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Evaluation of aeration strategy in moving bed sequencing batch reactor performing simultaneous 4-chlorophenol and nitrogen removal

Lim JW, Lim PE, Seng CE, Adnan R

Appl Biochem Biotechnol, 2013 Jun;170(4):831-40.
PMID: 23613119 DOI: 10.1007/s12010-013-0245-8

The aeration strategy ranging from intermittent to continuous aeration in the REACT period of moving bed sequencing batch reactor (MBSBR) was evaluated for simultaneous removal of 4-chlorophenol (4-CP) and nitrogen. The results show that the removal rates of 4-CP and ammonium nitrogen (NH(4)(+)-N) increased with the increase of continuous aeration period. In the presence of 4-CP, NH(4)(+)-N removal was mainly by the assimilation process. The removal of NH(4)(+)-N to oxidized nitrogen via oxidation was only observed after 4-CP was completely degraded with sufficient aeration period provided indicating the inhibitory effect of 4-CP on nitrification. As the intermittent aeration strategy would lead to slower 4-CP degradation resulting in the delay of nitrification process, continuous aeration would be the preferred strategy in the simultaneous removal of 4-CP and nitrogen in the MBSBR system.

Matched MeSH terms: Oxidation-Reduction
Production and characterization of violacein by locally isolated Chromobacterium violaceum grown in agricultural wastes

Ahmad WA, Yusof NZ, Nordin N, Zakaria ZA, Rezali MF

Appl Biochem Biotechnol, 2012 Jul;167(5):1220-34.
PMID: 22278051 DOI: 10.1007/s12010-012-9553-7

The present work highlighted the production of violacein by the locally isolated Chromobacterium violaceum (GenBank accession no. HM132057) in various agricultural waste materials (sugarcane bagasse, solid pineapple waste, molasses, brown sugar), as an alternative to the conventional rich medium. The highest yield for pigment production (0.82 g L⁻¹) was obtained using free cells when grown in 3 g of sugarcane bagasse supplemented with 10% (v/v) of L-tryptophan. A much lower yield (0.15 g L⁻¹) was obtained when the cells were grown either in rich medium (nutrient broth) or immobilized onto sugarcane bagasse. Violacein showed similar chemical properties as other natural pigments based on the UV-Vis, Fourier transform infrared spectroscopy, thin-layer chromatography, nuclear magnetic resonance, and mass spectrometry analysis. The pigment is highly soluble in acetone and methanol, insoluble in water or non-polar organic solvents, and showed good stability between pH 5-9, 25-100 °C, in the presence of light metal ions and oxidant such as H₂O₂. However, violacein would be slowly degraded upon exposure to light. This is the first report on the use of cheap and easily available agricultural wastes as growth medium for violacein-producing C. violaceum.

Matched MeSH terms: Oxidation-Reduction
Solid-state fermentation of palm kernel cake with Aspergillus flavus in laterally aerated moving bed bioreactor

Wong YP, Saw HY, Janaun J, Krishnaiah K, Prabhakar A

Appl Biochem Biotechnol, 2011 May;164(2):170-82.
PMID: 21080102 DOI: 10.1007/s12010-010-9124-8

Solid-state fermentation (SSF) was employed to enhance the nutritive values of palm kernel cake (PKC) for poultry feeding. Aspergillus flavus was isolated from local PKC and utilized to increase the mannose content of PKC via the degradation of β-mannan in PKC; evaluation was done for batch SSF in Erlenmeyer flasks and in a novel laterally aerated moving bed (LAMB) bioreactor. The optimum condition for batch SSF in flasks was 110% initial moisture content, initial pH 6.0, 30 °C, 855 μm particle size, and 120 h of fermentation, yielding 90.91 mg mannose g⁻¹ dry PKC (5.9-fold increase). Batch SSF in the LAMB at the optimum condition yielded 79.61 mg mannose g⁻¹ dry PKC (5.5-fold increase) within just 96 h due to better heat and mass transfer when humidified air flowed radially across the PKC bed. In spite of a compromise of 12% reduction in mannose content when compared with the flasks, the LAMB facilitated good heat and mass transfer, and improved the mannose content of PKC in a shorter fermentation period. These attributes are useful for batch production of fermented PKC feed in an industrial scale.

