Study of antimutagenic and antioxidant activities of Gallic acid and 1,2,3,4,6-pentagalloylglucose from Pistacia lentiscus

In vitro antioxidant and antimutagenic activities of two polyphenols isolated from the fruits of Pistacia lentiscus was assessed. Antioxidant activity was determined by the ability of each compound to scavenge the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH*), to inhibit xanthine oxidase and to inhibit the lipid peroxidation induced by H(2)O(2) in K562 cell line. Antimutagenic activity was assayed with SOS chromotest using Escherichia coli PQ37 as tester strain and Comet assay using K562 cell line. 1,2,3,4,6-Pentagalloylglucose was found to be more effective to scavenge DPPH* radical and protect against lipid peroxidation. Moreover, these two compounds induced an inhibitory activity against nifuroxazide and aflatoxin B1 mutagenicity. The protective effect exhibited by these molecules was also determined by analysis of gene expression as response to an oxidative stress. For this purpose, we used a cDNA-microarray containing 82 genes related to cell defense, essentially represented by antioxidant and DNA repair proteins. We found that 1,2,3,4,6-pentagalloylglucose induced a decrease in the expression of 11 transcripts related to antioxidant enzymes family (GPX1, TXN, AOE372, SHC1 and SEPW1) and DNA repair (POLD1, APEX, POLD2, MPG, PARP and XRCC5). The use of Gallic acid, induced expression of TXN, TXNRD1, AOE372, GSS (antioxidant enzymes) and LIG4, POLD2, MPG, GADD45A, PCNA, RPA2, DDIT3, HMOX2, XPA, TDG, ERCC1 and GTF2H1 (DNA repair) as well as the repression of GPX1, SEPW1, POLD1 and SHC1 gene expression.

In vitro antioxidant and antigenotoxic potentials of myricetin-3-o-galactoside and myricetin-3-o-rhamnoside from Myrtus communis: modulation of expression of genes involved in cell defence system using cDNA microarray

Antioxidant activity of myricetin-3-o-galactoside and myricetin-3-o-rhamnoside, isolated from the leaves of Myrtus communis, was determined by the ability of each compound to inhibit xanthine oxidase activity, lipid peroxidation and to scavenge the free radical 1,1-diphenyl-2-picrylhydrazyl. Antimutagenic activity was assessed using the SOS chromotest and the Comet assay. The IC50 values of lipid peroxidation by myricetin-3-o-galactoside and myricetin-3-o-rhamnoside are respectively 160 microg/ml and 220 microg/ml. At a concentration of 100 microg/ml, the two compounds showed the most potent inhibitory effect of xanthine oxidase activity by respectively, 57% and 59%. Myricetin-3-o-rhamnoside was a very potent radical scavenger with an IC50 value of 1.4 microg/ml. Moreover, these two compounds induced an inhibitory activity against nifuroxazide, aflatoxine B1 and H2O2 induced mutagenicity. The protective effect exhibited by these molecules was also determined by analysis of gene expression as response to an oxidative stress using a cDNA micro-array. Myricetin-3-o-galactoside and myricetin-3-o-rhamnoside modulated the expression patterns of cellular genes involved in oxidative stress, respectively (GPX1, TXN, AOE372, SEPW1, SHC1) and (TXNRD1, TXN, SOD1 AOE372, SEPW1), in DNA damaging repair, respectively (XPC, LIG4, RPA3, PCNA, DDIT3, POLD1, XRCC5, MPG) and (TDG, PCNA, LIG4, XRCC5, DDIT3, MSH2, ERCC5, RPA3, POLD1), and in apoptosis (PARP).

