Chemical composition and antioxidant properties of biologically active compounds from Euphrasia brevipila

Fractions of biologically active substances, including polysaccharides, iridoids, phenolic acids, and flavonoids, have been isolated from eyebright (Euphrasia brevipila) plants (Scrophulariaceae family) by chromatography on a polyamide sorbent. The following compounds were identified: aucubin; chlorogenic, ferulic, and caffeic acids; apigenin; luteolin; diosmetin; cinaroside; and cosmosiin. The antioxidant activity of the isolated biologically active substances was assessed on the model of lanolin autooxidation at 70°C in comparison to butyloxytoluene. The maximum antioxidant activity was observed for the fraction of phenolic acids that produced a fourfold increase in the stability of lanolin with respect to oxidation. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 6, pp. 22–26, June, 2006.     

The Influence of Humic Substances on the Absorption and Distribution of Cadmium in Mice

Abstract: The complex binding of cadmium ions to humic and fulvic acids in water may influence the absorption and distribution of drinking-water Cd in humans. Thus, in the present study mice were given a single oral dose of Cd (¹⁰⁹CdCl₂, 25 μg/l) in 100 μl Millipore® water containing different concentrations of humic compounds (0, 1, 10 and 100 mg dissolved organic carbon/l). The complex binding of Cd was studied by dialysis. At neutral pH, 1 mg dissolved organic carbon/l caused complex binding of more than 50% of the Cd, whereas more than 90% of Cd was bound at 10 and 100 mg dissolved organic carbon/l. At pH 3 the complex binding of Cd decreased somewhat, but over 90%) of the Cd was bound at 100 mg dissolved organic carbon/l. Complex binding of Cd increased the lipid solubility of Cd, expressed as an octanol/water partition coefficient, Nevertheless, more than 99% of the bound Cd was present as hydrophilic binding forms. Irrespective of the bound of Cd, the intestinal uptake and intracellular distribution (gel filtration on Sephadex G-75 column) were not affected by the humic substances 6 hr after dosage. Moreover, complex binding did not influence the intestinal absorption of Cd 24 hr after exposure. The median Cd retention in the kidneys of the 100 mg dissolved organic carbon/1 group was 23%> and 46% lower than that of the control group 6 and 24 hr after administration, respectively, indicating alterations in the distribution of Cd after absorption. Thus humic substances may affect the metabolism of toxic heavy metals, such as Cd, in vivo in mice, indicating that the presence of humic and fulvic acids in drinking water should be considered in future risk assessments of metals in drinking water.     

Chlorophytum borivilianum as potential terminator of free radicals in various in vitro oxidation systems

Chlorophytum borivilianum is a very popular herb in traditional Indian medicine and used as a potent “Rasayana” drug in “Ayurveda” as a rejuvenator. Currently, a large body of evidence supports the key role of free radicals in diverse pathological conditions such as aging and atherosclerosis. The present investigation essentially focuses on the comprehensive account of in vitro antioxidant activity exerted by C.borivilianum root extracts (i.e., aqueous and ethanolic), to clarify the pharmacological antagonism of chemicals/metals-mediated oxidation. Graded-dose (25 to 1000 µg/ml) of aqueous extract exhibited higher antioxidant potency as evidenced by powerful nitric oxide, superoxide, hydroxyl, DPPH and ABTS^·+ radicals scavenging activity along with reducing capacity (Fe³⁺/ferricyanide complex and FRAP assays), metal chelating ability, as well as markedly suppressed the lipid peroxidation in mitochondrial fractions as compared to ethanolic extract. Further, aqueous extract significantly decreased (P?<?0.05) copper-mediated human serum and kinetics of LDL oxidation, as demonstrated by prolongation of lag phase time with decline of oxidation rate, conjugated dienes, lipid hydroperoxides and thiobarbituric acid reactive substances. In addition, the total polyphenol and flavonoid contents of aqueous extract were higher than that of ethanolic extract, which indicated a positive correlation between antioxidant activity and contents of total phenols. The IC₅₀ values of both extracts were also compared with appropriate antioxidant standards. Overall, aqueous extract of C.borivilianum root has significant powerful antioxidant activity and may favorably affect atherosclerosis risk status by reducing LDL oxidation susceptibility.     

