Genoprotective Activity Research Articles

Microbially mediated phenolic catabolites exert differential genoprotective activities in normal and adenocarcinoma cell lines

Age-associated decline of nuclear factor erythroid 2-related factor 2 (Nrf2) activity and DNA repair efficiency leads to the accumulation of DNA damage and increased risk of cancer. Understanding the mechanisms behind increased levels of damaged DNA is crucial for developing interventions to mitigate age-related cancer risk. Associated with various health benefits, (poly)phenols and their microbially mediated phenolic catabolites represent a potential means to reduce DNA damage. Four colonic-microbiota-derived phenolic catabolites were investigated for their ability to reduce H2O2-induced oxidative DNA damage and modulate the Nrf2-Antixoidant Response Element (ARE) pathway, in normal (CCD 841 CoN) and adenocarcinoma (HT29) colonocyte cell lines. Each catabolite demonstrated significant (p < .001) genoprotective activity and modulation of key genes in the Nrf2-ARE pathway. Overall, the colon-derived phenolic metabolites, when assessed at physiologically relevant concentrations, reduced DNA damage in both normal and adenocarcinoma colonic cells in response to oxidative challenge, mediated in part via upregulation of the Nrf2-ARE pathway.

Assessment of cytoprotective and genoprotective effects of Moringa oleifera and Tinospora cordifolia extracts in vitro.

Moringa oleifera and Tinospora cordifolia is extensively used as an ingredient of food and in traditional medicine for the management of a variety of diseases. The extracts of leaf of Moringa oleifera and stem of Tinospora cordifolia were assessed to examine their ability to inhibit the oxidative DNA damage (by DNA protection assay), cytoprotective and genoprotective potential (by Comet assay) in V79 cells individually and in combinations. It was found that these extracts could significantly inhibit the OH-dependent damage of pUC18 plasmid DNA. M. oleifera extract (160 and 320μg/mL) and Tinospora cordifolia extract (640, 1,280 and 2,560μg/mL) individually showed higher DNA protection activity. M. oleifera (1,280μg/mL) combined with Tinospora cordifolia (640μg/mL) showed best cytoprotective and genoprotective activities among different concentration combinations and various concentrations of individual plants in V79 cell line against hydrogen peroxide induced cytotoxicity and genotoxicity. This study demonstrates the cytoprotective and genoprotective activity of M. oleifera and Tinospora cordifolia individually or in combination.

Determination of genoprotection against cyclophosphamide induced toxicity in bone marrow of Swiss albino mice by Moringa oleifera leaves and Tinospora cordifolia stem

ABSTRACT The present study aimed to determine the genoprotective activity and safety of Moringa oleifera leave and Tinospora cordifolia stem extracts against cyclophosphamide (CP)-induced genotoxicity utilizing Swiss albino mice. Animals were divided into 14 groups for subacute treatment with either M. oleifera or T. cordifolia extracts daily for 28 days. The extract doses selected were 100, 200 or 400 mg/kg b.w administered orally alone or combined with CP (50 mg/kg b.w. intraperitoneally daily for 5 days). Analyses performed included the comet assay, micronucleus test (MN) in bone marrow cells and sperm head abnormality assay (SHA). M. oleifera and T. cordifolia extracts induced no significant genotoxic effects on somatic and germ cells. In contrast, for all cells examined M. oleifera and T. cordifolia extracts inhibited DNA damage initiated by CP. Taken together data demonstrated that both plant extracts did not exhibit marked genotoxic effects but displayed potential chemoprotective properties against CP-induced genotoxicity in Swiss mice.

The Bioactivity of a Hydroxytyrosol-Enriched Extract Originated after Direct Hydrolysis of Olive Leaves from Greek Cultivars.

