Nader A. Ashmawy

Chemotyping of diverse Eucalyptus species grown in Egypt and antioxidant and antibacterial activities of its respective essential oils

The chemical composition of the essential oil from the leaves of Eucalyptus camaldulensis, Eucalyptus camaldulensis var. obtusa and Eucalyptus gomphocephala grown in northern Egypt was analysed by using GC-FID and GC–MS techniques. The antibacterial (agar disc diffusion and minimum inhibitory concentration methods) and antioxidant activities (2,2′-diphenypicrylhydrazyl) were examined. The main oils constituents were 1,8-cineole (21.75%), β-pinene (20.51%) and methyleugenol (6.10%) in E. camaldulensis; spathulenol (37.46%), p-cymene (17.20%) and crypton (8.88%) in E. gomphocephala; spathulenol (18.37%), p-cymene (19.38%) and crypton (16.91%) in E. camaldulensis var. obtusa. The essential oils from the leaves of Eucalyptus spp. exhibited considerable antibacterial activity against Gram-positive and Gram-negative bacteria. The values of total antioxidant activity were 70 ± 3.13%, 50 ± 3.34% and 84 ± 4.64% for E. camaldulensis, E. camaldulensis var. obtusa and E. gomphocephala, respectively. The highest antioxidant activity value of 84 ± 4.64% could be attributed to the high amount of spathulenol (37.46%).

Essential Oils of Mint between Benefits and Hazards

Abstract The history of local Egyptian mint dates back to at least 1,000 BC, when the ancient Egyptians used it as part of their herbal medicine as found in Ebers papyrus. Our study focused on essential oil composition of local and recently introduced Mentha sp. and either suitability or toxicity for humans as traditional medicines. Leaf oils composition of four different Mentha sp.; spicata L. “mint”, longifolia L. “wild mint”, suaveolens “apple mint” and piperita “chocolate” of Egypt were analyzed using GC and GC-MS. The antibacterial (agar disc diffusion and minimum inhibitory concentrations methods) and antioxidant activities (2,2- diphenypicrylhydrazyl (DPPH) and β-carotene-linoleic acid assays) were examined. Main oils constituent were 1-carvone (53.90 %), pulegone (56.43 %), piperitenone oxide (35.14 %) and L-menthol (30.84 %) in Mentha sp.; spicata L., longifolia L., suaveolens “Apple Mint” and piperita “Chocolate”; respectively. The essential oil from M. longifolia demonstrated strong antibacterial activity against all tested plant and human bacterial pathogens, followed by apple mint. The highest total antioxidant activity was found in M. Spicata (79-85 %); supporting ancient Egyptians believes and traditional folk. M. longifolia and M. piperita leaves essential oils enclosed toxic compounds and possible to use of Mentha oils as alternative of antibiotics.

In vitro antibacterial, antifungal and antioxidant activities of Eucalyptus spp. leaf extracts related to phenolic composition

Abstract The crude methanolic extracts from leaves of Eucalyptus camaldulensis L., E. camaldulensis var obtusa and E. gomphocephala grown in Egypt were investigated to explore their chemical composition as well as their antibacterial, antifungal and antioxidant activities. Major phenolics found were ellagic acid, quercetin 3-O-rhamnoside, quercetin 3-O-b-D-glucuronide, caffeic acid and chlorogenic acid. The antioxidant activities were examined by the 2,2′-diphenypicrylhydrazyl (DPPH) and β-Carotene-linoleic acid assays. E. camaldulensis extracts showed the highest phenolic content, antioxidant and antimicrobial activities compared to other cultivars. MIC values reported for antibacterial activity of E. camaldulensis ranged from 0.08 μg/mL (Bacillus cereus) to 0.22 μg/mL (Staphylococcus aureus), while MBC values ranged from 0.16 μg/mL (Dickeya solani and B. cereus) to 0.40 μg/mL (S. aureus). The inhibitory activities against growth of bacteria and fungi used is an indication that E. camaldulensis a might be useful resource for the development and formulation of antibacterial and antifungal drugs.

