Antioxidant, Cytotoxic, Genotoxic, and DNA-Protective Potential of 2,3-Substituted Quinazolinones: Structure-Activity Relationship Study

The evaluation of antioxidant compounds that counteract the mutagenic effects caused by the direct action of reactive oxygen species on DNA molecule is of considerable interest. Therefore, a series of 2,3-substituted quinazolinone derivatives (Q1-Q8) were investigated by different assays, and the relationship between their biological properties and chemical structure was examined. Genotoxicity and the potential DNA-protective effects of Q1-Q8 were evaluated by comet assay and DNA topology assay. Antioxidant activity was examined by DPPH-radical-scavenging, reducing-power, and total antioxidant status (TAS) assays. The cytotoxic effect of compounds was assessed in human renal epithelial cells (TH-1) and renal carcinoma cells (Caki-1) by MTT assay. Analysis of the structure-activity relationship disclosed significant differences in the activity depending on the substitution pattern. Derivatives Q5-Q8, bearing electron-donating moieties, were the most potent members of this series. Compounds were not genotoxic and considerably decreased the levels of DNA lesions induced by oxidants (H2O2, Fe2+ ions). Furthermore, compounds exhibited higher cytotoxicity in Caki-1 compared to that in TH-1 cells. Substantial antioxidant effect and DNA-protectivity along with the absence of genotoxicity suggested that the studied quinazolinones might represent potential model structures for the development of pharmacologically active agents.

Evaluation of genotoxicity and subchronic toxicity of the standardized leaves infusion extract of Copaifera malmei Harms in experimental models

ETHNOPHARMACOLOGICAL RELEVANCE

Copaifera malmei Harms (Fabaceae), known mainly as óleo-mirim, is a native and endemic plant found in the states of Mato Grosso and Goiás of Brazil. The plant's leaves infusion is popularly used by riverine communities of the northern Araguaia microregion, Mato Grosso, Brazil, for the treatment of gastric ulcers and inflammatory diseases of the respiratory tract. The gastric antiulcer activity of the standardized leaves infusion extract of Copaifera malmei (SIECm) in rodents has been reported. The objective of this study was to advance the investigation of the safety profile of SIECm by evaluating the genotoxicity and subchronic toxicity using in vitro and in vivo experimental models.

MATERIALS AND METHODS

SIECm was prepared by infusion, by incubating the powdered dried leaves material in boiled water for 15min. In vitro genotoxicity of SIECm (10, 30 or 100μg/mL) was assessed by micronucleus and comet tests using Chinese hamster ovary (CHO-k1) epithelial cells. The evaluation of subchronic toxicity profile was performed by daily oral administration of SIECm (100, 400 or 1000mg/kg) to Wistar rats for 30 days. Clinical observations of toxicological related parameters were done every 6 days. After the treatment period, blood was collected for hematological and biochemical analysis, and some organs were removed for macroscopic and histopathological analysis.

RESULTS

In the micronucleus assay, SIECm demonstrated anti-mutagenic activity. In the comet assay, SIECm presented anti-genotoxic effect preventing DNA damage at all the three concentrations tested with pre-treatment, while the same effect was only observed in the co-treatment at the lowest concentration. Post-treatment with SIECm increased the genetic damage induced by hydrogen peroxide (H₂O₂) at the highest concentration. In the subchronic toxicity test, few changes were observed, such as increase in feed consumption in the group of animals treated with 100mg/kg of the SIECm, which reversed after 6 days. There were no macroscopic, histological and relative weights changes in the organs of animals treated with SIECm. No toxicologically relevant changes were observed in the hematological analysis. Subchronic administration of SIECm reduced levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in animals treated with 100mg/kg and serum triglyceride levels at 400 and 1000mg/kg. However, the hematological and biochemical changes observed are within the physiological ranges for this animal species.

CONCLUSION

The results demonstrate that SIECm is not genotoxic, and does not present toxicity when used orally for up to 30 days. In addition, it showed protection to the genetic damage induced by H₂O_2. The SIECm therefore has a high safety margin for therapeutic use.

Chemical composition and biological activities of Helicteres vegae and Heliopsis sinaloensis

CONTEXT

Helicteres vegae Cristóbal (Sterculiaceae) (Hv) and Heliopsis sinaloensis B.L. Turner (Asteraceae) (Hs) are endangered and poorly studied plant species; related plants have been used against chronic-degenerative and infectious diseases. Therefore, Hv and Hs could be sources of bioactive compounds against these illnesses.

OBJECTIVE

To determine the chemical composition and biological activities (antioxidant, antimutagenic and antimicrobial) of Hv and Hs leaves (L) and stems (S).

MATERIALS AND METHODS

Methanol extracts (ME) of each plant/tissue were evaluated for their phytochemicals; phenolics (HPLC-DAD-ESI-MS); antioxidant activity (AA) (0.125-4 mg/mL) (DPPH, ABTS, ORAC and β-carotene discoloration); antimutagenicity (0.5 and 1 mg/plate) (Ames assay, tester strain Salmonella enterica serovar Typhimurium YG1024, 1-nitropyrene as mutagen); activity against human pathogens (1 mg/mL); and toxicity (0.01-2 mg/mL) (Artemia salina assay).

RESULTS

All ME showed flavonoids and triterpenes/steroids. The ME-SHv had the highest content of total phenolics (TP) (2245.82 ± 21.45 mg GAE/100 g d.w.) and condensed tannins (603.71 ± 1.115 mg CE/100 g d.w.). The compounds identified were flavonoids (kaempferol 7-O-coumaroylhexoside, and two kaempferol 7-O-rhamnosylhexosides) and phenolics [rosmarinic acid, and 3'-O-(8″-Z-caffeoyl) rosmarinic acid]. The ME-LHs showed the highest content of flavonoids (357.88 mg RE/g d.w.) and phenolic acids (238.58 mg CAE/g d.w.) by HPLC. The ME-SHv showed the highest AA. All ME were strong antimutagens (63.3-85.7%). Only the Hs extracts were toxic (ME-LHs, LC₅₀ = 94.9 ± 1.7 μg/mL; ME-SHs, LC₅₀ = 89.03 ± 4.42 μg/mL).

DISCUSSION AND CONCLUSIONS

Both Hv and Hs are potential sources of preventive and therapeutic agents against chronic-degenerative diseases.

The mutagenic, antimutagenic and antioxidant properties of Hypericum lydium

CONTEXT

There is a growing market demand for Hypericum sp., a pharmacologically active plant that has been traditionally used to treat various ailments. However, there have been limited studies on the extract or essential oil of Hypericum lydium Boiss (Hypericaceae).

OBJECTIVE

This study investigates for the first time the antioxidant, mutagenic and antimutagenic activity of an ethanol extract of H. lydium.

MATERIAL AND METHODS

Ethanol extract from aerial parts of H. lydium harvested from Turkey were tested for this mutagenic and antimutagenic activities (2.0-0.002 mg/plate) using Ames Salmonella/microsome test system. 4-Nitro-o-phenylenediamine (4-NPD) (3 μg/plate) for the Salmonella typhimurium TA98 and sodium azide (NaN3) (8 μg/plate) for the S. typhimurium TA100 were used as positive controls. The antioxidant activity, total antioxidant activity and phenolic constituent of the extract (2.0-0.002 mg/mL) was determined by the inhibition of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), β-carotene-linoleic acid model and by means of Folin-Ciocalteu reagent, respectively.

RESULTS

The extract showed no sign of mutagenicity at the tested concentrations (0.002-2.0 mg/mL), and showed concentration-dependent antimutagenic activity against NaN3 and 4-NPD ranging from 26.8 to 81.5%. The extract was found to be an efficient scavenger of DPPH (IC50 0.165 ± 0.23 mg/mL) and to inhibit β-carotene-linoleic acid bleaching (IC50 0.39 ± 0.11 mg/mL).

DISCUSSION AND CONCLUSION

These findings indicate ethanol extract of H. lydium to be a safe and effective agent that may be incorporated into new strategies for the prevention of cancer and mutagenesis.