Nowadays, olive leaf polyphenols have been at the center of scientific interest due to their beneficial effects on human health. The most abundant polyphenol in olive leaves is oleuropein. The biological properties of oleuropein are mainly due to the hydroxytyrosol moiety, a drastic catechol group, whose biological activity has been mentioned many times in the literature. Hence, in recent years, many nutritional supplements, food products, and cosmetics enriched in hydroxytyrosol have been developed and marketed, with unexpectedly positive results. However, the concentration levels of hydroxytyrosol in olive leaves are low, as it depends on several agricultural factors. In this study, a rapid and easy methodology for the production of hydroxytyrosol-enriched extracts from olive leaves was described. The proposed method is based on the direct acidic hydrolysis of olive leaves, where the extraction procedure and the hydrolysis of oleuropein are carried out in one step. Furthermore, we tested the in vitro bioactivity of this extract using cell-free and cell-based methods, evaluating its antioxidant and DNA-protective properties. Our results showed that the hydroxytyrosol-enriched extract produced after direct hydrolysis of olive leaves exerted significant in vitro antioxidant and geno-protective activity, and potentially these extracts could have various applications in the pharmaceutical, food, and cosmetic industries.

The Modulatory Effect of an Ethanolic Extract of Anredera cordifolia (Ten.) on the Proliferation and Migration of Hyperglycemic Fibroblasts in an In Vitro Diabetic Wound Model.

Diabetes mellitus is associated with chronic wound-healing problems that significantly impact patients' quality of life and substantially increase expenditure on healthcare. Therefore, the identification of compounds that can aid healing is justified. Anredera cordifolia (Ten.) has been used in folk medicine for curative purposes; however, the causal mechanisms underlying its healing effects remain to be elucidated. In this study, the effect of the ethanolic extract of A. cordifolia was evaluated in an in vitro healing model using fibroblasts cultivated under normoglycemic and hyperglycemic environments. The extract was predominantly composed of phytol and exhibited genoprotective activity. Fibroblast migration attenuated the adverse effects of hyperglycemia, favoring cell proliferation. Collagen levels were significantly increased in ruptured fibroblasts under both standard and hyperglycemic environments. The phytogenomic effect of the extract on three genes related to extracellular matrix formation, maintenance, and degradation showed that A. cordifolia increased the expression of genes related to matrix synthesis and maintenance in both normoglycemic and hyperglycemic individuals. Furthermore, it reduced the expression of genes related to matrix degradation. Overall, this is the first study to demonstrate the effectiveness of A. cordifolia in wound healing, elucidating possible causal mechanisms that appear to be based on the genoprotective effect of this plant on the migratory and proliferative phases of the wound healing process; these effects are probably related to phytol, its main constituent.

A Side-by-Side Comparison of Wildtype and Variant Melanocortin 1 Receptor Signaling with Emphasis on Protection against Oxidative Damage to DNA.

Common variants of the MC1R gene coding the α-melanocyte stimulating hormone receptor are associated with light skin, poor tanning, blond or red hair, and increased melanoma risk, due to pigment-dependent and -independent effects. This complex phenotype is usually attributed to impaired activation of cAMP signaling. However, several MC1R variants show significant residual coupling to cAMP and efficiently activate mitogenic extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling. Yet, residual signaling and the key actions of wildtype and variant MC1R have never been assessed under strictly comparable conditions in melanocytic cells of identical genetic background. We devised a strategy based on CRISPR-Cas9 knockout of endogenous MC1R in a human melanoma cell line wildtype for BRAF, NRAS and NF1, followed by reconstitution with epitope-labeled MC1R constructs, and functional analysis of clones expressing comparable levels of wildtype, R151C or D294H MC1R. The proliferation rate, shape, adhesion, motility and sensitivity to oxidative DNA damage were compared. The R151C and D294H RHC variants displayed impaired cAMP signaling, intracellular stability similar to the wildtype, triggered ERK1/2 activation as effectively as the wildtype, and afforded partial protection against oxidative DNA damage, although less efficiently than the wildtype. Therefore, common melanoma-associated MC1R variants display biased signaling and significant genoprotective activity.

