Inherent Antioxidant Research Articles

Cyanidin-3-O-glucoside enhanced the function of syngeneic mouse islets transplanted under the kidney capsule or into the portal vein.

It was previously shown that islets are susceptible to oxidative stress due to their inherent low antioxidant capacity. Therefore, in this study, we determined whether treatment of mouse islets with an antioxidant cyanidin-3-O-glucoside (C3G) could enhance their function after transplantation under the kidney capsule or into the portal vein. B6 mouse islets were treated with various concentrations of C3G, their viability, and the expression of antioxidant (HO-1) and antiapoptotic (Bcl-2 and Survivin) genes were determined. The C3G-treated (1.0 μM) or untreated B6 mouse islets (100, 200, and 400 IEQ) were transplanted under the kidney capsule or into the portal vein of diabetic B6 mice, and their blood glucose levels were monitored for more than 100 days after transplantation. The C3G-treated islets showed higher cell viability compared to untreated control and the expression of HO-1; Bcl-2 and Survivin genes were enhanced in a concentration-dependent manner. All mice that were transplanted with C3G-treated islets achieved normoglycemia faster than recipients of untreated islets. Mice that received 400, 200, or 100 treated islets transplanted under the kidney capsule achieved normoglycemia, whereas only mice that were transplanted with 400 and 200 treated islets into the portal vein achieved normoglycemia. The mean blood glucose levels of mice that received C3G-treated islets were lower compared to those observed in mouse recipients of untreated islets transplanted under the kidney capsule or into the portal vein. Our results show that C3G could enhance the viability of mouse islets and improve their function after transplantation.

효소처리 가공이 당근(Daucus carota var. sativa)의 항산화 활성 변화에 미치는 영향

The purpose of this research is to minimize the loss of nutrients in (Daucus carota var. sativa). A protopectinase was used to enzymatically macerated and separate cells without damage. The enzyme modification groups collection rate was 81% (residue rate 19%), while the grinding process groups collection rate was 56% (residue rate 44%)-an over 20% of collection rate difference. Thus we predicted a big difference in transference number after the process and wastage. In comparing ingredient changes in the enzyme modification group versus the grinding process group, the content of β-carotene (the carrots main ingredient) showed a change in protection factor (PF) (2.2±0.2 PF, 1.4±0.4 PF, respectively), total polyphenol content (89±3.42 μg/g, 64±4.16 μg/g, respectively), and total flavonoid content (68±2.73 μg/g, 41±3.26 μg/g, respectively). Thus we confirmed that nutrient destruction, due to cell membrane preservation, occurred less often in the enzyme modification process than the mechanical grinding process group. We also measured DPPH radical scavenging activity, hydroxyl radical scavenging activity, and nitrite scavenging activity. DPPH radical scavenging activity was 87±0.29% and 74±1.56% in the enzymatic modification group compared to the mechanical grinding process group, respectively. Hydroxyl radical scavenging activity was 44±0.49% and 32±0.48% in the enzymatic modification group compared to the mechanical grinding process group, respectively. Nitrite scavenging activity was 59±0.53% and 46±0.62% in the enzymatic modification group compared to the mechanical grinding process group, respectively. Our results show that cell membrane preservation, via the protopectinase enzyme process, decreases the loss of nutrients and still preserves inherent antioxidants.