The antioxidant, cytotoxic, and antigenotoxic effects of galangin, puerarin, and ursolic acid in mammalian cells

Phenolic compounds not only contribute to the sensory qualities of fruits and vegetables but also exhibit several health protective properties. Galangin, puerarin, and ursolic acid are commonly used plant phenolics in folk medicine. In this study, the antioxidant capacities of galangin, puerarin, and ursolic acid by the trolox equivalent antioxidant capacity (TEAC) assay and the cytotoxic effects by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in V79 cells were investigated. The genotoxic potentials of galangin, puerarin, and ursolic acid were evaluated by micronucleus (MN) and alkaline COMET assays in human lymphocytes and in V79 cells. Galangin, puerarin, and ursolic acid (10, 100, 500, 1000, 2000, 5000, 10 000, and 20 000 μM) were found to have antioxidant activities at the studied concentrations. IC50 values of galangin, puerarin, and ursolic acid in V79 cells were found to be 275.48 μM, 2503.712 μM, and 224.85 μM, respectively. Galangin, puerarin, and ursolic acid, at the all concentrations, have not exerted genotoxic effects and galangin, puerarin, and ursolic acid revealed a reduction in the frequency of MN and DNA damage induced by H2O2.

Assessment in vitro of the genotoxicity, antigenotoxicity and antioxidant of Ceratonia siliqua L. extracts in murine leukaemia cells L1210 by comet assay

Genotoxicity of Ceratonia siliqua extracts, was investigated by assessing their capacity to induce nucleus DNA degradation of murine leukaemia cells L1210, using the "Comet assay". The ability of total oligomer flavonoids (TOF) and aqueous extracts to protect cell DNA against oxidative stress induced by H2O2, was performed by pre- co or post-treatment of cells with the before mentioned extracts for different periods preceding exposure to H2O2 stress. No significant genotoxic effect was detected at different exposure times, except at the lowest concentration of TOF extract (16.25 μg/ml). It appears that extracts decreased DNA damage, induced by H2O2. Both of TOF and aqueous extracts exhibited cellular antioxidant capacity, with EC50 values of respectively <16.25 and < 35 μg/ml, as well as, a protective capacity against lipidperoxidation inducing using L1210 cells line as a cellular model. MDA inhibition percentages reached 88.43% and 90.52% with respectively 35.5 μg/ml of TOF extract and 70 μg/ml of aqueous extract. Antioxidant properties of carob leaf extracts revealed by our study make a good antioxidant protection and thus a good candidate as food addition component.

Chemical and biological characterisation of Machaerium hirtum (Vell.) Stellfeld: absence of cytotoxicity and mutagenicity and possible chemopreventive potential

Machaerium hirtum (Vell.) Stellfeld (M.hirtum) is a plant known as 'jacarandá-bico-de-pato' whose bark is commonly used against diarrhea, cough and cancer. The aim of this study was to phytochemically characterise the hydroethanolic extract of this plant, investigate its antimutagenic activities using the Ames test and evaluate its effects on cell viability, genomic instability, gene expression and cell protection in human hepatocellular carcinoma cells (HepG2). Antimutagenic activity was assessed by simultaneous pre- and post-treatment with direct and indirect mutagens, such as 4-nitro-o-phenylenediamine (NPD), mitomycin C (MMC), benzo[a]pyrene (B[a]P) and aflatoxin B1 (AFB1), using the Ames test, cytokinesis blocking micronucleus and apoptosis assays. Only 3 of the 10 concentrations evaluated in the MTT assay were cytotoxic in HepG2 cells. Micronucleated or apoptotic cells were not observed with any of the tested concentrations, and there were no mutagenic effects in the bacterial system. However, the Nuclear Division Index and flow cytometry data showed a decrease in cell proliferation. The extract showed an inhibitory effect against direct (NPD) and indirect mutagens (B[a]P and AFB1). Furthermore, pre- and post-treated cells showed significant reduction in the number of apoptotic and micronucleated cells. This effect is not likely to be associated with the modulation of antioxidant genes, as shown by the RT-qPCR results. Six known flavonoids were identified in the hydroethanolic extract of Machaerium hirtum leaves, and their structures were elucidated by spectroscopic and spectrophotometric methods. The presence of the antioxidants apigenin and luteolin may explain these protective effects, because these components can inhibit the formation of reactive species and prevent apoptosis and DNA damage. In conclusion, the M.hirtum extract showed chemopreventive potential and was not hazardous at the tested concentrations in the experiments presented here. Moreover, this extract should be investigated further as a chemopreventive agent.

In vitro cytotoxic and anticlastogenic activities of saxifragifolin B and cyclamin isolated from Cyclamen persicum and Cyclamen libanoticum

CONTEXT

The genus Cyclamen L. (Primulaceae) is rich in saponins known to have interesting biological activities.

OBJECTIVE

To isolate saxifragifolin B and cyclamin, two triterpene saponins, from Cyclamen libanoticum Hildebr and Cyclamen persicum Mill, and to assess their cytotoxic, clastogenic/aneugenic, and anticlastogenic effects, as well as antioxidant potential.

MATERIALS AND METHODS

Saxifragifolin B and cyclamin were tested for their cytotoxicity against SK-BR-3, HT-29, HepG2/3A, NCI-H1299, BXPC-3, 22RV1, and normal DMEM cell lines using WST-1 assay. Their clastogenic/aneugenic activities and anticlastogenic effects against the anticancer drug mitomycin C were assessed by the in vitro micronucleus assay in CHO cells. Their antioxidant capacities were determined using Fe(2+)-chelating and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays.

RESULTS

Both saponins were described for the first time in Cyclamen libanoticum. They showed strong cytotoxic activities against the tested cancer cell lines. Saxifragifolin B was found to be 56- and 37-times more active than mitomycin C against breast adenocarcinoma (SK-BR-3) and lung carcinoma (NCI-H1299), respectively. Also, saxifragifolin B did not induce micronuclei formation and prevented cells from mitomycin C clastogenic effect. Cyclamin induced a significant increase of micronucleated cells after metabolic activation with S9 mix, and did not possess any anticlastogenic activity. Both molecules exhibited low antioxidant activities as compared to reference compounds.

DISCUSSION AND CONCLUSIONS

This study showed the remarkable cytotoxic activity of saxifragifolin B, especially against breast adenocarcinoma and lung carcinoma and its chemoprotective activity against mitomycin C. Thus, saxifragifolin B could be suggested as a potential cytotoxic drug with a preventive effect against possible exposures to genotoxic agents.

Anti-genotoxicity and anti-mutagenicity of Apis mellifera venom

The search for substances able to inhibit and/or diminish the effects of genotoxic and mutagenic substances has been the target of several investigations performed in recent times. Hymenoptera venoms constitute a considerable source of substances with pharmacological potential. The present study aimed to evaluate the cytotoxic, genotoxic and anti-genotoxic, mutagenic and anti-mutagenic potentials of Apis mellifera venom in HepG2 cells. In this evaluation, the MTT test was applied to determine the most appropriate concentrations for the genotoxicity and mutagenicity tests. It was verified that the concentrations of 0.1, 0.05 and 0.01μg/mL were not cytotoxic, hence these concentrations were used in the experiments. For the evaluation of the genotoxic and mutagenic potential of the bee venom the comet assay and the micronucleus test were applied, respectively. The concentrations mentioned above presented both genotoxic and mutagenic potential for HepG2 cells and it was necessary to test lower concentrations of the venom (10pg/mL, 1pg/mL and 0.1pg/mL) for the anti-genotoxicity and anti-mutagenicity tests, which were performed subjecting the cells to the action of MMS (methyl methanesulfonate) in order to verify the ability of the venom to inhibit or diminish the action of this compound, which has a recognized action on the genetic material. Pre-, post-treatment and simultaneous treatment with and without incubation with the venom were performed. It was observed that the lowest three concentrations tested did not present any anti-genotoxic and anti-mutagenic activity on the cells. The use of bee venom for pharmacological purposes in treatments such as cancer must be done with extreme caution, since it was observed that even at very low concentrations the venom can induce genotoxicity and mutagenicity in human cells, as was verified for the HepG2 cells.