Matched MeSH terms: Oxidation-Reduction
An improved enzyme assay for molybdenum-reducing activity in bacteria

Shukor MY, Rahman MF, Shamaan NA, Lee CH, Karim MI, Syed MA

Appl Biochem Biotechnol, 2008 Mar;144(3):293-300.
PMID: 18556818

Molybdenum-reducing activity in the heterotrophic bacteria is a phenomenon that has been reported for more than 100 years. In the presence of molybdenum in the growth media, bacterial colonies turn to blue. The enzyme(s) responsible for the reduction of molybdenum to molybdenum blue in these bacteria has never been purified. In our quest to purify the molybdenum-reducing enzyme, we have devised a better substrate for the enzyme activity using laboratory-prepared phosphomolybdate instead of the commercial 12-phosphomolybdate we developed previously. Using laboratory-prepared phosphomolybdate, the highest activity is given by 10:4-phosphomolybdate. The apparent Michaelis constant, Km for the laboratory-prepared 10:4-phosphomolybdate is 2.56 +/- 0.25 mM (arbitrary concentration), whereas the apparent V(max) is 99.4 +/- 2.85 nmol Mo-blue min(-1) mg(-1) protein. The apparent Michaelis constant or Km for NADH as the electron donor is 1.38 +/- 0.09 mM, whereas the apparent V(max) is 102.6 +/- 1.73 nmol Mo-blue min(-1) mg(-l) protein. The apparent Km and V(max) for another electron donor, NADPH, is 1.43 +/- 0.10 mM and 57.16 +/- 1.01 nmol Mo-blue min(-1) mg(-1) protein, respectively, using the same batch of molybdenum-reducing enzyme. The apparent V(max) obtained for NADH and 10:4-phosphomolybdate is approximately 13 times better than 12-phoshomolybdate using the same batch of enzyme, and hence, the laboratory-prepared phosphomolybdate is a much better substrate than 12-phoshomolybdate. In addition, 10:4-phosphomolybdate can be routinely prepared from phosphate and molybdate, two common chemicals in the laboratory.

Matched MeSH terms: Oxidation-Reduction
Hexavalent molybdenum reduction to molybdenum blue by S. marcescens strain Dr. Y6

Shukor MY, Habib SH, Rahman MF, Jirangon H, Abdullah MP, Shamaan NA, et al.

Appl Biochem Biotechnol, 2008 Apr;149(1):33-43.
PMID: 18350385 DOI: 10.1007/s12010-008-8137-z

A molybdate-reducing bacterium has been locally isolated. The bacterium reduces molybdate or Mo(6+) to molybdenum blue (molybdate oxidation states of between 5+ and 6+). Different carbon sources such as acetate, formate, glycerol, citric acid, lactose, fructose, glucose, mannitol, tartarate, maltose, sucrose, and starch were used at an initial concentration of 0.2% (w/v) in low phosphate media to study their effect on the molybdate reduction efficiency of bacterium. All of the carbon sources supported cellular growth, but only sucrose, maltose, glucose, and glycerol (in decreasing order) supported molybdate reduction after 24 h of incubation. Optimum concentration of sucrose for molybdate reduction is 1.0% (w/v) after 24 h of static incubation. Ammonium sulfate, ammonium chloride, valine, OH-proline, glutamic acid, and alanine (in the order of decreasing efficiency) supported molybdate reduction with ammonium sulfate giving the highest amount of molybdenum blue after 24 h of incubation at 0.3% (w/v). The optimum molybdate concentration that supports molybdate reduction is between 15 and 25 mM. Molybdate reduction is optimum at 35 degrees C. Phosphate at concentrations higher than 5 mM strongly inhibits molybdate reduction. The molybdenum blue produced from cellular reduction exhibits a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. The isolate was tentatively identified as Serratia marcescens Strain Dr.Y6 based on carbon utilization profiles using Biolog GN plates and partial 16s rDNA molecular phylogeny.

