Naturally-occurring Antioxidants Research Articles

The effect of enzymatic hydrolysis on the antioxidant activities and amino acid profiles of defatted chia (Salvia hispanica L.) flour

The aim of this study was to determine the effect of enzymatic hydrolysis using different proteases (Alcalase® and papain) and hydrolysis period on antioxidative activities and amino acid profiles of hydrolysed chia peptides. The experiment has been carried out using a completely randomized block design. The protein from defatted chia flour (DCF) was first isolated using different extraction pH (pH 10; 11; 12) and precipitation pH (pH 3.5, 4.0 and 4.5) to determine the highest protein isolated (CI) yield. The chia isolate (CI) extracted using the combination treatment (pH 12, 3.5) demonstrated the highest protein content of 17.22% and was selected to further hydrolysed using Alcalase® and papain enzyme at different hydrolysis time. The degree of hydrolysis (DH), protein solubility and peptide content of the chia protein hydrolysates (CH) were observed. Alcalase®-CH and Papain-CH demonstrated the highest DH at 60 mins of hydrolysis with the value of 47.09% and 44.29%, respectively. The protein solubility and peptide content were directly proportional to the DH. The Alcalase®-CH hydrolysed at 60 mins exhibited the highest antioxidant activities as measured by DPPH, ABTS and FRAP assays with values of 35.46µM AAE, 34.45µM TE and 23.11 µM FeSO4.7H2O E, respectively. The Alcalase®- CH demonstrated higher (p<0.05) hydrophobic amino acid (42.51%) compared to and Papain-CH (37.25%,). The highest aromatic amino acid content also recorded by Alcalase®-CH (20.10%), whereas Papain-CH with the value of 15.54%. However, both CH exhibited higher hydrophilic and aromatic amino acid compared to DCF and CI. This result has proved that the enzymatic hydrolysis of CH using Alcalase® and papain improved the nutritional and antioxidant capabilities, thus potentially represent a naturally occurring antioxidant ingredient in the production of functional food and nutraceutical appliance with significant health benefits.

Natural antioxidant potential of selected underutilized wild yams (Dioscorea spp.) for health benefit.

Modern research is directed towards finding naturally-occurring antioxidants of plant origin for improving nutrition and health benefit. Wild yam species are used as indigenous food and medicine by various tribal groups of Koraput, India. However, detailed analysis of health promoting bioactive compounds and antioxidant properties are lacking. The present study aims to evaluate the flavonoid, total antioxidant capacity and in vitro antioxidant activity of different wild and cultivated Dioscorea species of Koraput. The extract of these tuber was screened for its potential antioxidant activities by various tests, such as DPPH, nitric oxide, superoxide and ABTS radical cation assay. The phenol, flavonoid and total antioxidant capacity of the samples were ranged from 2.19 to 9.62mgg-1 dry weight, 0.62-0.85mgg-1 dry weight and 1.63-5.59%, respectively. The IC50 values were 77.9-1164, 101.2-1031.6, 27.0-1022.6 and 47.1-690µgml-1 for DPPH, ABTS, superoxide and nitric oxide scavenging activity, respectively. Taken together, some wild yam species such as D. bulbifera, D. pubera and D. pentaphylla had significantly higher flavonoids content and antioxidant capacity along with the lower IC50 values than the standards in compared to the other species. The present studies confirmed that some wild yam tubers have superior potential for scavenging deleterious free radicals effectively. Results indicated that these wild yam species should be promoted as natural source of antioxidants.

Uric Acid and High-Density Lipoprotein Cholesterol Are Differently Associated with Alzheimer's Disease and Vascular Dementia.