Estrogenic and chemopreventive activities of xanthones and flavones of Syngonanthus (Eriocaulaceae)

The possible benefits of some bioactive flavones and xanthones present in plants of the genus Syngonanthus prompted us to screen them for estrogenic activity. However, scientific research has shown that such substances may have undesirable properties, such as mutagenicity, carcinogenicity and toxicity, which restrict their use as therapeutic agents. Hence, the aim of this study was to assess the estrogenicity and mutagenic and antimutagenic properties. We used recombinant yeast assay (RYA), with the strain BY4741 of Saccharomyces cerevisiae, and Ames test, with strains TA100, TA98, TA97a and TA102 of Salmonella typhimirium, to evaluate estrogenicity, mutagenicity and antimutagenicity of methanolic extracts of Syngonanthus dealbatus (S.d.), Syngonanthus macrolepsis (S.m.), Syngonanthus nitens (S.n.) and Syngonanthus suberosus (S.s.), and of 9 compounds isolated from them (1=luteolin, 2=mix of A-1,3,6-trihydroxy-2-methoxyxanthone and B-1,3,6-trihydroxy-2,5-dimethoxyxanthone, 3=1,5,7-trihydroxy-3,6-dimethoxyxanthone, 4=1,3,6,8-tetrahydroxy-2,5-dimethoxyxanthone, 5=1,3,6,8-tetrahydroxy-5-methoxyxanthone, 6=7-methoxyluteolin-8-C-β-glucopyranoside, 7=7-methoxyluteolin-6-C-β-glucopyranoside, 8=7,3'-dimethoxyluteolin-6-C-β-glucopyranoside and 9=6-hydroxyluteolin). The results indicated the estrogenic potential of the S. nitens methanol extract and four of its isolated xanthones, which exhibited, respectively, 14.74±1.63 nM; 19.54±6.61; 7.20±0.37; 6.71±1.02 e 10.01±4.26 nM of estradiol-equivalents (EEQ). None of the extracts or isolated compounds showed mutagenicity in any of the test strains and all of them showed antimutagenic potential, in particular preventing mutations caused by aflatoxin B1 (AFB1) and benzo[a]pyrene (B[a]P). The results show that the xanthones, only isolated from the methanol extract of S. nitens capitula, probably were the responsible for its estrogenic activity and could be useful as phytoestrogens, providing a new opportunity to develop hormonal agents. In addition, flavones and xanthones could also be used as a new antimutagenic agent. Since, the mutagens are involved in the initiation and promotion of several human diseases, including cancer, the significance of novel bioactive phytocompounds in counteracting these pro-mutagenic and carcinogenic effects is now gaining credence.

Sodium copper chlorophyllin (SCC) induces genetic damage in postmeiotic and somatic wing cells of Drosophila melanogaster

There is no apparent evidence to indicate that sodium copper chlorophyllin (SCC) is mutagenic. The aim of the present study was thus to determine the mutagenic effect of SCC, in postmeiotic germ cells of the adult male Drosophila. This investigation was based on the ability to examine whether SCC induced sex-linked recessive lethal mutations (SLRL), as well as the somatic mutation and recombination test (SMART). Four different SCC concentrations were used: 0, 45, 69, 80, and 100 mM. For SLRL, two broods were generated to test sperm and primarily spermatids. Results showed a significant frequency of recessive lethal mutations compared with control sperm cells with SCC at 69, 80, and 100 mM. In contrast, the frequency of somatic mutations rose by 0.21 only with 100 mM of SCC. These findings provide evidence that SCC is a weak mutagen in both cell lines. The differential response may be attributed to repair mechanisms that are active in somatic cells but almost absent in germ cells.

In vitro and in vivo evaluation of antioxidant and antigenotoxic potential of Punica granatum leaf extract

CONTEXT

Several studies have reported the antioxidant activity and potential therapeutic properties of Punica granatum L. (Lythraceae) fruit. Medicinal properties have also been attributed to other parts of P. granatum tree, which are rich in bioactive phytochemicals.

OBJECTIVE

To explore the phytochemical characteristics, in vitro and in vivo antioxidant and in vivo antigenotoxic potential of P. granatum leaf extract (PLE).

MATERIALS AND METHODS

The in vitro antioxidant potential of PLE was assessed by DPPH (1,1-diphenyl-2-picrylhydrazyl), ferric reducing antioxidant power (FRAP). Inhibition of lipid peroxidation (LPO) and the total phenolic content of the samples were also determined. Thirty-six male Swiss albino mice were divided into six groups (six animals each). Group 1 (control) and group 2 mice received vehicle and genotoxin alone, respectively. Groups 3, 4 and 5 were pretreated with PLE (400, 600 and 800 mg/kg body weight, respectively) prior to the administration of genotoxin. Group 6 received highest test dose of PLE. DNA damage in the bone marrow cells, hepatic LPO and antioxidants were recorded.

RESULTS

Phytochemical analysis of PLE showed the presence of flavonoids, phenols, phytosterols, tannins and carbohydrates. Aqueous PLE demonstrated free radical scavenging activity, reducing power and inhibition of LPO with the EC₅₀ values of 10.25, 59.88 and 20.05, respectively. A significant protective effect was observed against cyclophosphamide induced DNA damage and inhibition of hepatic LPO with concomitant increase in reduced glutathione (GSH) glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) in mice pretreated with PLE.

DISCUSSION AND CONCLUSION

PLE demonstrated a significant antioxidant and antigenotoxic potential and hence can be a potential natural source in health and medicine.

Evaluation of the genotoxic and antigenotoxic potential of Brassica oleracea L. var. acephala D.C. in different cells of mice

ETHNOPHARMACOLOGICAL RELEVANCE

Brassica oleracea L. var. acephala D.C. has been extensively used in Brazilian traditional medicine to treat gastric ulcer.

AIM OF THE STUDY

This study was conducted to evaluate the in vivo genotoxic and/or antigenotoxic potential of a Brassica oleraceae hydroalcoholic extract obtained from the leaves, in different cells of mice.

MATERIALS AND METHODS

Analyses were performed using the comet assay, on leukocytes (collected 4 and 24 h after treatment), liver, brain, bone marrow and testicular cells (collected 24 h after treatment), and using the micronucleus test (MN) in bone marrow cells. Eight groups of albino Swiss mice were treated (N=6): control (C), positive control (doxorubicin 80 mg/kg (DXR)), and six experimental groups, which received 500, 1000 and 2000 mg/kg of Brassica oleraceae extract alone by gavage, while a further three groups received the same doses plus DXR (80 mg/kg). We calculated the damage scores, and their averages were compared by ANOVA followed by the Tukey test for multiple comparisons.

RESULTS

The results demonstrated that none of the tested doses of Brassica oleraceae extract showed genotoxic effects by the comet assay, or clastogenic effects by the MN test. On the other hand, for all cells evaluated, the three tested doses of the Brassica extract promoted inhibition of DNA damage induced by DXR.

CONCLUSIONS

Under our experimental conditions, Brassica oleraceae leaf extract showed no genotoxic or clastogenic effects in different cells of mice. However, it did show a significant decrease in DNA damage induced by doxorubicin. It is suggested that the antigenotoxic properties of this extract may be of great pharmacological importance, and may be beneficial for cancer prevention.

Adipokine expression in brown and white adipocytes in response to hypoxia

BACKGROUND

Adipose tissue has emerged as an important endocrine regulator by secreting hormones referred to as adipokines. Recent studies showed that adipose tissue considerably responds to hypoxia. Although the impact of white adipose tissue on regulative processes is established, the importance of brown adipose tissue in adults has emerged just recently.

METHODS

Brown (BA) and white adipocytes (WA) were cultured either in the presence of chemical hypoxia-mimetics or under hypoxic atmosphere of 1% oxygen. Expression of hypoxia-inducible factor 1α (HIF- 1α) was assessed by western blot. The expression levels of several known HIF-1α-regulated proteins [vascular endothelial growth factor (VEGF), leptin, adiponectin, and angiotensinogen (AGT)] were quantified.

RESULTS

Both chemical hypoxia-mimetics and physical hypoxia led to increased nuclear HIF-1α expression and to decreased cytoplasmatic adiponectin in both cell types. In contrast, VEGF and AGT expression did not change upon hypoxic stimulation. Leptin was exclusively detectable in WA, while uncoupling-protein 1 (UCP-1) was expressed in BA only.