Matched MeSH terms: Oxidation-Reduction/drug effects
Reductive alkylation of lipase: experimental and molecular modeling approaches

Rahman RN, Tejo BA, Basri M, Rahman MB, Khan F, Zain SM, et al.

Appl Biochem Biotechnol, 2004 8 12;118(1-3):11-20.
PMID: 15304735

Candida rugosa lipase was modified via reductive alkylation to increase its hydrophobicity to work better in organic solvents. The free amino group of lysines was alkylated using propionaldehyde with different degrees of modification obtained (49 and 86%). Far-ultraviolet circular dichroism (CD) spectroscopy of the lipase in aqueous solvent showed that such chemical modifications at the enzyme surface caused a loss in secondary and tertiary structure that is attributed to the enzyme unfolding. Using molecular modeling, we propose that in an aqueous environment the loss in protein structure of the modified lipase is owing to disruption of stabilizing salt bridges, particularly of surface lysines. Indeed, molecular modeling and simulation of a salt bridge formed by Lys-75 to Asp-79, in a nonpolar environment, suggests the adoption of a more flexible alkylated lysine that may explain higher lipase activity in organic solvents on alkylation.

Matched MeSH terms: Oxidation-Reduction
Melatonin improves cognitive behavior, oxidative stress, and metabolism in tumor-prone lethal giant larvae mutant of Drosophila melanogaster

Wong KC, Sankaran S, Jayapalan JJ, Subramanian P, Abdul-Rahman PS

Arch Insect Biochem Physiol, 2021 May;107(1):e21785.
PMID: 33818826 DOI: 10.1002/arch.21785

Mutant lethal giant larvae (lgl) flies (Drosophila melanogaster) are known to develop epithelial tumors with invasive characteristics. The present study has been conducted to investigate the influence of melatonin (0.025 mM) on behavioral responses of lgl mutant flies as well as on biochemical indices (redox homeostasis, carbohydrate and lipid metabolism, transaminases, and minerals) in hemolymph, and head and intestinal tissues. Behavioral abnormalities were quantitatively observed in lgl flies but were found normalized among melatonin-treated lgl flies. Significantly decreased levels of lipid peroxidation products and antioxidants involved in redox homeostasis were observed in hemolymph and tissues of lgl flies, but had restored close to normalcy in melatonin-treated flies. Carbohydrates including glucose, trehalose, and glycogen were decreased and increased in the hemolymph and tissues of lgl and melatonin-treated lgl flies, respectively. Key enzymes of carbohydrate metabolism showed a significant increment in their levels in lgl mutants but had restored close to wild-type baseline levels in melatonin-treated flies. Variables of lipid metabolism showed significantly inverse levels in hemolymph and tissues of lgl flies, while normalization of most of these variables was observed in melatonin-treated mutants. Lipase, chitinase, transaminases, and alkaline phosphatase showed an increment in their activities and minerals exhibited decrement in lgl flies; reversal of changes was observed under melatonin treatment. The impairment of cognition, disturbance of redox homeostasis and metabolic reprogramming in lgl flies, and restoration of normalcy in all these cellular and behavioral processes indicate that melatonin could act as oncostatic and cytoprotective agents in Drosophila.

Matched MeSH terms: Oxidation-Reduction/drug effects
Fulltext Palm oil and palm olein frying applications

