Seham S. El Hawary

Composition and Bioactivities of the Essential Oil from Leaves of Lippia citriodora Kunth Cultivated in Egypt

Abstract Analysis of the hydrodistilled essential oil from the fresh leaves of Lippia citriodora Kunth (Verbenaceae), cultivated in Egypt at two different growth stages, by gas chromatography-mass spectrometry (GC-MS) resulted in the identification of 22 and 25 components in the oils prepared during the vegetative (June) and flowering (October) stages, respectively. The composition of the essential oils differed quantitatively and qualitatively according to the time of collection. The four major detected constituents (neral, geranial, dl-limonene and α-curcumene) exhibited remarkable differences between the two stages. Total percentage of oxygenated monoterpene aldehydes, represented by neral and geranial, decreased from 41.2 % to 35.2 % in June and October, respectively. On the other hand, the percentage of α-curcumene increased from 5.6 % to 14.5 %, while dl-limonene, the major monoterpene hydrocarbon was found only in June (10.6 %). The essential oil exhibited variable anti-inflammatory, antipyretic, analgesic and antioxidant properties. It also showed a moderate antibacterial activity.

Phenolic content and anti-hyperglycemic activity of pecan cultivars from Egypt.

Abstract Context: Pecans are commonly used nuts with important health benefits such as anti-hyperglycemic and anti-hyperlipidemic effects. Objective: A comparative investigation of the antihyperglycemic and total phenolic content of the leaves and shells of four pecan cultivars growing in Egypt was carried out. The selected cultivars (cv.) were Carya illinoinensis Wangneh. K. Koch. cv. Wichita, cv. WesternSchely, cv. Cherokee, and cv. Sioux family Juglandaceae. Materials and methods: Total phenolic and flavonoid contents of the leaves and shells of pecan cultivars were carried out using Folin–Ciocalteu’s and aluminum chloride assays, respectively. Moreover, HPLC profiling of phenolic and flavonoid contents was carried out using RP-HPLC-UV. In addition, in vivo anti-hyperglycemic activity of the ethanolic extracts (125 mg/kg bw, p.o.) of C. illinoinensis cultivars was carried out using streptozotocin (STZ)-induced diabetes in Sprague–Dawley rats for 4 weeks. Results and discussion: Phenolic contents were higher in shells than leaves in all studied cultivars, while flavonoids were higher in leaves. Leaves and shells of cv. Sioux showed the highest phenolics (251.7 µg gallic acid equivalent (GAE)/g), and flavonoid contents (103.27 µg rutin equivalent (RE)/g and 210.67 µg quercetin equivalent (QE)/g), respectively. The HPLC profiling of C. illinoinensis cultivars resulted in the identification of eight flavonoids (five of these compounds are identified for the first time from pecan), and 15 phenolic acids (six are identified for the first time from pecan). Leaves of cv. Sioux revealed the most potent decrease in blood glucose and glycated hemoglobin (HbA1c%) (194.9 mg/dl and 6.52%, respectively), among other tested cultivars. Moreover, leaves of cv. Sioux significantly elevated serum total antioxidant capacity (TAC) and reduced glutathione (GSH) (0.33 mMol/l and 30.68 mg/dl, respectively), and significantly suppressed the markers of both lipid peroxidation (malondialdehyde, MDA) and protein oxidation (protein carbonyl, PC) (14.25 µmol/ml and 3.18 nmol/mg protein, respectively). Conclusion: Different pecan cultivars showed significant variation in its phenolic and flavonoid contents and consequently their antioxidant and anti-hyperglycemic effects.

Comparative Study of Volatile Oil Content and Antimicrobial Activity of Pecan Cultivars Growing in Egypt

The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. β-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies.