CONCLUSIONS

WA and BA are sensitive to hypoxia, in which HIF-1α expression is induced. Protein expression of adiponectin is hypoxia-dependent, whereas AGT, VEGF, leptin, and UCP-1 expression do not change secondary to hypoxia.

An AD-related neuroprotector rescues transformed rat retinal ganglion cells from CoCl₂-induced apoptosis

Some ocular diseases characterized by apoptotic death of retinal ganglion cells (RGCs) and Alzheimer's disease (AD) are chronic neurodegenerative disorders and have similarities in neuropathology. Humanin (HN) is known for its ability to suppress neuronal death induced by AD-related insults. In present study, we investigated the neuroprotective effects of HN on hypoxia-induced toxicity in RGC-5 cells. Hypoxia mimetic compound cobalt chloride (CoCl₂) could increase the cell viability loss and apoptosis, whereas HN can significantly attenuate these effects. This finding may provide new therapeutics for the retinal neurodegenerative diseases targeting neuroprotection.

Comparative study of antioxidant and anti-inflammatory activities and genotoxicity of alcoholic and aqueous extracts of four Fabiana species that grow in mountainous area of Argentina

ETHNOPHARMACOLOGICAL RELEVANCE

Fabiana species (Solanaceae family) extracts have long been used in Argentinean traditional medicine as anti-inflammatories, antiseptic, bone fractures and others diseases, but there is no scientific evidence which supports their use.

AIM OF THE STUDY

The present study was conducted to evaluate the ability of aqueous and ethanolic extracts of four Fabiana species (Fabiana bryoides Phil., Fabiana punensis A.C. Arroyo, Fabiana densa J. Rèmy and Fabiana patagonica Speg.) to inhibit key enzymes in inflammatory processes, free radical scavenging properties and genotoxic effects.

MATERIALS AND METHODS

HPLC-DAD of aqueous and ethanolic extracts from four Fabiana species was established. All Fabiana extracts were evaluated on their ability to inhibit hyaluronidase and lipoxygenase enzymes to assess their activity against inflammatory mediators. Antioxidant capacity was determined using the 2,2'-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assays and β-carotene-linolenic acid assay. Genotoxicity was evaluated by the Ames assay.

RESULTS

The results indicated that the chromatographic patterns of four Fabiana species were different in quantity and absorption intensity of peaks. The alcoholic extract of Fabiana punensis was the most active scavenger of DPPH and ABTS(+) radicals (SC(50) values of 3.85 ± 0.24 and 2.56 ± 0.10 μgGAE/mL, respectively). Fabiana patagonica extracts exhibited the highest peroxyl radical scavenging activity compared with the other three taxa (IC(50) values between 1.00 ± 0.04 and 4.46 ± 0.40 μg GAE/mL for all extracts) and anti-lipoxygenase activity with IC(50) values between 12.5 and 15.5 μg GAE/mL. The absence of mutagenicity indicates that the DNA does not seem to be a relevant target for these extracts. Fabiana bryoides ethanolic extract showed an interesting effect: it inhibited spontaneous mutagenesis, which could be considered as an antimutagenic effect in the TA98 (+S9) and TA100 (+S9/-S9) strains. The potency differences found between the species could be consequence of the different phytochemical pattern observed by HPLC.

CONCLUSIONS

The inhibitory effects on lipoxygenase and hyaluronidase, free radical scavenging activities and lack of genotoxicity of Fabiana extracts may support the folk use of Fabiana punensis, Fabiana patagonica, Fabiana bryoides and Fabiana densa as inhibitor of inflammatory mediators.

Genotoxic and antigenotoxic effects of Hemidesmus indicus R. Br. root extract in cultured lymphocytes

AIM OF THE STUDY

The genotoxic and antigenotoxic potential of the ethanolic extract of Hemidesmus indicus roots were evaluated in cultured human lymphocytes using cisplatin as the positive mutagen.

MATERIALS AND METHODS

Cytogenetic damage and cytotoxicity were determined in cells exposed to different doses of the extract, ranging from 2 to 32 microg/ml of culture medium, either alone or together with cisplatin.

RESULTS

There was a significant reduction in cisplatin-induced frequencies of sister chromatid exchanges, chromosome aberrations and micronucleated binucleate cells at the lower concentrations of 4 and 8 microg/ml (P<0.05). However, the extract by itself reduced the proliferative rate index, mitotic index and cytokinesis-block proliferative index (P<0.05). Further, a significant increase in the percentage of chromosome aberrations was noticed at the higher concentrations.

CONCLUSION

Hemidesmus indicus root extract possesses significant genoprotective effect at the lower concentrations although it is cytotoxic and probably genotoxic at higher doses.

Mutagenic and antimutagenic activities of aqueous and methanol extracts of Euphorbia hirta

Euphorbia hirta (E. hirta) is a weed commonly found in tropical countries and has been used traditionally for asthma, bronchitis and conjunctivitis. However, one of the constituents in this plant, quercetin, was previously reported to be mutagenic. This work aimed to determine the level of quercetin in the aqueous and methanol plant extracts and to investigate the mutagenic effects of quercetin and the extracts in the Ames test utilising the mutant Salmonella typhimurium TA98 and TA100 strains. The antimutagenic activity of Euphorbia hirta aqueous and methanol extracts was also studied in Salmonella typhimurium TA98. HPLC analyses showed that quercetin and rutin, a glycosidic form of quercetin, were present in the acid-hydrolysed methanol extract and non-hydrolysed methanol extract respectively. The quercetin concentration was negligible in both non-hydrolysed and acid-hydrolysed aqueous extracts. The total phenolic contents in Euphorbia hirta were determined to be 268 and 93 mg gallic acid equivalent (GAE) per gram of aqueous and methanol extracts, respectively. Quercetin (25 microg/mL) was found to be strongly mutagenic in Salmonella typhimurium TA98 in the absence and presence of S-9 metabolic activation. However, both the aqueous and methanol extracts did not demonstrate any mutagenic properties when tested with Salmonella typhimurium TA98 and TA100 strains at concentrations up to 100 microg/mL in the absence and presence of S-9 metabolic activation. In the absence of S-9 metabolic activation, both the extracts were unable to inhibit the mutagenicity of the known mutagen, 2-nitrofluorene, in Salmonella typhimurium TA98. On the other hand, the aqueous extracts at 100 microg/mL and methanol extracts at 10 and 100 microg/mL exhibited strong antimutagenic activity against the mutagenicity of 2-aminoanthracene, a known mutagen, in the presence of S-9 metabolic activating enzymes. The results indicated that these extracts could modulate the xenobiotic metabolising enzymes in the liver at the higher concentrations.

Mutagenic and antimutagenic properties of extracts from South African traditional medicinal plants

AIM OF THE STUDY

The aim of this paper was to summarize the results of our investigations on the in vitro genotoxic as well as antigenotoxic effects of a great number of selected South African traditional medicinal plants.

MATERIALS AND METHODS

Investigations of methanol and dichloromethane extracts of selected plants were conducted with the bacterial Ames, Umu-C and VITOTOX tests, and with the cytochalasin B micronucleus test and alkaline comet assay in human white blood cells.

RESULTS

A number of extracts were found to have genotoxic properties. Amongst the genotoxic plant extracts, especially methanol extracts of Helichrysum simillimum DC. (Asteraceae) should be highlighted. On the other hand, some plant extracts also showed antimutagenic potential. Here Bauhinia galpinii N.E.Br. (Fabaceae) and especially Chlerodendrum myricoides (Hochst.) Vatke (=Rotheca myricoides (Hochst.) Steane & Mabb.; Lamiaceae) appear to have antimutagenic properties.

CONCLUSION

The safe use of Helichrysum similimum should be questioned and further investigations on its mutagenicity and overall biological properties should be encouraged. Antimutagenic properties of especially Bauhinia galpinii and Rotheca myricoides are considered of particular interest as it may be assumed that these antimutagenic natural substances are able to lower the cancer risk from everyday exposures to environmental mutagens as well as to mutagenic pharmaceuticals.