<Emphasis Type="Italic">In Vitro</Emphasis> antioxidant and anti-inflammatory activities of Jaceosidin from <Emphasis Type="Italic">Artemisia princeps</Emphasis> Pampanini <Emphasis Type="Italic">cv.</Emphasis> Sajabal

Oxidized low-density lipoprotein (oxLDL) plays a key role in the inflammatory processes of atherosclerosis. Jaceosidin isolated from the methanolic extracts of the aerial parts of Artemisia princeps Pampanini cv. Sajabal was tested for antioxidant and anti-inflammatory activities. Jaceosidin inhibited the Cu²⁺-mediated LDL oxidation with IC₅₀ values of 10.2 μM in the thiobarbituric acid-reactive substances (TBARS) assay as well as the macrophage-mediated LDL oxidation. The antioxidant activities of jaceosidin were exhibited in the conjugated diene production, relative electrophoretic mobility, and apoB-100 fragmentation on copper-mediated LDL oxidation. Jaceosidin also inhibited the generation of reactive oxygen species (ROS) concerning in regulation of NF-κB signaling. And jaceosidin inhibited nuclear factor-kappa B (NF-κB) activity, nitric oxide (NO) production, and suppressed expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.     

Bioaccumulation of ionic titanium and titanium dioxide nanoparticles in zebrafish eleutheroembryos

Abstract

The production of titanium dioxide nanoparticles (TiO₂ NPs) for commercial applications has greatly increased over the last years and consequently the potential risk for human health. There is a growing awareness of the need to understand the behavior and influence these nanoparticles exert on the environment. Bioaccumulation serves as a good integrator to assess chemical exposure in aquatic systems and is dependent on factors, such as the exposure routes, diet and the aqueous medium. We analyzed the experimental bioaccumulation capability of ionic titanium and TiO₂ NPs by zebrafish (Danio rerio) eleutheroembryos through bioconcentration factors (BCFs), after 48 or 72?h of exposure. The stability of both chemical forms in an aquatic medium was fully characterized for further bioaccumulation studies. Several stabilizing agents (humic acids, soluble starch, polyethylene glycol, Na₄P₂O₇ and Na₂HPO₄) for anatase and rutile, the two allotrophs of TiO₂ NPs, were evaluated to check the evolution of the aggregation process. Around 60% of TiO₂ NPs remained disaggregated under simulated environmental conditions with the addition of 50?mg?L^?1 of humic acids. However, the presence of eleutheroembryos in the exposure medium increased TiO₂ NPs aggregation in the experimental tests. The BCFs values obtained in all cases were <100, which classifies ionic titanium and TiO₂ NPs as non-bioaccumulative substances, under the REACH regulations.     

Antioxidant potential of Amorphophallus paeoniifolius in relation to their phenolic content

The present study evaluates the antioxidative and radical scavenging potential of the tuber extract of Amorphophallus paeoniifolius (Dennst.) Nicolson, (Araceae). The ethanol extract of A. paeoniifolius (APE) was studied for the inhibition of lipid peroxidation estimated in terms of thiobarbituric acid reactive substances (TBARS) and the levels were reduced by 4.3% to 67.2% in a dose-dependent manner. Further, APE was analyzed for scavenging capacities based on 1,1-diphenyl-2-picrylhydrazyl-2-radical (DPPH) assay and percentage inhibition activity based on 2,2-azinobis-(-3-ethyl) benzo-thiozoline-6-sulfonate (ABTS⁺) and H₂O₂. The A. paeoniifolius extract showed a maximum of 68.6% of DPPH scavenging activity and the maximum inhibition of 74% and 67.2% in the case of ABTS and H₂O₂, respectively. The antioxidant efficiency and inhibition of oxidation of the extract was found to be dose-dependent at the tested concentrations of 1-50?µg/mL. High-performance thin layer liquid chromatography (HPTLC) profile of the extract suggests the presence of polyphenols such as gallic acid, resveratrol, quercetin and two unidentified compounds. The results suggest that the ethanol extract of A. paeoniifolius has a potent antioxidant activity in vitro and can be utilized as an effective and safe source of antioxidants.     

