“In vitro” protection of DNA from Fenton reaction by plant polyphenol verbascoside

Changes in Growth and Heavy Metal and Phenolic Compound Accumulation in Buddleja cordata Cell Suspension Culture under Cu, Fe, Mn, and Zn Enrichment

Buddleja cordata cell suspension cultures could be used as a tool for investigating the capabilities of this species to tolerate heavy metals (HMs) and for assessing the effects of HMs on the accumulation of phenolic compounds in this species. It grows in a wide range of habitats in Mexico, including ultramafic soils, and mobilizes some HMs in the soil. The mobilization of these HMs has been associated with phenolic substances. In addition, this species is used in Mexican traditional medicine. In the present study, a B. cordata cell suspension culture was grown for 18 days in a culture medium enriched with Cu (0.03-0.25 mM), Fe (0.25-1.5 mM), Mn (0.5-3.0 mM), or Zn (0.5-2.0 mM) to determine the effects of these HMs on growth and HM accumulation. We also assessed the effects of the HMs on phenolic compound accumulation after 1 and 18 days of HM exposure. Cells were able to grow at almost all tested HM concentrations and accumulated significant amounts of each HM. The highest accumulation levels were as follows: 1160 mg Cu kg-1, 6845 mg Fe kg-1, 3770 mg Mn kg-1, and 6581 mg Zn kg-1. Phenolic compound accumulation was affected by the HM exposure time and corresponded to each HM and its concentration. Future research should analyze whole plants to determine the capabilities of Buddleja cordata to accumulate abnormally high amounts of HM and to evaluate the physiological impact of changes in the accumulation of phenolic compounds.

Tannin complexation with metal ions and its implication on human health, environment and industry: An overview

Tannins, also known as plant polyphenols (PPs), are secondary metabolites widely existing in higher plants and are a kind of natural renewable resource with wide distribution, variety and quantity. Tannin has become an important class of fine chemicals due to the easily modified molecular structure and the properties of antibacterial and antioxidant, combining with protein and complexing with metal ion. Besides being used for tanning leather, tannins are also widely used in wood adhesive, concrete water-reducing agents, oil drilling fluid viscosity-reducing agents, pharmaceutical, mineral processing, water treatment, gas desulfurization, metal anticorrosion, wood anticorrosion, printing and dyeing, liquor clarification, oil antioxidant, daily chemical products and other products preparation. There are two groups of tannins: condensed tannins (CTs) (flavonoid-derived proanthocyanidins) and hydrolysable tannins (HTs) (gallic acid ester-derived). Tannins can form complexes with metals through the ortho-dihydroxyphenolic group(s), especially with transition metals. The structure-activity relationships, stoichiometry, and origin of the insolubility of which were emphasized. Furthermore, this paper proposed an in-depth discussion of the associations of tannins-metal complexes in human health, environment and industries.

An Antifungal Polycyclic Tetramate Macrolactam, Heat-Stable Antifungal Factor (HSAF), Is a Novel Oxidative Stress Modulator in Lysobacter enzymogenes

Polycyclic tetramate macrolactams (PoTeMs) are a fast-growing family of antibiotic natural products found in phylogenetically diverse microorganisms. Surprisingly, none of the PoTeMs have been investigated for potential physiological functions in their producers. Here, we used heat-stable antifungal factor (HSAF), an antifungal PoTeM from Lysobacter enzymogenes, as a model to show that PoTeMs form complexes with iron ions, with an association constant (K_a ) of 2.71 × 10⁶ M^-1 The in vivo and in vitro data showed formation of 2:1 and 3:1 complexes between HSAF and iron ions, which were confirmed by molecular mechanical and quantum mechanical calculations. HSAF protected DNA from degradation in high concentrations of iron and H₂O₂ or under UV radiation. HSAF mutants of L. enzymogenes barely survived under oxidative stress and exhibited markedly increased production of reactive oxygen species (ROS). Exogenous addition of HSAF into the mutants significantly prevented ROS production and restored normal growth in the mutants under the oxidative stress. The results reveal that the function of HSAF is to protect the producer microorganism from oxidative damage rather than as an iron-acquisition siderophore. The characteristic structure of PoTeMs, a 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. The study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damage to the cells.IMPORTANCE PoTeMs are a family of structurally distinct metabolites that have been found in a large number of bacteria. Although PoTeMs exhibit diverse therapeutic properties, the physiological function of PoTeMs in the producer microorganisms had not been investigated. HSAF from Lysobacter enzymogenes is an antifungal PoTeM that has been subjected to extensive studies for mechanisms of biosynthesis, regulation, and antifungal activity. Using HSAF as a model system, we here showed that the characteristic structure of PoTeMs, a 2,4-pyrrolidinedione-embedded macrolactam, may represent a new iron-chelating scaffold of microbial metabolites. In L. enzymogenes, HSAF functions as a small-molecule modulator for oxidative damage caused by iron, H₂O₂, and UV light. Together, the study demonstrated a previously unrecognized strategy for microorganisms to modulate oxidative damage to the cells. HSAF represents the first member of the fast-growing PoTeM family of microbial metabolites whose potential biological function has been studied.