The Comparison of Honey Enriched with Laboratory Fermented Pollen vs. Natural Bee Bread in Terms of Nutritional and Antioxidant Properties, Protein In Vitro Bioaccessibility, and Its Genoprotective Effect in Yeast Cells.

The aim of the study was to compare the nutritional value and bioactivity of honey enriched with a 10% addition of natural bee bread and its substitutes obtained as a result of laboratory fermentation of bee pollen. Physicochemical parameters, antioxidant properties, as well as the bioaccessibility of proteins using an in vitro static digestion model were analyzed. The bioactivity of the obtained enriched honeys was tested using the yeast model. The research indicates the similarity of honeys with the addition of "artificial bee bread" to honey with natural ones. During in vitro digestion, good bioaccessibility of the protein from the tested products was demonstrated. The ability of the products to protect yeast cells against hydrogen superoxide-induced oxidative stress was demonstrated using a qualitative spot test, which was stronger in the case of enriched honey than in pure rapeseed control honey. Significant inhibition of the growth of both strains of yeast exposed to bee pollen-enriched honeys was also demonstrated. Furthermore, all tested samples showed significant genoprotective activity against the genotoxic effect of zeocin and the reduction of the number of DNA double-strand breaks by a minimum of 70% was observed.

Antioxidant and Anti-Mutagenic Potential of Mint (Mentha Arvensis) and its Chemical Characterization by HPLC

Background: Mentha arvensis has been used for medicinal purposes by Asian countries for ages. It is used to cure various ailments such as diarrhea, asthma, piles, cancer, dementia, hyperglycemia, and aging. Aim: This study aims to evaluate the antioxidant and anti-mutagenic (geno-protective) properties of four different solvent extracts (methanol, ethanol, acetone, and distilled water). Methodology: The antioxidant properties were determined by DPPH and reducing power assays, while the DNA damaging assay was used to evaluate the anti-mutagenic activity. Results: Among the four extracts, the methanol extract of Mentha arvensis showed 30.48 ± 0.95 mg QE/gm of flavonoid, and the aqueous extract showed the highest total phenolic content (142.2±0.83 mg QE/gm) and total alkaloids content (78.2±0.21 mg TE/gm) compared to the other three solvent extracts. The ethanol extract of Mentha arvensis exhibited the maximum value for total tannin content (17.41±0.38 mg ETA/g CE) and reducing power (41.17±0.87 mg ETA/gm). It also exhibited significant geno-protective activity. Conclusion: These results indicate that among the four solvent extracts, the ethanolic extract of Mentha arvensis has the highest value for phenolic content. Moreover, all four solvents, except distilled water, showed valuable anti-mutagenic behavior. The HPLC results corroborate our findings, suggesting that these plants have great potential for use as antioxidant and anti-mutagenic agents. Keywords: Mentha arvensis, Antioxidant agents, Anti-mutagenic agents, Geno-protective activity.

Putative application of Najas marina L. extracts as a source of bioactive compounds and their antioxidant, antimicrobial, antibiofilm, and genotoxic properties.

In this research paper, the total phenols (TP), flavonoids (TF), and tannins (TT) content in the acetone and ethyl acetate extracts of Najas marina L. and the identification and quantification of phenolic acids and flavonoids from the ethyl acetate extract were performed. Antioxidant, antimicrobial, and antibiofilm properties of the mentioned extracts were investigated in vitro. The genotoxic potential was analyzed in cultured human peripheral blood lymphocytes (PBL). The TP and TF content was higher in the ethyl acetate extract, dominated by quercetin (172.4 µg mg-1) and ferulic acid (22.74 µg mg-1), while the TT content was slightly higher in the acetone extract. Both extracts tested showed limited antioxidant effects compared to ascorbic acid. The strongest antibacterial activity was observed with Gram-positive bacteria, particularly Staphylococcus aureus (MIC and MMC at 0.31 mg ml-1) and S. aureus ATCC 25923 (MIC at<0.02 mg ml-1), while antifungal activity was limited. Both extracts tested showed better activity on preformed biofilms. Acetone extract had no genotoxic activity but showed significant genoprotective activity against mitomycin C-induced DNA damage in cultured PBLs. Results of our research demonstrate the potential for the development of plant-based antibacterial and biofilm agents.

