Deoxyribose Degradation Research Articles

Radical-scavenging activity of penicillin G, ampicillin, oxacillin, and dicloxacillin.

The aim of this study was to characterize the antioxidant activity of penicillin G (PG), ampicillin (AMP), oxacillin (OX) and dicloxacillin (DOX) through their reactivity towards reactive oxygen species (superoxide anion radical, O2•̅; hydroxyl radical, HO• ; peroxyl radical, ROO• ; hydrogen peroxide, H2 O2 ; DPPH• ) using various in vitro antioxidant assays with chemiluminescence (CL) and spectrophotometry as measurement techniques. In hydroxyl radical assays , PG, OX and AMP were found to inhibit the CL signal arising from the Fenton-like reaction in a dose-dependent manner with IC50 =0.480±0.020mM, IC50 =0.569±0.021mM, and IC50 =0.630±0.019mM, respectively. The highest reactivity of PG among the tested penicillins towards the HO radical was confirmed in the deoxyribose degradation assay. In the ABAP-derived ROO radical assay, the radical-scavenging ability of the test penicillins was in the following order: AMP>PG>DOX>OX. The number of reduced DPPH radicals by the drugs tested was <1 being the biggest for PG. The weak antioxidant capacity of the test penicillins was confirmed in the trolox antioxidant capacity assay (0.075±0.004; 0.093±0.006; 0.123±0.005; 0.126±0.004) for OX, AMP, DOX, PG, respectively. Use of luminol as a CL probe for estimation of penicillin reactivity towards H2 O2 showed that only AMP was able to quench light emission; the remaining antibiotics demonstrated a strong enhancing effect. All the examined compounds showed a weak antioxidant potential when estimated using the ferric-ferrozine assay. This study is the first to report the evaluation of test penicillins as antioxidants under the same reaction conditions.

Fisetin Protects DNA Against Oxidative Damage and Its Possible Mechanism.

The paper tries to assess the protective effect of fisetin against •OH-induced DNA damage, then to investigate the possible mechanism. The protective effect was evaluated based on the content of malondialdehyde (MDA). The possible mechanism was analyzed using various antioxidant methods in vitro, including •OH scavenging (deoxyribose degradation), •O2 (-) scavenging (pyrogallol autoxidation), DPPH• scavenging, ABTS•(+) scavenging, and Cu(2+)-reducing power assays. Fisetin increased dose-dependently its protective percentages against •OH-induced DNA damage (IC50 value =1535.00±29.60 µM). It also increased its radical-scavenging percentages in a dose-dependent manner in various antioxidants assays. Its IC50 values in •OH scavenging, •O2(-) scavenging, DPPH• scavenging, ABTS•(+) scavenging, and Cu(2+)-reducing power assays, were 47.41±4.50 µM, 34.05±0.87 µM, 9.69±0.53 µM, 2.43±0.14 µM, and 1.49±0.16 µM, respectively. Fisetin can effectively protect DNA against •OH-induced oxidative damage possibly via reactive oxygen species (ROS) scavenging approach, which is assumed to be hydrogen atom (H•) and/or single electron (e) donation (HAT/SET) pathways. In the HAT pathway, the 3',4'-dihydroxyl moiety in B ring of fisetin is thought to play an important role, because it can be ultimately oxidized to a stable ortho-benzoquinone form.

Chemical composition and biological activity of the essential oil from Thymus lanceolatus.

Thymus lanceolatus is a rare species, which grows wild in Algeria and Tunis. It is used traditionally as a drink and to flavor and preserve meat and poultry. The composition of the essential oil was determined by GLC/FID and GLC/MS. Forty-nine components were identified and quantified, accounting for 96.75% of the total detected components in the oil. The oxygenated monoterpenes (74.85%) constitute the major class of volatile secondary metabolites in the oil. Thymol was the most abundant constituent (69.61%) followed by γ-terpinene (8.38%). The antioxidant activity was evaluated using both diphenylpicrylhydrazyl (DPPH˙) reduction and 2-deoxyribose (2-DR) degradation prevention methods. The oil showed a very potent antioxidant activity with IC(50) values of 0.20 ± 0.07 and 4.96 ± 0.39 μg/mL for the DPPH˙ and 2-DR methods, respectively. The antimicrobial activity of the oil was assessed using the agar diffusion method, and the in vitro cytotoxicity on five different cancer cells was examined using the MTT assay. The oil revealed promising inhibitory activity against Gram positive bacteria, especially Bacillus subtilis and Streptococcus pyogenes with an MIC value of 62.5 μg/mL. Additionally, the highest cytotoxic activity was observed against the HL-60 cells with an IC(50) of 113.5 μg/mL. These results validate some of their traditional uses in food preservation.

