Mahmoud A. Saleh

Chemical Composition, Antimicrobial and Antioxidant Activities of Essential Oils from Organically Cultivated Fennel Cultivars

Essential oils of the fruits of three organically grown cultivars of Egyptian fennel (Foeniculum vulgare var. azoricum, Foeniculum vulgare var. dulce and Foeniculum vulgare var. vulgare) were examined for their chemical constituents, antimicrobial and antioxidant activities. Gas chromatography/mass spectrometry analysis of the essential oils revealed the presence of 18 major monoterpenoids in all three cultivars but their percentage in each oil were greatly different. trans-Anethole, estragole, fenchone and limonene were highly abundant in all of the examined oils. Antioxidant activities of the essential oils were evaluated using the DPPH radical scavenging, lipid peroxidation and metal chelating assays. Essential oils from the azoricum and dulce cultivars were more effective antioxidants than that from the vulgare cultivar. Antimicrobial activities of each oil were measured against two species of fungi, two species of Gram negative and two species of Gram positive bacteria. All three cultivars showed similar antimicrobial activity.

Status and environmental impact of toxaphene in the Third World — A case study of African agriculture

Toxaphene was early introduced to Egypt by Hercules Co. in 1955 to combat the main cotton insect pests: the cotton leaf worm Spodoptera littoralis, the pink bollworm Pectinophera gossypiella, and the spiny bollworm Earias insulana. Formulated Emulsfiable concentrate (E.C.). Toxaphene (60% Chlorinated camphene) was used in four successive sprays during the cotton season on an area of 1.5 million acres at the rate of 2L/acre during the first three seasons (1956–1958). The rate was then increased to 3L/acre during the next two seasons (1959–1960). In the 1961 season, a disaster occurred when toxaphene even at 4L/acre failed to stop the infestation outbreak of the cotton leaf worm resulting in a loss of 50% of the national cotton yield of that season. This failure was caused by the build up of cotton leaf worm resistance to toxaphene. The total amount of toxaphene used during these six seasons was estimated to be 54,000 metric tons of the active ingredient. Although the use of Toxaphene in Egypt was banned in 1962 due to the irreversible cotton leaf worm resistance, new sources of toxaphene residues kept comming to Egypt across the River Nile Basin countries which were still heavily using toxaphene (Sudan, Ethiopia, Tanzania and Congo). As well, the illegal use of toxaphene by fishermen was another source of toxaphene pollution. The residues of toxaphene seem to be quite persistent as shown by the few studies carried out. Levels up to 10 ppm were detected in the River Nile water, soil and other biological samples in the Egyptian environment. (Saleh, 1981). Long term exposure to sublethal levels are expected to be a potential hazard to human health and the environment. A follow up program to monitor and assess the risk and hazards of toxaphene exposure is suggested for implementation in Egypt as a model for developing countries heavily exposed to toxaphene residues.

Fungicidal Activity of Artemisia herba alba Asso (Asteraceae)

The antifungal activity of Artemisia herba alba was found to be associated with two major volatile compounds isolated from the fresh leaves of the plant. Carvone and piperitone were isolated and identified by GC/MS, GC/IR, and NMR spectroscopy. Antifungal activity was measured against Penicillium citrinum (ATCC 10499) and Mucora rouxii (ATCC 24905). The antifungal activity (IC50) of the purified compounds was estimated to be 5 μ g/ml, 2 μ g/ml against Penicillium citrinum and 7 μ g/ml, 1.5 μ g/ml against Mucora rouxii carvone and piperitone, respectively.

Uscharin, the most potent molluscicidal compound tested against land snails.

Calotropis procera, is a shrub with broad ovate fleshy leaves that grows wild in the Egyptian deserts. The plant was discovered to be highly toxic to the land snailsThepa pisana. The active ingredient responsible for the molluscicidal activity was isolated from its latex by solvent extraction and partitioning and was finally purified by fractional crystallization from 95% aqueous ethanol. The purity of the isolated material was monitored by TLC. Chemical identification was carried out using mass, infrared, and proton magnetic resonance spectroscopic methods. The active compound was found to be uscharin, and its identity was confirmed by comparing its spectroscopic data with the literature values. The isolated compound was 128 times more toxic than methomyl to the snails tested.