Antioxidant cosmeto-textiles: Skin assessment

Resveratrol, a natural product, has been reported to have antioxidant activities such as the scavenging of free radicals. This compound could be used in the dermocosmetic field to protect the skin from oxidative stress. In this work, the percutaneous profile of resveratrol in ethanol solutions through pig skin was determinated by an in vitro methodology. The percutaneous absorption of resveratrol was measured and compared with trolox, an analogous of Vitamin E. Both antioxidants were found in all skin sections (stratum corneum, epidermis, and dermis). Besides, the free radical scavenging activity of resveratrol and trolox has been evaluated using DPPH method. The effective dose (ED50) of compounds and DPPH radical inhibition in each skin layer were evaluated. Under the conditions used for these experiments, it can be deduced that resveratrol is more efficient than trolox as an antioxidant, also in the inner skin layers. The cosmeto-textiles with an active substance incorporated into their structure are increasingly used in the cosmetics and pharmaceutical industries. The action of several cosmeto-textiles on the skin was assessed by in vitro and in vivo methodologies. Samples of these cosmeto-textiles were prepared with resveratrol incorporated into cotton and polyamide fabrics. An in vitro percutaneous absorption was used to demonstrate the delivery of the resveratrol from the textile to the different skin layers (stratum corneum, epidermis, and dermis). Additionally, these cosmeto-textiles containing the antioxidant were applied onto the forearms of volunteers to evaluate the textiles’ efficacy in skin penetration. The antioxidant’s antiradical capacity was evaluated using the DPPH method. Results showed that resveratrol could be detected in the dermis, epidermis, and stratum corneum (SC) by an in vitro percutaneous absorption method and was also detected in the outermost layers of the SC by an in vivo method (stripping). A smaller amount of resveratrol was penetrated through the skin layers when cosmeto-textiles were used compared to direct topical application of the antioxidant solution. The cosmeto-textiles investigated can act as a reservoir system capable of progressively deliver the active substance to the skin layers. From the skin penetration profiles and the antioxidant efficacy assessment of resveratrol, it is possible to ameliorate the inherent antioxidant capacity of skin.

Prenatal exposure to MAM forms basis for persistent neural impairment in young and adult rat offspring

Reactive oxygen species (ROS) are active byproducts of aerobic metabolism. Although they are constantly produced during normal cellular activities in the mitochondria, their action is counteracted by inherent antioxidant systems. This equilibrium is distorted in the case of acute or chronic inflammation, which results in increased ROS production and, ultimately, oxidative stress. In sperm, ROS are produced by both spermatozoa and circulating leucocytes and may be part of normal adaptive reactions, such as the capacitation process. However, a number of external toxicants may also contribute to ROS production in the testis and epididymis, leading to a decrease in sperm viability and motility and, therefore, an increased onset of the male factor of infertility. Such pro-oxidative conditions include, among others, exposure to radiation, extreme temperature, certain drugs, toxins, heavy metals, smoking and biological hazards. The current review paper summarizes the available evidence incriminating ROS and oxidative stress as the underlying pathophysiological mechanism leading to the onset of reproductive toxicity in each of these settings.

Myrtenal attenuates diethylnitrosamine-induced hepatocellular carcinoma in rats by stabilizing intrinsic antioxidants and modulating apoptotic and anti-apoptotic cascades

Myrtenal, a natural monoterpene occurred in cumin, pepper, mint and eucalyptus. Monoterpenes are naturally occurring plant hydrocarbons composed of two isoprene units and are widely distributed in plant flora and are best known for occurrence in essential oils. Monoterpenes have been shown to have remarkable biological activities such as antioxidant, chemotherapeutic and chemopreventive effects in different models of cancer. The aim of the study was to investigate the antioxidant and anticancer activity of myrtenal against carcinogen induced hepatocellular caricinoma in rats. The antioxidant properties of myrtenal were evaluated by using different in vitro antioxidant assays such as by determining its scavenging effect against hydroxyl (OH(•)), superoxide anion (O2(•-)), nitric oxide, 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation (ABTS(•+)). In vivo antioxidant and anticancer activity of myrtenal were evaluated by determining the antioxidant enzymes, apoptotic and anti-apoptotic proteins such as Bcl-2, Bax and caspase-3 expression and histopathological analysis against the diethylnitrosamine induced hepatocellular carcinoma in wistar albino rats. Our results demonstrated that myrtenal exhibits strong antioxidant property in all the in vitro assays and the in vivo results revealed that the antioxidant status was significantly decreased in hepatoma bearing animals. The expression of anti-apoptotic proteins was up regulated and in contrast the apoptotic protein was down regulated in hepatoma bearing animals. Treatment with myrtenal to cancer bearing animals resulted in remarkable increase in the inherent antioxidants and excellent modulation in the proteins of apoptotic and anti-apoptotic cascade. Further, the RT-PCR analysis of protein expressions and histological analysis of liver tissues inevitably confirms the anticancer property of myrtenal. It is concluded that myrtenal exhibits excellent free radical scavenging activity and anticancer activity through the suppression of hepatocellular carcinoma in wistar rats. Thereby giving a positive insight to take this compound as an effective therapeutic agent against hepatoma.