Sida tuberculata (Malvaceae): a study based on development of extractive system and in silico and in vitro properties.

Sida tuberculata (Malvaceae) is a medicinal plant traditionally used in Brazil as an antimicrobial and anti-inflammatory agent. Here, we aimed to investigate the different extractive techniques on phytochemical parameters, as well as to evaluate the toxicity and antioxidant capacity of S. tuberculata extracts using in silico and in vitro models. Therefore, in order to determine the dry residue content and the main compound 20-hydroxyecdysone (20E) concentration, extracts from leaves and roots were prepared testing ethanol and water in different proportions. Extracts were then assessed by Artemia salina lethality test, and toxicity prediction of 20E was estimated. Antioxidant activity was performed by DPPH and ABTS radical scavenger assays, ferric reducing power assay, nitrogen derivative scavenger, deoxyribose degradation, and TBARS assays. HPLC evaluation detected 20E as main compound in leaves and roots. Percolation method showed the highest concentrations of 20E (0.134 and 0.096 mg/mL of extract for leaves and roots, respectively). All crude extracts presented low toxic potential on A. salina (LD50 >1000 µg/mL). The computational evaluation of 20E showed a low toxicity prediction. For in vitro antioxidant tests, hydroethanolic extracts of leaves were most effective compared to roots. In addition, hydroethanolic extracts presented a higher IC50 antioxidant than aqueous extracts. TBARS formation was prevented by leaves hydroethanolic extract from 0.015 and 0.03 mg/mL and for roots from 0.03 and 0.3 mg/mL on egg yolk and rat tissue, respectively (P<0.05). These findings suggest that S. tuberculata extracts are a considerable source of ecdysteroids and possesses a significant antioxidant property with low toxic potential.

Polyphenolic content and biochemical evaluation of fijk, alomo, osomo and oroki herbal mixtures in vitro

BackgroundThe current upsurge in the use of herbal remedies coupled with loose regulation on public access to these products underscore research efforts to evaluate their biochemical effect, noting also that many of the herbal medicines lack scientific credence to support medicinal claims. ObjectiveDetermination of in vitro antioxidant capacity and membrane stabilizing potential of some herbal remedies (Fijk, Osomo, Alomo and Oroki) respectively. MethodologyRed blood cells (RBCs) were prepared from rat blood and exposed to the therapeutic doses of Fijk, Alomo, Osomo and Oroki herbals in order to estimate relative hemolysis. Distilled water treatment of RBCs was taken as 100% hemolysis. Subsequently, the hemolysates were used for the determination of glucose-6-phosphate dehydrogenase (G6PD), superoxide dismutase (SOD), reduced glutathione (GSH) and malondialdehyde (MDA). The herbals were further evaluated for their polyphenolic content, free radical scavenging activity as well as total antioxidant capacity. ResultsThe herbals showed low polyphenolic content, reduced antioxidant capacity and offered no protection against free radical-induced degradation of deoxyribose. On the other hand, the herbal mixtures caused appreciable hemolysis of RBCs as well as depleted the levels of rat erythrocyte G6PD, GSH and SOD. Also, the erythrocyte level of MDA was elevated (p < 0.05) by exposure to Oroki herbal mixture. ConclusionThe herbal mixtures have low polyphenolic content as well as poor antioxidant property. This may impede their capacity to protect against oxidative stress.