Comparative analysis of medicinal plants used in traditional medicine in Italy and Tunisia

BACKGROUND

Italy and Tunisia (Africa for the Romans), facing each other on the opposite sides of the Mediterranean Sea, have been historically linked since the ancient times. Over the centuries both countries were mutually dominated so the vestiges and traces of a mutual influence are still present. The aim of the present study is to conduct a comparative analysis of the medicinal species present in the respective Floras in order to explore potential analogies and differences in popular phytotherapy that have come out from those reciprocal exchanges having taken place over the centuries

METHODS

The comparative analysis based on the respective floras of both countries takes into consideration the bulk of medicinal species mutually present in Italy and Tunisia, but it focuses on the species growing in areas which are similar in climate. The medicinal uses of these species are considered in accordance with the ethnobotanical literature.

RESULTS

A list of 153 medicinal species belonging to 60 families, present in both floras and used in traditional medicine, was drawn. A considerable convergence in therapeutic uses of many species emerged from these data.

CONCLUSION

This comparative analysis strengthens the firm belief that ethno-botanical findings represent not only an important shared heritage, developed over the centuries, but also a considerable mass of data that should be exploited in order to provide new and useful knowledge.

Phytochemistry and biological activities of Phlomis species

The genus Phlomis L. belongs to the Lamiaceae family and encompasses 100 species native to Turkey, North Africa, Europe and Asia. It is a popular herbal tea enjoyed for its taste and aroma. Phlomis species are used to treat various conditions such as diabetes, gastric ulcer, hemorrhoids, inflammation, and wounds. This review aims to summarize recent research on the phytochemistry and pharmacological properties of the genus Phlomis, with particular emphasis on its ethnobotanical uses. The essential oil of Phomis is composed of four chemotypes dominated by monoterpenes (alpha-pinene, limonene and linalool), sesquiterpenes (germacrene D and beta-caryophyllene), aliphalic compounds (9,12,15-octadecatrienoic acid methyl ester), fatty acids (hexadecanoic acid) and other components (trans-phytol, 9,12,15-octadecatrien-1-ol). Flavonoids, iridoids and phenylethyl alcohol constitute the main compounds isolated from Phlomis extracts. The pharmacological activities of some Phlomis species have been investigated. They are described according to antidiabetic, antinociceptive, antiulcerogenic, protection of the vascular system, anti-inflammatory, antiallergic, anticancer, antimicrobial and antioxidant properties.

Flavonoids and sesquiterpenes from Tecurium ramosissimum promote antiproliferation of human cancer cells and enhance antioxidant activity: a structure-activity relationship study

Fractionation of the chloroformic extracts from Teucrium ramosissimum leaves resulted in the isolation of three flavonoids: genkwanin (1), cirsimaritin (2) and 4',7-dimethoxy apigenin (4) and one sesquiterpene: β-eudesmol (3). The structures were determined using data obtained from (1)H and (13)C NMR spectra, as well as by various correlation experiments (COSY, HMQC and HMBC). The antioxidant activities of the isolated flavonoids from T. ramosissimum leaves were evaluated by measuring their ability to scavenge the radical ABTS(+) and through chemical assays: cupric reducing antioxidant capacity (CUPRAC), reducing power (RP) and ferric reducing antioxidant power (FRAP). Furthermore, the effects of T. ramosissimum isolated molecules, on inhibition of cell proliferation and induction of apoptosis in human leukemia cells, were also examined. Cirsimaritin showed the best activity in the ABTS assay with TEAC value 2.04μM, whereas apigenin and 4',7-dimethoxy apigenin exhibited the highest antioxidant activity using the CUPRAC, RP and FRAP assays with TEAC values 10.5, 1.39 and 0.71μM respectively. The cytotoxic activity revealed that the β-eudesmol inhibited significantly the proliferation of K562 cells (IC(50)=20μg/ml).

Effect of apigenin-7-glucoside, genkwanin and naringenin on tyrosinase activity and melanin synthesis in B16F10 melanoma cells

AIMS

In this study, we have investigated the effects of apigenin-7-glucoside, genkwanin and naringenin, on mouse melanoma B16F10 cell proliferation. Influence of these natural products on percentage cell distribution in cycle phases and melanogenesis was also studied.