Protective effect of Phyllanthus niruri against cyclosporine A-induced nephrotoxicity in rats

Phyllanthus niruri (Euphorbiaceae) is a popular plant in folk medicine, whole plant, fresh leaves, and fruits are used in the treatment of various diseases. In the present study, nephroprotective potential of aqueous extract of P. niruri was investigated against cyclosporine A (CsA) induced changes in kidney of Wistar rats. Nephrotoxicity was induced by oral administration of CsA (25 mg/kg/b.w.) dissolved in olive oil for a period of 21 days. Nephrotoxicity induced rats were treated with aqueous extract of P. niruri (200 mg/kg/b.w.) for a period of 21 days. Levels of serum creatinine and blood urea nitrogen, renal marker enzymes in serum and different enzymic and non-enzymic antioxidants, lipid peroxidation products, as well as ATPases in kidney homogenates were measured in normal, control (toxicity induced), and P. niruri treated rats. Histopathological studies were also been carried out. Administration of CsA increased the serum levels of creatinine and blood urea nitrogen, alkaline phosphatase, alanine aminotransaminase, and lactate dehydrogenase thereby indicating damage to kidneys. Increased lipid peroxidation and a decrease in antioxidants enzymes were observed in toxicity-induced rats. The levels of membrane-bound ATPases were also significantly altered. Upon administration of P. niruri, the levels of serum creatinine and blood urea nitrogen and also lipid peroxidation were found to be markedly reduced. Renal antioxidant defense systems, such as superoxide dismutase, catalase, glutathione peroxidase activities and reduced glutathione, and vitamins e and c, depleted by cyclosporine A, were restored to normalcy by treatment with the extract. The drug also effectively attenuated renal dysfunction and normalized the altered renal morphology and also restored the activities of renal ATPases. The results suggest that the nephroprotective effect of P. niruri could be due to the inherent antioxidant and free-radical scavenging principle(s) contained in the extract. In conclusion, our study indicates that P. niruri through its antioxidant activity effectively salvaged CsA induced nephrotoxicity.

Ultrahigh Pressure Liquid Chromatographic Determination of Tocopherols in B100 Biodiesel

AbstractA reversed‐phase gradient ultrahigh pressure liquid chromatographic method with a water–acetonitrile mobile phase and UV detection has been developed to rapidly determine the concentration of the major tocopherol components in B100. The described method requires minimal sample preparation and provides short analysis times compatible with the needs of small to mid‐size laboratories involved in B100 analyses. The objectives of this work were twofold. We wished to develop an analytical method both to rapidly screen B100 samples for their tocopherol content and to provide additional information on the source (from the distribution of tocopherols) and the nature of the processing of the B100 (absence of tocopherols would suggest distillation). Information on the tocopherol content of the B100 can be used to assess the inherent antioxidant content of the B100 and the extent to which additional stabilizers are required. The method determines the concentration of alpha, gamma and delta tocopherols and has a chromatographic run time of 4.5 min with minimal sample preparation. Calibration curves were linear over the range of 5–350 μg/mL and had correlation coefficients exceeding 0.999. The short term precision of the method was evaluated, and relative standard deviations were typically 2 % or less. Recovery of spiked tocopherols averaged 97 %.

Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test

BackgroundDietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20 g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1 ± 5.8 years old) immediately before and 5 and 60 min after the exhaustive Wingate test.ResultsMaximum anaerobic power was improved by acute creatine supplementation (10.5 %), but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP), leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects.ConclusionsOur data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent) and inherent antioxidant activity of creatine.