Attenuation of Oxidative Damage by Boerhaavia diffusa L. Against Different Neurotoxic Agents in Rat Brain Homogenate

ABSTRACTDue to a high rate of oxidative metabolic activity in the brain, intense production of reactive oxygen metabolite occurs, and the subsequent generation of free radicals is implicated in the pathogenesis of traumatic brain injury, epilepsy, and ischemia as well as chronic neurodegenerative diseases. In the present study, protective effects of polyphenol rich ethanolic extract of Boerhaavia diffusa (BDE), a neuroprotective edible medicinal plant against oxidative stress induced by different neurotoxic agents, were evaluated. BDE was tested against quinolinic acid (QA), 3-nitropropionic acid (NPA), sodium nitroprusside (SNP), and Fe (II)/EDTA complex induced oxidative stress in rat brain homogenates. QA, NPA, SNP, and Fe (II)/EDTA treatment caused an increased level of thiobarbituric acid reactive substances (TBARS) in brain homogenates along with a decline in the activities of antioxidant enzymes. BDE treatment significantly decreased the production of TBARS (p < .05) and increased the activities of antioxidant enzymes like catalase and superoxide dismutase along with increased concentration of non-enzymatic antioxidant, reduced glutathione (GSH). Similarly, BDE caused a significant decrease in the lipid peroxidation (LPO) in the cerebral cortex. Inhibitory potential of BDE against deoxyribose degradation (IC50 value 38.91 ± 0.12 μg/ml) shows that BDE can protect hydroxyl radical induced DNA damage in the tissues. Therefore, B. diffusa had high antioxidant potential that could inhibit the oxidative stress induced by different neurotoxic agents in brain. Since many of the neurological disorders are associated with free radical injury, these data may imply that B. diffusa, functioning as an antioxidant agent, may be beneficial for reducing various neurodegenerative complications.

Antioxidant Activity of some Medicinal Plant Extracts: Implications for Neuroprotection

Background and Objective: This study was conducted in order to evaluate the effect of aqueous and ethanolic extracts of Phyllanthus niruri, Uncaria tomentosa and Mentha pulegium against Lipid Peroxidation (LP). Additionally, it was determined the ability of these plants to scavenge specific free radicals and the interaction with iron ions. Methodology: The LP, scavenging activity, total phenolics and flavonoids were determined by colorimetric methods, whereas HPLC analysis was used to characterize the phytoconstituents. Results: Extracts significantly prevented both basal or induced (by Fe 2+ , malonate, sodium nitroprusside or ferrocyanide) LP. Accordingly, the extracts were better antioxidants at higher used concentrations, the effect of aqueous seems to be higher than ethanolic; the effect of plants were found to be P. niruri>M. pulegium>U. tomentosa; extracts were better antioxidants when used in rat brain homogenates, as compared to yolk phospholipids. Extracts also presented significant scavenging activity, prevented deoxyribose degradation and chelate Fe 2+ . The HPLC analysis revealed that the extracts have different types and quantities of phytoconstituents. Conclusion: Altogether, presented results support the idea that antioxidant activities of extracts are related to the ability to scavenge specific free radicals and/or interaction with redox chemistry of iron ions. Thus, the broad range of antioxidant activity of these plants indicates the use with potential application to reduce LP associated to neurodegenerative disorders.

In vitro antioxidant and free radical scavenging activities of stem extract of Euphorbia trigona Miller

Antioxidative and free radical scavenging properties of different stem extracts of Euphorbia trigona were evaluated and correlated with its total phenolic content. Aqueous, acetone and methanolic extracts of shade dried stem were obtained and were concentrated in vacuo. The antioxidant and free radical scavenging activities of stem extracts was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, reducing power assay, deoxyribose degradation assay and Fe2+chelating assay. Total phenolic contents (TPC) were evaluated using Folin-Ciocalteu reagent. The results confirmed that the plant is a rich source of polyphenolic compounds which are invariably higher compared to other herbs. All extracts showed TPC in the range of 146.6 ? 168.6 mg/g gallic acid equivalents at 300 μg/ml of extract. Among the three extracts ME showed highest scavenging activity as evidenced by maximum scavenging of DPPH (83.2%), OH? radicals (94.81%), Fe 2+ chelating activity (88.59%) and a high reducing power 0.623 at 300 μg/ml. Our results demonstrate that Euphorbia trigona, an unexplored xerophytic plant could be potential source of natural antioxidants and phytotherapeutic agents. The plant possess invariably high amount of polyphenolic compounds with a broad spectrum of antioxidant properties and could be further used for food, feed and pharmaceutical applications.

