Superoxide dismutase overexpression and cellular oxidative damage in diabetes. A commentary on "Overexpression of mitochondrial superoxide dismutase in mice protects the retina from diabetes-induced oxidative stress"

Molecular and biological functions of gingerol as a natural effective therapeutic drug for cervical cancer

Cervical cancer is one of the most common and important gynecological cancers, which has a global concern with an increasing number of patients and mortality rates. Today, most women in the world who suffer from cervical cancer are developing advanced stages of the disease. Smoking and even exposure to secondhand smoke, infections caused by the human papillomavirus, immune system dysfunction and high-risk individual-social behaviors are among the most important predisposing factors for this type of cancer. In addition, papilloma virus infection plays a more prominent role in cervical cancer. Surgery, chemotherapy or radical hysterectomy, and radiotherapy are effective treatments for this condition, the side effects of these methods endanger a person's quality of life and cause other problems in other parts of the body. Studies show that herbal medicines, including taxol, camptothecin and combretastatins, have been shown to be effective in treating cervical cancer. Ginger (Zingiber officinale, Zingiberaceae) is one of the plants with valuable compounds such as gingerols, paradols and shogoals, which is a rich source of antioxidants, anti-cancer and anti-inflammatory agents. Numerous studies have reported the therapeutic effects of this plant through various pathways in cervical cancer. In this article, we look at the signaling mechanisms and pathways in which ginger is used to treat cervical cancer.

Insight into anti-oxidative carbohydrate polymers from medicinal plants: Structure-activity relationships, mechanism of actions and interactions with bovine serum albumin

Recently, research associated with natural anti-oxidants leads to the chemical characterization of many compounds possessing strong anti-oxidant activity. Among these anti-oxidants, naturally occurring carbohydrate polymers containing pectic arabinogalactans esterified with phenolic acids in monomeric and dimeric forms are noteworthy. The presence of highly branched arabinogalactan type II side chains and sugar linked phenolic acid residues have been resolved as important parameters. The anti-oxidant activity of these compounds depend on their ability to convert free radicals into stable by-products and themselves oxidized to more stable and less reactive resonance stabilized radicals. Moreover, these carbohydrate polymers form water soluble stable complexes with protein. Such findings support their applications in a diversity of fields including food industry and pharmacy. This review highlights experimental evidences supporting that the carbohydrate polymers containing phenolic polysaccharides may become promising drug candidate for the prevention of aging and age related diseases.

Optimization of extraction of antioxidant polysaccharide from Pleurotus ostreatus (Jacq.) P. Kumm and its cytotoxic activity against murine lymphoid cancer cell line

The purpose of this study was to optimize the extraction method for polysaccharide from the fruiting bodies of Pleurotus ostreatus (Jacq.) P. Kumm and to assess the antioxidant and cytotoxic potentials of polysaccharide. In this investigation, polysaccharides from Pleurotus ostreatus (Jacq.) P. Kumm were extricated by utilizing the hot water. One-single factor and response surface methodology was established to optimize the extraction conditions for polysaccharide from Pleurotus ostreatus (Jacq.) P. Kumm. Examination of antioxidant activity of Pleurotus ostreatus polysaccharide (POP) was directed by utilizing 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2-azino-bis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) techniques. Cytotoxicity of POP was evaluated using an MTT assay. The experimental data were fitted to a quadratic equation utilizing multiple regression investigations, and the ideal conditions were as per the following: water/crude material proportion, 26.04 mL/g; an extraction time of 62.08 minutes; and an extraction temperature 70.5°C. Under such conditions, the polysaccharide yield was 5.32 ± 0.12% with the anticipated yield. POP showed good scavenging activity against DPPH radical (p<0.001, EC50 = 1036.38 μg/mL, R2 = 0.8313) and ABTS radicals (p<0.001, EC50 = 824.37 μg/mL, R2 = 0.8223), with a dose (p<0.001)-and-time (p<0.001) dependent cytotoxic potential on Ehrlich ascites carcinoma cell line in vitro. This demonstrated that polysaccharides (POP) had certain cancer prevention agent exercises. In this manner, these examinations give reference to additionally research and reasonable improvement of Pleurotus ostreatus (Jacq.) P. Kumm polysaccharide and POP may prove a useful therapeutic agent, due to its robust antioxidant and cytotoxic activity.