Effect of New Zealand blueberry consumption on recovery from eccentric exercise-induced muscle damage

BackgroundExercise-induced muscle damage (EIMD) is accompanied by localized oxidative stress / inflammation which, in the short-term at least, is associated with impaired muscular performance. Dietary antioxidants have been shown to reduce excessive oxidative stress; however, their effectiveness in facilitating recovery following EIMD is not clear. Blueberries demonstrate antioxidant and anti-inflammatory properties. In this study we examine the effect of New Zealand blueberries on EIMD after strenuous eccentric exercise.MethodsIn a randomized cross-over design, 10 females consumed a blueberry smoothie or placebo of a similar antioxidant capacity 5 and 10 hours prior to and then immediately, 12 and 36 hours after EIMD induced by 300 strenuous eccentric contractions of the quadriceps. Absolute peak and average peak torque across the knee, during concentric, isometric, and eccentric actions were measured. Blood biomarkers of oxidative stress, antioxidant capacity, and inflammation were assessed at 12, 36 and 60 hours post exercise. Data were analyzed using a two-way ANOVA.ResultsA significant (p < 0.001) decrease in isometric, concentric and eccentric torque was observed 12 hours following exercise in both treatment groups. During the 60 hour recovery period, a significant (p = 0.047) interaction effect was seen for peak isometric tension suggesting a faster rate of recovery in the blueberry intervention group. A similar trend was observed for concentric and eccentric strength. An increase in oxidative stress and inflammatory biomarkers was also observed in both treatment groups following EIMD. Although a faster rate of decrease in oxidative stress was observed in the blueberry group, it was not significant (p < 0.05) until 36 hours post-exercise and interestingly coincided with a gradual increase in plasma antioxidant capacity, whereas biomarkers for inflammation were still elevated after 60 hours recovery.ConclusionsThis study demonstrates that the ingestion of a blueberry smoothie prior to and after EIMD accelerates recovery of muscle peak isometric strength. This effect, although independent of the beverage’s inherent antioxidant capacity, appears to involve an up-regulation of adaptive processes, i.e. endogenous antioxidant processes, activated by the combined actions of the eccentric exercise and blueberry consumption. These findings may benefit the sporting community who should consider dietary interventions that specifically target health and performance adaptation.

Protective effects of the aqueous leaf extract of Aloe barbadensis on gentamicin and cisplatin–induced nephrotoxic rats

ObjectiveTo study the protective effects of the aqueous leaf extract of Aloe barbadensis(AEAB) on gentamicin and Cisplatin–induced nephrotoxic Wistar rats. MethodsIn each model of nephrotoxicity, thirty adult male Wistar rats were evenly divided into 5 groups. Groups I and II served as untreated and model controls, respectively while groups III-V were the treatment groups which were pretreated with 100-200 mg/kg bodyweight per day of AEAB 1 h before each dose of the nephrotoxicants. On the 8th day(in case of gentamicin) and on 6th day(in case of Cisplatin), blood samples for serum urea, total protein and creatinine as well as some ions like sodium, potassium, chloride and uric acid while the rat kidneys for histology were obtained under inhaled diethyl ether anesthesia. ResultsIn the gentamicin nephrotoxic rats, 100-200 mg/kg bodyweight per day significantly attenuated elevations in the serum creatinine, total protein and blood urea nitrogen levels in dose related fashion and no treatment related effect on uric acid and ions, and attenuated the gentamicin-induced tubulonephrosis. Similar effects were also recorded in the Cisplatin model of acute renal injury. ConclusionsThe nephroprotective effect of AEAB could be due to the inherent antioxidant and free-radical-scavenging principle(s) contained in the extract. In the near future, AEAB could constitute a lead to discovery of a novel drug for the treatment of drug-induced nephrotoxicity.

Enzymatically Synthesized Feruoloyl Dioleoylglycerol: Antioxidant Behavior and Position in Phospholipid Vesicles

Ferulic acid and its ester derivatives are known to be effective antioxidants and as such have been investigated as a potential antioxidant agent for cosmetic and pharmaceutical uses. Using immobilized Candida antarctica lipase B we synthesized ferulic acid lipophilic derivatives from vegetable oils. After synthesis we isolated the predominate species, feruloyl dioleoylglycerol (FDOG), and incorporated it into model phospholipid vesicles at 1 and 5 mol percent. Membrane leakage experiments showed that FDOG did not disturb the phospholipid membrane integrity. Fluorescence quenching experiments and molecular modeling determined that the feruloyl moiety rested within the hydrophobic/hydrophilic interface of the bilayer. This was further supported by NMR analysis that showed FDOG exists with its feruloyl moiety far away from its oleoyl groups. Lipid peroxidation inhibition and free-radical-scavenging analysis indicated that FDOG retained its inherent antioxidant capability, possibly by intercepting aqueous-phase free radicals as they penetrate the bilayer.