Phytochemical analysis and antioxidant activities of Lantana camara and Lantana montevidensis extracts

There is currently a growing interest of the industry to replace synthetic products by natural ones with bioactive properties. The aim of this work is the phytochemical analysis of phenolic compounds and antioxidant activities of Lantana camara and Lantana montevidensis. ethanolic extracts. Folin–Ciocalteu and aluminum chloride methods were used for the analysis of the phenolic compounds, checking higher concentrations in the extracts of the leaves of both species. Phenolic compounds such as quercetin, rutin, gallic acid, chlorogenicacid and caffeic acid were identified and quantified by HPLC-DAD. Antioxidant activity of these species was determined using assay systems: inhibition of production of thiobarbituric acid reactive substances (TBARS), iron-chelating activity, deoxyribose degradation and ferric-reducing antioxidant power (FRAP). The ethanolic extracts exhibited more antioxidant activity recording major activities in TBARS and FRAP, being more effective extracts of leaves toward the root extracts. The results suggest the potential use of L. camara and L. montevidensis for the treatment of several diseases due to its ability to act as an antioxidant.

Reactivity of pyruvic acid and its derivatives towards reactive oxygen species.

Pyruvic acid and its derivatives occurring in most biological systems are known to exhibit several pharmacological properties, such as anti-inflammatory, neuroprotective or anticancer, many of which are suggested to originate from their antioxidant and free radical scavenger activity. The therapeutic potential of these compounds is a matter of particular interest, due to their mechanisms of action, particularly their possible antioxidant behaviour. Here, we report the results of a study of the effect of pyruvic acid (PA), ethyl pyruvate (EP) and sodium pyruvate (SP) on reactions generating reactive oxygen species (ROS), such as superoxide anion radicals, hydroxyl radicals and singlet oxygen, and their total antioxidant capacity. Chemiluminescence (CL) and spectrophotometry techniques were employed. The pyruvate analogues studied were found to inhibit the CL signal arising from superoxide anion radicals in a dose-dependent manner with IC50 = 0.0197 ± 0.002 mM for EP and IC50 = 69.2 ± 5.2 mM for PA. These compounds exhibited a dose-dependent decrease in the CL signal of the luminol + H2O2 system over the range 0.5-10 mM with IC50 values of 1.71 ± 0.12 mM for PA, 3.85 ± 0.21 mM for EP and 22.91 ± 1.21 mM for SP. Furthermore, these compounds also inhibited hydroxyl radical-dependent deoxyribose degradation in a dose-dependent manner over the range 0.5-200 mM, with IC50 values of 33.2 ± 0.3 mM for SP, 116.1 ± 6.2 mM for EP and 168.2 ± 6.2 mM for PA. All the examined compounds also showed antioxidant capacity when estimated using the ferric-ferrozine assay. The results suggest that the antioxidant activities of pyruvate derivatives may reflect a direct effect on scavenging ROS and, in part, be responsible for their pharmacological actions.

Effects of endogenous neurotoxin quinolinic acid on reactive oxygen species production by Fenton reaction catalyzed by iron or copper

The tryptophan metabolite, quinolinic (2,3-pyridinedicarboxylic) acid, is known as an endogenous neurotoxin. Quinolinic acid can form coordination complexes with iron or copper. The effects of quinolinic acid on reactive oxygen species production in the presence of iron or copper were explored by a combination of chemical assays, classical site-specific and ascorbic acid-free variants of the deoxyribose degradation assay, and mass spectrometry (ESI–MS). Quinolinic acid showed evident antioxidant activity in chemical assays, but the effect was more pronounced in the presence of copper as transition metal catalyst than in presence of iron. Nano-ESI–MS confirmed the ability of quinolinic acid to form coordination complexes with iron(II) or copper(II) and quinolinic acid stability against oxidative attack by hydroxyl radicals. The results illustrate a highly milieu-dependent quinolinic acid chemistry when it enters reactions as competitive ligand.