Antioxidant activity of synthetic analogs and pure active principles of rhodiola rosea and raspberry ketone

The antioxidant action of natural tyrosol derivatives, raspberry ketone, and their synthetic analogs was studied in comparison with α-tocopherol and butylhydroxytoluene. It is shown that hydroxylation of tyrosol increases the antioxidant activity 1.5 times. The introduction of one o-tert-butyl substituent increases the inhibiting action by a factor of 3.5; of two o-tert-butyl substituents, by greater than 4.0 times. The maximum inhibiting effect was observed for tert-butylhydroxytyrosol, the structural modification of which included simultaneously both hydroxylation and alkylation. The antioxidant activity of the studied substances was lower than that of α-tocopherol and butylhydroxytoluene. It was established that the induction periods of the studied antioxidants (AOs) in addition to many natural inhibitors (α-tocopherol, carotenoids, flavonoids) as functions of the concentrations of the studied AOs exhibit peaks. Thus, directed structural modifications of natural compounds yielded new effective oxidation inhibitors, the application of which will probably avoid undesired effects related to overdoses of the existing drugs.     

Synthesis and biological activity of organosilicontitanium glycerohydrogels

A series of organosilicontitanium (OST) glycerohydrogels with the general formula 2Si(C₃H₇O₃)₄ ⋅ Ti(C₃H₇O₃)₄ ⋅ xC₃H₈O₃ ⋅ yH₂O (where 9 ≤ x ≤ 30 and 60 ≤ y ≤ 120) were synthesized and some of their pharmacological properties were studied. High percutaneous activity of the compounds was revealed by measuring the diffusion of sodium diclofenac through intact skin membranes in vitro. It was established that all of the synthesized substances are nontoxic. The wound-healing and antioxidant properties of the glycerohydrogels were studied. The experimental results show that OST glycerohydrogels can be recommended for further testing as effective percutaneous vehicles of medicines with wound-healing, burn-healing, and antioxidant action. Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 43, No. 2, pp. 26–32, February, 2009.     

Antioxidant and antiradical properties of new amino-acid derivatives of aminoalcohols

The antioxidant, antiradical, and membranotropic properties of newly synthesized compounds of the group of N-[3-hydroxy-3-(p-substituted phenyl)-1-propyl] amino acids were studied on model systems in vitro.According to the results, amino-acid derivatives of aminopropanols did not exhibit any significant antioxidant or antiradical activity as evidenced by Fe(II)-stimulated ascorbate-dependent peroxidation, by spectrophotometric monitoring of a decrease in the concentration of stable 2,2-diphenyl-1-picrylhydrazyl radical, or by photochemiluminescence techniques. However, these compounds revealed a membrane-stabilizing effect preventing hemolytic destruction of cells under conditions of H₂O₂-stimulated oxidative stress of erythrocytes. In this respect, derivatives of glycine, leucine, and methionine were most interesting.     

Biological activity assessment and phenolic compounds characterization from the fruit pericarp of Litchi chinensis for cosmetic applications

Context: Litchi chinensis Sonn. (Spindaceae) is an important economic fruit of Thailand. Therapeutic effects of the fruits are contributed by anti-inflammatory phenolics.

Objective: To extract the litchi fruit pericarp in order to identify biologically actives substances with potential for cosmetic application.

Materials and methods: The litchi pericarp was macerated by 70% ethanol (EtOH) and partitioned using n-hexane and ethyl acetate (EtOAc). In vitro antioxidant activities were assessed by 1, 1-diphenyl-2-picrylhydrazyl (DPPH), ABTS and ferric reducing ability of plasma (FRAP) assays including tyrosinase inhibitory effect. Cellular radical scavenging capacity was monitored in a normal human fibroblast cell culture (NHF). Total phenolic content was determined and characterized by HPLC.

Results: The EtOAc fraction was a significant antioxidant, stronger than ascorbic acid (p < 0.01), as assessed by ABTS (IC₅₀ = 7.137 ± 0.021 μg/mL), DPPH (IC₅₀ = 2.288 ± 0.063 μg/mL) and FRAP (EC_1mMFeSO4 = 8013.183 ± 58.804 μg/mL) assays. It demonstrated an antityrosinase effect (IC₅₀ = 197.860 ± 1.230 μg/mL) and showed no cytotoxic activity toward Vero and NHF cells, at a maximum tested concentration (50 μg/mL), with cellular antioxidant activity. Total phenolic content was highest in the most potent antioxidant fraction. Quercetin, rosmarinic and gallic acids were found. Total phenolic content is highly related to FRAP, antityrosinase, and ABTS activities.

Discussion and conclusion: Pericarp from litchi fruit can be obtained abundantly from agricultural waste, and the strong antioxidant activity demonstrated in this report may have application in topical cosmetic products. This ecological antioxidant can be prepared using a feasible method resulting in less waste and increased agro-industrial profitability.     