Uric acid (UA) is a major contributor to naturally-occurring antioxidant activity and is thought to have protective effects against neurodegenerative processes. However, UA is also implicated as a risk factor in vascular, including cerebrovascular, disease. Its association with, and role in, dementia and its component diseases including Alzheimer's disease (AD) and vascular dementia (VaD) remains unclear and inconsistently studied. Changes in blood lipids, particularly cholesterol measures, have also been implicated in dementias although the relationship or interactions with UA have been little studied.We have measured plasma UA and lipids taken from 187 subjects first attending a general hospital neurology department for symptoms associated with dementia, and from a series of 79 healthy control subjects. Diagnoses of AD and VaD were made following neuroimaging; laboratory measures were compared between dementia and control groups and between AD and VaD subgroups. No overall change in UA was seen in dementia, although a substantial and highly significant reduction was found in the AD patients. Reduced values in total cholesterol, HDL, and LDL were found in dementia, independent of statin treatment. Further investigation found a significant reduction of HDL only in the VaD group, while total cholesterol was significantly reduced in both AD and VaD subjects.These findings indicate that in our Chinese sample, UA deficits are specifically associated with AD, while deficits in HDL cholesterol found in dementia tend to be greater in VaD.

Free Radical Scavenging Activity of Ethanolic Extract of Citrus paradisi and Naringin -An In vitro Study

The present study attempts to find naturally-occurring antioxidants of fruit-based which give efficacy by additive activities. Citrus paradisi, known as Grape fruit contains significant bioactive components such as Naringin. The present study examines the free radical scavenging activity of ethanolic extract of Citrus paradisi and Naringin. The study was carried out with different radical scavenging assays like hydroxyl, DPPH, hydrogen peroxide, nitric oxide, super oxide. Citrus paradisi extracts showed lower radical scavenging activities in assays such as DPPH, superoxide and hydroxyl when compared with Naringin. Naringin showed the higher radical scavenging effect with nitric oxide, and hydrogen peroxide in comparison with citrus paradisi extract. However, both were analysed by using ascorbic acid as standard. The current study gives evidence that both showed potential free radical scavenging activity.

A comparative study of effects of extraction solvents/techniques on percentage yield, polyhenolic composition, and antioxidant potential of various extracts obtained from stems ofNepeta leucophylla: RP-HPLC-DAD assessment of its polyhenolic constituents

In the present study, the methanol, chloroform, and hexane extracts were isolated from the stems of Nepeta leucophylla using maceration method, soxhlet extraction method, and ultrasonic assisted extraction method. These extracts were analyzed for their total flavonoids content (TFC), total polyphenolic content (TPC), and antioxidant potential using nitric oxide scavenging (NOS), DPPH˙ (2,2-diphenyl-1-picrylhydrazyl radical scavenging), total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP) assays. The results of percentage yield, TPC, and TFC for various extracts varied from 0.99 to 12.16%, 0.34 to 133.7 mg GAE/g DPE, and 20.21 to 282.74 mg RE/g DPE, respectively, whereas the results of antioxidant potential of TAC, FRAP, percentage inhibition of NO and DPPH˙ scavenging activity ranged from 0.11 to 40.74 mg AAE/g DPE, 4.41 to 148.65 mg Fe (II) E/g DPE, 1.29 to 35.56%, and 14.93 to 90.43%, respectively. Practical applications N. leucophylla is an important wild Himalayan aromatic plant. Traditionally, it is used for the cure of malarial fever and its leaves are consumed as herbal tea. It is also known to have antifungal and antibacterial activity. The present results indicate that the SEM is the best technique for the isolation of naturally occurring antioxidants (NOAs) using methanol as a solvent from the powdered stem of N. leucophylla. Our research findings also indicate that the various extracts obtained from the stem of N. leucophylla show high antioxidant potential (FRAP, TAC, NO, and DPPH˙ radical scavenging activity) and are rich source of different NOAs viz. polyphenolics, flavonoids, coumarins, steroids etc. These classes of NOAs are also well known for their therapeutic potential like antitumor, anti-inflammatory, antiviral, antimicrobial, and antifungal properties. Hence, the stem of N. leucophylla may play a promising role in health benefits, pharmaceutical, nutraceutical, and functional foods development.