Assessment of antimutagenic and genotoxic potential of senna (Cassia angustifolia Vahl.) aqueous extract using in vitro assays

Senna (Cassia angustifolia Vahl.) is widely used as a laxative, although potential side effects, such as toxicity and genotoxicity, have been reported. This study evaluated genotoxic and mutagenic effects of senna aqueous extract (SAE) by means of four experimental assays: inactivation of Escherichia coli cultures; bacterial growth inhibition; reverse mutation test (Mutoxitest) and DNA strand break analysis in plasmid DNA. Our results demonstrated that SAE produces single and double strand breaks in plasmid DNA in a cell free system. On the other hand, SAE was not cytotoxic or mutagenic to Escherichia coli strains tested. In effect, SAE was able to avoid H(2)O(2)-induced mutagenesis and toxicity in Escherichia coli IC203 (uvrA oxyR) and IC205 (uvrA mutM) strains, pointing to a new antioxidant/antimutagenic action of SAE.

Antimutagenic potential of the Thai herb, Mucuna collettii Lace

Mucuna collettii Lace is a Thai herb with a long record of consumption among mature Thai males for the promotion of sexual potency. The mutagenic and antimutagenic potentials of Mucuna collettii extract were carried out by using the Ames test pre-incubation method in the presence and absence of S9 mixture. Salmonella typhimurium strains TA 98 and TA 100 were applied as the tester strains. Prior to mutagenic and antimutagenic tests, the survival of the tester strains was performed by treating with the plant extract. Results showed Mucuna collettii extract exhibited strong cytotoxic effects in a dose-dependent manner. Toxicity of the plant was confirmed in mice in which negative adverse effect was found in kidney, uterus, ovary, and testis. Mucuna collettii extract in the presence and absence of S9 mixture was negative for mutagenic Ames test. Mucuna collettii extract in the presence and absence of S9 mixture was positive for antimutagenic Ames test towards either one or both of the tested mutagens: 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) and benzo(a)pyrene. The antimutagenic activity of the plant extract was confirmed in rec-assays. Micronucleus test demonstrated that Mucuna collettii extract at high dose and a long incubation time could induce micronucleus formation in tested animals, but less than the response of the positive control. The overall mutagenic and antimutagenic assays are further evidences for the antimutagenic potential of Mucuna collettii.

Effects of aqueous extracts of medicinal plants on MNNG-treated rat hepatocytes in primary cultures

Aqueous extracts of Nigella sativa (Ranunculaceae) (Ns), Teucrium polium (Labiatae) (Tp) and Trigonella foenum-graecum (Fabaceae) (Tf) have been traditionally used to treat inflammations, liver disorders, and arthritis. Experimentally, it has been demonstrated that these herbs possess antioxidant, anti-inflammatory and hepatoprotective properties. To evaluate their in vitro toxicological properties and potential antimutagenic effects aqueous extracts of the three plants were tested in primary rat hepatocyte cultures against N-methyl-N'-nitro-N-nitrosoguanidine. The extracts were applied before, during and after application of MNNG to discriminate between different mechanisms of action. Tp itself significantly increased apoptosis, but in the combined treatment with MNNG significantly reduced it. Post-treatment with Ns or combined treatment with Tf significantly reduced the percentages of necrotic cells. The three plant extracts themselves significantly increased the frequency of chromosomal aberrations. Summarizing, our results suggest that aqueous extracts of the three herbs have neither cytoprotective nor antimutagenic activity, instead there is evidence for a mutagenic potential.

Cobaltous chloride and hypoxia inhibit aryl hydrocarbon receptor-mediated responses in breast cancer cells

The aryl hydrocarbon receptor (AhR) is expressed in estrogen receptor (ER)-positive ZR-75 breast cancer cells. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces CYP1A1 protein and mRNA levels and also activates inhibitory AhR-ERalpha crosstalk associated with hormone-induced reporter gene expression. In ZR-75 cells grown under hypoxia, induction of these AhR-mediated responses by TCDD was significantly inhibited. This was not accompanied by decreased nuclear AhR levels or decreased interaction of the AhR complex with the CYP1A1 gene promoter as determined in a chromatin immunoprecipitation assay. Hypoxia-induced loss of Ah-responsiveness was not associated with induction of hypoxia-inducible factor-1alpha or other factors that sequester the AhR nuclear translocation (Arnt) protein, and overexpression of Arnt under hypoxia did not restore Ah-responsiveness. The p65 subunit of NFkappaB which inhibits AhR-mediated transactivation was not induced by hypoxia and was primarily cytosolic in ZR-75 cells grown under hypoxic and normoxic conditions. In ZR-75 cells maintained under hypoxic conditions for 24 h, BRCA1 (an enhancer of AhR-mediated transactivation in breast cancer cells) was significantly decreased and this contributed to loss of Ah-responsiveness. In cells grown under hypoxia for 6 h, BRCA1 was not decreased, but induction of CYP1A1 by TCDD was significantly decreased. Cotreatment of ZR-75 cells with TCDD plus the protein synthesis inhibitor cycloheximide for 6 h enhanced CYP1A1 expression in cells grown under hypoxia and normoxia. These results suggest that hypoxia rapidly induces protein(s) that inhibit Ah-responsiveness and these may be similar to constitutively expressed inhibitors of Ah-responsiveness (under normoxia) that are also inhibited by cycloheximide.

Vanillin as a modulator agent in SMART test: Inhibition in the steps that precede N-methyl-N-nitrosourea-, N-ethyl-N-nitrosourea-, ethylmethanesulphonate- and bleomycin-genotoxicity

Vanillin (VA), the world's major flavoring compound used in food industry and confectionery products - that has antimutagenic and anticarcinogenic activity against a variety of mutagenic/carcinogenic agents - was tested for the interval between the formation of premutational lesion and it is finalization as a DNA lesion. The overall findings using co-treatment protocols in SMART test suggest that VA can lead to a significant protection against the general genotoxicity of ethylmethanesulphonate (EMS), N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU) and bleomycin sulphate (BLEO). Considering MNU, ENU and EMS the desmutagenic activity observed could result from VA-stimulation of detoxification, via induction of glutathione S-transferase. However, the protector effect related to BLEO could be attributed to its powerful scavenger ability, which has the potential to prevent oxidative damage induced by BLEO.

Antioxidant activity, mutagenicity/anti-mutagenicity, and clastogenicity/anti-clastogenicity of lutein from marigold flowers

High dietary intake of lutein has been associated with risk reduction of many chronic diseases, including age-related macular degeneration (AMD), cancer, and cardiovascular diseases. Lutein in food is generally regarded as safe. However, information on the toxicological and beneficial effect of lutein at higher doses is limited. In this study, large amount of lutein was extracted and purified from marigold flower (Tagetes erecta L.). The antioxidant activity of lutein was examined by using the photochemiluminescence (PCL) assay and the beta-carotene-linoleic acid model system (beta-CLAMS). Lutein showed a greater antioxidant activity than the other two common carotenoids, beta-carotene and lycopene. The mutagenicity and anti-mutagenicity of lutein at 334, 668 and 1335 microg/plate were examined using the standard Ames test in the presence and absence of S9 mix. Lutein was not only found to be non-mutagenic at all doses, but it showed an anti-mutagenic effect in a dose-dependent manner. Similar results were found in a chromosome aberration test using Chinese hamster ovary cells for the evaluation of clastogenicity and anti-clastogenicity of lutein at 66.8, 133.5 and 267.0 mg/L. Our findings provided scientific evidence for the safe use and health beneficial effects of lutein.

Safety studies on epigallocatechin gallate (EGCG) preparations. Part 3: teratogenicity and reproductive toxicity studies in rats

Green tea and its principal active ingredient, epigallocatechin gallate (EGCG), have been demonstrated to have anticancer properties through interactions with multiple biochemical processes. Since these processes are often crucial in normal fetal development it is important to evaluate the potential effects of EGCG on the fetus. EGCG preparations of >91% purity were administered to pregnant rats during organogenesis and development in order to define the safety of Teavigo, a high-concentration EGCG extract produced by the same novel method. In an initial preliminary study using subcutaneous and gavage routes, there was no evidence of any direct embryo-fetal toxicity, although some maternal toxicity was seen. In the main teratogenicity study, feeding pregnant rats diets supplemented at 1400, 4200 or 14,000 ppm during organogenesis was non-toxic to dams or fetuses. A two-generation study in rats fed 1200, 3600 or 12,000 ppm EGCG preparation showed no adverse effects on reproduction or fertility. The highest dose reduced the growth rate of offspring, and there was a slight increase in pup loss. A growth effect among pups was also seen at 3600 ppm, but in the second generation only. The lowest dose was considered the overall no-observed adverse effect level (NOAEL). As dams consumed twice the amount of feed during the crucial lactation period, the NOAEL was equivalent to 200 mg/kg/day EGCG preparation.