MAIN METHODS

Cell viability was determined at various periods using the MTT assay, whereas effects of tested compounds on progression through the cell cycle were analyzed by flow cytometry. In addition, amounts of melanin and tyrosinase were measured spectrophotometrically at 475 nm. Besides, the mechanism involved on the death route induced by the tested molecules was evaluated using the bis-benzimide trihydrochloride coloration method (Hoechst 33258).

KEY FINDINGS

Apigenin-7-glucoside, genkwanin and naringenin exhibited significant anti-proliferative activity against B16F10 melanoma cells after 24 and 48 h of incubation. Furthermore, apigenin-7-glucoside, genkwanin and naringenin provoked an increase of subG0/G1, S and G2/M phase cell proportion with a significant decrease of cell proportion in G0/G1 phases. The results evaluated using Hoechst 33,258, confirm that the percentage of B16F10 cells observed in the sub G0/G1 phase were undergoing apoptosis. Moreover, apigenin-7-glucoside and naringenin revealed an ability to enhance melanogenesis synthesis and tyrosinase activity of B16F10 melanoma cells. Whereas genkwanin induces a decrease of melanin synthesis by inhibiting tyrosinase activity.

SIGNIFICANCE

Our results promote the introduction of genkwanin in cosmetic preparations, as skin whitening agent, whereas apigenin-7-glucoside and naringenin should be introduced into cosmetic products as natural tanning agents.

Anti-genotoxic and free-radical scavenging activities of extracts from (Tunisian) Myrtus communis

The effect of extracts from leaves of Myrtus communis on the SOS reponse induced by Aflatoxin B1 (AFB1) and Nifuroxazide was investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37. Aqueous extract, the total flavonoids oligomer fraction (TOF), hexane, chloroform, ethyl acetate and methanol extracts and essential oil obtained from M. communis significantly decreased the SOS response induced by AFB1 (10 microg/assay) and Nifuroxazide (20 microg/assay). Ethyl acetate and methanol extracts showed the strongest inhibition of the induction of the SOS response by the indirectly genotoxic AFB1. The methanol and aqueous extracts exhibited the highest level of protection towards the SOS-induced response by the directly genotoxic Nifuroxazide. In addition to anti-genotoxic activity, the aqueous extract, the TOF, and the ethyl acetate and methanol extracts showed an important free-radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. These results suggest the future utilization of these extracts as additives in chemoprevention studies.

Comparative study of Cyperus rotundus essential oil by a modified GC/MS analysis method. Evaluation of its antioxidant, cytotoxic, and apoptotic effects

Gas chromatography coupled with mass spectrometry (GC/MS), using both electron impact (EI) and chemical ionization (CI) detection modes on apolar and polar stationary phases, led to the determination of the volatile composition of the essential oil obtained from tubers of Cyperus rotundus (Cyperaceae). In this study, more than 33 compounds were identified and then compared with the results obtained in our previous work. Cyperene, alpha-cyperone, isolongifolen-5-one, rotundene, and cyperorotundene were the principal compounds comprising 62% of the oil. An in vitro cytotoxicity assay with MTT indicated that this oil was very effective against L1210 leukaemia cells line. This result correlates with significantly increased apoptotic DNA fragmentation. The oxidative effects of the essential oil were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH), xanthine/xanthine oxidase assays, and the scavenging of superoxide radical assay generated by photo-reduction of riboflavin. The antimutagenic activity of essential oil has been examined by following the inhibition of H(2)O(2) UV photolysis which induced strand-break formation in pBS plasmid DNA scission assay. Based on all these results, it is concluded that C. rotundus essential-oil composition established by GC/MS analysis, in EI- and CI-MS modes, presents a variety of a chemical composition we were not able to detect with only GC/MS analysis in our previous work. This essential oil exhibited antioxidant, cytotoxic, and apoptotic properties.