Protective effect of mitochondrial-targeted antioxidant MitoQ against iron ion 56Fe radiation induced brain injury in mice

Exposure to iron ion ⁵⁶Fe radiation (IR) during space missions poses a significant risk to the central nervous system and radiation exposure is intimately linked to the production of reactive oxygen species (ROS). MitoQ is a mitochondria-targeted antioxidant that has been shown to decrease oxidative damage and lower mitochondrial ROS in a number of animal models. Therefore, the present study aimed to investigate role of the mitochondrial targeted antioxidant MitoQ against ⁵⁶Fe particle irradiation-induced oxidative damage and mitochondria dysfunction in the mouse brains. Increased ROS levels were observed in mouse brains after IR compared with the control group. Enhanced ROS production leads to disruption of cellular antioxidant defense systems, mitochondrial respiration dysfunction, altered mitochondria dynamics and increased release of cytochrome c (cyto c) from mitochondria into cytosol resulting in apoptotic cell death. MitoQ reduced IR-induced oxidative stress (decreased ROS production and increased SOD, CAT activities) with decreased lipid peroxidation as well as reduced protein and DNA oxidation. MitoQ also protected mitochondrial respiration after IR. In addition, MitoQ increased the expression of mitofusin2 (Mfn2) and optic atrophy gene1 (OPA1), and decreased the expression of dynamic-like protein (Drp1). MitoQ also suppressed mitochondrial DNA damage, cyto c release, and caspase-3 activity in IR-treated mice compared to the control group. These results demonstrate that MitoQ may protect against IR-induced brain injury.

Anticancer activity of essential oils: a review

Natural essential oil constituents play an important role in cancer prevention and treatment. Essential oil constituents from aromatic herbs and dietary plants include monoterpenes, sesquiterpenes, oxygenated monoterpenes, oxygenated sesquiterpenes and phenolics among others. Various mechanisms such antioxidant, antimutagenic and antiproliferative, enhancement of immune function and surveillance, enzyme induction and enhancing detoxification, modulation of multidrug resistance and synergistic mechanism of volatile constituents are responsible for their chemopreventive properties. This review covers the most recent literature to summarize structural categories and molecular anticancer mechanisms of constituents from aromatic herbs and dietary plants.

Antioxidant potential, cytotoxic activity and total phenolic content of Alpinia pahangensis rhizomes

Background

Alpinia pahangensis, a wild ginger distributed in the lowlands of Pahang, Malaysia, is used by the locals to treat flatulence. In this study, the antioxidant and cytotoxic activities of the crude aqueous methanol and fractionated extracts of Alpinia pahangensis against five different cancer and one normal cell lines were investigated. The total phenolic content of each extract and its fractions were also quantified. This is the first report on the antioxidant and cytotoxic activities of Alpinia pahangensis extract.

Methods

In the current study, the crude methanol and fractionated extract of the rhizomes of Alpinia pahangensis were investigated for their antioxidant activity using four different assays namely, the DPPH scavenging activity, superoxide anion scavenging, β-carotene bleaching and reducing power assays whilst their phenolic contents were measured by the Folin-Ciocalteu’s method.

In vitro neutral red cytotoxicity assay was employed to evaluate the cytotoxic activity against five different cancer cell lines, colon cancer (HCT 116 and HT-29), cervical cancer (Ca Ski), breast cancer (MCF7) and lung cancer (A549) cell lines, and one normal cell line (MRC-5). The extract that showed high cytotoxic activity was further investigated for its chemical constituents by GC-MS (gas chromatography–mass spectrometry) analysis.