Kinetic Reaction Mechanism of Sinapic Acid Scavenging NO2 and OH Radicals: A Theoretical Study.

The mechanism and kinetics underlying reactions between the naturally-occurring antioxidant sinapic acid (SA) and the very damaging ·NO2 and ·OH were investigated through the density functional theory (DFT). Two most possible reaction mechanisms were studied: hydrogen atom transfer (HAT) and radical adduct formation (RAF). Different reaction channels of neutral and anionic sinapic acid (SA-) scavenging radicals in both atmosphere and water medium were traced independently, and the thermodynamic and kinetic parameters were calculated. We find the most active site of SA/SA- scavenging ·NO2 and ·OH is the –OH group in benzene ring by HAT mechanism, while the RAF mechanism for SA/SA- scavenging ·NO2 seems thermodynamically unfavorable. In water phase, at 298 K, the total rate constants of SA eliminating ·NO2 and ·OH are 1.30×108 and 9.20×109 M-1 S-1 respectively, indicating that sinapic acid is an efficient scavenger for both ·NO2 and ·OH.

Protective Effect of Cleistocalyx nervosum var. paniala Fruit Extract against Oxidative Renal Damage Caused by Cadmium.

Cadmium nephrotoxicity is a serious environmental health problem as it will eventually end up with end stage renal disease. The pathobiochemical mechanism of this toxic heavy metal is related to oxidative stress. This study investigated whether Cleistocalyx nervosum var. paniala fruit extract (CNFE) could protect the kidney against oxidative injury caused by cadmium. Initial analysis of the extract revealed antioxidant abilities and high levels of polyphenols, particularly catechin. Its potential renal benefits was further explored in rats treated with vehicle, CNFE, cadmium (2 mg/kg), and cadmium plus CNFE (0.5, 1, 2 g/kg) for four weeks. Oxidative renal injury was developed after cadmium exposure as evidenced by blood urea nitrogen and creatinine retention, glomerular filtration reduction, renal structural damage, together with increased nitric oxide and malondialdehyde, but decreased antioxidant thiols, superoxide dismutase, and catalase in renal tissues. Cadmium-induced nephrotoxicity was diminished in rats supplemented with CNFE, particularly at the doses of 1 and 2 g/kg. It is concluded that CNFE is able to protect against the progression of cadmium nephrotoxicity, mostly via its antioxidant power. The results also point towards a promising role for this naturally-occurring antioxidant to combat other human disorders elicited by disruption of redox homeostasis.

Platinum nanoparticles inhibit antioxidant effects of vitamin C via ascorbate oxidase-mimetic activity.

The development and application of nanomaterials as consumer products including food, drugs, and cosmetics are rapidly expanding. However, interactions between these novel materials and other chemical components of consumer products have not been thoroughly studied. Here, by using electron spin resonance techniques, we compared the effects of Au, Ag, and Pt nanoparticles (NPs) on the antioxidant activity of vitamin C (sodium l-ascorbate, NaA). Chemical studies showed that Pt NPs exhibit ascorbate oxidase-mimetic activity, thereby oxidizing NaA but Au and Ag NPs do not. This ascorbate oxidase-mimetic activity of Pt NPs results in a dramatic loss of antioxidant activity of NaA for scavenging hydroxyl radicals and superoxide radicals. A further study suggested that the ascorbate oxidase-mimetic activity of Pt NPs is critically dependent on the particle size. Finally, in vitro cell studies demonstrated that Pt NPs with ascorbate oxidase-mimetic activity inhibit the cytoprotective effect of NaA on cells challenged by oxidative stress. Our findings provide a better understanding of enzyme-mimicking NP interactions with naturally-occurring antioxidants and should guide future applications.

Cellular metabolic energy modulation by tangeretin in 7,12-dimethylbenz(a) anthracene-induced breast cancer.

