Magda K. Ezz

Purification and characterization of a novel tannase produced by Kluyveromyces marxianus using olive pomace as solid support, and its promising role in gallic acid production

Tannase is considered one of the most important industrial enzymes that find great applications in various sectors. Production of tannases through solid state fermentation (SSF) using agro-industrial wastes is an eco-friendly and cheap technology. Tannase was produced by the yeast Kluyveromyces marxianus using olive pomace as a solid support under SSF. It was purified using ammonium sulfate fractional precipitation followed by Sephadex G-200 gel filtration resulting in 64.6% enzyme yield with 1026.12U/mg specific activity and 24.21 purification fold. Pure tannase had molecular weight of 65 KDa and 66.62 KDa by SDS-PAGE and gel filtration, respectively. It showed a maximal activity at 35°C having two different pH optima, one of which is acidic (4.5) and the other one is alkaline (8.5). The enzyme was stable in the acidic range of pH (4.0-5.5) for 30min, and thermostable within the temperature range 30-70°C. Using tannic acid, the enzyme had a Km value of 0.77mM and Vmax of 263.20μmolemin-1ml-1. The effect of different metal ions on enzymatic activity was evaluated. HPLC analysis data indicated that the purified enzyme could carry out 24.65% tannic acid conversion with 5.25 folds increase in gallic acid concentration within 30min only.

Therapeutic impact of grape leaves polyphenols on certain biochemical and neurological markers in AlCl3-induced Alzheimer’s disease

Alzheimers disease (AD) is a grave and prevailing neurodegenerative disease, characterized by slow and progressive neurodegeneration in different brain regions. Aluminum (Al) is a potent and widely distributed neurotoxic metal, implicated in the neuropathogenesis of AD. This study aimed to evaluate the possible neurorestorative potential of Vitis vinifera Leaves Polyphenolic (VLP) extract in alleviating aluminum chloride (AlCl3)-induced neurotoxicity in male rats. AlCl3 neurotoxicity induced a significant decrease in brain/serum acetylcholine (ACh) contents and serum dopamine (DA) levels, along with a significant increment of brain/serum acetylcholinesterase (AChE) activities. In addition, Al treatment resulted in significantly decreased serum levels of both total antioxidant capacity (TAC) and brain-derived neurotrophic factor (BDNF), and significantly increased serum levels of both interleukin-6 (IL-6) and total homocysteine (tHcy), as compared to control. Behavioral alterations, assessed by the T-maze test, showed impaired cognitive function. Furthermore, AD-brains revealed an increase in DNA fragmentation as evidenced by comet assay. AlCl3 induction also caused histopathological alterations in AD-brain. Treatment of AD-rats with VLP extract (100mg/kg body weight/day) improved neurobehavioral changes, as evidenced by the improvement in brain function, as well as, modulation of most biochemical markers, and confirmed by T-maze test, the histopathological study of the brain and comet assay. The current work indicates that the VLP extract has neuroprotective, antioxidative, anti-inflammatory, and anti-amnesic activities against AlCl3-induced cerebral damages and neurocognitive dysfunction.

Improving the nutritive value of olive pomace by solid state fermentation of Kluyveromyces marxianus with simultaneous production of gallic acid