Photoprotective Activity of Buddleja cordata Cell Culture Methanolic Extract on UVB-irradiated 3T3-Swiss Albino Fibroblasts

The research on compounds exhibiting photoprotection against ultraviolet radiation (UVR) is a matter of increasing interest. The methanolic extract of a cell culture of Buddleja cordata has potential photoprotective effects as these cells produce phenolic secondary metabolites (SMs). These metabolites are attributed with biological activities capable of counteracting the harmful effects caused by UVR on skin. In the present work, the methanolic extract (310–2500 µg/mL) of B. cordata cell culture showed a photoprotective effect on UVB-irradiated 3T3-Swiss albino fibroblasts with a significant increase in cell viability. The greatest photoprotective effect (75%) of the extract was observed at 2500 µg/mL, which was statistically comparable with that of 250 µg/mL verbascoside, used as positive control. In addition, concentrations of the extract higher than 2500 µg/mL resulted in decreased cell viability (≤83%) after 24 h of exposure. Phytochemical analysis of the extract allowed us to determine that it was characterized by high concentrations of total phenol and total phenolic acid contents (138 ± 4.7 mg gallic acid equivalents and 44.01 ± 1.33 mg verbascoside equivalents per gram of extract, respectively) as well as absorption of UV light (first and second bands peaking at 294 and 330 nm, respectively). Some phenylethanoid glycosides were identified from the extract.

Comparative Evaluation of Oxidative Stress Modulating and DNA Protective Activities of Aqueous and Methanolic Extracts of Acacia catechu

Background: Plant-derived bioactive compounds are becoming immensely important as potential drugs. Different solvents are being used for extraction of these phytochemicals. Evaluation of biological activities of aqueous plant extracts is important as water soluble compounds would be more beneficial with respect to certification, safety and commercial issues. Oxidative stress is involved in development of many diseases; therefore, antioxidants are now being looked upon as convincing therapeutics against such diseases. Natural antioxidants are in high demand because of their lesser side effects. This study aims to compare the antioxidant activity of aqueous and methanolic extracts of Acacia catechu—a traditional medicinal plant. Methods: The activity was examined using different in vitro systems including radical scavenging activity, lipid peroxidation and inhibition of ^•OH radical induced DNA damage using standard protocols. Results: Both aqueous and methanolic extracts of Acacia catechu show significant activities with no differences in the efficacies of water and methanol soluble bioactive compounds. Conclusions: Present study revealed that aqueous extract of A. catechu has equal potential to be used as antioxidants as compared to methanolic extract. This can contribute to increased demand of physiologically compatible bioactive compounds of natural origin.

Effect of Acacia catechu (L.f.) Willd. on Oxidative Stress with Possible Implications in Alleviating Selected Cognitive Disorders