Adenosine triphosphate in human semen: a quantitative estimate of fertilizing potential

The concentration of adenosine triphosphate (ATP) per milliliter of ejaculate was found to be significantly correlated with the following parameters: sperm concentration, number of motile spermatozoa per milliliter, capacity of spermatozoa to migrate against gravity, and in vitro potential to penetrate zona-free hamster ova. The ATP concentration was significantly lower in the semen of infertile men with normal sperm concentration and motility, compared with matched fertile donors. The ATP concentration of deep-frozen donor semen was significantly correlated with its fertilizing potential as estimated from the pregnancy per cycle index in an artificial insemination by donor semen program. These qualities suggest that measurement of semen ATP may be a possible biochemical method for the quantitation of the actual fertilizing potential of the ejaculate.

Evaluation of genotoxicity and pro-oxidant effect of the azo dyes: Acids yellow 17, violet 7 and orange 52, and of their degradation products by Pseudomonas putida mt-2

Acids yellow 17, violet 7 and orange 52, very important commercial azo dyes used in the textile, food, paper and cosmetic industries, were degraded by Pseudomonas putida mt-2 at concentrations up to 100mg/l. The culture media was completely decolorized under static incubation for 60 h, this faster than under continuous shaking incubation. SOS chromotest using Escherichia coli PQ37, with and without metabolic activation (S-9 preparations), was used to assess genotoxicity potential of these dyes before and after biodegradation. None of these dyes or their metabolites was found to be genotoxic in the absence of "Araclor-Induced rat liver microsome" preparations (S-9). However, in presence of the preparation S-9, the genotoxicity of the biodegradation products was highlighted. Metabolites resulting from static cultures were more genotoxic than those obtained in shaken conditions. In addition to genotoxic effects, metabolites have shown a significant ability to induce the formation of superoxide free radical anion (O(2)(*-)). The toxicities generated by the pure azo dyes and the pure azo-reduction products (sulfanilic acid, N,N'-dimethyl-p-phenylenediamine and 4'-aminoacetanilid) were compared. These results suggest that P. putida mt-2 degrades the studied azo dyes in two steps: an azo-reduction followed by an oxygen-dependent metabolization. Some of the derived metabolites would be responsible of genotoxicity and metabolic toxicity.

In vitro evaluation of antibacterial, antioxidant, cytotoxic and apoptotic activities of the tubers infusion and extracts of Cyperus rotundus

The in vitro antibacterial, antioxidant, cytotoxic and apoptotic activities from tubers extracts of Cyperus rotundus (Cyperaceae) were investigated. Antibacterial activity of different extracts was evaluated against five bacterial reference strains. A marked inhibitory effect was observed against Salmonella enteritidis, Staphylococcus aureus and Enterococcus faecalis with total oligomers flavonoids (TOFs) and ethyl acetate extracts. In addition to their antibacterial activity, the same extracts showed a significant ability to inhibit nitroblue tetrazolium reduction by the superoxide radical in a non-enzymatic superoxide generating system. Apoptosis, a highly organized physiological mechanism to eliminate injured or abnormal cells, is also implicated in multistage carcinogenesis. It was observed that TOF and ethyl acetate extracts suppressed growth and proliferation of L1210 cells derived from murine lymphoblastic leukaemia. Morphological features of treated cells and characteristic DNA fragmentation revealed that the cytotoxicity was due to induction of apoptosis. This study confirms that TOF and ethyl acetate extracts of C.rotundus possess antibacterial and antioxidant properties and provoke DNA fragmentation, a sign of induction of apoptosis. These results were correlated with chemical composition of the tested extracts.