AbstractPurposeOlive oil industry is a growing industrial sector in Mediterranean countries. Unfortunately, about 30–35% of total olive weight is discarded as olive pomace (OP), a highly environmental-polluting solid waste. OP is mostly used for composting and production of animal feed; nevertheless, the high oil content, phenolic compounds and fiber contents in addition to its low protein content represent major obstacles for both applications. So, the present study was conducted to evaluate the role of solid state fermentation (SSF) in OP using Kluyveromyces marxianus NRRL Y-8281 yeast on the chemical composition and tannin content of OP in a trial for its bioconversion into a value-added animal feed.MethodsChemical composition, nutritive and energetic values, tannin and gallic acid contents of unfermented and fermented olive pomace were investigated.ResultsThe fermentation altered the chemical composition of OP, so that crude fiber was decreased by 8.56%, while crude protein, fat and carbohydrate contents were increased by 2.74, 2.63 and 3.57%, respectively. Moreover, the effect of fermentation on cell wall constituents, gross energy, digestible energy, total digestible nutrients and digestible crude protein was evaluated. Furthermore, HPLC analysis revealed that K. marxianus mediated fermentation of OP resulted in a sharp decrease in tannin content by 96.75% with 2.8 times increase in gallic acid concentration.ConclusionSSF of OP by K. marxianus does not only eliminate the environmental pollution resulting from its accumulation, but also presents a new eco-friendly valorization technique which leaves OP with an altered chemical composition allowing its use as animal feed or compost.

Protective and Curative Antiobesity Potential of Lemon Peel Extract in Rats Fed on High Fat Diet: Mechanism of Action

Aim: This study was to investigate the effect of dietary lemon peel extract (LPE) on high fat diet induced obesity in rats. Some of the LPE mechanism of action was also elucidated. Fifty adult rats were divided into five groups: 1) normal control, 2) lemon peel extract group supplemented with 0.5 g% LPE for 12 weeks, 3) high fat diet-fed (HFD) for 12 weeks, 4) preventive group fed on high fat diet supplemented with LPE 0.5 g% for 12 weeks and 5) therapeutic group fed on high fat diet for 12 weeks then supplemented with LPE 0.5 g% further 6 weeks. Methodology: Body weight gain, feed efficiency ratio, serum lipid profile, serum glucose, serum insulin, erythrocytes glucose-6-phosphate dehydrogenase (G6PD) activity, serum adiponectin, leptin, acyl coenzyme A oxidase (ACO) and medium chain acyl coenzyme A dehydrogenase (MCAD) activities were measured. Original Research Article Ezz et al.; IJBCRR, 12(4): 1-17, 2016; Article no.IJBCRR.26651 2 Results: Body weight gain, lipid profile, glucose, insulin, G6PD activity and leptin were significantly suppressed by the effect of LPE in treated groups. LPE also, up-regulated ACO and MCAD activities in the LPE-treated groups. Additionally mRNA level of ACO in the liver was up-regulated in LPE-treated groups compared with HFD. Conclusion: These findings demonstrate that LPE prevent body weight gain and fat accumulation through improvement of lipid metabolism by up-regulating the activities of MCAD and ACO while down regulating the activity of glucose 6 phosphate dehydrogenase. In this context, the preventive effect of LPE was more pronounced than the therapeutic effect.

The Beneficial Radioprotective Effect of Tomato Seed Oil Against Gamma Radiation–Induced Damage in Male Rats

ABSTRACT Radiation protection research receives intense focus due to its significant impact on human health. The present study was undertaken to investigate the protective effect of pretreatment with tomato seed oil (TSO) against gamma radiation–induced damage in rats. Male Wistar rats were divided into four groups: (1) untreated control; (2) TSO-supplemented; (3) gamma-irradiated; (4) TSO-pretreated and gamma-irradiated. Acute exposure of animals to a single gamma radiation dose (6 Gy) induced oxidative stress in major body organs, altered serum lipid homeostasis, significantly increased serum testosterone and sorbitol dehydrogenase levels, and elicited a systemic inflammation as manifested by the induction of serum vascular cell adhesion molecule-1. Oral pretreatment with TSO (1 ml/kg; 3 times/week for 8 weeks) before exposure to gamma radiation protected rats against ionizing radiation-induced oxidative stress, restored lipid homeostasis, and suppressed systemic inflammation. Histological findings of target tissues verified biochemical data. The radioprotective ability of TSO was attributed to its content of phytosterols, policosanol, and antioxidants, including lycopene, β-carotene, lutein, and tocopherols. TSO is considered a promising radioprotective agent that can be effectively used to protect the body from the damaging effects of harmful radiation.