Ismail R

Asia Pac J Clin Nutr, 2005;14(4):414-9.
PMID: 16326649

Several million tones of palm oil and palm olein are used annually in the world for frying. This paper will discuss their frying performances in three major applications - industrial production of potato chips/crisps, industrial production of pre-fried frozen French fries and in fast food outlets. In the first study, about four tones of potato chips were continuously fried 8 hours a day and five days a week. The palm olein used (with proper management) performed well and was still in excellent condition and usable at the end of the trial. This was reflected in its low free fatty acid (FFA) content of around 0.23%, peroxide value of 4 meq/kg, anisidine value of 16, low polar and polymer contents of 10% and 2%, respectively, induction period (OSI) of 21 hours and high content of tocopehrols and tocotrienols of 530 ppm even after >1900 hours. In the second study in which an average 12 tones pre-fried frozen French fries were continuously fried a day for 5 days a week, palm oil performed excellently as reflected by its low FFA of 0.34%, food oil sensor reading of 1.1, low polar and polymer contents of 17% and 2.8%, respectively, over the 12 days of trial. In the third study in which palm shortening, palm oil and palm olein were simultaneously used to intermittently fry chicken parts in the laboratory simulating the conditions in fast food outlets, the three frying oils also performed very satisfactorily as reflected by their reasonably low FFA of <1%, smoke points of >180 degrees C, and polar and polymer contents of <25% and <6%, respectively, after 5 days of consecutive frying. All the quality indicators did not exceed the maximum discard points for frying oils/fats in the three applications, while the fried food product was well accepted by the in-house train sensory panel using a-nine point hedonic score.

Matched MeSH terms: Oxidation-Reduction
Performance of phytochemical antioxidant systems in refined-bleached-deodorized palm olein during frying

Jaswir I, Che Man YB, Hassan TH

Asia Pac J Clin Nutr, 2005;14(4):402-13.
PMID: 16326648

Antioxidants are important inhibitory compounds against the oxidative deterioration of food. This study investigated the effects of various phytochemical antioxidant systems [oleoresin rosemary (OR), oleoresin sage (OS) and citric acid (CA)] on the physico-chemical characteristics of refined, bleached and deodorized (RBD) palm olein during the frying of potato chips. The effects of various mixtures of the antioxidants on the oil was also studied in repeated deep frying. The response surface methodology was used to optimize the composition of mixed antioxidants used. A comparative study was carried out with synthetic antioxidants. Samples of the oil after frying were analyzed for different physical and chemical properties. OR and OS were found to be effective phytochemical antioxidants protecting RBD palm olein against oxidative deterioration during frying.

Matched MeSH terms: Oxidation-Reduction
Polyphenol-enriched extract of oil palm fronds (Elaeis guineensis) promotes vascular relaxation via endothelium-dependent mechanisms

Abeywardena M, Runnie I, Nizar M, Suhaila M, Head R, Suhaila Momamed

Asia Pac J Clin Nutr, 2002;11 Suppl 7:S467-72.
PMID: 12492636

Plant-based polyphenolic compounds have been reported to possess cardiovascular health benefits. Several dietary sources, including herbs and spices, fruits and vegetables, and tea and wine, contain an array of biologically active compounds that have been shown to be effective in retarding oxidation of low-density lipoproteins (LDL) and promoting vascular relaxation. In the present study four different plant sources, both edible and non-edible, were evaluated for potential activity. Organic extracts enriched in polyphenols were prepared from palm fronds (Elaesis guineensis); lemongrass (Cymbopogon citrates); papaya shoots (Carica papaya) and green chilli (Capsicum frutescenes) and tested for their ability to prevent in vitro oxidation of LDL, and for potential vascular relaxation actions. Rings of rat thoracic aorta and isolated perfused mesenteric vascular beds were mounted in organ baths, contracted using a half-maximal dose of noradrenaline and exposed to cumulative additions of test extracts. Palm frond extract resulted in considerable relaxation (>75%) in both preparations and was found to be endothelium-dependent as removal of endothelium or inhibition of endogenous nitric oxide (NO) led to a total loss in relaxant activity. Lemongrass extract caused a greater relaxation action in the mesenteric preparation compared to aortic rings, and appears to be mediated via NO-independent and non-prostanoid mechanisms. Of the extracts tested, palm fronds also demonstrated the highest antioxidant capacity, as determined by the ferric reducing activity/potential assay, and resulted in a significant delay (P < 0.05) in the oxidation of LDL. Collectively, these preliminary findings lend further support to the potential cardiovascular actions of plant polyphenols and also identify oil palm fronds as containing constituents that promote vascular relaxation via endothelium-dependent mechanisms.

Matched MeSH terms: Oxidation-Reduction
Vitamin E in cardiovascular disease: has the die been cast?