Isolation, structural elucidation of flavonoid constituents from Leptadenia pyrotechnica and evaluation of their toxicity and antitumor activity

An investigation of Leptadenia pyrotechnica (Forsk.) Decne (Asclepiadaceace) chemical constituents led to the isolation of six flavonoids, kaempferol-3-O-α-l-rhamnopyranosyl (1′″→6″)-O-β-d-glucopyranoside (E-I.1), kaempferol-3-O-β-d-rhamnopyranosyl (1′″→6″)-O-β-d-glucopyranoside (E-I.2), texasin-7-O-β-d-glucopyranoside E-II.2, kaempferol-3-O-β-d-glucopyranoside (E-III.1), kaempferol (E-IV.1) and kaempferide-3-O-α-l-rhamnopyranosyl (1′″→6″)-O-β-d-glucopyranoside (E-I.1a). The isolation of these compounds was carried out using Sephadex LH-20 low pressure liquid chromatography (LPLC), preparative paper chromatography (PC), and high performance liquid chromatography (HPLC). The chemical structures of the isolated compounds were established by mass spectrometry (FAB- and EI- techniques), nuclear magnetic resonance NMR (1H-, 13C- and COSY) spectral data and ultraviolet (UV) spectroscopic techniques. The acute toxicity of total alcoholic and total flavonoid extracts were examined by brine shrimp. The LC50 values were 11.89 and 84.14 ppm for the total alcoholic and total flavonoid extracts, respectively. The mortality rates of the isolated flavonoid fractions of E-I, E-I.1, E-I.2 represent the higher percentages of mortality compared with the rest of the flavonoid fractions. The plant exhibited activity as an antitumor agent in the initial potato disc screen.

Regional distribution of lead in human milk from Egypt

Bioaccumulation of lead during chronic exposure and its mobilization and secretion with mothers milk constitute a serious health hazard to the newly born children. Lead levels in human breast milk of 120 Egyptian women representing 20 different governorates throughout Egypt were determined using a graphite furnace Atomic Absorption spectrometer. According to the daily permissible intake (DPI) value established by the WHO of 5.0 micrograms/kg/d in mothers milk, the mean values of lead were around the permissible level in most of the Egyptian governorates. However, lead levels in mothers milk from Alexandria, Assiut and Cairo were significantly higher than the permissible value. Higher lead levels in mothers milk from these governorates may be attributed to heavy automobile traffic using leaded gasoline in addition to the use of lead water pipelines in these areas.

Free Radical Scavenging and Antioxidant Activities of Silymarin Components

Silymarin is an over the counter food supplement that is sold as a liver enhancement and liver protection preparation. It is a major constituent of the seeds of Silybum marianum which is composed of a mixture of seven major components and several minor compounds. The seven major components: taxifolin, silychristin, silydianin, silybin A, silybin B, iso-silybin A and iso-silybin B were isolated and purified from the crude mixture of silymarin using preparative high performance liquid chromatography to determine which were the most effective for liver protection. Free radical scavenging, hydroxyl radical antioxidant capacity, oxygen radical antioxidant capacity, trolox-equivalent antioxidant capacity and total antioxidant capacity antioxidant activities were determined for each of the individual purified components as well as the crude silymarin mixture. Taxifolin was the most effective component for scavenging free radicals in the DPPH assay with an EC50 of 32 µM far more effective than all other components which showed EC50 ranging from 115 to 855 µM. Taxifolin was also found to be the most effective antioxidant in the oxygen radical antioxidant capacity (ORAC) assay with a trolox equivalent of 2.43 and the second most effective in the hydroxyl radical antioxidant capacity (HORAC) assay with a gallic acid equivalent of 0.57. Other antioxidants assays did not show significant differences between samples.