Identification and Characterization of Polyphenolic Antioxidants Using On-Line Liquid Chromatography, Electrochemistry, and Electrospray Ionization Tandem Mass Spectrometry

It is demonstrated that electrochemistry (EC) coupled to liquid chromatography (LC) and electrospray ionization tandem mass spectrometry (LC/EC/ESI-MS/MS) can be used to rapidly obtain information about the antioxidant activity (i.e., oxidation potential) and capacity (i.e., amount) of polyphenolic compounds, including catechin, kaempferol, resveratrol, quercetin, and quercetin glucosides. The described on-line LC/EC/ESI-MS/MS method facilitates the detection and characterization of individual antioxidants based on a combination of the obtained m/z values for the antioxidants and their oxidation products, the potential dependences for the ion intensities, and correlations between the retention times in the LC, EC, and MS chromatograms. As these results provide patterns that can be used in rapid screening for antioxidants in complex samples, the method should be a valuable complement to chemical assays commonly used to determine the total antioxidant capacity of samples. It is shown that the antioxidant capacity for a mixture of polyphenolic compounds depends on the redox potential employed in the evaluation, and this should consequently be taken into account when comparing results from different total antioxidant capacity assays. It is also demonstrated that the inherent antioxidant capacities of phenolic compounds increase with an increasing number of hydroxyl groups and that the potential needed to oxidize the remaining hydroxyl groups increases successively upon oxidation of the compound. Unlike chemical assays, which generally do not provide any information about the identities of the compounds on the molecular level, the present screening method can be used to identify individual antioxidants, rank compounds with respect to their ease of oxidation, and to study the antioxidant capacity at any redox potential of interest.

Current Antioxidant Molecular Therapies for Oxidative Stress-Related Ailments

Oxidative cell damage is a natural occurring phenomenon due to the aerobic conditions where cells are embedded; however, such injury can efficiently be controlled and repaired by the inherent antioxidants of the cell. When the oxidant/antioxidant balance is disrupted towards the former by any chemical, biological or physical insult a pathological state could be developed, therefore, an extensive list of compounds with proved or assumed antioxidants properties has largely been used for improving or restoring the health status. Pharmacological therapies as well as dietary or complementary therapies are continuously being investigated for the counteracting of the harmful or damaging effects of oxidation in cells or tissues. However, critical antioxidant levels are not always achieved at the target damaged cells by these approaches; on the other side, the expression of recombinant antioxidant genes specifically directed to the afflicted cell by gene delivery has shown remarkable results. In this review we summarize the literature focused on some of the current antioxidant molecular pharmacological strategies with particular emphasis to the gene transfer protocols involved in the treatment of oxidative stress-related disorders.

Protective effect of the aqueous leaf and seed extract of Phyllanthus amarus on gentamicin and acetaminophen-induced nephrotoxic rats

Aim of the study In African traditional medicine, different parts of Phyllanthus amarus Schum. and Thonn. (family: Euphorbiaceae) are highly valued for the treatment of array of human diseases including hepatic and urolithic and/or other renal diseases. In the present study, single oral 100–400 mg/kg/day of the leaf and seed aqueous extract of Phyllanthus amarus ( PA) were studied for their protective effects in acetaminophen- and gentamicin-induced nephrotoxic Wistar rats for 14 days. Materials and methods In each model of nephrotoxicities, thirty adult male Wistar rats were evenly divided into 5 groups. Groups I and II served as untreated and model controls, respectively while groups III–V were the treatment groups which were pretreated with 100–400 mg/kg/day of PA 1 hr before each dose of the nephrotoxicants for 14 days. On the 15th day, blood samples for serum urea and creatinine while the rat kidneys for histology were obtained under inhaled diethyl ether anesthesia. Results In the acetaminophen nephrotoxic rats, 100–400 mg/kg/day significantly ( p < 0.05, p < 0.01, p < 0.001) attenuated elevations in the serum creatinine and blood urea nitrogen levels in dose related fashion, as well as, attenuation of acetaminophen-induced tubulonephrosis. Similar effects were also recorded in the gentamicin model of acute renal injury. Results suggest that the nephroprotective effect of PA could be due to the inherent antioxidant and free-radical-scavanging principle(s) contained in the extract. Conclusions In the near future, PA could constitute a lead to discovery of a novel drug for the treatment of drug-induced nephrotoxicity.