Breast cancer is the leading cause of death among women worldwide. Chemoprevention and chemotherapy play beneficial roles in reducing the incidence and mortality of cancer. Epidemiological and experimental studies showed that naturally-occurring antioxidants present in the diet may act as anticancer agents. Identifying the abnormalities of cellular energy metabolism facilitates early detection and management of breast cancer. The present study evaluated the effect of tangeretin on cellular metabolic energy fluxes in 7,12-dimethylbenz(a) anthracene (DMBA)-induced proliferative breast cancer. The results showed that the activities of glycolytic enzymes significantly increased in mammary tissues of DMBA-induced breast cancer bearing rats. The gluconeogenic tricarboxylic acid (TCA) cycle and respiratory chain enzyme activities significantly decreased in breast cancer-bearing rats. In addition, proliferating cell nuclear antigen (PCNA) was highly expressed in breast cancer tissues. However, the activities of glycolytic enzymes were significantly normalized in the tangeretin pre- and post-treated rats and the TCA cycle and respiratory chain enzyme activities were significantly increased in tangeretin treated rats. Furthermore, tangeretin down-regulated PCNA expression on breast cancer-bearing rats. Our study demonstrates that tangeretin specifically regulates cellular metabolic energy fluxes in DMBA-induced breast cancer-bearing rats.

Antioxidant, Antimicrobial Effects and Phenolic Profile of Lycium barbarum L. Flowers.

L. barbarum L. is a widely-accepted nutraceutical presenting highly advantageous nutritive and antioxidant properties. Its flowers have been previously described as a source of diosgenin, β-sitosterol and lanosterol that can be further pharmaceutically developed, but no other data regarding their composition is available. The purpose of this work was to investigate the chemical constituents, antioxidant and antimicrobial activities of L. barbarum flowers, as an alternative resource of naturally-occurring antioxidant compounds. The free radical scavenging activity of the ethanolic extract was tested by TEAC, two enzymatic assays with more physiological relevance and EPR spectroscopy. The presence of several phenolic compounds, such as chlorogenic, p-coumaric and ferulic acids, but also isoquercitrin, rutin and quercitrin, was assessed by an HPLC/MS method. The antioxidant assays revealed that the extract exhibited a moderate antioxidant potential. The antimicrobial activity was mild against Gram-positive bacteria and lacking against Escherichia coli. These findings complete the scarce existing data and offer new perspectives for further pharmaceutical valorization of L. barbarum flowers.

Catechol-Bearing Polymeric Nanoparticles for Antioxidant Therapy

ABSTRACTPolymeric nanoparticles having redox-active catechol moieties, a common structural motif found in naturally-occurring antioxidants, were developed. We synthesized an amphiphilic catechol-bearing polymer that self-assembled to form nanoparticles with a diameter of 126 nm. The nanoparticles showed enhanced ROS-scavenging activity compared to the small catecholic compound dopamine. Furthermore, the nanoparticles inhibited ROS-mediated angiogenesis as shown by the endothelial cell tube formation assay and the chicken chorioallantoic membrane (CAM) assay.

Chocolate flavanols and skin photoprotection: a parallel, double-blind, randomized clinical trial.