Evaluation of the anti-genotoxicity of leaf extract of Ashwagandha

We have undertaken the studies to investigate the presence of various activities of the leaf extract of Ashwagandha (Lash), a commonly used shrub in Indian traditional medicine, Ayurveda. In the present study, we studied the effect of Lash against MNNG-induced genotoxicity in onion root tip cells. We report that Lash offered substantial protection against the mutagenic effects of MNNG.

In vitro antimutagenicity of capsaicin toward heterocyclic amines in Salmonella typhimurium strain TA98

Capsicum fruits are widely consumed as a component of the human diet. Capsaicin is the principle substance responsible for their hot, pungent taste. Heterocyclic amines (HCAs) are formed during cooking of meats and are mutagenic/carcinogenic compounds. In this study, we looked at whether capsaicin showed anti-mutagenic effects toward HCA-induced mutagenesis in Salmonella typhimurium TA98 when incubated with 0.5 mg liver S9 protein from rat, hamster and human. The HCAs used were Trp-P-2, Glu-P-1 and PhIP. Capsaicin, at non-toxic amounts of 0.25 and 0.5 micromole/plate, expressed a dose-dependent inhibition of the mutagenicity of Glu-P-1 and PhIP when they are metabolically activated by rat, hamster and human liver S9 and of Trp-P-2 when activated by rat and hamster liver S9. In contrast, capsaicin enhanced the mutagenicity of Trp-P-2 in TA98 when incubated with human liver S9. The lack of consistency in the anti-mutagenic action of capsaicin toward HCAs is puzzling and currently unresolved.

[Chemopreventive effect of resveratrol to cancer]

BACKGROUND & OBJECTIVE

Carcinogenesis is a complex process and at least 3 stages, including initiation, promotion, and progression, have been proposed in the process of carcinogenesis. Resveratrol has attracted considerable attention due to its low toxicity and unique chemical structure. This study was designed to test chemopreventive effect of resveratrol to cancer using various animal models.

METHODS

Ames assay and micronucleus formation assay were used to test the antimutagenic activities of resveratrol. Croton oil-induced enhancement of ornithine decarboxylase (ODC) activities of dorsal epidermis cells in mouse and mouse ear edema model were used to investigate the anti-promotion effect of resveratrol. In addition,7,12-dimenthylbenz[a]anthracene (DMBA)/croton oil-induced mouse skin tumor model was used to evaluate chemopreventive effect of resveratrol to cancer in vivo.

RESULTS

In Ames test,100 microg/plate of resveratrol exhibited 42.2% of inhibition on the reversion of Salmonella typhimurium TA100 induced by methylmethansulfonate, and 200 microg/plate of resveratrol exhibited 91.8% of inhibition on the reversion induced by benzopyrene. Pretreatment of resveratrol prevented cyclophosphamide (CTX)-induced micronucleus formation of polychromatic erythrocytes of mice bone marrow in dose-dependent manner. Mice treated with 30 mg/kg of resveratrol for 6 days before croton oil exposure have palliative ear edema. Treatment of 180 mg/kg resveratrol for 3 days caused 69.3% decrease of ODC activities in croton oil-induced dorsal epidermis. It was shown that resveratrol could inhibit DMBA/croton oil-induced mouse skin papilloma, which includes prolonging the latent period of tumor occurrence, decreasing the incidence of papilloma, and reducing tumor number per mouse in dose-dependent manner.

CONCLUSION

Resveratrol has the ability of anti-mutation and anti-promotion of cancer and merit further studies as a potential cancer chemopreventive agent.

Antigenotoxic effects of water extract from Korean fermented soybean paste (doen-jang)

Aflatoxin B1 is a major metabolite of the toxigenic molds Aspergillus flavus and Aspergillus parasiticus. In this study, a bacterial reverse mutation assay with Salmonella Typhimurium strains TA1535, TA1537, TA98, TA100, and TA102 and an in vitro chromosome aberration test with Chinese hamster lung (CHL) cells were used to investigate the genotoxicity of water extract from Korean soybean paste (doen-jang [dwen-jahng]) and its antigenotoxic activity against aflatoxin B1. The water extract itself did not exhibit cytotoxicity or mutagenicity. The extract significantly reduced the numbers of revertants when it was added to the assay system with Salmonella Typhimurium TA100 (P < 0.05). The extract also exhibited significant inhibitory effects on chromosome aberration in CHL cells (P < 0.05). Dose-response relationships were observed between the concentration of the water extract and both its antimutagenic effect and its suppression of chromosome aberration. The results of this work indicate that water extract from Korean soybean paste could have potential as an antigenotoxic substance.

Vanillins--a novel family of DNA-PK inhibitors

Non-homologous DNA end-joining (NHEJ) is a major pathway of double strand break (DSB) repair in human cells. Here we show that vanillin (3-methoxy-4-hydroxybenzaldehyde)--a naturally occurring food component and an acknowledged antimutagen, anticlastogen and anticarcinogen--is an inhibitor of NHEJ. Vanillin blocked DNA end-joining by human cell extracts by directly inhibiting the activity of DNA-PK, a crucial NHEJ component. Inhibition was selective and vanillin had no detectable effect on other steps of the NHEJ process, on an unrelated protein kinase or on DNA mismatch repair by cell extracts. Subtoxic concentrations of vanillin did not affect the ATM/ATR-dependent phosphorylation of Chk2 or the S-phase checkpoint response after ionising radiation. They significantly potentiated the cytotoxicity of cisplatin, but did not affect sensitivity to UVC. A limited screen of structurally related compounds identified two substituted vanillin derivatives that were 100- and 50-fold more potent than vanillin as DNA-PK inhibitors. These compounds also sensitised cells to cisplatin. The inhibition of NHEJ is consistent with the antimutagenic and other biological properties of vanillin, possibly altering the balance between DSB repair by NHEJ and homologous recombination.

Use of in vitro assays to assess the potential antigenotoxic and cytotoxic effects of saffron (Crocus sativus L.)

Saffron is harvested from the dried, dark red stigmas of Crocus sativus L. flowers. It is used as a spice for flavoring and coloring food and as a perfume. It is often used for treating several diseases. We assessed the antimutagenic, comutagenic and cytotoxic effects of saffron and its main ingredients using the Ames/Salmonella test system, two well known mutagens (BP, 2AA), the in vitro colony formation assay and four different cultured human normal (CCD-18Lu) and malignant (HeLa, A-204 and HepG2) cells. When only using the TA98 strain in the Ames/Salmonella test system, saffron showed non-mutagenic, as well as non-antimutagenic activity against BP-induced mutagenicity, and demonstrated a dose-dependent co-mutagenic effect on 2-AA-induced mutagenicity. The saffron component responsible for this unusual comutagenic effect was safranal. In the in vitro colony formation test system, saffron displayed a dose-dependent inhibitory effect only against human malignant cells. All isolated carotenoid ingredients of saffron demonstrated cytotoxic activity against in vitro tumor cells. Saffron crocin derivatives possessed a stronger inhibitory effect on tumor cell colony formation. Overall, these results suggest that saffron itself, as well as its carotenoid components might be used as potential cancer chemopreventive agents.