Results

The ethyl acetate fraction showed the strongest DPPH radical scavenging (0.35 ± 0.094 mg/ml) and SOD activities (51.77 ± 4.9%) whilst the methanol extract showed the highest reducing power and also the strongest antioxidant activity in the β-carotene bleaching assays in comparison to other fractions. The highest phenolic content was found in the ethyl acetate fraction, followed by the crude methanol extract, hexane and water fractions. The results showed a positive correlation between total phenolic content with DPPH radical scavenging capacities and SOD activities. The hexane fraction showed potent cytotoxic effect against KB, Ca Ski and HCT 116 cell lines with IC₅₀ of 5.8 ± 0.1 and 9.1 ± 2.0 ug/ml, respectively. The major components of hexane fraction analysed by GC-MS analysis were mostly methyl esters.

Conclusions

The current study suggests that the methanol extract and ethyl acetate fraction of A. pahangensis is a potential source of natural antioxidant for protective as well as prevention of life-threatening diseases. The hexane fraction of A. pahangensis may have the potential to be developed into therapeutic option for treating cancer.

Does diabetes mellitus-induced bladder remodeling affect lower urinary tract function? ICI-RS 2011

AIMS

Due to an increase in aging population and changing eating habits diabetes mellitus (DM) type II is a rapidly increasing condition worldwide. Although not so detrimental as other co-morbidities, uropathy contributes to a significantly reduced quality-of-life in those affected. The purpose of this ICS-RS report is to highlight clinical and basic research data to outline directions for further research and possible treatment approaches.

METHODS

This report is based on a think tank presentation and discussion at the ICI-RS 2011, original research data and literature research.

RESULTS

Clinical and experimental data confirm that detrusor overactivity, both neurogenic and myogenic, and changes in transmitter regulation leading to a hyper- excitability of the detrusor are the major findings in diabetic neuropathic bladders. These findings seem to be related to an earlier stage of DM, whereas detrusor underactivity appears to be linked to later stages of DM. Detrusor smooth muscle cells seem to be modulated directly by hyperglycemia. Data support the theory that hyperglycemia-induced oxidative stress in the detrusor smooth muscle and that micro- and macrovascular events are also responsible for urologic complications of DM.

CONCLUSIONS

DM causes bladder remodelling leading to uropathy in a mulitfactorial way. Future research should focus on the effects of DM as a function of time and develop novel animal models looking at defined aspects as well as interaction of different aspects- such as oxidative stress in neurogenic, myogenic and urothelial components and the role of inflammation and hypoxia caused by vascular complications.

Antioxidant/anti-inflammatory activities and total phenolic content of extracts obtained from plants grown in Vietnam

BACKGROUND

Medicinal plants have been used to treat various diseases since ancient times. Their specific activities, such as antioxidant, anti-inflammatory and anti-cancer, have been studied intensively. In particular, plants grown in Vietnam have attracted considerable attention among food chemists as ideal sources of natural medicinal chemicals.

RESULTS

The methanol extracts from three edible Vietnamese-grown plants, Tram, Voi and Gac, tested with the DPPH assay showed antioxidant activities of 91.7 ± 0.4, 63.4 ± 0.7 and 3.7 ± 0.1% respectively. The malonaldehyde/gas chromatography assay also revealed strong antioxidant activity in Tram and Voi at a level of 25 µg mL(-1) (95.5 ± 0.3 and 78.5 ± 1.4% respectively). These results were confirmed by the thiobarbituric acid assay. The antioxidant activities correlated positively with the level of total phenolics in all plants. Tram exhibited dose response-related lipoxygenase-inhibitory activity, with values of 74.2 ± 3.1% at 5 µg mL(-1) , 62.0 ± 0% at 0.5 µg mL(-1) and 3.0 ± 1.5% at 0.05 µg mL(-1) . Conversely, Voi and Gac showed negative anti-lipoxygenase activity.

CONCLUSION

The antioxidant/anti-inflammatory activities and total phenolic contents of the three edible plants grown in Vietnam revealed that they are good sources of supplements for human health.