BackgroundSolar ultraviolet (UV) radiation has deleterious effects on the skin, including sunburn, photoaging and cancer. Chocolate flavanols are naturally-occurring antioxidant and anti-inflammatory molecules that could play a role in preventing cutaneous UV damage. We investigated the influence of 12-week high-flavanol chocolate (HFC) consumption on skin sensitivity to UV radiation, measured by minimal erythema dose (MED). We also evaluated skin elasticity and hydration.MethodsIn this 2-group, parallel, double-blind, randomized controlled trial, 74 women aged 20–65 years and Fitzpatrick skin phototypes I or II were recruited from the general community in Quebec City, for randomization to either HFC (n = 33) or low-flavanol chocolate (LFC) (n = 41). A blocked randomisation (4), considering date of entry, skin type and age as factors, generated a sequentially-numbered allocation list. Study participants and research assistants were blinded. Totally, 30 g of chocolate were consumed daily for 12 weeks, followed by a 3-week washout period. MED was assessed at baseline and at 6, 9, 12 and 15 weeks. Main outcome was changes in MED at week 12.Results33 participants in the HFC group and 41 in the LFC group were analyzed with 15 weeks of follow-up. Both groups showed similarly-increased MED at 12 weeks (HFC: 0.0252 ± 0.1099 J/cm2 [mean ± standard deviation (SD)]; LFC: 0.0151 ± 0.1118; mean difference (MD): 0.0100 J/cm2; 95% confidence interval (CI): -0.0417 to 0.0618). However, after 3-week washout, the HFC group presented decreased MED (-0.0248 ± 0.1145) whereas no effect was seen in the LFC group (0.0168 ± 0.1698) (MD: -0.0417; 95% CI: -0.1106 to 0.0272). Net temple elasticity increased slightly but significantly by 0.09 ± 0.12 mm in the HFC group at 12 weeks compared to 0.02 ± 0.12 mm in the LFC group (MD: 0.06; 95% CI: 0.01 to 0.12 ). No significant adverse events were reported.ConclusionOur study failed to demonstrate a statistically-significant protective effect of HFC vs. LFC consumption on skin sensitivity to UV radiation as measured by MED.Trial registrationClinicalTrials.gov identifier: NCT01444625

English

To explore the naturally-occurring antioxidants having anticancer properties from plant origin since oxidants play a crucial role in developing various human diseases. The purpose of this research was to explore the antioxidant and anticancer properties of Sapindus trifoliatus (ST). The dried leaves of S. trifoliatus were ground into coarse powder and were exhaustively extracted with methanol; and the resulting crude methanolic extract (CME) was successively fractionated with petroleum ether, chloroform and ethyl acetate to obtain final extracts of petroleum ether (PEF), chloroform (CHF), ethyl acetate (EAF) and lastly the fractions of aqueous (AQF). Several assays were employed to determine the antioxidant activities, such as, 1,1-diphenyl-2-picrylhydrazine (DPPH) free radical scavenging assay, total antioxidant capacity assay, ferrous reducing antioxidant capacity, hydroxyl radical scavenging assay and lipid peroxidation inhibition assay. The in vivo anticancer activity of S. trifoliatus was deduced on Ehrlich’s Ascites cell (EAC) induced Swiss albino mice. Majority of the extracts showed strong antioxidant activities related to the standard. Key words: Sapindus trifoliatus, Sapindaceae, free radicals, polyphenolics, flavonoids, antioxidant activity, anticancer activity.

Antioxidant potential and its relationship with polyphenol content and degree of polymerization in Opuntia elatior Mill. fruits.

Background:Opuntia elatior Mill. (Nagaphani) fruits are traditionally recommended as an expectorant, remedy for whooping cough, asthma, gonorrhea, ulcers, tumors, in the treatment of diarrhea and syphilis. Many of these diseases are allied with oxidative stress caused by free radicals. Thus, current research is directed towards finding naturally-occurring antioxidants of plant origin.Aim:To evaluate antioxidant potential of hydro-alcoholic extract of the O. elatior fruits (HAOE) and its fractions.Materials and Methods:Using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide radical scavenging assay, total polyphenolic, flavonoid (FA), flavanone (FO) contents and degree of polymerization in relation with its antioxidant activity were examined.Results:The experimental data indicated that the HAOE, ethyl acetate (EAOE) and butanol (BFOE) soluble fractions have shown significant antioxidant activity. The highest polyphenolic, FA, FO contents and degree of polymerization were found in EAOE. The scavenging potential was in the order of Ascorbic Acid > EAOE > BFOE > HAOE > BIOE, where ascorbic acid was used as a positive control. The increased antioxidant potential of EAOE and BFOE fractions over HAOE extract may be attributed to the purification achieved by fractionation of the extract which in turn resulted in an increase in the degree of polymerization and segregation of secondary metabolites.Conclusion:The fruit of O. elatior can be used as the best alternative for synthetic antioxidants.