A comparative study of genoprotective activity of phenolic catabolites between normal and adenocarcinoma colonic cells in vitro

A comparative study of genoprotective activity of phenolic catabolites between normal and adenocarcinoma colonic cells in vitro

Bauhinia forficata Link, Antioxidant, Genoprotective, and Hypoglycemic Activity in a Murine Model.

Bauhinia forficata L. is a tree used in alternative medicine as an anti-diabetic agent, with little scientific information about its pharmacological properties. The hypoglycemic, antioxidant, and genoprotective activities of a methanolic extract of B. forficata leaves and stems combined were investigated in mice treated with streptozotocin (STZ). Secondary metabolites were determined by qualitative phytochemistry. In vitro antioxidant activity was determined by the DPPH method at four concentrations of the extract. The genoprotective activity was evaluated in 3 groups of mice: control, anthracene (10 mg/kg), and anthracene + B. forficata (500 mg/kg) and the presence of micronuclei in peripheral blood was measured for 2 weeks. To determine the hypoglycemic activity, the crude extract was prepared in a suspension and administered (500 mg/kg, i.g.) in previously diabetic mice with STZ (120 mg/kg, i.p.), measuring blood glucose levels every week as well as the animals' body weight for six weeks. The extract showed good antioxidant activity and caused a decrease in the number of micronuclei. The diabetic mice + B. forficata presented hypoglycemic effects in the third week of treatment, perhaps due to its secondary metabolites. Therefore, B. forficata is a candidate for continued use at the ethnomedical level as an adjuvant to allopathic therapy.

Genoprotective activity of the Pleurotus eryngii mushrooms following their in vitro and in vivo fermentation by fecal microbiota.

Pleurotus eryngii mushrooms are commercially cultivated and widely consumed due to their organoleptic properties, and the low caloric and high nutritional value. In addition, they contain various biologically active and health-promoting compounds; very recently, their genoprotective effect in Caco-2 cells after their fermentation by the human fecal microbiota was also documented. In the current study, the effect of P. eryngii pre- and post-fermentation supernatants in micronuclei formation was evaluated in human lymphocytes. In addition, the genoprotective properties of increasing concentrations of aqueous extracts from P. eryngii mushrooms (150, 300, 600 mg/kg) against the cyclophosphamide-induced DNA damage were studied in young and elderly female and male mice in bone marrow and whole blood cells. The ability of the highest dose (600 mg/kg) to regulate the main cellular signaling pathways was also evaluated in gut and liver tissues of female animals by quantifying the mRNA expression of NrF2, Nfkβ, DNMT1, and IL-22 genes. P. eryngii post-fermentation, but not pre-fermentation, supernatants were able to protect human lymphocytes from the mitomycin C-induced DNA damage in a dose-dependent manner. Similarly, genoprotection was also observed in bone marrow cells of mice treated by gavage with P. eryngii extract. The effect was observed in all the experimental groups of mice (young and elderly, male and female) and was more potent in young female mice. Overexpression of all genes examined was observed in both tissues, mainly among the elderly animals. In conclusion, P. eryngii mushrooms were shown to maintain genome integrity through protecting cells from genotoxic insults. These beneficial effects can be attributed to their antioxidant and immunomodulatory properties, as well as their ability to regulate the cell’s epigenetic mechanisms and maintain cell homeostasis.

A Study of Phytochemistry, Genoprotective Activity, and Antitumor Effects of Extracts of the Selected Lamiaceae Species.