Iron chelation and redox chemistry of anthranilic acid and 3-hydroxyanthranilic acid: A comparison of two structurally related kynurenine pathway metabolites to obtain improved insights into their potential role in neurological disease development

Anthranilic acid (ANA) and 3-hydroxyanthranilic acid (3-HANA) are kynurenine pathway intermediates of the tryptophan metabolism. A hitherto unemployed method combination, differential pulse voltammetry, mass spectrometry (nano-ESI–MS), deoxyribose degradation and iron(II) autoxidation assays has been employed for studying of their redox chemistry and their interactions with iron(II) and iron(III) ions. Both acids inhibited the Fenton reaction by iron chelation and ROS scavenging in the deoxyribose degradation assay. In the iron(II) autoxidation assay, anthranilic acid showed antioxidant effects, whereas 3-hydroxyanthranilic acid exhibited apparent pro-oxidant activity. The differential pulse voltammograms of free metabolites and their iron(II) coordination complexes reflected these properties. Nano-ESI–MS confirmed ANA and 3-HANA as efficient iron(II) chelators, both of which form coordination complexes of ligand:iron(II) ratio 1:1, 2:1, and 3:1. In addition, nano-ESI–MS analyses of the oxidation effects by hydroxyl radical attack identified 3-HANA as strikingly more susceptible than ANA. 3-HANA susceptibility to oxidation may explain its decreased concentrations in the reaction mixture. The presented observations can add to explaining why 3-HANA levels decrease in patients with some neurological and other diseases which can often associated with elevated concentrations of ROS.

Antioxidant Activity of Anthocyanins Extracted from Iraqi &amp;lt;i&amp;gt;Iresine herbstii&amp;lt;/i&amp;gt; L. Flowers after Drying and Freezing

Any processing method that maintains the level of compounds known for their health benefits will be of interest to the food industries. Therefore, the effects of vacuum drying, storage and freezing on the anthocyanin content and their antioxidant properties of Iresine herbstii L. flowers were investigated. The results showed that fresh samples (AEFF) had the highest amount of total anthosyanin content (8.31 ± 0.23 mg/g dry matter, expressed as cyaniding 3-glucoside equivalents), followed by 7.17 ± 0.12 mg/g solid content, 13.72% loss of vacuum dried samples (AEDF). In comparison with fresh samples, total anthocyanins in stored samples for two weeks at 5°C (AESF) and frozen samples during 1 (AEZF1) and 3 months (AEZF3) of storage were significantly (P I. herbstii L. flowers exhibited a dose-dependent (AEFF > AEDF > AESF > AEZF1 > AEZF3, respectively) antioxidant activity against lipid peroxidation in a linoleic acid model system as well as strong reducing power and ferrous ion chelating abilities. Moreover, the anthocyanins extracted were found to show remarkable scavenging activity on superoxide anion radicals, hydroxyl radicals, hydrogen peroxide, nitric oxide radicals and deoxyribose degradation. Based on the results obtained, we can concluded that the Iresine herbstii L. flowers may be valuable natural antioxidant sources and are potentially applicable in both pharmacy and food industry

Evaluation of the antioxidant activity and the healing action of the ethanol extract of Calotropis procera bark against surgical wounds.

The objective of the present study was to evaluate the antioxidant potential and the wound healing effect of the ethanolic extract of the bark of Calotropis procera. The antioxidant study was evaluated in vitro, using 2,2-diphenylpicrylhydrazyl (DPPH) and deoxyribose degradation assays. Wound healing was studied using excision and incision wound on normal and dexamethasone-suppressed wound healing rodent models. Alkaloids, flavonoids, proteins and phenols were screened in the extract used whereas saponins and true tannins were absent. The extract contains only 12.5 gallic acid equivalent and 399.54 rutin equivalent. It was found to inhibit DPPH and deoxyribose oxidation (IC50 = 24.24 and 5.40 respectively). In vivo study demonstrated a significant reduction in the epithelialization time (P < 0.001) to 17-18 days in normal and dexamethasone treated rats following the ethanolic extract of the bark of C. procera application. The same extract also significantly increased the breaking strength in dexamethasone treated rats. Histological examination of incision wounds of treated group showed matured extracellular matrix, numerous fibroblasts. This study illustrated an excellent potential of the bark of C. procera therapy on dermal wound healing, with a tentative mechanism of action related to improved collagen deposition and reduced inflammatory reaction.