DNA fingerprinting, biological and chemical investigation of certain Yucca species

Abstract Yucca aloifolia, Y. aloifolia variegata, Y. elephantipes and Y. filamentosa were investigated. DNA sequencing was performed for the four plants and a genomic DNA fingerprint was obtained and provided. The cytotoxic activities against four human cancer cell lines were investigated. The ethanolic extracts of leaves of Y. aloifolia variegata prevailed, especially against liver cancer HepG-2 and breast cancer MCF-7. In vivo assessment of hepatoprotective activity in rats also revealed the hepatoprotective potential of the ethanolic extracts of the four plants against CCl4- induced rats’ liver damage. Qualitative and quantitative analysis of the flavonoid and phenolic content of the promising species was performed using HPLC. The analysis identified and quantified 18 flavonoids and 19 phenolic acids in the different fractions of Y. aloifolia variegata, among which the major flavonoids were hesperidin and kaemp-3-(2-p-coumaroyl) glucose and the major phenolic acids were gallic acid and protocatechuic acid.

PHYTOCHEMICAL INVESTIGATION AND ANTIOXIDANT ACTIVITIES OF CERTAIN HAWORTHIA AND GASTERIA SPECIES

The cultivation of Haworthia limifolia Marloth, Gasteria carinata (Mill.) Duval and Gasteria minima Poelln is obviously increasing in Egypt as ornamental plants. Although they are widely used in folk medicine specially in South Africa, little is known about their phytochemical and pharmacological properties. Thus, this study was conducted to investigate their phytochemical and antioxidant properties. The preliminary phytochemical screening of their aerial parts revealed the presence of carbohydrates and/or glycosides, flavonoids, sterols, tannins and anthraquinones. The concentration of tannins was determined using modified vanillinhydrochloric acid assay. HPLC analysis of phenolics and flavonoids resulted in the identification of 31 compounds involving 21 phenolic compounds and 10 flavonoids. H. limifolia Marloth extract showed higher concentration of phenolic compounds and flavonoids followed by G. carinata (Mill.) Duval then G. minima Poelln. Salicylic acid and vanillic acid were the major identified phenolic acids. The investigated species were rich in polysaccharides whose chromatographic investigation recorded the presence of seven saccharides, glucuronic acid, stachyose, galacturonic acid, sucrose, glucose, galactose, rhamnose and arabinose in the three species, but their quantitative composition differed among the species. Stachyose, was the highest detected sugar in the three-investigated species. Concerning sugar acids, galacturonic acid was detected in the three-investigated species in higher concentration than glucuronic acid. H. limifolia Marloth and G. carinata (Mill.) Duval showed DPPH scavenging activity (IC50 = 143.6 μg/ml and 249.1 μg/ml, respectively), while G. minima Poelln. showed weak antioxidant activity (IC50 ≥ 3000 μg/ml) and this difference in antioxidant activity is closely related to the phytochemical findings.

INTER SIMPLE SEQUENCE REPEAT (ISSR) AND START CODON TARGETED POLYMORPHISM (SCOT) AS DISCRIMINATION TECHNIQUES BETWEEN CERTAIN APPLE AND PEAR CULTIVARS

Rosaceae is a large family in the plant regality, includes 3200 species in 115 genera such as Malus and Pyrus to which belong Malus domestica Borkh. fruits (apples) and Pyrus communis L. fruits (pears). Apples and pears have a wide variety of active constituents like anthocyanins, flavonoids, sterols, and tannins. P. communis and M. domestica fruits exhibit good antioxidant, antihyperglycemic, and chemopreventive activities. Botanists prefer to keep apple and pear under genus Pyrus but recently, American authors keep them distinct, apple under genus Malus and pear under genus Pyrus. Hybrids were developed to produce cultivars adapted to Egypt warm weather, so there is a large similarity between the different pear and apple cultivars which requires accurate and rapid techniques for their differentiation. The genetic discrimination between apple cultivars, Anna (1), Volus (2), Dorset golden (3) and pear cultivars, Le-Conte (4), MKM (5) and Flordahome (6) were carried out using start codon targeted and inter simple sequence repeat techniques with ten decamer primers, five for each technique. All primers gave bands with all cultivars with total 49 bands, 26 with ISSR and 23 with SCoT techniques, respectively with 27, 19 and 3 monomorphic, polymorphic and unique bands, respectively. According to combined dendrogram and similarity matrix, apple and pear cultivars grouped into two main groups, one contains the apple cultivars and the other contains pear cultivars with similarity coefficient 0.76-0.92. As a result, we can use ISSR and SCoT techniques for differentiation between apple and pear cultivars which have large morphological similarity.