This study was designed to evaluate the genoprotective, antigenotoxic, as well as antitumor potential of methanolic, ethanolic, and aqueous extracts of Melissa officinalis, Mentha × piperita, Ocimum basilicum, Rosmarinus officinalis, Salvia officinalis, and Satureja montana (Lamiaceae), in different model systems. The polyphenols in these extracts were quantified both spectrophotometrically and using HPLC-DAD technique, while DPPH assay was used to assess the antioxidant activity. The genoprotective potential was tested on pUC19 Escherichia coli XL1-blue, and the antigenotoxicity on Salmonella typhimurium TA1535/pSK1002 and human lung fibroblasts, while the antitumor activity was assessed on colorectal cancer cells. Rosmarinic acid, quercetin, rutin, and luteolin-7-O-glucoside were among the identified compounds. Methanolic extracts had the best DPPH-scavenging and SOS-inducing activities, while ethanolic extracts exhibited the highest antigenotoxicity. Additionally, all extracts exhibited genoprotective potential on plasmid DNA. The antitumor effect was mediated by modulation of reactive oxygen species (ROS), nitric oxide (NO) production, and exhibition of genotoxic effects on tumor cells, especially with O. basilicum ethanolic extract. Generally, the investigated extracts were able to provide antioxidant protection for the acellular, prokaryotic, and normal human DNA, while also modulating the production of ROS and NO in tumor cells, leading to genotoxicity toward these cells and their decrease in proliferation.

Antioxidative properties and antigenotoxic potential of Gentiana lutea extracts against the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine, PhIP

Lipid oxidation that occurs in different types of food can cause alterations in nutritional qualities, flavour, texture and shelf life of foods. Furthermore, high temperature cooking of protein-rich food can lead to formation of heterocyclic aromatic amines capable of compromising the integrity of DNA molecules. To reduce these harmful effects, research has been focused on investigating plants as a source of potential natural food additives and preservatives. Thus, the aim of this study was to estimate antioxidant and antigenotoxic activities of 50% ethanolic-aqueous root and leaf extracts of the medicinal plant, Gentiana lutea. Antioxidative effect was investigated using the DPPH assay, while antigenotoxicity against the mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was determined using Salmonella Typhimurium TA 1535 in the SOS/umuC assay. Leaf extract showed high antioxidative effect with the ability to neutralize up to 87% of free radicals at 400 µg mL-1. Antigenotoxicity testing revealed that both extracts exhibited remarkable genoprotective activity against PhIP-induced DNA damage, with the highest inhibition levels being 70% and 85% for root and leaf extracts, respectively. Results obtained are encouraging and suggest further research of G. lutea extracts as potential food preservatives and additives in improving food quality and human health.

In vivo photoprotective potential evaluation and in vitro genoprotective of red propolis from Apis mellifera in Rio Grande do Norte (semiarid region), Brazil

The objective of this study was to evaluate the levels of phenols, total flavonoids, as well as the antioxidant, genoprotective, and photoprotective activities of the red propolis ethanolic extract produced by Apis mellifera. Different concentrations of the extract were analyzed In vitro by spectrophotometry. The photoprotective effect of the extract was evaluated In vivo in 30 Wistar rats divided into three groups: Group 1 - the skin received no topical application of the extract and was not subjected to ultraviolet irradiation; Group 2 - the skin was not subjected to topical application of the extract and was irradiated; Group 3 – the skin underwent topical application of the extract and was irradiated. The skin was evaluated macroscopically, and the density of inflammatory cells, mast cells, necrotic cells, and collagen fibers were quantified. The extract contained high levels of phenols and flavonoids, with antioxidant and genoprotective capacity, protecting the skin from irradiation. In group II, erythemas, blisters, and superficial crusting were observed. No significant differences in mean values of mast cell density and collagen fibers were observed between groups I and III. It was concluded that the ethanolic extract of red propolis exerted genoprotective and photoprotective effects by promoting satisfactory absorbance of ultraviolet radiation and was able to protect the skin from lesions induced by UVB irradiation.

