Day and Night GSH and MDA Levels in Healthy Adults and Effects of Different Doses of Melatonin on These Parameters

The pineal secretory product melatonin (chemically, N-acetyl-5-methoxytryptamine) acts as an effective antioxidant and free-radical scavenger and plays an important role in several physiological functions such as sleep induction, immunomodulation, cardiovascular protection, thermoregulation, neuroprotection, tumor-suppression and oncostasis. Membrane lipid-peroxidation in terms of malondialdehyde (MDA) and intracellular glutathione (GSH) is considered to be a reliable marker of oxidative stress. The present work was undertaken to study the modulating effect of melatonin on MDA and GSH in human erythrocytes during day and night. Our observation shows the modulation of these two biomarkers by melatonin, and this may have important therapeutic implications. In vitro dose-dependent effect of melatonin also showed variation during day and night. We explain our observations on the basis of melatonin's antioxidative function and its effect on the fluidity of plasma membrane of red blood cells. Rhythmic modulation of MDA and GSH contents emphasized the role of melatonin as an antioxidant and its function against oxidative stress

Plant polyphenols as dietary antioxidants in human health and disease

Polyphenols are secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens. In the last decade, there has been much interest in the potential health benefits of dietary plant polyphenols as antioxidant. Epidemiological studies and associated meta-analyses strongly suggest that long term consumption of diets rich in plant polyphenols offer protection against development of cancers, cardiovascular diseases, diabetes, osteoporosis and neurodegenerative diseases. Here we present knowledge about the biological effects of plant polyphenols in the context of relevance to human health

Markers of oxidative stress in erythrocytes and plasma during aging in humans

Aging is an inevitable universal biological process, which can be characterized by a general decline in physiological function with the accumulation of diverse adverse changes and increased probability of death. Among several theories, oxidative stress/free radical theory offers the best mechanistic elucidation of the aging process and other age-related phenomenon. In the present paper, we discuss the aging process and have focused on the importance of some reliable markers of oxidative stress which may be used as biomarkers of the aging process

Modulation Effects of Curcumin on Erythrocyte Ion-Transporter Activity

Curcumin ((1E,6E)-1,7-Bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), the yellow biphenolic pigment isolated from turmeric (Curcuma longa), has various medicinal benefits through antioxidation, anti-inflammation, cardiovascular protection, immunomodulation, enhancing of the apoptotic process, and antiangiogenic property. We explored the effects of curcumin in vitro (10−5 M to 10−8 M) and in vivo (340 and 170 mg/kg b.w., oral) on Na+/K+ ATPase (NKA), Na+/H+ exchanger (NHE) activity, and membrane lipid hydroperoxides (ROOH) in control and experimental oxidative stress erythrocytes of Wistar rats. As a result, we found that curcumin potently modulated the membrane transporters activity with protecting membrane lipids against hydro-peroxidation in control as well as oxidatively challenged erythrocytes evidenced by stimulation of NKA, downregulation of NHE, and reduction of ROOH in the membrane. The observed results corroborate membrane transporters activity with susceptibility of erythrocyte membrane towards oxidative damage. Results explain the protective mechanism of curcumin against oxidative stress mediated impairment in ions-transporters activity and health beneficial effects

Tripartite analysis across business cycles in Turkey: A multi-timescale inquiry of efficiency, volatility and integration

AbstractIn the current era of globalization, deregulation and liberalization of markets have led to financial integration amongst developing and developed countries. The sudden massive inflow of capital into developing country's stock markets begs the question of whether or not the markets are sufficiently efficient to handle the increasing integration of markets. Furthermore, the relationship between the integration and efficiency of stock markets tends to be of greater importance during economic downturns. Taking Turkey as a case study owing to its economic growth and importance in two successful blocs, i.e. the EU and the OIC, we attempt to analyse the linkages between stock market efficiency and integration during the different phases of the economy. The findings of our study provide an interesting insight into the relative improvement in volatility, efficiency and integration across business cycles, in a multi time scale analysis