Comprehensive assessment of antioxidant activity of essential oils.

UNLABELLED Essential oils have been studied for their unique ability to act as antioxidants. Antioxidant activities of 423 essential oils of 48 different botanical families were evaluated for their antioxidant activities as free radical scavenging agents using the 1,1-diphenyl-2-picrylhydrazyl method. Seventy-three oils showed 50% or more inhibition at a concentration of 1.25 mg/mL. The 73 most active oil samples were further evaluated for their scavenging activities using series of dilutions to estimate their EC(50) . The EC(50) of the 73 most active oils ranged from 4 to 2000 μg/mL. Oils having an EC(50) of less than 300 μg/mL (20 selected samples) were subjected to β-carotene bleaching antioxidant activity test and more detailed analysis including thin layer chromatography, gas chromatography/mass spectrometry, high performance liquid chromatography and bioautography. Essential oils of the botanical families Lamiaceae and Myrtaceae were the most effective antioxidants. Thymol and carvacrol were the major constituents in most of the essential oils of the family Lamiaceae and eugenol was the major terpene in all of the essential oils of the family Myrtaceae. PRACTICAL APPLICATIONS Supplementation of food with spices containing essential oils may counteract and retard the process of oxidative damage, lipid oxidation and elevate antioxidant activity of the final product.

Chemical, microbial and physical evaluation of commercial bottled waters in greater Houston area of Texas

Due to the increased demand and consumption of bottled water in the United States, there has been a growing concern about the quality of this product. Retail outlets sell local as well as imported bottled water to consumers. Three bottles for each of 35 different brands of bottled water were randomly collected from local grocery stores in the greater Houston area. Out of the 35 different brands, 16 were designated as spring water, 11 were purified and/or fortified tap water, 5 were carbonated water and 3 were distilled water. Chemical, microbial and physical properties of all samples were evaluated including pH, conductivity, bacteria counts, anion concentration, trace metal concentration, heavy metal and volatile organics concentration were determined in all samples. Inductively coupled plasma/mass spectrometry (ICPMS) was used for elemental analysis, gas chromatography with electron capture detector (GCECD) as well as gas chromatography mass spectrometry (GCMS) were used for analysis of volatile organics, ion chromatography (IC) and selective ion electrodes were used for the analysis of anions. Bacterial identification was performed using the Biolog software (Biolog, Inc., Hayward, Ca, USA). The results obtained were compared with guidelines of drinking water recommended by the International Bottled Water Association (IBWA), United States Food and Drug Administration (FDA), United States Environmental Protection Agency (EPA) and the World Health Organization (WHO) drinking water standard. The majority of the analyzed chemicals were below their respective drinking water standards for maximum admissible concentrations (MAC). Volatile organic chemicals were found to be below detection limits. Four of the 35 brands of the bottled water samples analyzed were found to be contaminated with bacteria.

Nematicidal activity of terpenoids

Thirty four phytoterpenoids were evaluated for their nematicidal effect using the model nematode Caenorhabditis elegans. Nematicidal activities of the tested compounds at concentrations of 50 μg/mL showed wide variation in their effects ranging from no effect, weak, moderate and strong effects. Terpenoids exerting 50% or higher mortality at 50 μg/mL were further tested at five different concentrations to calculate the concentration that will kill 50% of the nematode population (LC50). Among the most effective terpenoids were carvacrol, thymol, nerolidol, α-terpinene, geraniol, citronellol, farnesol, limonene, pseudoionone and eugenol in a descending order. These compounds exhibited a dose-dependent effect. The results suggest that the selected monoterpenoids and essential oils with a high concentration of these compounds mayprovide potential natural nematicides and merit further study as botanical nematicides for the control of both plant and animal parasitic nematodes. In general, oxygenated terpenoids and phenolic terpenoids exhibited higher nematicidal activity than hydrocarbons terpenoids.