Marine Cyclic Dipeptide Cyclo (L-Leu-L-Pro) Protects Normal Breast Epithelial Cells from tBHP-induced Oxidative Damage by Targeting CD151

Background: Oxidative stress plays a key role in breast carcinogenesis. Cyclo (L-Leu-L-Pro) (CLP) is a homodetic cyclic dipeptide with 2,5-diketopiperazine scaffold isolated from marine actinobacteria. This study aimed to evaluate the protective activity of CLP and linear - (L-Leu-L-Pro) (LP) from tert-butyl hydroperoxide (tBHP)-induced damage using normal breast epithelial cell line model (MCF-12A). Methods: The cytoprotective activity was evaluated by detecting the changes in intracellular ROS, mitochondrial superoxide, hydroxyl radical, hydrogen peroxide, and lipid peroxidation detection assays as well as cytotoxic assays of MTT, LDH assays and phase contrast microscopy. Genoprotective activity was evaluated by (Apurinic/Apyrimidinic) AP site, alkaline Comet, and 8-hydroxy-2-deoxyguanosine assays. Results: The marine cyclic peptide, CLP, significantly protected MCF-12A cells by scavenging tBHP induced intracellular ROS such as super oxide, hydroxyl radicals and hydrogen peroxide, and by reducing the cytotoxicity and genotoxicity effect compared to LP. Moreover, the results showed that CD151 gene silencing by shRNA significantly reduced the overexpression of CD151, tBHP-induced ROS generation, cytotoxicity and genotoxicity in MCF-12A cells. The overexpression of CD151 caused increased levels of cytochrome P450, but was reduced following the application of CD151shRNA and CLP which led to elevated levels of intracellular ROS. Conclusion: In the present study we noticed that CD151 gene silencing by shRNA and treatment with CLP have similar effects on reducing the intracellular ROS. This study uncovers the protective activity of CLP against a CD151-mediated oxidative stress-induced cellular damage. Our observations suggest that the anti-stress and anti-inflammation properties of CLP might have implications in cancer and are worth testing in cancer cell lines and tumor cells.

New insight into the antigenotoxic activity of Gentiana lutea extracts – Protective effect against food borne mutagens

Food mutagens formed from amino acids during heating of meat have the potential to induce serious consequences on human health. As a result, the identification of naturally occurring, genoprotective agents, is of great importance. The aim of this study was to chemically characterize a root and leaf extracts of Gentiana lutea and to investigate the antigenotoxic effects of extracts and pure constituents (gentiopicroside and mangiferin). Antigenotoxic effects were shown for combinations with the food borne mutagens IQ and PhIP using hepatoma HepG2 cells. Furthermore, their antioxidant activity and their capacity to modulate Nrf2 expression and affect the glutathione redox status were tested. Chemical analyses showed that the most abundant constituents found in root extract are gentiopicroside and sweroside. On the other hand, homoorientin and isovitexin were the dominant ones in leaf extract. Strong genoprotective activities of all tested compounds against both mutagens were observed in alkaline comet assays (up to 77% of tail intensity inhibition, p < 0.001). The protection against glutathione depletion was partially due to the radical scavenging activity and up-regulation of Nrf2 expression by the substances. The results of this study strongly encourage further investigations of the antimutagenic properties of G. lutea.