Antibacterial activity of extracted bioactive molecules of Schinus terebinthifolius ripened fruits against some pathogenic bacteria

The aim of this work is to identify the chemical constituents and the bioactivity of essential oil (EO), acetone extract (ACE) and n-hexane extract (HexE) of S. terebinthifolius ripened fruits using GC-MS. Total phenolic content and antioxidant activity of extracts were determined using the Folin-Ciocalteu and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assays, respectively. The toxicity against the growth of Acinetobacter baumannii, Bacillus subtilis, Escherichia coli, Micrococcus flavus, Pseudomonas aeruginosa, Sarcina lutea, and Staphylococcus aureus was determined with measuring the inhibition zones (IZs) using the disc diffusion method at the concentrations from 125 to 2000 μg/mL, also, the minimum inhibitory concentrations (MICs) using 96-well micro-plates and ranged from 4 to 2000 μg/mL. The major components in EO were α-pinene (36.9%), and α-phellandrene (32.8%). The major components in ACE were oleic acid (38.7%), α-phellandrene (13.33%), and δ-cadinene (11.1%), while the major methyl esters of fatty acids detected in HexE were oleic (12.8%), and palmitic (10.9%). The EO showed good activity against the growth of Staph. aureus and P. aeruginosa with MIC values of 16 μg/mL and 32 μg/mL, the ACE showed broad activity against the studied bacterial pathogens with MIC values ranged from of 4-128 μg/mL against the studied bacterial isolates, while HexE, however, showed weak antibacterial activity. The IC50 values of EO, ACE and HexE were 15.11 ± 0.99, 118.16 ± 1.7 and 324.26 ± 2.45 μg/mL, respectively, compared to IC50 of Tannic acid (23.83 ± 1.9 μg/mL) and butylated hydroxytoluene (BHT, 2.9 ± 0.1 μg/mL). Data suggested that the ripened fruits of S. terebinthifolius have potent antioxidant and antibacterial activities.

Molecular and Biological Identification of Erwinia amylovora Egyptian Isolates Compared with Other German Strains

Molecular and Biological Identification of Erwinia amylovora Egyptian Isolates Compared with Other German Strains Thirty one isolates of the enterobacterium Erwinia amylovora the causal agent of the fire blight disease were collected from different locations in Egypt and Germany. The E. amylovora (Ea) isolates were identified by biochemical tests and the obtained results were confirmed by polymerase chain reaction (PCR) using 16S universal primers. The results showed that, all the examined isolates are E. amylovora with different percentage of similarity. The phylogenetic tree constructed based on the DNA nucleotide sequences of the 16S rRNA gene revealed that the Egyptian isolates have specific roots and they are close similar to Italian isolate (AJ746202). Two specific genes Amsb1 and PEA29 plasmid were detected in all the examined isolates and amplicons with 1600 and 1200 bp were observed. Moreover, the pathogenicity for virulence using the immature pear fruits (IPF) test was carried out and results divided the 31 isolates into 3 virulent groups, it was evident that twelve isolates were highly virulent whereas three were moderately virulent and sixteen were weakly virulent. These isolates were also fingerprinted using RAPD-PCR, the constructed phylogenetic tree based on RAPD data divided the isolates into two major clusters; cluster 1 includes all Egyptian isolates whenever cluster 2 includes all German isolates. It can conclude that more specific genes are still need to discover to differentiate between the closely related Erwinia amylovora bacterial isolates.

Antibacterial activity of the bioactive compounds identified in three woody plants against some pathogenic bacteria

Three bacterial isolates were identified from infected potato tubers showing soft and blackleg like symptoms as well as one isolate from infected pear tree showing crown gall symptom. Conventional and molecular identification proved that bacterial isolates belonging to Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, Dickeya solani and Agrobacterium tumefaciens. The above plant bacterial isolates and human pathogenic bacteria Escherichia coli, Sarcina lutea, and Staphylococcus aureus were used for the bioassay. The chloroform leaf extracts from Duranta plumieri variegata, Lantana camara, and Citharexylum spinosum were assayed for their antibacterial activity by measuring the inhibition zones and minimum inhibitory concentrations (MICs). The suggested chemical compositions of extracts were analyzed using GC/MS apparatus. The main compounds in leaf extract of L. camara were 5,8-diethyl-dodecane, pyrimidin-2-one, 4-[N-methylureido]-1-[4-methylaminocarbonyloxymethyl, oleic acid,3-(octadecyloxy)propyl ester; in D. plumieri were 4,7-dimethoxy-2-methylindan-1-one and 5-(hexadecyloxy)-2-pentadecyl-,trans-1,3-dioxane; and in C. spinosum were N-[5-(3-hydroxy-2-methylpropenyl)-1,3,4,5-tetrahydrobenzo[cd]indol-3-yl]-N-methylacetamide. Promising activity was found against A. tumefaciens, E. coli, P. carotovorum, Sar. lutea, and Staph. aureus with MIC values of 8, 128, 64, 500 and 500 μg/mL, respectively, as L. camara leaf extract was applied. D. plumieri leaf extract showed good activity against D. solani and P. atrosepticum with MIC values of 16 μg/mL and 128 μg/mL, respectively. On the other hand, weak bioactivity was found with leaf extract from C. spinosum. It could be concluded that leaf extracts from D. plumieri and L. camara have a promising antibacterial agents.