In human body, several categories of degenerative processes are largely determined by free radicals originating in cell. Free radicals are also known to have correlated with a variety of cognitive disorders (CDs) resulting in neuronal injury and eventually to death. Alzheimer's disease (AD) and Parkinson's disease (PD) are such kind of killer CDs that occur due to dysfunction of cholinergic and dopaminergic neurons. Plant parts of Ginkgo biloba, Bacopa monnieri etc. are being used for the treatment of cognitive disorders in several countries. The present study was aimed to explore the detailed antioxidant and anti-cholinesterase activity of Acaciacatechu leaf (ACL) over CDs. Gas chromatography-Mass spectroscopy (GC-MS) analysis and Nuclear Magnetic Resonance (NMR) were employed to identify the bioactive components present in ACL. Furthermore, the extract was evaluated to check the cytotoxic effects of ACL on normal cells. Amongst several antioxidant assays, DPPH assay, hydroxyl radical, nitric oxide radical and hypochlorous acid inhibitory activities were found to be greater in ACL than that of the respective standards while other assays exhibited a moderate or at per inhibitory activity with standards. Total phenolic and flavonoid content were also found to be present in decent amount. In addition, we found, a greater acetylcholinesterase (AChE) inhibitory activity of ACL when compared to other medicinally important plants, indicating its positive effect over CDs. Forty one bioactive components were explored through GC-MS. Of these, gallic acid, epicatechin, catechin, isoquercitrin etc. were found, which are potent antioxidant and a few of them have anti-neurodegenerative properties. Eventually, ACL was found to be nontoxic and safer to consume. Further studies with animal or human model however, would determine its efficacy as a potential anti-schizophrenic drug.

Protections of bovine serum albumin protein from damage on functionalized graphene-based electrodes by flavonoids

A sensitive electrochemical sensor based on bovine serum albumin (BSA)/poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene nanosheets (PDDA-G) composite film modified glassy carbon electrode (BSA/PDDA-G/GCE) had been developed to investigate the oxidative protein damage and protections of protein from damage by flavonoids. The performance of this sensor was remarkably improved due to excellent electrical conductivity, strong adsorptive ability, and large effective surface area of PDDA-G. The BSA/PDDA-G/GCE displayed the greatest degree of BSA oxidation damage at 40 min incubation time and in the pH 5.0 Fenton reagent system (12.5 mM FeSO4, 50 mM H2O2). The antioxidant activities of four flavonoids had been compared by fabricated sensor based on the relative peak current ratio of SWV, because flavonoids prevented BSA damage caused by Fenton reagent and affected the BSA signal in a solution containing Co(bpy)3(3+). The sensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). UV-vis spectrophotometry and FTIR were also used to investigate the generation of hydroxyl radical and BSA damage, respectively. On the basis of results from electrochemical methods, the order of the antioxidant activities of flavonoids is as follows: (+)-catechin>kaempferol>apigenin>naringenin. A novel, direct SWV analytical method for detection of BSA damage and assessment of the antioxidant activities of four flavonoids was developed and this electrochemical method provided a simple, inexpensive and rapid detection of BSA damage and evaluation of the antioxidant activities of samples.

Characterization of free and conjugated phenolic compounds in fruits of selected wild plants

A gas chromatography-mass spectrometric (GC-MS) method was utilized for the separation, and systematic characterization of phenolic compounds as trimethylsilyl derivatives in fruits of wild plants including Olive, Jujube and Common Fig. Both the free and conjugate phenolic acids (rarely determined before and several are reported first time here) were characterized. A baseline separation of the 20 phenolics was achieved in 25 min with standard calibration curves linear over the concentration range from the detection limits to 20 μg/mL. Total of fourteen phenolic acids were identified in wild Olive fruit, eight in wild Jujube fruit and ten in wild Common Fig fruit, out of which 2,4-dihydroxybenzoic acid and trans-cinnamic acid were dominant in these fruits with concentration of 87.02, 5.25 and 14.16 mg/kg and 32.43, 5.77 and 11.70 mg/kg (dry weight), respectively. The results of this study support the utilization of the tested wild fruits as a potential source of valuable phenolics for functional food and nutraceutical applications.

Verbascoside--a review of its occurrence, (bio)synthesis and pharmacological significance

Phenylethanoid glycosides are naturally occurring water-soluble compounds with remarkable biological properties that are widely distributed in the plant kingdom. Verbascoside is a phenylethanoid glycoside that was first isolated from mullein but is also found in several other plant species. It has also been produced by in vitro plant culture systems, including genetically transformed roots (so-called 'hairy roots'). Verbascoside is hydrophilic in nature and possesses pharmacologically beneficial activities for human health, including antioxidant, anti-inflammatory and antineoplastic properties in addition to numerous wound-healing and neuroprotective properties. Recent advances with regard to the distribution, (bio)synthesis and bioproduction of verbascoside are summarised in this review. We also discuss its prominent pharmacological properties and outline future perspectives for its potential application.