Comparative genoprotection ability of wild-harvested vs. aqua-cultured Ulva rigida coupled with phytochemical profiling

Antigenotoxic properties of plant- and plant-like derived foods may embody nutritional strategies against DNA damage. Marine macroalgae have shown DNA-protective effects, but their nutraceutical potential and the influence of growing conditions on these properties is underexplored. Hence, we aimed to assess the genoprotection potential of wild-harvested vs. aquacultured Ulva rigida on Drosophila melanogaster, following a dietary exposure, in the presence and absence of a genotoxic agent (streptonigrin) using phytochemical profiling. DNA damage was evaluated with a single cell gel electrophoresis (comet) assay improved with endonucleases. An origin-based phytochemical profile was found, with aquacultured algae showing higher relative amounts of fatty alcohols, sterols, sesquiterpenoids and glycerol esters. Although U. rigida from both sources showed a DNA-protective action, especially against streptonigrin-induced genotoxicity, aquacultured algae demonstrated higher potential, which may be linked to the distinctive phytochemical profile. Overall, this study provided scientific evidence for the genoprotective activity of U. rigida and its confirmation as a functional food.

ASSESSMENT OF ANTIOXIDANT POTENTIAL AND ANTIGENOTOXICITY ANALYSIS THROUGH HYDROGEN PEROXIDE-INDUCED OXIDATIVE STRESS IN TERMINALIA PANICULATA ROTH

Objective: The present study is mainly focused on the antigenotoxicity and antioxidant potential of the fruit extract of an important dye yielding plant Terminalia paniculata Roth.&#x0D; Methods: Genoprotective activity of the fruit extract was studied by Allium cepa root tip assay. Three modes of treatment were used to perform the antigenotoxicity, that is, pre-treatment, post-treatment, and simultaneous treatment. For the study of antioxidant potential, four different assays were performed.&#x0D; Results: Antigenotoxicity studies revealed the protective role of the extract in chromosomal aberrations induced by 2% hydrogen peroxide (H2O2) on A. cepa root tip meristem. The fruit extract showed a significant modulatory effect by means of an inhibition percentage and also it showed a characteristic reversing of chromosomal aberrations induced by H2O2. While in the case of antioxidant activity, the plant extract showed an appreciable antioxidant potential. Four different assays were used to determine the antioxidant potential of T. paniculata. Of these 2,2-diphenyl-1-picryl-hydrazyl-hydrate radical scavenging activity revealed almost equal effect to that of the standard.&#x0D; Conclusions: In the present investigation, it has been found that the important dye yielding plant T. paniculata has a significant role in various commercial industries such as food, cosmetics, clothes, and pharmaceutics due to its efficient protective role.

DNA damage and DNA protection from digested raw and griddled green pepper (poly)phenols in human colorectal adenocarcinoma cells (HT-29).

To determine whether (poly)phenols from gastrointestinal-digested green pepper possess genoprotective properties in human colon cells and whether the application of a culinary treatment (griddling) on the vegetable influences the potential genoprotective activity. (Poly)phenols of raw and griddled green pepper (Capsicum annuum L.) submitted to in vitro-simulated gastrointestinal digestion were characterized by LC-MS/MS. Cytotoxicity (MTT, trypan blue and cell proliferation assays), DNA damage and DNA protection (standard alkaline and formamidopyrimidine DNA glycosylase (Fpg)-modified comet assay) of different concentrations of (poly)phenolic extracts were assessed in colon HT-29 cells. A total of 32 (poly)phenolic compounds were identified and quantified in digested raw and griddled green pepper. Twenty of them were flavonoids and 12 were phenolic acids. Griddled pepper doubled the (poly)phenol concentration compared to raw; luteolin 7-O-(2-apiosyl)-glucoside and quercitrin constituted the major (poly)phenols in both extracts. Raw and griddled pepper (poly)phenolic extracts impaired cell proliferation and induced low levels of Fpg-sensitive sites, in a dose-dependent manner, even at a non-cytotoxic concentration. None of the concentrations tested induced DNA strand breaks or alkaline labile sites. Nor did they show significant genoprotection against the DNA damage induced by H2O2 or KBrO3. Green pepper (poly)phenols did not show genoprotection against oxidatively generated damage in HT-29 cells at simulated physiological concentrations, regardless of the application, or not, of a culinary treatment (griddling). Furthermore, high concentrations of (poly)phenolic extracts induced a slight pro-oxidant effect, even at a non-cytotoxic concentration.