Immunomodulatory and cellular anti-oxidant activities of caffeic, ferulic, and p-coumaric phenolic acids: a structure-activity relationship study

Many studies have been performed to assess the potential utility of natural products as immunomodulatory agents to enhance host responses and to reduce damage to the human body. To determine whether phenolic compounds (caffeic, ferulic, and p-coumaric acids) have immunomodulatory effects and clarify which types of immune effector cells are stimulated in vitro, we evaluated their effect on splenocyte proliferation and lysosomal enzyme activity. We also investigated the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL). In addition, induction of the cellular antioxidant activity in splenocytes, macrophages, and red blood cells was determined by measuring the fluorescence of the DCF product. The study first results indicated that caffeic, ferulic, and p-coumaric acids significantly promote LPS-stimulated splenocyte proliferation, suggesting a potential activation of B cells, and enhanced humoral immune response in hosts treated by the tested natural products. Phenolic acids significantly enhanced the killing activity of isolated NK and CTL cells but had negligible effects on mitogen-induced proliferation of splenic T cells. We showed that caffeic acid enhances lysosomal enzyme activity in murine peritoneal macrophages, suggesting a potential role in activating such cells. Immunomodulatory activity was concomitant with the cellular antioxidant effect in macrophages and splenocytes of caffeic and ferulic acids. We conclude from this study that caffeic, ferulic, and p-coumaric acids exhibited an immunomodulatory effect which could be ascribed, in part, to their cytoprotective effect via their antioxidant capacity. Furthermore, these results suggest that these natural products could be potentially used to modulate immune cell functions in physiological and pathological conditions.

Limoniastrum guyonianum aqueous gall extract induces apoptosis in human cervical cancer cells involving p16 INK4A re-expression related to UHRF1 and DNMT1 down-regulation

Several reports have described the potential effects of natural compounds as anti-cancer agents in vitro as well as in vivo. The aim of this study was to evaluate the anti-cancer effect of Limoniastrum guyonianum aqueous gall extract (G extract) and luteolin in the human cervical cancer HeLa cell line, and, if so, to clarify the underlying mechanism. Our results show that G extract and luteolin inhibited cell proliferation and induced G2/M cell cycle arrest in a concentration and time-dependent manner. Both natural products induced programmed cell death as confirmed by the presence of hypodiploid G0/G1 cells. These effects are associated with an up-regulation of the expression of the tumor suppressor gene p16INK4A and a down-regulation of the expression of the anti-apoptotic actor UHRF1 and its main partner DNMT1. Moreover, G extract- and luteolin-induced UHRF1 and DNMT1 down-regulation is accompanied with a global DNA hypomethylation in HeLa cell line. Altogether our results show that G extract mediates its growth inhibitory effects on human cervical cancer HeLa cell line likely via the activation of a p16INK4A-dependent cell cycle checkpoint signalling pathway orchestrated by UHRF1 and DNMT1 down-regulation.

Antiinflammatory and analgesic activities of Zizyphus lotus root barks

The root barks of Zizyphus lotus were extracted with water, chloroform, ethyl acetate and methanol to determine their antiinflammatory and analgesic activities. Aqueous extract (50, 100 and 200 mg/kg) given intraperitoneally (i.p.) showed a significant and dose-dependent antiinflammatory and analgesic activity.

Investigation of extracts from (Tunisian) Cyperus rotundus as antimutagens and radical scavengers

This study evaluates mutagenic and antimutagenic effects of aqueous, total oligomers flavonoïds (TOF), ethyl acetate and methanol extracts from aerial parts of Cyperus rotundus with the Salmonella typhimurium assay system. The different extracts showed no mutagenicity when tested with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1538 either with or without the S9 mix. On the other hand, our results showed that all extracts have antimutagenic activity against Aflatoxin B1 (AFB1) in TA100 and TA98 assay system, and against sodium azide in TA100 and TA1535 assay system. TOF, ethyl acetate and methanol extracts exhibited the highest inhibition level of the Ames response induced by the indirect mutagen AFB1. Whereas, ethyl acetate and methanol extracts exhibited the highest level of protection towards the direct mutagen, sodium azide, induced response. In addition to antimutagenic activity, these extracts showed an important free radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. TOF, ethyl acetate and methanol extracts showed IC(50) value of 15, 14 and 20μg/ml, respectively. Taken together, our finding showed that C. rotundus exhibits significant antioxidant and antimutagenic activities.