Synthesis and effect of biguanide derivatives on biochemiluminescence and level of reduced glutathione in rat blood serum and brain under ischemia-reperfusion conditions

We have studied the effect of the newly synthesized biguanides N-[amino(imino)methyl]morpholine-4-carboximidamide (I) and N-[amino(imino)methyl]piperidine-1-carboximidamide (II) on biochemiluminescence (BCL) parameters including (i) lightsum (S) and maximum flash intensity (I _max), which characterize the level of free-radical processes, and (ii) the slope of the BCL kinetic curve (tan α₂), which characterizes general antioxidant activity, and on the reduced glutathione level in rats brain and blood serum under post-ischemic reperfusion conditions. It was found that the investigated parameters, which increased in response to the development of oxidative stress with brain pathology, changed toward normalization under the influence of the biguanides. A dose-dependent action of these substances has been established. The administration of I and II in 25 and 50 mg/kg led to the most pronounced decrease in the BCL parameters and reduced glutathione concentration while 12.5 and 75 mg/kg doses did not lead to significant changes in the studied parameters. The results show that biguanides introduced in certain doses can decrease the free-radical oxidation level and produce a neuroprotective effect.     

Geographic origin influences the phenolic composition and antioxidant potential of wild Crataegus monogyna from Spain

Context: Crataegus monogyna Jacq L. (Lind.) (Rosaceae) is used in folk medicine as a sedative, aerial parts being rich in polyphenols with antioxidant ability.

Objectives: To study the variation in polyphenolic composition and antioxidant ability of spontaneous samples of C. monogyna in order to assess the relationship among these variables.

Materials and methods: Aerial parts of C. monogyna were collected from nine different locations in central Spain and extracted with methanol after drying. Total polyphenols were determined by the Folin-Ciocalteu method using gallic acid (GA) as standard. Sixteen polyphenolic compounds (11 flavonoids and 5 phenolic acids) were identified and quantified by reversed-phase HPLC in one single analysis. The antioxidant ability was evaluated by the oxygen radical absorbance capacity (ORAC) and the free radical scavenging activity (DPPH) methods. Linear correlation analysis was used to explore the relationships between the studied variables.

Results: Total polyphenol content ranged between 117.729?±?0.011 and 204.286?±?0.015?mg GAE/g extract, depending on the geographic origin. No relationship was found between total polyphenols and antioxidant ability by the ORAC or DPPH methods. Chromatographic analysis yielded lower amounts of polyphenols (23.3–143.26?mg/kg), as only flavonoids and phenolic acids were quantified. All the samples exhibited antioxidant activity between 1.32?±?0.08 and 2.76?±?0.007?μmol Trolox equivalents/mg and IC₅₀ from 0.82?±?0.10 to 3.76?±?0.67?μg/mL.

Conclusion: A statistically significant relationship between flavonoids and phenolic acids content and the antioxidant potential obtained by the ORAC method for C. monogyna samples was proven.     

Use of in vitro assays to assess the potential cytotoxic,genotoxic and antigenotoxic effects of vanillic and cinnamic acid

Vanillic acid (VA) found in vanilla and cinnamic acid (CA) the precursor of flavonoids and found in cinnamon oil, are natural plant phenolic acids which are secondary aromatic plant products suggested to possess many physiological and pharmacological functions. In vitro and in vivo experiments have shown that phenolic acids exhibit powerful effects on biological responses by scavenging free radicals and eliciting antioxidant capacity. In the present study, we investigated the antioxidant capacity of VA and CA by the trolox equivalent antioxidant capacity (TEAC) assay, cytotoxicity by neutral red uptake (NRU) assay in Chinese Hamster Ovary (CHO) cells and also the genotoxic and antigenotoxic effects of these phenolic acids using the cytokinesis-blocked micronucleus (CBMN) and the alkaline comet assays in human peripheral blood lymphocytes. At all tested concentrations, VA (0.17–67.2?μg/ml) showed antioxidant activity but CA (0.15–59.2?μg/ml) did not show antioxidant activity against 2,2-azino-bis (3-ethylbenz-thiazoline-6-sulphonic acid) (ABTS). VA (0.84, 4.2, 8.4, 16.8, 84 and 168?μg/ml) and CA (0.74, 3.7, 7.4, 14.8, 74, 148?μg/ml) did not have cytotoxic and genotoxic effects alone at the studied concentrations as compared with the controls. Both VA and CA seem to decrease DNA damage induced by H₂O₂ in human lymphocytes.     