Antioxidant assays for plant and food components

Recently, research on natural antioxidants has become increasingly active in various fields. Accordingly, numerous articles on natural antioxidants, including polyphenols, flavonoids, vitamins, and volatile chemicals, have been published. Assays developed to evaluate the antioxidant activity of plants and food constituents vary. Therefore, to investigate the antioxidant activity of chemical(s), choosing an adequate assay based on the chemical(s) of interest is critical. There are two general types of assays widely used for different antioxidant studies. One is an assay associated with lipid peroxidations, including the thiobarbituric acid assay (TBA), malonaldehyde/high-performance liquid chromatography (MA/HPLC) assay, malonaldehyde/gas chromatography (MA/GC) assay, beta-carotene bleaching assay, and conjugated diene assay. Other assays are associated with electron or radical scavenging, including the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, ferric reducing/antioxidant power (FRAP) assay, ferrous oxidation-xylenol orange (FOX) assay, ferric thiocyanate (FTC) assay, and aldehyde/carboxylic acid (ACA) assay. In this review, assays used recently were selected for extended discussion, including discussion of the mechanisms underlying each assay and its application to various plants and foods.

Vascular endothelial growth factor in eye disease

Collectively, angiogenic ocular conditions represent the leading cause of irreversible vision loss in developed countries. In the US, for example, retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration are the principal causes of blindness in the infant, working age and elderly populations, respectively. Evidence suggests that vascular endothelial growth factor (VEGF), a 40kDa dimeric glycoprotein, promotes angiogenesis in each of these conditions, making it a highly significant therapeutic target. However, VEGF is pleiotropic, affecting a broad spectrum of endothelial, neuronal and glial behaviors, and confounding the validity of anti-VEGF strategies, particularly under chronic disease conditions. In fact, among other functions VEGF can influence cell proliferation, cell migration, proteolysis, cell survival and vessel permeability in a wide variety of biological contexts. This article will describe the roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. The potential disadvantages of inhibiting VEGF will be discussed, as will the rationales for targeting other VEGF-related modulators of angiogenesis.

Arterial hypertension exacerbates oxidative stress in early diabetic retinopathy

The present study was undertaken to investigate the redox status in the retina of an experimental model that combines hypertension and diabetes. Spontaneously hypertensive rats (SHR) and their control Wystar Kyoto (WKY) rats were rendered diabetic and, after 20 days, the rats were sacrificed and the retinas collected. The superoxide production was higher in diabetic than in control WKY (p < 0.03) and SHR rats showed elevated superoxide production compared with WKY groups (p < 0.009). The glutathione antioxidant system was diminished only in diabetic SHR (p < 0.04). Tirosyne nitration was higher in diabetic WKY and control SHR compared with control WKY (p < 0.03), and further increment was observed in diabetic SHR (p < 0.02). The DNA damage estimated by immunohystochemistry for 8-OHdG was higher in control SHR than in WKY, mainly in diabetic SHR (p < 0.0001). Hypertension aggravates oxidative-induced cytotoxicity in diabetic retina due to increasing of superoxide production and impairment of antioxidative system.

Superoxide dismutase enhanced the formation of hydroxyl radicals in a reaction mixture containing xanthone under UVA irradiation

To clarify the effect of superoxide dismutase (SOD) on the formation of hydroxyl radical in a standard reaction mixture containing 15 microM of xanthone, 0.1 M of 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and 45 mM of phosphate buffer (pH 7.4) under UVA irradiation, electron paramagnetic resonance (EPR) measurements were performed. SOD enhanced the formation of hydroxyl radicals. The formation of hydroxyl radicals was inhibited on the addition of catalase. The rate of hydroxyl radical formation also slowed down under a reduced oxygen concentration, whereas it was stimulated by disodium ethylenediaminetetraacetate (EDTA) and diethyleneaminepentaacetic acid (DETAPAC). Above findings suggest that O(2), H(2)O(2), and iron ions participate in the reaction. SOD possibly enhances the formation of the hydroxyl radical in reaction mixtures of photosensitizers that can produce O(2)(-.).