Resveratrol may protect plasma proteins from oxidation under conditions of oxidative stress in vitro

Proteins are vulnerable to oxidative stress; attack by reactive oxygen species causes oxidation and formation of carbonyl moieties, advanced oxidation protein products (AOPPs) and other undesired oxidation products. Resveratrol, a polyphenolic phytoalexin found abundantly in grapes and red-wine, is one of the most extensively studied natural products, with wide ranging biological activities including cardio-protective, neuro-protective, anti-aging, and anti-cancer. Most of the effects of these stilbenes are attributed to their antioxidant property. In the present study we have evaluated the role of resveratrol in the protection of plasma protein oxidation after induction of in vitro oxidative stress. Inducing oxidative stress by incubating with 10-5 mol L-1 tert-butylhydroperoxide caused a significant elevation in plasma protein carbonyls (PCO) and AOPPs, and decrease in -SH groups. Presence of resveratrol protected proteins from oxidation, an effect which was concentration dependent. On the basis of our experiments and effects shown by resveratrol we substantiate existing evidence for the strong antioxidant property of resveratrol

Antioxidant and anti-diabetic potential of rebaudioside A and a mixture of steviol glycosides in alloxan-induced diabetic rats

391-399Diabetes mellitus, a metabolic disorder rapidly spreading worldwide affects multiple organs and body functions. Stevia rebaudiana (Bertoni), belonging to the Asteraceae family is a herb with medicinal and commercial importance to cure chronic diseases like diabetes mellitus. The present study was aimed to explore the antidiabetic effect of two reference standards like Steviol Glycosides System Suitability (SGSS, a mixture of nine steviol glycosides) and Rebaudioside A in alloxan-induced diabetic rats. In this regard, diabetes was induced in rats by administration of a single intraperitoneal (i.p.) injection of alloxan monohydrate (150 mg/kg body weight). After exposure to alloxan monohydrate, the overall intracellular antioxidant functions get disturbed which significantly increase the blood glucose levels, plasma malondialdehyde and sialic acid content. The oral administration of SGSS and Reb A at a dose of (20 and 30 mg/kg b.wt.) for a period of 21 days to diabetic rats significantly (P ˂0.05) reduced the blood glucose levels when compared with alloxan-induced diabetic control (DC) rats of group II and restore the antioxidant potential by decreasing the oxidative damage and also normalizes hyperlipidemic indices. The study demonstrated that bioactive components (steviol glycosides) of S. rebaudiana have potential therapeutic prospects to attenuate diabetes and its related complications

Antioxidant and anti-diabetic potential of rebaudioside A and a mixture of steviol glycosides in alloxan-induced diabetic rats

Diabetes mellitus, a metabolic disorder rapidly spreading worldwide affects multiple organs and body functions. Stevia rebaudiana (Bertoni), belonging to the Asteraceae family is a herb with medicinal and commercial importance to cure chronic diseases like diabetes mellitus. The present study was aimed to explore the antidiabetic effect of two reference standards like Steviol Glycosides System Suitability (SGSS, a mixture of nine steviol glycosides) and Rebaudioside A in alloxan-induced diabetic rats. In this regard,  diabetes was induced in rats by administration of a single intraperitoneal (i.p.) injection of alloxan monohydrate (150 mg/kg body weight). After exposure to alloxan monohydrate, the overall intracellular antioxidant functions get disturbed which significantly increase the blood glucose levels, plasma malondialdehyde and sialic acid content. The oral administration of SGSS and Reb A at a dose of (20 and 30 mg/kg b.wt.) for a period of 21 days to diabetic rats significantly (P ˂0.05) reduced the blood glucose levels when compared with alloxan-induced diabetic control (DC) rats of group II and restore the antioxidant potential by decreasing the oxidative damage and also normalizes hyperlipidemic indices. The study demonstrated that bioactive components (steviol glycosides) of S. rebaudiana have potential therapeutic prospects to attenuate diabetes and its related complications