Antioxidant Activities of Nine Selected Culinary Spices from China

The antioxidant activities and the total phenolic contents of the water and/or ethanol extracts of the nine selected culinary spices from China were systematically investigated. Both ethanol extracts and water extracts had high ability of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 2, 2'-azinobis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing antioxidant power (FRAP). The ethanol extract of Sichuan pepper showed the highest ability of DPPH radical scavenging. The extract with the highest ABTS radical scavenging effect was that of ethanol extract of cinnamon. Both ethanol and water extracts of cinnamon possessed the high ferric reducing antioxidant power (FRAP) with the values of 4 541.87 and 1 134.52 µmol of Fe (II)/g. The extracts with high hydroxyl radical-mediated deoxyribose degradation were all the ethanol extracts as follows: cinnamon, bay leaf, Sichuan pepper, star anise and fennel. The extracts with high antioxidant activities also had the high contents of the phenols. The study indicated that these spices might be potentially be used as natural antioxidants in food.

Todralazine protects zebrafish from lethal effects of ionizing radiation: role of hematopoietic cell expansion.

The Johns Hopkins Clinical Compound Library (JHCCL), a collection of Food and Drug Administration (FDA)-approved small molecules (1400), was screened in silico for identification of novel β2AR blockers and tested for hematopoietic stem cell (HSC) expansion and radioprotection in zebrafish embryos. Docking studies, followed by the capacity to hasten erythropoiesis, identified todralazine (Binding energy, -8.4 kcal/mol) as a potential HSC-modulating agent. Todralazine (5 μM) significantly increased erythropoiesis in caudal hematopoietic tissue (CHT) in wild-type and anemic zebrafish embryos (2.33- and 1.44-folds, respectively) when compared with untreated and anemic control groups. Todralazine (5 μM) treatment also led to an increased number of erythroid progenitors, as revealed from the increased expression of erythroid progenitor-specific genes in the CHT region. Consistent with these effects, zebrafish embryos, Tg(cmyb:gfp), treated with 5 μM todralazine from 24 to 36 hours post fertilization (hpf) showed increased (approximately two-folds) number of HSCs at the aorta-gonad-mesonephros region (AGM). Similarly, expression of HSC marker genes, runx1 (3.3-folds), and cMyb (1.41-folds) also increased in case of todralazine-treated embryos, further supporting its HSC expansion potential. Metoprolol, a known beta blocker, also induced HSC expansion (1.36- and 1.48-fold increase in runx1 and cMyb, respectively). Todralazine (5 μM) when added 30 min before 20 Gy gamma radiation, protected zebrafish from radiation-induced organ toxicity, apoptosis, and improved survival (80% survival advantage over 6 days). The 2-deoxyribose degradation test further suggested hydroxyl (OH) radical scavenging potential of todralazine, and the same is recapitulated in vivo. These results suggest that todralazine is a potential HSC expanding agent, which might be acting along with important functions, such as antioxidant and free radical scavenging, in manifesting radioprotection.