Yusoff K

Asia Pac J Clin Nutr, 2002;11 Suppl 7:S443-7.
PMID: 12492632

Cardiovascular disease, in particular coronary artery disease (CAD), remains the most important cause of morbidity and mortality in developed countries and, in the near future, more so in the developing world. Atherosclerotic plaque formation is the underlying basis for CAD. Growth of the plaque leads to coronary stenosis, causing a progressive decrease in blood flow that results in angina pectoris. Acute myocardial infarction and unstable angina were recently recognised as related to plaque rupture, not progressive coronary stenosis. Acute thrombus formation causes an abrupt coronary occlusion. The characteristics of the fibrin cap, contents of the plaque, rheological factors and active inflammation within the plaque contribute to plaque rupture. Oxidative processes are important in plaque formation. Oxidized low density lipoproteins (LDL) but not unoxidized LDL is engulfed by resident intimal macrophages, transforming them into foam cells which develop into fatty streaks, the precursors of the atherosclerotic plaque. Inflammation is important both in plaque formation and rupture. Animal studies have shown that antioxidants reduce plaque formation and lead to plaque stabilisation. In humans, high intakes of antioxidants are associated with lower incidence of CAD, despite high serum cholesterol levels. This observation suggests a role for inflammation in CAD and that reducing inflammation using antioxidants may ameliorate these processes. Men and women with high intakes of vitamin E were found to have less CAD. Vitamin E supplementation was associated with a significant reduction in myocardial infarction and cardiovascular events in the incidence of recurrent myocardial infarction. In the hierarchy of evidence in evidence-based medicine, data from large placebo-controlled clinical trials is considered necessary. Results from various mega-trials have not shown benefits (nor adverse effects) conferred by vitamin E supplementation, suggesting that vitamin E has no role in the treatment of CAD. These results do not seem to confirm, at the clinical level, the effect of antioxidants against active inflammation during plaque rupture. However, a closer examination of these studies showed a number of limitations, rendering them inconclusive in addressing the role of vitamin E in CAD prevention and treatment. Further studies that specifically address the issue of vitamin E in the pathogenesis of atherosclerosis and in the treatment of CAD need be performed. These studies should use the more potent antioxidant property of alpha-tocotrienol vitamin E.

Matched MeSH terms: Oxidation-Reduction
Fulltext Interaction between vitamin E and glutathione in rat brain: Effect of chronic ethanol administration

Marcus SR, Chandrakala MV, Nadiger HA

Asia Pac J Clin Nutr, 1998 Dec;7(3/4):201-5.
PMID: 24393672

The protection against ethanol-induced lipid peroxidation is rendered by antioxidants such as vitamin E and glutathione (GSH) interacting with each other and also functioning independently. A study of the levels of GSH and activities of glutathione peroxidase (GP), glutathione reductase (GR) and glutathione transferase (GST) in the cerebral cortex (CC), cerebellum (CB) and brain stem (BS) of vitamin E-supplemented and -deficient rats subjected to ethanol administration for 30 days was carried out. Chronic ethanol administration to vitamin E-supplemented rats elevated GP, GR and GST activities in the three regions and GSH levels in the CB. Chronic ethanol administration to vitamin E-deficient rats elevated GR activity in the three regions and GP activity in the CC and CB, decreased GST activity in the CC and CB, but did not alter GSH levels compared with normal rats subjected to chronic ethanol administration. The results indicate that vitamin E helps to maintain GSH levels to combat increased peroxidation while its absence has a deleterious effect.