Evaluation of antioxidant and anticancer properties of the seed extracts of Syzygium fruticosum Roxb. growing in Rajshahi, Bangladesh.

BackgroundThe use of plants and their derived substances increases day by day for the discovery of therapeutic agents owing to their versatile applications. Current research is directed towards finding naturally-occurring antioxidants having anticancer properties from plant origin since oxidants play a crucial role in developing various human diseases. The present study was designed to investigate the antioxidant and anticancer properties of Sygygium fruticosum (Roxb.) (abbreviated as SF).MethodsThe dried coarse powder of seeds of SF was exhaustively extracted with methanol and the resulting crude methanolic extract (CME) was successively fractionated with petroleum ether, chloroform and ethyl acetate to get petroleum ether (PEF), chloroform (CHF), ethyl acetate (EAF) and lastly aqueous (AQF) fraction. The antioxidant activities were determined by several assays: total antioxidant capacity assay, DPPH free radical scavenging assay, hydroxyl radical scavenging assay, ferrous reducing antioxidant capacity and lipid peroxidation inhibition assay. The in vivo anticancer activity of SF was determined on Ehrlich’s Ascite cell (EAC) induced Swiss albino mice.ResultsAll the extractives showed strong antioxidant activities related to the standard. The total antioxidant capacity (TAC) of the fractions was in the following order: EAF>AQF>CME>PEF>CHF. The TAC of EAF at 320 μg/mL was 2.60±0.005 which was significantly higher (p < 0.01) than that of standard catechin (1.37 ± 0.005). The ferrous reducing antioxidant capacity of the extracts was in the following order: EAF>AQF>CME>AA>CHF>PEF. In DPPH free radical scavenging assay, the IC50 value of EAF was 4.85 μg/mL, whereas that of BHT was 9.85 μg/mL. In hydroxyl radical scavenging assay and lipid peroxidation inhibition assay, the EAF showed the most potent inhibitory activity with IC50 of 43.3 and 68.11 μg/mL, respectively. The lipid peroxidation inhibition assay was positively correlated (p < 0 .001) with both DPPH free radical scavenging and hydroxyl radical scavenging assay. The total phenolic contents of SF were also positively correlated (p < 0 .001) with DPPH free radical scavenging, hydroxyl radical scavenging and lipid peroxidation inhibition assay. Based on antioxidant activity, EAF was selected for cytotoxic assay and it was found that EAF inhibited 67.36% (p < 0.01) cell growth at a dose of 50 mg/kg (ip) on day six of EAC cell incubation.ConclusionsOur results suggest that EAF of seeds of SF possess significant antioxidant and moderate anticancer properties. Seeds of SF may therefore be a good source for natural antioxidants and a possible pharmaceutical supplement.

Synthesis of caffeic acid molecularly imprinted polymer microspheres and high-performance liquid chromatography evaluation of their sorption properties