GDNF reduces oxidative stress in a 6-hydroxydopamine model of Parkinson's disease

Many current theories of Parkinson's disease (PD) suggest that oxidative stress is involved in the neurodegenerative process. Potential neuroprotective agents could protect neurons through inherent antioxidant properties or through the upregulation of the brain's antioxidant defenses. Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect and restore dopamine neurons in experimental models of PD and to improve motor function in human patients. This study was designed to investigate GDNF's effect on oxidative stress in a model of PD. GDNF or vehicle was injected into the right striatum of male Fischer-344 rats. Three days later 6-OHDA or saline was injected into the same striatum. The striatum and substantia nigra from both sides of the brain were removed 24 h after 6-OHDA or saline injection and analyzed for the oxidative stress markers protein carbonyls and 4-hydroxynonenal. Both markers were significantly reduced in GDNF + 6-OHDA treated animals compared to vehicle + 6-OHDA treated animals. In addition, in animals allowed to recover for 3.5–4 weeks after the 6-OHDA administration, the GDNF led to significant protection against loss of striatal and nigral tissue levels of dopamine. These results suggest that the protective effects of GDNF against 6-OHDA involve a reduction in oxidative stress.

Effect of natural coagula maturation on the processability, cure, and mechanical properties of unfilled vulcanizates of Hevea natural rubber

AbstractFresh latex from different Hevea brasiliensis clones was naturally coagulated, subjected to different durations of maturation, processed into solid rubber, and compounded into pure gum stocks and vulcanized. Coagula maturation had clone‐specific effects on the processability of the raw rubber: reduced for some clones, while others was less sensitive. The cure and mechanical behaviors of the compounded stocks and vulcanizates, respectively, were not sensitive to the clonal origin of coagula and their duration of maturation. Although coagula maturation could be associated with leaching, deactivation of inherent antioxidants in Hevea latex, as well as crosslinking and/or oxidation of polyisoprene chains, these results show that compounding with a standard pure gum recipe compensates for the Hevea latex constituents affected by maturation. Hence, extended maturation of Hevea coagula, for economic or other reasons, would influence much more the bulk behavior of raw rubber and have insignificant effects on the compounded stocks and vulcanizates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2359–2363, 2007

Evaluation of antioxidant activity of parsley (Petroselinum crispum) essential oil and identification of its antioxidant constituents

Abstract Antioxidant capacities of the essential oil extracted from parsley (Petroselinum crispum) were evaluated by three different in vitro assays: β-carotene bleaching assay, DPPH free radical scavenging assay and Fe2+-metal chelating assay. Results showed that the parsley oil (PO) possessed a certain degree of antioxidant activities in terms of β-carotene bleaching capacity and free radical scavenging activity, but its metal chelating capacity was negligible. The antioxidant EC50 values of the β-carotene bleaching assay and DPPH free radical scavenging assay of the crude PO dissolved in methanol were measured in about 5.12 and 80.21 mg/mL, respectively. However, these values were much weaker than those of BHT in 0.01 and 0.58 mg/mL, and of α-tocopherol in 0.01 and 0.10 mg/mL. Isolation and identification of the inherent antioxidants in PO involved using various chromatographic techniques including silica gel open column chromatography, normal phase-HPLC and GC–MS. Myristicin in PO was found as a dominant compound (32.75%) that exhibited a moderate antioxidant activity. Apiol was the second dominant compound (17.54%), but it might be the major contributor to the antioxidant activity of PO. These results suggest that the PO and its two major components can be potential alternative natural antioxidants.