Effect of heated naringenin on immunomodulatory properties and cellular antioxidant activity

Naringenin is one of the most popular flavonoids derived from citrus. It has been reported to be an effective anti-inflammatory compound. Citrus fruit may be used raw, cooked, stewed, or boiled. The present study was conducted to investigate the effect of thermal processes on naringenin in its immunomodulatory and cellular antioxidant activities. The effects of flavonoids on B and T cell proliferation were assessed on splenocytes stimulated or not with mitogens. However, their effects on cytotoxic T lymphocyte (CTL) and natural killer (NK) activities were assessed in splenocytes co-incubated with target cells. The amount of nitric oxide production and the lysosomal enzyme activity were evaluated in vitro on mouse peritoneal macrophages. Cellular antioxidant activity in splenocytes and macrophages was determined by measuring the fluorescence of the dichlorofluorescin (DCF). Our findings revealed that naringenin induces B cell proliferation and enhances NK activity. The highest concentration of native naringenin exhibits a significant proliferation of T cells, induces CTL activity, and inhibits cellular oxidation in macrophages. Conversely, it was observed that when heat-processed, naringenin improves the cellular antioxidant activity in splenocytes, increases the cytotoxic activity of NK cells, and suppresses the cytotoxicity of T cells. However, heat treatment maintains the anti-inflammatory potency of naringenin.

Study of genotoxic, antigenotoxic and antioxidant activities of the digallic acid isolated from Pistacia lentiscus fruits

The digallic acid obtained from the fruit Pistacia lentiscus exhibits an inhibitory activity against nitrofurantoine and B[a]P induced genotoxicity when tested by the SOS chromotest bacterial assay system in the presence of Escherichia coli PQ37 strain. The antioxidant activity of the tested compound was determined by its ability to scavenge the free radical ABTS(+), to inhibit the xanthine oxidase, involved in the generation of free radicals, and to inhibit the lipid peroxidation induced by H(2)O(2) in the K562 cell line. Our results revealed that digallic acid shows an important free radical scavenging activity towards the ABTS(+) radical (99%) and protection against lipid peroxidation (68%).

Immunomodulatory potential of hesperetin and chrysin through the cellular and humoral response

Flavonoids are polyphenols frequently consumed in the diet they have been suggested to exert a number of beneficial actions on human health, including anti-inflammatory activity. This study investigated the immunomodulatory effects of two flavonoids, Chrysin and Hesperetin. The effects of flavonoids on B and T cell proliferation were assessed on splenocytes stimulated or not with mitogens. However, their effects on cytotoxic T lymphocyte (CTL) and natural killer (NK) activities were assessed in splenocytes co-incubated with target cells. We report for the first time that both tested flavonoids enhance lymphocyte proliferation at 3.12μM. Chrysin significantly inhibited lipopolysaccharide (LPS) and lectin stimulated splenocyte proliferation. Whereas, hesperetin enhanced LPS and lectin stimulated splenocyte proliferation. In addition, both flavonoids significantly enhance NK cell and CTL activities. Furthermore, our study demonstrated that depending on the concentrations, flavonoid molecules affect macrophage functions by modulating their lysosomal activity and nitric oxide (NO) release, suggesting a potential anti-inflammatory effect. We conclude that flavonoids such as chrysin and hesperetin may be potentially useful for modulating immune cell functions in physiological and pathological conditions and thus a good candidate as food addition component.