Suppression of SOS response in E. coli PQ 37, antioxidant potential and antiproliferative action of methanolic extract of Pteris vittata L. on human MCF-7 breast cancer cells

Pteris vittata L. from the foothills of Kangra district, Himachal Pradesh, India has been investigated for its potential to combat reactive oxygen species and DNA damaging agents. DPPH radical, superoxide anion radical, ABTS+. radical cation decolorization, reducing power, deoxyribose degradation, plasmid nicking and lipid peroxidation assays were carried out to evaluate the antioxidant potential of methanolic of P. vittata L. (PME). The extract showed a significant potential in scavenging the free radicals and an IC50 of 64.425 µg/ml and 90.143 µg/ml was obtained in superoxide radical scavenging and reducing power assays respectively. PME inhibited lipid peroxidation with an IC50 of 34.35 µg/ml and protected the plasmid DNA from damage by hydroxyl radicals to varying degrees. Percentage inhibition of 81.22 and 89.36 at a concentration of 160 µg/ml was obtained in non site specific and site specific deoxyribose degradation assays respectively. PME significantly inhibited 4NQO induced mutagenicity in Escherichia coli PQ 37 and a decrease in induction factor was observed with increasing concentration. The amount of total phenolic and flavonoid content were also determined and HPLC analysis was carried out for the identification of phytoconstituents. A dose dependent decrease in viability of MCF-7 cells was observed with GI50 value of 153.967 µg/ml.

Hydroxyl radical reactions and the radical scavenging activity of β-carboline alkaloids

β-Carbolines are bioactive pyridoindole alkaloids occurring in foods, plants and the human body. Their activity as hydroxyl radical (OH) scavengers is reported here by using three different methods: deoxyribose degradation, hydroxylation of benzoate and hydroxylation of 2′-deoxyguanosine to give 8-hydroxy-2′-deoxyguanosine (8-OHdG) as assessed by RP-HPLC (MS). Fenton reactions (Fe2+/Fe3+ plus H2O2) were used for OH generation, and the radical increased in the presence of ascorbic acid or 6-hydroxydopamine as pro-oxidants. β-Carbolines were scavengers of OH in the three assays and in the presence of pro-oxidants. Tetrahydro-β-carboline-3-carboxylic acids were active against the hydroxylation of 2′-deoxyguanosine. β-Carbolines reacted with hydroxyl radicals (OH) affording hydroxy-β-carbolines, whereas tetrahydro-β-carbolines gave oxidative and degradation products. On the basis of IC50 and reaction rates (k), β-carbolines (norharman and harman), and tetrahydro-β-carbolines (tetrahydro-β-carboline, 1-methyltetrahydro-β-carboline and pinoline) were good OH radical scavengers and their activity was comparable to that of the indole, melatonin, which is an effective hydroxyl radical scavenger and antioxidant.

English

The antidenaturation and antioxidant properties of Spondias mombin Linn (Anacardiaceae) methanol leaf extract (SMC) and fractions prepared from it were evaluated in this study. SMC and its fractions: ether (SME), saponin-rich (SMS) and flavonoid-rich (SMF) were phytochemically screened and evaluated for total antioxidant activity (TAA), ability to inhibit deoxyribose degradation (DEO), lipid peroxidation inhibitory activity (LPIA), 2,2 - diphenyl-1-picryl hydrazyl scavenging activity, ability to chelate ferrous ions and protein denaturation inhibitory activity (PRO). The antioxidant and antidenaturation activities were in the order SME &gt; SMF &gt; SMC &gt; SMS. TAA strongly correlated with DEO, LPIA and PRO. The results indicate that S. mombin contains a diverse array of phytochemicals with potent antioxidant and bio-preservative properties which can serve as candidates for food preservation and drug development. Key words: Spondias mombin, phytoconstituents, antioxidant activity, protein denaturation.

In vitro antioxidant and cytotoxic activities of essential oil of Feronia elephantum Correa

To analyse the chemical composition and evaluation of antioxidant, cytotoxic and DNA fragmentation activities of essential oil of Feronia elephantum Correa. Chemical composition analysis of hydrodistilled essential oil was determined by gas chromatography-mass spectrometry and in vitro antioxidant activity of oil was determined by DPPH free radical, hydroxyly radical scavenging, metal chelating and prevention of deoxyribose degradation. Cytotoxicity and DNA fragmentation activities against breast cancer cells (MCF-7) were also analyzed. Gas chromatography-mass spectrometry analysis revealed the presence of 24 compounds with caryophyllene oxide (62.29%) as major compound. A considerable antioxidant, cyotoxic and DNA fragmentation activities of oils was observed. The result of this study clearly indicates oil could be useful for food preservation and preparation.