In the current work, a molecularly imprinted polymer (MIP) has been synthesised and used to enable the extraction of a naturally-occurring antioxidant from complex media. More specifically, we describe the first example of a caffeic acid (CA) MIP which has been synthesised in the form of well-defined polymer microspheres, and its use for the extraction of CA from fruit juice sample. The CA MIP was synthesised by precipitation polymerisation using 4-vinylpyridine as functional monomer, divinylbenzene-80 as crosslinker and acetonitrile:toluene (75/25, v/v) as porogen. The particle sizing and morphological characterisation of the polymers was carried out by means of scanning electron microscopy (narrow particle size distribution; ∼5 and 1.5 μm particle diameters for the MIP and NIP [non-imprinted polymer], respectively) and nitrogen sorption porosimetry (specific surface areas of 340 and 350 m 2 g −1, and specific pore volumes of 0.17 and 0.19 cm 3 g −1 for the MIP and NIP, respectively). The polymers were evaluated further by batch rebinding experiments, and from the derived isotherms their binding capacity and binding strength were determined (number of binding sites ( N K ) = 0.6 and 0.3 mmol g −1 for the MIP and NIP, respectively, and apparent average adsorption constant ( K N ) = 10.0 and 1.6 L mmol −1 for the MIP and NIP, respectively). To evaluate the molecular recognition character of the MIP it was packed into a stainless steel column (50 mm × 4.6 mm i.d.) and evaluated as an HPLC-stationary phase. The mobile phase composition, flow rate, and the elution profile were then optimised in order to improve the peak shape without negatively affecting the imprinting factor ( IF). Very interesting, promising properties were revealed. The imprinting factor ( IF) under the optimised conditions was 11.9. Finally, when the imprinted LC column was used for the selective recognition of CA over eight related compounds, very good selectivity was obtained. This outcome enabled the direct extraction of CA in commercial apple juice samples with recoveries in excess of 81% and, rather significantly, without any need for a clean-up step prior to the extraction.

Polyphenols: A Potential New Strategy for the Prevention and Treatment of Anxiety and Depression

Following recent evidence that disturbances in oxidative metabolism are involved in anxiety disorders, high anxiety levels and depression, the use of antioxidants has been proposed as a novel approach for the prevention or treatment of these conditions. Polyphenols are naturally-occurring antioxidant substances which can have pharmacological actions on the central nervous system. This mini-review aims to examine the current evidence for the potential use of dietary polyphenols as neuroprotective agents to reduce anxiety and to manage depression. I will outline recent findings which demonstrate that polyphenols have anti-anxiety effects at higher doses (300/60/30/20 mg/kg body weight) as well as at lower doses (2-4 mg/kg); this can be compared to conventional anxiolytics, which only have anxiolytic effects at lower doses (1-5 mg/kg). To circumvent problems associated with polyphenols (e.g., quercetin) having difficulty crossing the blood-brain barrier and to effectively reduce the active dose, intranasal administration in the form of liposomes could be an interesting approach. I also suggest that dietary polyphenols could be a new alternative approach to treat depression, because they exhibit antidepressant activity with relatively lower doses (0.3-2 mg/kg) than commonlyused antidepressants such as imipramine (10 mg/kg). The polyphenols discussed in this mini-review are found in vegetables and fruits such as apples, plums, cherries, onions and tea. Therefore, a varied diet that is rich in naturallyoccurring polyphenols could be an effective means to prevent (or delay) anxiety, depression and other diseases linked to oxidative stress.

Raised natriuretic peptides, Big-endothelin-1 and improved beta-cell function in type 2 diabetic males with hyperuricaemia

Urate, a naturally-occurring antioxidant, is a marker/factor for cardiovascular disease. Hyperuricaemia is associated with IR, MetS and endothelial dysfunction. We characterised the associations between neurohormones, uricaemia, and glucose homeostasis in type 2 diabetes mellitus (T2DM) males. Cross-sectional; 705 T2DM males divided into two groups: uric acid < 7.0 mg/dl (normouricaemic; n=476) versus uric acid >or= 7.0 mg/dl (hyperuricaemic; n=229). HOMA beta-cell function (B), insulin sensitivity (S), hyperbolic product (BxS), and (BxS) loss rate were determined alongside neurohormones (Nt-proANP, BNP, Big ET-1 and UII). Mean age and diabetes duration were not different between groups. Hyperuricaemics had more macroangiopathy, total/central adiposity, IR, hypertension, dyslipidemia and MetS prevalence. Nt-proANP and BNP levels were more than twice as high in hyperuricaemics, whereas Big ET-1 and UII were higher by 46% and 14%, respectively. HOMA (BxS) was higher in hyperuricaemics: 31 (16)% vs. 26 (18)% (p=0.0004). BxS loss rate was faster in normouricaemics: 1.36 (0.54)% vs. 1.20 (0.43)%/year(-1) (p<0.0001 ). The proportion with HbA(1C) < 7.0% was 39% (normouricaemics) vs. 49% (hyperuricaemics; p=0.0091). In T2DM males, hyperuricaemia is associated with raised neurohormones together with better beta-cell indices. Urate's dual properties may translate into beneficial (glucose homeostasis) and detrimental (raised neurohormones) effects.