Protective effect of Pterostilbene against free radical mediated oxidative damage

Background

Pterostilbene, a methoxylated analog of Resveratrol, is gradually gaining more importance as a therapeutic drug owing to its higher lipophilicity, bioavailability and biological activity than Resveratrol. This study was undertaken to characterize its ability to scavenge free radicals such as superoxide, hydroxyl and hydrogen peroxide and to protect bio-molecules within a cell against oxidative insult.

Methods

Anti-oxidant activity of Pterostilbene was evaluated extensively by employing several in vitro radical scavenging/inhibiting assays and pulse radiolysis study. In addition, its ability to protect rat liver mitochondria against tertiary-butyl hydroperoxide (TBHP) and hydroxyl radical generated oxidative damage was determined by measuring the damage markers such as protein carbonyls, protein sulphydryls, lipid hydroperoxides, lipid peroxides and 8-hydroxy-2'-deoxyguanosine. Pterostilbene was also evaluated for its ability to inhibit •OH radical induced single strand breaks in pBR322 DNA.

Result

Pterostilbene exhibited strong anti-oxidant activity against various free radicals such as DPPH, ABTS, hydroxyl, superoxide and hydrogen peroxide in a concentration dependent manner. Pterostilbene conferred protection to proteins, lipids and DNA in isolated mitochondrial fractions against TBHP and hydroxyl radical induced oxidative damage. It also protected pBR322 DNA against oxidative assault.

Conclusions

Thus, present study provides an evidence for the strong anti-oxidant property of Pterostilbene, methoxylated analog of Resveratrol, thereby potentiating its role as an anti-oxidant.

Filamentous fungi from Plantago lanceolata L. leaves: contribution to the pattern and stability of bioactive metabolites

The aim of this study was to test contribution of plant-associated microorganism (PAMs) to metabolite stability/instability in a medicinal plant matrix. Therefore, PAM strains were isolated and identified based on relevant DNA sequences from Plantago lanceolata leaves. Sterile water extracts of P. lanceolata were incubated with the isolated strains and antioxidants (ascorbic acid (AA), and EDTA) for 15 days, and changes in the concentrations of chief bioactive constituents (aucubin, catalpol, acteoside (=verbascoside)) were quantified by capillary electrophoresis. Phenolic breakdown-products were identified by GC-MS. PAMs were identified from the genera Epicoccum, Bipolaris, Cladosporium, Leptosphaerulina, Aspergillus, Eurotium and Penicillium (pathongens, endophytes, and other species). Some fungi caused significant decomposition of the chief constituents (p<0.001). Surprisingly, some strains inhibited breakdown of acteoside (p<0.001). Meanwhile, concentration of several phenolic acids increased in fungi-infested extracts (p<0.001). Gentisic acid, 4-hydroxyphenyl acetic acid, 4-hydroxybenzoic acid and hydroxytyrosol were only present when the extract was infested with a PAM. The products are powerful antioxidants and chelators. Concentrations of phenolic acids influenced acteoside stability significantly (p<0.01), as shown by basic data-mining techniques. AA and EDTA also significantly inhibited acteoside breakdown in sterile model solutions (p<0.05). Our results suggest that the phenolic acid mixture (produced during the fungal proliferation) protected acteoside from breakdown, possibly via its antioxidant activity and metal complexing ability. It was shown that PAMs can increase or decrease the stability of chief metabolites in herbal matrices, and can significantly alter the chemical pattern of the plant matrix.

