sativa grains increased with increasing concentration in a dose dependent manner. Thus, different concentrations of the studied species were significantly inhibited shoot growth of Echinocholae crusgalli. Higher inhibition percentages were recorded at 10% concentration and the inhibition percent increased with increasing concentration. Also, the studied species extracts were significantly inhibited root growth of Echinocholae crusgalli in the same manner of shoot inhibition as higher inhibition percentages were recorded at 10% concentration and the inhibition percent increased with increasing concentration. Regarding, Oryza sativa the inhibition percent increase by increasing the concentration of the extract where the best concentration that stimulated the growth of Oryza sativa and provided the lowest inhibition percent was 10% that also perfectly inhibited the growth of Echinocholae crusgalli. Gas chromatography-Mass Spectrometry (GC-MS) analysis was applied to C. sempervirens methanol extract. 20 compounds were deduced. The results specified that pyrocatechol (13.10%), methyl oleate (28.62%), palmitic acid (5.32%), oleic acid (31.73%), and stearic acid (6.89%) are the most major abundant components comprising 85.66% of the total. Alternatively, three main classes were considered for the extracted volatile components of C. sempervirens by GC-MS were categorized as hydrocarbons (17.87%), esters of fatty acids (34.6%), and fatty acids (47.56%). The class of fatty acids is the major abundant although it compromises only five components owing to the majority of abundance of palmitic (5.32%), oleic (31.73%), and stearic acids (6.89%). The lipid “ester of fatty acid” class involved six volatile components with the major abundant molecule for methyl oleate (28.62%), while hydrocarbon class comprised nine components with the major abundance for pyrocatechol (13.10%). In conclusion, the extracts of C. sempervirens contain some important bioactive components with pronounced antioxidant, antimicrobial and allelopathic activities in addition to some important nutritional components. Further studies are recommended to be carried out on the plant in order to isolate, identify and characterize more active compounds so as to maximize the medicinal and nutritional value of this plant.