Antimutagenicity of supercritical CO2 extracts of Terminalia catappa leaves and cytotoxicity of the extracts to human hepatoma cells

Natural antimutagens may prevent cancer and are therefore of great interest to oncologists and the public at large. Phytochemicals are potent antimutagen candidates. When the Ames test was applied to examine the antimutagenic potency of supercritical carbon dioxide (SC-CO(2)) extracts of Terminalia catappa leaves at a dose of 0.5 mg/plate, toxicity and mutagenicity were not detected. The antimutagenic activity of SC-CO(2) extracts increased with decreases of temperature (60, 50, and 40 degrees C) and pressure (4000, 3000, and 2000 psi) used for extraction. The most potent antimutagenicity was observed in extracts obtained at 40 degrees C and 2000 psi. At a dose of 0.5 mg of extract/plate, approximately 80% of the mutagenicity of benzo[a]pyrene (B[a]P, with S-9) and 46% of the mutagenicity of N-methyl-N '-nitroguanidine (MNNG, without S-9) were inhibited. Media supplemented with SC-CO(2) extracts at a range of 0-500 microg/mL were used to cultivate human hepatoma (Huh 7) and normal liver (Chang liver) cells. The viability of the cells was assayed by measuring cellular acid phosphatase activity. A dose-dependent growth inhibition of both types of cells was observed. The SC-CO(2) extracts were more cytotoxic to Huh 7 cells than to Chang liver cells. The observation that SC-CO(2) extracts of T. catappa leaves did not induce mutagenicity at the doses tested while exhibiting potent antimutagenicity and were more cytotoxic to human hepatoma cells than to normal liver cells is of merit and warrants further investigation.

Effects of chlorophyllin on mouse embryonic and fetal development in vivo

Chlorophyllin (CHL) has proven that there is antimutagenic and anticarcinogenic activity in several organisms without causing lethal effects. However, there is no information about its effects when it is administered in gestation. In the present study, we assessed possible effects of CHL when it was administered to CD-1 mice on the 8th day of gestation using the same doses and administration route used in ours previous antimutagenic and antigenotoxic studies. Females were exposed to a single dose of CHL by i.p. injection (20, 40, 50, or 100mg/kg b.w.). On day 18 all dams were subjected to cesarean section and the fetuses were examined with common teratological methods. Results show that CHL-treatment induced total litter loss and is dose-dependent, probably due to either the interaction between CHL and some general control mechanisms of embryo development or by an impairment of maternal-fetal interactions. The analysis of uterine horns of the CHL-treated females with total litter loss revealed the presence of green rings in the uterus. Results show the inverse relationship between the number of live implants and the frequency of green rings, indicating implantation sites where embryo death and early resorptions occurred. Although CHL was given in a single dose on day 8 in this study, the results indicate that CHL is associated with significant embryo lethality.

The effects of methyl methacrylate on nasal cavity, lung, and antioxidant system (an experimental inhalation study)

Methyl methacrylate (MMA) is a monomer, commonly used in neurosurgery, orthopedic surgery, and in dental clinics. The adverse effects of this monomer are well described in the literature. This study was designed to evaluate the effects of MMA on nasal cavity, lung, and antioxidant status. For this purpose, two experimental groups of rats were exposed to MMA (at 1,000 ppm, 6 h/day, 5 days/week for 4 weeks) by inhalation under poor (group A, n = 12) and normal ventilation (group B, n = 11) conditions. A control group (group C, n = 10) received normal air. Degeneration of olfactory epithelium, bronchopneumonia, interstitial pneumonia, hemorrhage, atelectasis, edema, emphysema, and bronchial epithelial hyperplasia were observed in groups A and B. Emphysema was the most common lesion. Bronchopneumonia with abscesses was only observed in group A. Glutathione levels were significantly decreased and malondialdehyde levels were significantly increased in group A. No significant difference was observed in superoxide dismutase levels between the groups. The data presented indicate that before using MMA, adequate protection systems should be in place to prevent occupationally related MMA respiratory-tract injuries.

Partial chemical/structural elucidation of anti-mutagenic compounds from corn

In this study, corn fractions obtained from an isolation process of anti-mutagenic factors in our previous research work (Burgos-Hernández et al., 2001), were subjected to several analyses for chemical/structural elucidation. The anti-mutagenic activity of these fractions was tested against aflatoxin B(1) (AFB(1)) and 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), a mutagen that does not require bioactivation. Two concentrations of this agent in the corn fractions were tested for anti-mutagenicity in the Salmonella/microsomal mutagenicity assay, using tester strain TA100 with no metabolic activation. Corn fractions tested showed evidence of anti-mutagenic activity by producing a dose-response type of relationship between a constant amount of MNNG and several concentrations of tested corn fraction. Five different varieties of yellow corn were tested in order to determine if the anti-mutagenic factors were intrinsic to corn. Variety of the corn did not show an effect on the reduction of the mutagenic potential of AFB(1) suggesting that anti-mutagenic compounds are intrinsic to corn. Four corn fractions, previously obtained after the isolation process were analyzed by MALDI-MS and GC-MS. MALDI-MS showed the presence of two groups of molecules or molecular fragments. The molecular mass of one group ranged from 250 to 370 m/z, the other ranged from 540 to 640 m/z. GC-MS identified linoleic acid as one of the compounds responsible for the anti-mutagenic activity present in corn.

Antitumor, genotoxicity and anticlastogenic activities of polysaccharide from Curcuma zedoaria

The antitumor effect of the partially purified polysaccharide from Curcuma zedoaria was studied in mice transplanted with sarcoma 180 cells. The polysaccharide fraction, CZ-1-III, at dose of 6.25 mg/kg/d showed 50% inhibition in solid tumor growth. When mice were injected with fractions, CZ-1 and CZ-1-III, at the dose of 100.0 mg/kg, 91.6% and 97.1% of tumor growth were inhibited, respectively, indicating that the cytotoxic effect of polysaccharide on sarcoma 180 cells increases upon increasing the amount of polysaccharide administered. To assess the genotoxicity of CZ-1-III fraction, several classical toxicological tests were performed. In Ames test, CZ-1-III did not show any transformation of revertant with or without S-9 metabolic activating system, indicating the lack of mutagenic effect of the compound. To assess clastogenic effect, micronucleus and chromosomal aberration assays were performed using Chinese hamster lung (CHL) fibroblast cells. However, up to 259.0 microg/ml concentration of CZ-1-III, neither micronucleus formation nor chromosomal aberration was induced regardless of the presence of S-9 metabolic activating system. Inhibition of CZ-1-III on micronucleus formation induced by mitomycin C was exhibited in a dose-dependent manner, maximally up to 52.0%. These results strongly suggest that CZ-1-III, the polysaccharide fraction from C. Zedoaria, decreases tumor size of mouse and prevents chromosomal mutation.

Phyllanthus orbicularis aqueous extract: cytotoxic, genotoxic, and antimutagenic effects in the CHO cell line

The present work evaluates the cytotoxic, genotoxic, and antimutagenic effects of Phyllanthus orbicularis (plant of genus Phyllantus) aqueous extract in Chinese hamster ovary (CHO) cells. P. orbicularis aqueous extracts are used in Cuban traditional medicine for their antiviral activity against Hepatitis B virus and A and B flu virus. The cytotoxicity of the extract was tested by means of colony-forming ability and growth-inhibition assays as well as by measuring the mitotic index. Apoptosis induction and cell-cycle kinetics were analyzed by cytofluorimetric methods. Chromosome aberration assays were performed to study the genotoxic and antimutagenic activity of the extract. Results show that doses of up to 100 microg/ml of the extract did not induce any cytotoxic effects. Cell survival and mitotic index decreased significantly at doses higher than 100 microg/ml as a function of dose as well as of treatment time. Moreover, continuous treatments of up to 18 h induced the appearance of a significant number of apoptotic cells. Following a 3-h exposure to a dose of 750 microg/ml, cells accumulated significantly in G(2)-M phase and remained blocked in G(1-) and G(2)-M phases after several posttreatments in fresh growth medium. The aqueous extract alone did not induce chromosome aberrations but, in combined treatment with H(2)O(2), significantly reduced H(2)O(2)-induced chromosome aberrations. Flow cytometric analysis of DCFH intracellular oxidation showed that the extract decreased the oxidizing power of H(2)O(2.) This ability could possibly explain the extract's antigenotoxic activity. Absence of cytotoxicity at the lower tested doses and the antimutagenic properties of the extract stimulate the interest in studying possible new pharmaceutical uses of P. orbicularis.