Characterization of the Anti-Diabetic and Antioxidant Effects of Rehmannia Glutinosa in Streptozotocin-Induced Diabetic Wistar Rats

This study investigated the effects of Rehmannia glutinosa individually as well as in combination with the oral hypoglycemic agent, metformin in streptozotocin (STZ)-induced diabetic Wistar rats. R. glutinosa ethanolic extract was prepared and the constituents were characterized using fractionation by column chromatography, followed by high performance liquid chromatography-mass spectrometry. STZ (65 mg/kg) was injected intraperitoneally to induce diabetes in Wistar rats. The diabetic rats were divided into the following groups (each n = 6) and received the respective treatments for 30 days: (1) metformin (500 mg/kg), (2) R. glutinosa (200 mg/kg), (3) metformin (500 mg/kg) and R. glutinosa (200 mg/kg) and (4) diabetic control (DC). A reduction in plasma glucose levels caused by the herb was not as significant as metformin compared to the diabetic control ( p < 0.05). However, R. glutinosa-treated group showed reductions in plasma C-reactive protein (CRP) levels compared to the diabetic controls ( p < 0.05) as well as metformin-treated group ( p < 0.05). An enhanced reduction in CRP concentration was observed in the group receiving both herb and metformin compared to metformin-treated group ( p < 0.05). Reduction in CRP levels suggests an anti-inflammatory activity of the herb.

Verbascoside is not genotoxic in the ST and HB crosses of the Drosophila wing spot test, and its constituent, caffeic acid, decreases the spontaneous mutation rate in the ST cross

Verbascoside (VB) is a phenylpropanoid isolated from Buddleja species, some of which originate in Mexico, and was first described in the sixteenth century in the codices of Mexican traditional medicine. VB is present in alcohol extracts and is widely used in the north of Mexico as a sunscreen. VB absorbs UV-A and UV-B radiation and has high antioxidant and anti-inflammatory capacities. VB and its constituent caffeic acid (CA) were screened to determine their genotoxic activity using the Drosophila wing spot test. Third instar larvae (72±4 h) of the standard (ST) and high bioactivation (HB) crosses, with regulated and high levels of cytochrome P450s (Cyp450s), respectively, were exposed to VB or CA (0, 27, 57, 81, 135, and 173 mM). VB was not genotoxic at any of the concentrations tested in both crosses. The amount of VB residue as determined by HPLC in the adult flies that were fed with VB indicated a low metabolism of this compound, which explains the absence of genotoxicity. CA decreased the spontaneous frequencies of small and total spots and showed putative toxicity in the ST cross.

Antioxidant and prooxidant effects of polyphenol compounds on copper-mediated DNA damage

Inhibition of copper-mediated DNA damage has been determined for several polyphenol compounds. The 50% inhibition concentration values (IC(50)) for most of the tested polyphenols are between 8 and 480 μM for copper-mediated DNA damage prevention. Although most tested polyphenols were antioxidants under these conditions, they generally inhibited Cu(I)-mediated DNA damage less effectively than Fe(II)-mediated damage, and some polyphenols also displayed prooxidant activity. Because semiquinone radicals and hydroxyl radical adducts were detected by EPR spectroscopy in solutions of polyphenols, Cu(I), and H(2)O(2), it is likely that weak polyphenol-Cu(I) interactions permit a redox-cycling mechanism, whereby the necessary reactants to cause DNA damage (Cu(I), H(2)O(2), and reducing agents) are regenerated. The polyphenol compounds that prevent copper-mediated DNA damage likely follow a radical scavenging pathway as determined by EPR spectroscopy.

Pancreatic islets are very poor in rectifying oxidative DNA damage

OBJECTIVE

Free radicals that escape scavenging by antioxidant defense damage lipids, proteins, and DNA. Damage to DNA can be repaired. Therefore, both cells' antioxidant defense and their ability to repair oxidatively damaged DNA decide its fate to survive oxidative stress. Pancreatic islets cells with poor antioxidant defense were checked for their ability to remove oxidative damage form DNA.

METHODS

For ex vivo DNA repair, assay-cultured pancreatic islets and liver slices were treated with 1 and 10 mM H2O2, respectively, for 30 minutes. After incubation for different time intervals, 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA of these cells was estimated using monoclonal antibody raised against 8-OHdG by competitive enzyme-linked immunosorbent assay. For in vitro DNA repair assay, oxidatively damaged pBR322 was incubated with nuclear extracts of islet and liver cells, and 8-OHdG retained in the plasmid was quantitated.