Diphenyl diselenide in its selenol form has dehydroascorbate reductase and glutathione S‐transferase‐like activity dependent on the glutathione content

Objectives The antioxidant action of diphenyl diselenide ((PhSe)₂) is attributed to the mechanism by which (PhSe)₂ has pharmacological activity. Although (PhSe)₂ has glutathione peroxidase mimetic activity, the exact mechanism involved in its antioxidant effect has not yet been completely elucidated. In the present study, mechanisms involved in the antioxidant property of (PhSe)₂ (1–50 µm ) were investigated. Methods Dehydroascorbate (DHA) reductase‐ and glutathione S‐transferase (GST)‐like activity, 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS) radical‐scavenging activity and the protection against the oxidation of Fe²⁺ were evaluated. Key findings (PhSe)₂ at concentrations equal to, or greater than, 5 µm showed DHA reductase‐ and GST‐like activity. (PhSe)₂ was not a scavenger of DPPH or ABTS radicals and did not protect against the oxidation of Fe²⁺. Conclusions These results clearly indicated that DHA reductase‐ and GST‐like activity are the mechanisms involved in the antioxidant effect of (PhSe)₂.     

Free radical scavenging and antiatherogenic activities of Sesamum indicum seed extracts in chemical and biological model systems

An emerging consensus underscores the importance of oxidative events in vascular disease including excess production of reactive oxygen/nitrogen species (ROS/RNS), in addition to lipoprotein oxidation. Sesamum indicum has long been used extensively as a traditional food. The aim of present study was to evaluate antioxidant action of aqueous and ethanolic seed extracts from S. indicum using various in vitro ROS/RNS generated chemical and biological models. Results demonstrated that the graded-dose (25–1000 μg/ml) of aqueous and ethanolic extracts markedly scavenged the nitric oxide, superoxide, hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, showed metal chelating ability as well as reducing capacity in Fe³⁺/ferricyanide complex and ferric reducing antioxidant power assays. In biological models, both extracts were found to inhibit metal-induced lipid peroxidation in mitochondrial fractions, human serum and LDL oxidation models. In lipoprotein kinetics study, both extracts significantly (P < 0.05) increased lag phase time along with reduced oxidation rate and conjugated dienes production. Ethanolic extract of S. indicum showed higher amounts of total polyphenol and flavonoid content as compared to their counterpart. The IC₅₀ values of both extracts were compared with respective antioxidant standards. Overall, ethanolic extract of S. indicum possess strong antioxidant capacity and offering effective protection against LDL oxidation susceptibility.     

Studies on the antimicrobial effect of natural and synthetic humic acids (author's transl)]

Preparations of humic acids extracted from different soils by various methods and model humus substances obtained synthetically by oxidation of hydroquinone and pyrocatechin are tested for growth inhibition of representative strains of human pathogenic microorganisms using a micro serial dilution technique. Within the concentration range of less than or equal to 2500 micrograms/ml 57 of 81 natural and also the two synthetic humic acids show antimicrobial activity with differing spectra. These substances inhibit St. epidermidis, St. aureus, Str. pyogenes, S. typhimurium, Prot. vulgaris, Ent. cloacae, Ps. aeruginosa and C. albicans, but not Str. faecalis and E. coli. The degree of activity or the sensitivity of test organisms, respectively, amounts to 2500--1250 micrograms/ml predominantly, partially 625--312 micrograms/ml and can reach values of up to 39 micrograms/ml with synthetic hydroquinone humic acid. The spectrum and degree of activity vary according to the origin and extraction mode of the natural humic acids. The in vitro evidence of efficiacy against human pathogenic microorganisms gives a rational basis of therapeutic use of substances of humic acid type in infectious conditions.     

Synthesis and antimicrobial activity of cyclopentyl-substituted halogenophenoxyacetic acids and their amides

A series of cyclopentylhalogenoanisoles have been synthesized by alkylation of o- and p-chloro- and fluoroanisoles with cyclopentene in the presence of BF₃·H₃PO₄. The compositions and structures of the products were studied by GC, IR, and NMR spectroscopy. Demethylation of the cyclopentylhalogenoanisoles yielded cyclopentylhalogenophenols, which were reacted with chloroacetic acid and chloroacetamide to obtain cyclopentyl-substituted chloro- and fluorophenoxyacetic acids and their amides. Results of studying the antimicrobial activity of the synthesized acids and their amides against S. viridans, S. flexneri, P.aeruginosa, B. antracoides, K. rhinoscleromatis, and C. albicans are presented. All substances show moderate activity against the test microbes (minimum bacteriostatic concentrations from 31.25 to 125 μg/mL). Introduction of a cyclopentyl substituent into the structure of 2-chlorophenoxyacetic acid improves the activity against S. viridans, P. aeruginosa, and K. rhinoscleromatis. These data can be used to study the relationship between the structures and antimicrobial activity.     