Matched MeSH terms: Oxidation-Reduction
CD26: A Prognostic Marker of Acute Lymphoblastic Leukemia in Children in the Post Remission Induction Phase

Mehde AA, Yusof F, Adel Mehdi W, Zainulabdeen JA

Asian Pac J Cancer Prev, 2015;16(12):5059-62.
PMID: 26163641

BACKGROUND: ALL is an irredeemable disease due to the resistance to treatment. There are several influences which are involved in such resistance to chemotherapy, including oxidative stress as a result of the generation of reactive oxygen species (ROS) and presence of hypodiploid cells. Cluster of differentiation 26 (CD26), also known as dipeptidyl peptidase-4, is a 110 kDa, multifunctional, membrane-bound glycoprotein.
AIM AND OBJECTIVES: The aim of this study was to evaluate the clinical significance of serum CD26 in patients with acute lymphoblastic leukaemia patients in the post remission induction phase, as well as the relationship between CD26 activity and the oxidative stress status.
MATERIALS AND METHODS: CD26, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI), in addition to activity of related enzymes myeloperoxidase, glutathione- s-transferase and xanthine oxidase, were analysed in sixty children with acute lymphoblastic leukaemia in the post remission induction phase.
RESULTS: The study showed significant elevation in CD26, TOS and OSI levels in patients with acute lymphoblastic leukaemia in the post remission induction phase in comparison to healthy control samples. In contrast, myeloperoxidase, glutathione-s-transferase and xanthine oxidase activities were decreased significantly. A significant correlation between CD26 concentration and some oxidative stress parameters was evident in ALL patients.
CONCLUSIONS: Serum levels of CD26 appear to be useful as a new biomarker of oxidative stress in children with acute lymphoblastic leukaemia in the post remission induction phase, and levels of antioxidants must be regularly estimated during the treatment of children with ALL.

Matched MeSH terms: Oxidation-Reduction
Fulltext Antioxidant activity of methanol extracts of different parts of Lantana camara

Mahdi-Pour B, Jothy SL, Latha LY, Chen Y, Sasidharan S

Asian Pac J Trop Biomed, 2012 Dec;2(12):960-5.
PMID: 23593576 DOI: 10.1016/S2221-1691(13)60007-6

To investigate the antioxidant activity of methanolic extracts of Lantana camara (L. camara) various parts and the determination of their total phenolics content.

Matched MeSH terms: Oxidation-Reduction
Fulltext Free radical scavenging potential of Lagenaria siceraria (Molina) Standl fruits extract

Mayakrishnan V, Veluswamy S, Sundaram KS, Kannappan P, Abdullah N

Asian Pac J Trop Med, 2013 Jan;6(1):20-6.
PMID: 23317881 DOI: 10.1016/S1995-7645(12)60195-3

OBJECTIVE: To elucidate free radical scavenging activity of ethanolic extract Lagenaria siceraria (L. siceraria) (Molina) fruit.
METHODS: The free radical scavenging activity of the L. siceraria (Molina) fruit extract was assayed by using α,α-diphenyl-β-picrylhydrazyl (DPPH), 2,20-azinobis 3-ethyl benzothiazoline-6-sulfonate (ABTS), FRAP, reducing power, chelating ability and β-carotene bleaching assay.
RESULTS: The IC(50) values of DPPH and ABTS radical-scavenging activity was found to be 1.95 mg/mL and 19 mg/mL, respectively. In ferrous chelation assay, the percentage of inhibition was found to be 89.21%. The reducing power of ethanolic extract of L. siceraria (Molina) fruit was 0.068 at 1 mg/mL and increased to 0.192 at 5 mg/mL. The β-carotene linoleate bleaching assay was 46.7% at 5 mg/mL and antioxidant activity using FRAP at 0.305 for 1 mg/mL to 0.969 for 5 mg/mL.
CONCLUSIONS: The results indicate that L. siceraria (Molina) fruit could be an important sources of natural radical scavengers.

Matched MeSH terms: Oxidation-Reduction/drug effects
Lipid peroxidation: Its effects on the formulation and use of pharmaceutical emulsions

Khanum R, Thevanayagam H

Asian J Pharm Sci, 2017 Sep;12(5):401-411.
PMID: 32104352 DOI: 10.1016/j.ajps.2017.05.003