RESULTS

Oxidative damage induced by H2O2 was removed quickly and efficiently from DNA by liver cells compared with islet cells. The repair of oxidatively damaged plasmid DNA in vitro was also performed more efficiently (P < 0.05) by nuclear extracts from liver cells compared with islet cell.

CONCLUSIONS

We clearly demonstrate that in addition to their low antioxidant defense, islets are very poor in rectifying the oxidative DNA damage.

Antioxidant activity of the phenol rich fractions of leaves of Chukrasia tabularis A. Juss

The present study was designed to explore the antioxidant potential of chloroform, ethyl acetate, n-butanol and water fractions of 80% methanol extract of leaves Chukrasia tabularis by 2,2'-diphenyl-1-picrylhydrazyl (DPPH), deoxyribose degradation (non-site specific and site specific), reducing power and DNA nicking assays. The different fractions showed significant activities in all the free radical scavenging tests and these findings have also shown direct relationship between antioxidant activity and phenolic content. Among the fractions, ethyl acetate fraction exhibited highest inhibition of 93.14%, 89.99%, 87.04% in DPPH, non-site specific and site specific deoxyribose degradation assays, respectively and 91.20% reduction of ferricyanide to give Prussian blue coloured complex in reducing power assay at maximum concentration tested. This preliminary study indicates the antioxidant activity of the leaves of Chukrasia tabularis, and moreover the results showed correlation with the amount of phenolic content present in different fractions.

Studies on modulation of DNA integrity in Fenton's system by phytochemicals

Chronic exposure to oxidative stress especially to highly reactive hydroxyl radicals (HO*) could damage biomolecules, particularly DNA, that in turn would accelerate onset of degenerative diseases. In the present study a few standard phytochemicals (vitamin C, gallic acid, catechin, apigenin, naringenin and naringin) and plant extracts (Hippophae rhamnoides kernel (HRK), Syzygium cumini kernel (SCK) and Punica granatum pericarp (PGP)) were evaluated for their potential to protect/damage DNA in Fenton's system using in vitro models. The results indicated a significant DNA protective effect for naringin and PGP whereas other phytochemicals/extracts showed DNA damaging effect similar to or more than that of control value. The phytochemicals/extracts were also evaluated for their antioxidant and iron chelation properties. In general, the phytochemicals/extracts with high antioxidant activity but without iron chelation capacity failed to protect DNA in Fenton's system, suggesting that iron chelation was an essential requirement for the phytochemicals studied here to retard HO* generation by Fenton's reaction. This was demonstrated by the high iron chelation capacity of naringin and PGP (83.67% and 68.67% respectively) and their DNA protective effect. Commonly consumed phytochemicals such as vitamin C and gallic acid with their high reducing power and at higher physiological concentration, could regenerate free iron for Fenton's reaction leading to DNA damage as shown here.

Total phenol, antioxidant and free radical scavenging activities of some medicinal plants

Phenols, a major group of antioxidant phytochemicals, have profound importance due to their biological and free radical scavenging activities. To identify their potential sources, extracts of some plants were studied for their total phenolic content (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA) by different methods at multiple concentrations followed by specific phenolic composition. The amount of TPC varied from 2.8 mg/g (Withania somnifera, roots) to 107.8 mg/g (Cassia fistula, fruits) and the AOA from 24.2% (Curcuma zeoderia, leaves) to 96.9% (Trewia nudiflora, leaves). Bark of Azadirachta indica, fruits of C. fistula, and leaves and fruits of T. nudiflora were found to have high TPC (89.8- 107.8 mg/g) and high AOA (84.8-96.9%). Promising plant parts were studied for their FRSA and reducing power (RP), where the bark of A. indica, Casuarina equisetifolia and Cinnamomum zeylanicum, flowers of Indigofera tinctoria, fruits of Lawsonia inermis, and fruits and leaves of T. nudiflora showed a very low inhibitory concentration value ranging from 0.14 to 0.26 mg/ml, efficiency concentration value from 6.1 to 11.6 mg/mg DPPH and reducing power value from 0.6 to 2.8 ascorbic acid equivalents (ASE/ml), and reasonably high values (8.5 -16.2) of anti-radical power (ARP), indicating their strong FRSA. They also showed better inhibition of hydroxyl radical induced deoxyribose degradation than that of reference standard. Fruits of C. fistula with high phenols (107.8 mg/g) showed poor reducing power (5.9 ASE/ml) and ARP (4.7); in contrast, the bark of C. equisetifolia and fruits of L. inermis were with comparatively lower phenols (72.1 and 75.8 mg/g) but exhibited good ARP (16.2 and 14.4) and reducing power (0.7 and 0.6 ASE/ ml, respectively). Some of the plants were also found effective in protecting plasmid DNA nicking induced by hydroxyl radicals generated by Fenton's reaction. They were further assayed for their specific phenolic composition through high-performance liquid chromatography and MS/MS, where the amount of caffeic acid varied from 0.312 to 0.797 mg/g, chlorogenic acid from 0.018 to 2.109 mg/g, ellagic acid from 0.009 to 0.902 mg/g, ferulic acid from 0.036 to 0.078 mg/g, gallic acid from 0.192 to 3.597 mg/g, kaempferol from 0.011 to 0.910 mg/g, quercetin from 0.047 to 1.106 mg/g and rutin from 0.059 to 2.029 mg/g.