Effects of ultrasound on the extraction of antioxidants from bearberry (Arctostaphylos adans) leaves

The effects of ultrasound (f = 60 kHz) on the quantity of biologically active substances extracted from bearberry leaves into a water:ethanol (1:1) mixture were studied, along with their antioxidant properties. The optimal conditions for extract preparation were identified: the raw material:extractant ratio and the duration of ultrasound exposure. Positive and negative aspects of the ultrasound extraction of antioxidants are discussed. The antioxidant activity of the extract prepared in optimum conditions was greater than that of a bearberry leaf extract prepared without ultrasound, increasing the resistance of sunflower oil to oxidation by factors of 2–2.2. Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 42, No. 10, pp. 43–45, October, 2008.     

Protective effect of Dunaliella sp., lipid extract rich in polyunsaturated fatty acids,on hepatic and renal toxicity induced by nickel in rats

Aims: The present study was undertaken to investigate the protective effect of lipid extract of Dunaliella sp. (LE) rich in polyunsaturated fatty acids (PUFA), against oxidative stress induced by nickel in experimental rats.

Methods: Our investigation evaluated the antioxidant activity of LE using both DPPH and NBT assays. Twenty female albino Wistar rats, randomly allocated into four experimental groups, namely (C): control, (Ni_t): nickel-treated rats with 5?mg/kg/d of NiCl₂ during 30 days, (LE_a): lipid extract-administered rats with 5 mg/kg BW/d during 30 days and (Ni_t?+_?LE_a): rats treated with Ni and LE-administered during 30 days.

Results: The in vitro antioxidant activity demonstrated that LE presents an important antioxidant potential. In vivo, the (Ni_t?+_?LE_a) cotreatment decreased the level of malondialdehyde and restored the antioxidant enzyme activities (superoxide dismutase, catalase and glutathione peroxidase) in livers and kidneys in comparison with those treated with Ni only. LE administration to rats treated with Ni also ameliorated biochemical and histological parameters as compared to only Ni-treated group. LE of Dunaliella sp., rich in polyunsaturated fatty acids showed a significant hepato- and reno-protective effect against metal-induced toxicity.

Conclusion: LE of Dunaliella sp., rich in PUFA has been proven to be effective in protection against Ni-induced toxicity.     

Pomegranate (Punica granatum) peel extract provides protection against mercuric chloride-induced oxidative stress in Wistar strain rats

Context: Pomegranate [Punica granatum L. (Lythraceae)] is rich in antioxidants.

Objective: The present work was undertaken to evaluate the protective effects of methanol extract of pomegranate peel extract (PPE) against a rat model of oxidative stress generated by treatment with mercuric chloride (HgCl₂).

Materials and methods: Rats were injected with HgCl₂ (5?mg/kg body weight in 0.9% NaCl) for developing oxidative stress. The methanol extract of pomegranate peel (PPE) was suspended in 0.5% sodium carboxymethylcellulose and fed to rats at 50?mg/kg body weight/day up to 30 days after HgCl₂ treatment. Biomarkers of oxidative stress including erythrocyte plasma membrane redox system (PMRS), lipid peroxidation, advanced oxidation protein products (AOPP), intracellular glutathione, and plasma antioxidant capacity as FRAP values were measured after PPE supplementation.

Results: HgCl₂-treated rats showed increased oxidative stress as evidenced by increased activity of erythrocyte PMRS 153%, lipid peroxidation 31%, and AOPP 290%. There was a significant (p < 0.01) decrease (25%) in plasma antioxidant capacity and intracellular glutathione (75%). Supplementation with PPE protected rats from HgCl₂ induced oxidative damage. PPE supplementation to control rats increased antioxidant defense.

Discussion and conclusion: The results clearly demonstrate that PPE treatment augments the antioxidant defense mechanism in mercuric chloride-induced oxidant toxicity. To the best of our knowledge this is the first report of the increase in erythrocyte PMRS activity in rats after supplementation with any kind of antioxidant supplementation. This study emphasizes the need for characterizing PPE for potential unknown antioxidant compounds.