Pharmaceutical delivery systems are developed to improve the physicochemical properties of therapeutic compounds. Emulsions are one of these drug delivering systems formulated using water, oils and lipids as main ingredients. Extensive data are usually generated on the physical and chemical characteristics of these oil-in-water and lipid emulsions. However, the oxidative tendency of emulsions is often overlooked. Oxidation impacts the overall quality and safety of these pharmaceutical emulsions. Additionally, introducing oxidatively unstable emulsions into biological systems further promotes oxidation in situ. Products of these reactions then continue to pose serious harm to cells and fuel other physiological oxidation reactions. Consequently, the increase of oxidation products leads to oxidative damage to biological systems. Thus, emulsions with lower lipid peroxidation are more stable and will reduce the negative effects of oxidation in situ. Preventive measures during the formulation of emulsions are important. Many naturally occurring and cost effective substances possess low oxidation tendencies and confer oxidative protection when used in emulsions. Additionally, certain preparatory methods should be employed to reduce or better control lipid peroxidation. Finally, emulsions must be evaluated for their oxidation susceptibility using the various techniques available. Careful attention to the preparation of emulsions and assessment of their oxidative stability will help produce safer emulsions without compromising efficacy.

Matched MeSH terms: Oxidation-Reduction
Characterisation of a Ferrous Agarose Xylenol (FAX) gel for radiotherapy dose measurement

Leong LH, Kandaiya S, Seng NB

Australas Phys Eng Sci Med, 2007 Jun;30(2):135-40.
PMID: 17682403

The oxidation of ferrous to ferric ions due to ionizing radiation has been used for chemical dosimetry since 1927. The introduction of metal indicator dye xylenol orange (XO) sensitises the measurement of ferric ion yield. A ferrous sulphate- agarose- xylenol orange (FAX) gel was prepared and the gel then exposed to dose ranging from 0.2 to 10 Gy using various high energy photon and electron beams from a linear accelerator. Some general characteristics of FAX such as energy dependence, optical density (OD)-dose relationship, reproducibility and auto-oxidation of ferrous ions were analysed. The radiation yield G of the gel was calculated for gels prepared in oxygen and in air and the values were 46.3 +/- 2.1 and 40.9 +/- 1.4 Fe3+ per 100 eV for photons respectively. However for stock gel which was kept for 5 days pre-irradiation the G value decreased to 36.6 +/- 1.1. The gel shows linearity in OD-dose relationship, energy independence and reproducibility over the dose range investigated. Auto-oxidation of ferrous ions resulted in optical density changes of less than 1.5% per day.

Matched MeSH terms: Oxidation-Reduction
Fulltext Vernonia amygdalina simultaneously suppresses gluconeogenesis and potentiates glucose oxidation via the pentose phosphate pathway in streptozotocin-induced diabetic rats

Atangwho IJ, Yin KB, Umar MI, Ahmad M, Asmawi MZ

BMC Complement Altern Med, 2014;14:426.
PMID: 25358757 DOI: 10.1186/1472-6882-14-426

This study evaluated the impact of Vernonia amygdalina (VA) on the transcription of key enzymes involved in cellular modulation of glucose in streptozotocin-induced diabetic rats in a bid to understand the possible anti-diabetic mechanism of VA.

Matched MeSH terms: Oxidation-Reduction
Fulltext In vitro and ex-vivo cellular antioxidant protection and cognitive enhancing effects of an extract of Polygonum minus Huds (Lineminus™) demonstrated in a Barnes Maze animal model for memory and learning

George A, Ng CP, O'Callaghan M, Jensen GS, Wong HJ

BMC Complement Altern Med, 2014;14:161.
PMID: 24886679 DOI: 10.1186/1472-6882-14-161

Polygonum minus Huds.is a culinary flavouring that is common in South East Asian cuisine and as a remedy for diverse maladies ranging from indigestion to poor eyesight. The leaves of this herb have been reported to be high in antioxidants. Flavonoids which have been associated with memory, cognition and protection against neurodegeneration were found in P. minus.

Matched MeSH terms: Oxidation-Reduction
Fulltext Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide

Sazwi NN, Nalina T, Abdul Rahim ZH

BMC Complement Altern Med, 2013;13:351.
PMID: 24330738 DOI: 10.1186/1472-6882-13-351

Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined.

Matched MeSH terms: Oxidation-Reduction/drug effects

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