New triterpene glucosides, oligoporins A–C, from Oligoporus tephroleucus protect DNA from Fenton reaction

New triterpene glucosides, oligoporins A (1), B (2), and C (3), were isolated from the methanolic extract of the fruiting bodies of Oligoporus tephroleucus (Polyporaceae). Their structures were established by spectroscopic methods. These compounds significantly exhibited protective effect to plasmid DNA damage by hydroxyl radical (*OH) generated from the Fenton reaction with hydrogen peroxide and ferrous.

Identification of major metal complexing compounds in Blepharis aspera

Verbascoside and isoverbascoside, present at 0.7% and 0.2% (w/w dryweight), were identified to be major compounds that could contribute to the metal complexation in Blepharis aspera collected in Botswana, Africa. The metallophyte B. aspera has high ability to cope with a high level of metal accumulation. The presence of metal complexing compounds and/or antioxidants can prevent oxidative reactions in lipids, proteins and DNA that take place due to the metal accumulation. On-line liquid chromatography-solid phase extraction-nuclear magnetic resonance (LC-SPE-NMR) was applied for the identification, while electrospray-mass spectrometry (ESI-MS) and UV-vis spectroscopy was used to assess whether these compounds can complex with metals. It was found that verbascoside and isoverbascoside may form complexes with nickel, iron (verbascoside only) and copper. Thus, the presence of verbascoside and isoverbascoside can explain the survival of B. aspera in mineral-rich areas.

Antioxidant properties of -carboline alkaloids are related to their antimutagenic and antigenotoxic activities

The beta-carboline alkaloids found in medical plants and in a variety of foods, beverages and cigarette smoke have a range of action in various biological systems. In vitro studies have demonstrated that these alkaloids can act as scavengers of reactive oxygen species. In this paper, we report the in vivo antioxidative properties of the aromatic (harmane, harmine, harmol) and dihydro-beta-carbolines (harmaline and harmalol) studied by using Saccharomyces cerevisiae strains proficient and deficient in antioxidant defenses. Their antimutagenic activity was also assayed in S. cerevisiae and the antigenotoxicity was tested by the comet assay in V79 cell line, when both eukaryotic systems were exposed to H(2)O(2). We show that the alkaloids have a significant protective effect against H(2)O(2) and paraquat oxidative agents in yeast cells, and that their ability to scavenge hydroxyl radicals contributes to their antimutagenic and antigenotoxic effects.

Evaluation, in vitro, of the radioprotection of DNA from gamma-rays by naphazoline

Design of compounds that can protect efficiently against gamma-rays irradiation is a great challenge. An ionizing event can cause variety of DNA damage scenarios leading to mutagenesis, cell death. 2-(1-Naphthylmethyl)-2-imidazoline (naphazoline, NP) is a drug belonging to the vasoregulator class, which was shown to be a very interesting compound in radioprotection. In order to highlight the NP radioprotective activity, a comparison of its ability to protect DNA against either gamma-irradiation or radicals generated by Fenton's reaction was made. Results show that NP inhibits efficiently the generation of DNA single-strand breaks and that NP is a potent radioprotector and also an hydroxyl radical scavenger.