Antioxidant and free radical scavenging activity of Spondias pinnata.

BackgroundMany diseases are associated with oxidative stress caused by free radicals. Current research is directed towards finding naturally-occurring antioxidants of plant origin. The aim of the present study was to evaluate the in vitro antioxidant activities of Spondias pinnata stem bark extract.MethodsA 70% methanol extract of Spondias pinnata stem bark was studied in vitro for total antioxidant activity, for scavenging of hydroxyl radicals, superoxide anions, nitric oxide, hydrogen peroxide, peroxynitrite, singlet oxygen and hypochlorous acid, and for iron chelating capacity, reducing power, and phenolic and flavonoid contents.ResultsThe extract showed total antioxidant activity with a trolox equivalent antioxidant concentration (TEAC) value of 0.78 ± 0.02. The IC50 values for scavenging of free radicals were 112.18 ± 3.27 μg/ml, 13.46 ± 0.66 μg/ml and 24.48 ± 2.31 μg/ml for hydroxyl, superoxide and nitric oxide, respectively. The IC50 for hydrogen peroxide scavenging was 44.74 ± 25.61 mg/ml. For the peroxynitrite, singlet oxygen and hypochlorous acid scavenging activities the IC50 values were 716.32 ± 32.25 μg/ml, 58.07 ± 5.36 μg/ml and 127.99 ± 6.26 μg/ml, respectively. The extract was found to be a potent iron chelator with IC50 = 66.54 ± 0.84 μg/ml. The reducing power was increased with increasing amounts of extract. The plant extract (100 mg) yielded 91.47 ± 0.004 mg/ml gallic acid-equivalent phenolic content and 350.5 ± 0.004 mg/ml quercetin-equivalent flavonoid content.ConclusionThe present study provides evidence that a 70% methanol extract of Spondias pinnata stem bark is a potential source of natural antioxidants.

Astaxanthin: A Novel Potential Treatment for Oxidative Stress and Inflammation in Cardiovascular Disease

Oxidative stress and inflammation are implicated in several different manifestations of cardiovascular disease (CVD). They are generated, in part, from the overproduction of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that activate transcriptional messengers, such as nuclear factor-kappaB, tangibly contributing to endothelial dysfunction, the initiation and progression of atherosclerosis, irreversible damage after ischemic reperfusion, and even arrhythmia, such as atrial fibrillation. Despite this connection between oxidative stress and CVD, there are currently no recognized therapeutic interventions to address this important unmet need. Antioxidants that provide a broad, "upstream" approach via ROS/RNS quenching or free radical chain breaking seem an appropriate therapeutic option based on epidemiologic, dietary, and in vivo animal model data. However, human clinical trials with several different well-known agents, such as vitamin E and beta-carotene, have been disappointing. Does this mean antioxidants as a class are ineffective, or rather that the "right" compound(s) have yet to be found, their mechanisms of action understood, and their appropriate targeting and dosages determined? A large class of potent naturally-occurring antioxidants exploited by nature-the oxygenated carotenoids (xanthophylls)-have demonstrated utility in their natural form but have eluded development as successful targeted therapeutic agents up to the present time. This article characterizes the mechanism by which this novel group of antioxidants function and reviews their preclinical development. Results from multiple species support the antioxidant/anti-inflammatory properties of the prototype compound, astaxanthin, establishing it as an appropriate candidate for development as a therapeutic agent for cardiovascular oxidative stress and inflammation.