Simultaneous and ultrarapid determination of reactive oxygen species and reduced glutathione in apoptotic leukemia cells by microchip electrophoresis

A microchip electrophoresis method coupled with laser-induced fluorescence (LIF) detection was established for simultaneous determination of two kinds of intracellular signaling molecules (reactive oxygen species, ROS, and reduced glutathione, GSH) related to apoptosis and oxidative stress. As the probe dihydrorhodamine-123 (DHR-123) can be converted intracellularly by ROS to the fluorescent rhodamine-123 (Rh-123), and the probe naphthalene-2,3-dicarboxaldehyde (NDA) can react quickly with GSH to produce a fluorescent adduct, rapid determination of Rh-123 and GSH was achieved on a glass microchip within 27 s using a 20 mM borate buffer (pH 9.2). The established method was tested to measure the intracellular ROS and GSH levels in acute promyelocytic leukemia (APL)-derived NB4 cells. An elevation of intracellular ROS and depletion of GSH were observed in apoptotic NB4 cells induced by arsenic trioxide (As(2)O(3)) at low concentration (1-2 microM). Buthionine sulfoximine (BSO), in combination with As(2)O(3) enhanced the decrease of reduced GSH to a great extent. The combined treatment of As(2)O(3) and hydrogen peroxide (H(2)O(2)) led to an inverse relationship between the concentrations of ROS and GSH obtained, showing the proposed method can readily evaluate the generation of ROS, which occurs simultaneously with the consumption of the inherent antioxidant.

Dietary Antioxidants and Human Cancer

Epidemiological studies show that a high intake of anti-oxidant-rich foods is inversely related to cancer risk. While animal and cell cultures confirm the anticancer effects of antioxidants, intervention trials to determine their ability to reduce cancer risk have been inconclusive, although selenium and vitamin E reduced the risk of some forms of cancer, including prostate and colon cancer, and carotenoids have been shown to help reduce breast cancer risk. Cancer treatment by radiation and anticancer drugs reduces inherent antioxidants and induces oxidative stress, which increases with disease progression. Vitamins E and C have been shown to ameliorate adverse side effects associated with free radical damage to normal cells in cancer therapy, such as mucositis and fibrosis, and to reduce the recurrence of breast cancer. While clinical studies on the effect of anti-oxidants in modulating cancer treatment are limited in number and size, experimental studies show that antioxidant vitamins and some phytochemicals selectively induce apoptosis in cancer cells but not in normal cells and prevent angiogenesis and metastatic spread, suggesting a potential role for antioxidants as adjuvants in cancer therapy.

Prior Heat Acclimation Confers Protection against Noise-Induced Hearing Loss

Exposure to intense noise stress can cause a permanent noise-induced hearing loss which is thought to be due to elevation of reactive oxygen species in excess of the inherent antioxidant mechanisms of the cell. However, preconditioning to low levels of stress of one type can activate cellular mechanisms leading to the elevation of antioxidant levels so that the cell is then better able to tolerate subsequent severe stress of a different type. This has been called cross-tolerance. Here, we tested this hypothesis by acclimating rats to a moderate heat stress (30 days at 34°C). The rats were exposed to 113 dB SPL noise for 3 days (12 h/day) in three different groups: heat acclimated then noise exposed; noise exposed and then heat acclimated; heat acclimated, then noise exposed and then heat acclimated again. Permanent changes in auditory function – auditory nerve brainstem evoked responses (ABR) and distortion product otoacoustic emissions (DPOAEs) – were evaluated in each of these animals and compared with those in rats exposed to noise only and in control groups of rats. Statistical evaluation of the results showed that when assessed with ABR, each of the heat-acclimated, noise-exposed groups was protected from the noise, even the group that was heat-acclimated after the noise exposure. When assessed with DPOAE, protection was statistically apparent only in the group that was heat acclimated, then exposed to noise, and not in the other groups. Thus, heat acclimation provides protection against permanent noise-induced hearing loss.