Flavones induce immunomodulatory and anti-inflammatory effects by activating cellular anti-oxidant activity: a structure-activity relationship study

Flavonoids impart a variety of biological activities, including anti-oxidant, anti-inflammatory, and anti-genotoxic effects. This study investigated the effects of flavone luteolin and apigenin on immune cell functions, including proliferation, natural killer (NK) cell activity, and cytotoxic T lymphocyte (CTL) activity of isolated murine splenocytes. We report for the first time that flavones enhance lymphocyte proliferation at 10 μM. Luteolin and apigenin significantly promote lipopolysaccharide (LPS)-stimulated splenocyte proliferation and enhance humoral immune responses. Luteolin induces a weak cell proliferation of lectin-stimulated splenic T cells, when compared to apigenin. In addition, both flavones significantly enhance NK cell and CTL activities. Furthermore, our study demonstrated that both flavones could inhibit lysosomal enzyme activity, suggesting a potential anti-inflammatory effect. The anti-inflammatory activity was concomitant with the cellular anti-oxidant effect detected in macrophages, red blood cells, and splenocytes. We conclude from this study that flavones exhibited an immunomodulatory effect which could be ascribed, in part, to its cytoprotective capacity via its anti-oxidant activity.

Transcriptional response of genes involved in cell defense system in human cells stressed by H2O2 and pre-treated with (Tunisian) Rhamnus alaternus extracts: Combination with polyphenolic compounds and classic in vitro assays

The ability of three Rhamnus alaternus leaves extracts on antigenotoxic and gene expression level effects was respectively investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37 and in human K562 lymphoblast cell line. Total oligomers flavonoids (TOF) enriched, methanol and ethyl acetate extracts were prepared from powdered R. alaternus leaves and characterized quantitatively for the presence of polyphenolic compounds. We explored the response to oxidative stress using the transcriptional profile of genes in K562 cells stressed with H2O2 after incubation with plant extracts. For this purpose, we used a cDNA microarrays containing 82 genes related to cell defense, essentially represented by antioxidant and DNA repair genes. Analysis revealed that SOD1, AOE 372, TXN genes involved in the antioxidant defense system and XPC, LIG4, POLD2, PCNA genes implied in the DNA repair system were among the most expressed ones in the presence of the tested extracts. These results were in accordance with those obtained when we tested the antigenotoxic and antioxidant effects of the same extracts with, respectively the SOS chromotest and the xanthine/xanthine oxidase enzymatic assay system. The effect of the tested extracts on SOS response induced by both Aflatoxin B1 (AFB1: 10 microg/assay) and nifuroxazide (20 microg/assay) showed that the TOF extract exhibited the highest antimutagenic level towards the indirect mutagen AFB1. Whereas ethyl acetate extract showed the highest antimutagenic effect towards the direct mutagen, nifuroxazide. None of the tested extracts induced mutagenic activity. However all the tested extracts exhibited xanthine oxidase inhibiting and superoxide anions scavenging effects. R. alaternus extracts contain compounds with significant antioxidant and antigenotoxic activities. These compounds modulate gene expression as detected by using cDNA arrays.

Flavones inhibit the proliferation of human tumor cancer cell lines by inducing apoptosis

Dietary flavonoids have been shown to exert specific cytotoxicity toward some cancer cells, but the precise molecular mechanisms are still not completely understood. In this study, cytotoxic effects of flavones (apigenin and luteolin) on two different cancer cell lines, including human chronic myelogenous erythroleukaemia (K562) and bladder carcinoma (RT112), were determined, and the molecular mechanisms responsible for their cytotoxic effects were studied. The results of an MTT assay showed that luteolin and apigenin were able to induce cytotoxicity in K562 and RT112 cells in a dose- and time-dependent manner. The cytotoxic potency of luteolin was higher than that of apigenin. Flow-cytometry and DNA-fragmentation analysis indicated that the cytotoxicity induced by luteolin and apigenin was mainly due to apoptosis, with minor cell-cycle perturbations. This apoptotic response was characterized by an increase of the sub-G1 fraction of treated cells, poly(ADP-ribose) polymerase proteolysis, typical ladder of DNA fragmentation, and Annexin V-positive cells. In conclusion, luteolin and apigenin exert cytotoxic effects in different cancer cell lines in which apoptosis plays an important role. Thus, flavones could be considered as potential chemotherapeutic agents.