Disposition, toxicity, and intestinal absorption of cobaltous chloride in male Fischer 344 rats

The absorption and disposition of inorganic cobalt salts after oral administration have not been well characterized. The objectives of this study were to compare in vivo results with cobalt transport through the in vitro everted small intestine and to relate the disposition results to a biochemical indicator of cobalt toxicity. Cobalt chloride was given to male Fischer 344 rats orally at 33.3 mg Co(II)/kg or intravenously at 4.16 mg Co(II)/kg. By 36 h, 74.5% of the oral dose was eliminated in the feces. The liver, kidney, and heart accumulated cobalt to the greatest extent. Following the single oral dose, the blood cobalt concentration-time curve was triphasic, peaked at 3.2 h, and had an absorptive half-life of 0.9 h, an elimination phase half-life of 3.9 h, and a terminal elimination half-life of 22.9 h. Following intravenous administration, 10.1% of the dose was excreted in the feces, indicating that cobalt can be secreted in the bile. Following a single intravenous injection, the concentration-time curve displayed three segments. The first segment, which occurred during the first 4 h, had a rapid half-life of 1.3 h. The second phase, from 4 to 12 h, demonstrated a slower clearance rate with a half-life of 4.3 h. The final and slowest phase, from 12 to 36 h, had a half-life of 19 h. Intestinal jejunal ring experiments indicated that cobalt transport has both active and passive components; however, cobalt transport through the in vitro rat everted duodenum indicated that cobalt transport had almost exclusively passive components with facilitated diffusion. The finding that uptake was saturable may explain the small extent of absorption following oral dosing. Heme oxygenase studies following subcutaneous and intravenous administration resulted in an increase in activity (twofold) over controls, while oral administration did not. We concluded that the extent of cobalt absorption across the gastrointestinal tract is incomplete, and that the concentration administered and the route of exposure may determine its systemic toxicity.

Cobaltous chloride-induced mutagenesis in the supF tRNA gene of Escherichia coli

The spectrum of mutations induced by cobalt(II) chloride (CoCl2) was examined using plasmid pUB3 DNA, which was propagated after transfection into Escherichia coli SY1032/pKY241 host cells. The vector plasmid carried an E.coli supF suppressor tRNA gene as a target for mutations. After CoCl2 treatment, 64 independent nalidixic acid-resistant, ampicillin-resistant and Lac+ (SupF-) clones were obtained and the altered sequences of the mutated supF genes were determined. Deletions and frameshifts were the predominant mutational event (61%) induced by CoCl2 and base substitutions were induced to a lesser degree (29%). Analysis of sequence alterations at all the sites of mutation revealed that: (i) 18 of 19 base substitutions and eight of 10 frameshifts occurred at G:C sites, suggesting that the formation of N7G-Co(II) adducts may be responsible for premutagenic lesions of these mutations; (ii) short sequence repeats were mostly found at the sites of deletions and frameshifts. Slippage-misalignment is also suggested to be a mechanism for the induction of mutations at these sites.

Antimutagenic effect of crown ethers on heavy metal-induced sister chromatid exchanges

Macrocyclic polyethers (crown ethers) are a family of compounds that possess the ability to complex with and transport metal ions across membranes. Because of their unique ionophoric characteristic, they have wide application in industry and research, chemistry and biology. In the current investigation the relationship between heavy metal mutagenesis and crown ether co-mutagenicity and/or antimutagenicity in mammalian cells has been examined using sister chromatid exchange (SCE) as the cytogenetic end point. Chinese hamster ovary cells were treated with lead or cadmium, with and without selected crown ethers. Several genotoxic end points, including SCEs were scored and statistically compared. We report here that most of the crown ethers studied had little or no influence on lead- or cadmium-induced SCEs or chromosome aberrations. On the other hand, the substituted crown ether dicyclohexyl 21-crown-7 significantly decreased both spontaneous and metal-induced SCE frequencies, suggesting that this crown ether may possess antimutagenic activity.

Hazard assessment of germanium supplements

Germanium-containing dietary supplements became popular in the 1970s in Japan and later in other countries, as elixirs for certain diseases (e.g., cancer and AIDS). Germanium is not an essential element. Its acute toxicity is low. However, at least 31 reported human cases linked prolonged intake of germanium products with renal failure and even death. Signs of kidney dysfunction, kidney tubular degeneration, and germanium accumulation were observed. Other adverse effects were anemia, muscle weakness, and peripheral neuropathy. Recovery of renal function is slow and incomplete even long after germanium intake was stopped. The total dose of ingested germanium (as dioxide, carboxyethyl germanium sesquioxide, germanium-lactate-citrate, or unspecified forms) varied from 15 to over 300 g; the exposure duration varied from 2 to 36 months. In laboratory animals, elevated germanium in tissues and impaired kidney and liver function were observed in a life-time drinking water (5 ppm germanium) study. Other toxicities associated with ingested germanium products in human cases were also demonstrated in animal studies with germanium dioxide and sometimes other germanium compounds. Based on the evidence of persistent renal toxicity associated with germanium dioxide, the lack of conclusive findings of differential nephrotoxicity of organic germanium compounds, and the possibility of contamination of the organic germanium products with inorganic germanium, it is clear that germanium products present a potential human health hazard.

A bioactive triterpene from Lantana camara

Lantana camara afforded a novel triterpene 22 beta-acetoxylantic acid and the known triterpenes, lantic acid, 22 beta-dimethylacryloyloxylantonolic acid, a mixture of 22 beta-dimethylacryloyloxy lantanolic acid and 22 beta-angeloyloxylantanolic acid and lantanolic acid. 22 beta-Acetoxylantic acid showed antimicrobial activity against Staphylococcus aureus and Salmonella typhi. This compound and 22 beta-dimethylacryloyloxy lantanolic acid also showed antimutagenic activity.

Antimutagenic effect of methanolic extracts from peanut hulls

The antimutagenic effects of methanolic extracts of peanut hulls (MEPH) were evaluated by the Ames test. MEPH inhibited the mutagenicity of 4-nitroquinoline-N-oxide (NQNO), a direct-acting mutagen. MEPH also inhibited the mutagenicity of some indirect-acting mutagens and decreased in the order of 2-amino-3-methyl-imidazo(4,5-f)quinoline (IQ) > aflatoxin B1 (AFB1) > 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole (Glu-P-1) > 3 amino-1,4-dimethyl-5H-pyridol(4,3-b)indole (Trp-P-1) > benzo(a)pyrene (B(a)P for S. typhimurium TA98, and IQ > Trp-P-1 > Glu-P-1 > AFB1 > B(a)P for S. typhimurium TA100.

All-trans beta-carotene enhances mitogenic responses and ornithine decarboxylase activity of BALB/c 3T3 fibroblast cells induced by tumor promoter and fetal bovine serum but suppresses mutagen-dependent umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002)

Although previous epidemiological studies have indicated that beta-carotene is an important agent for the chemical prevention against carcinogenesis, a recent prospective study has strikingly suggested that supplementation with beta-carotene significantly increased the incidence of some types of cancer (The alpha-Tocopherol and beta-Carotene Cancer Prevention Study Group, New Engl. J. Med., 330 (1994) 1031-1035). To analyze the discrepancy of this problem, the authors analyze the effects of beta-carotene on biochemical and biological events associated with carcinogenesis by in vitro experiments. (1) All-trans beta-carotene enhanced the proliferation and DNA synthesis of BALB/c 3T3 cells induced by a tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and fetal bovine serum, although beta-carotene itself did not show mitogenic activity. (2) All-trans beta-carotene caused a remarkable stimulation for the early induction of ornithine decarboxylase (ODC) activity after the stimulation of TPA and fetal bovine serum. (3) All-trans beta-carotene exhibited significant antimutagenic activity which suppresses umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002) induced by a typical mutagen, 2-aminoanthracene (2-AA). These experimental results suggest that all-trans beta-carotene might cause beneficial and harmful effects on different phases of carcinogenesis.

Mutagenicity and antimutagenicity testing of six chemicals associated with the pungent properties of specific spices as revealed by the Ames Salmonella/microsomal assay

Three compounds, capsaicin, thymol and borneol, were initially screened for mutagenic activity using Salmonella typhimurium strains TA97, TA98 and TA100, with and without S9 metabolic activation, and 20 min standard preincubation time. Three other compounds, allyl isothiocyanate, eugenol and cinnamaldehyde, were screened for mutagenic activity as above, but with a prolonged, nonstandard preincubation time of up to 120 minutes. All six test compounds used in the assays are associated with the pungent properties of some specific spices in which the test compounds can be found to exist naturally. The first objective of this study was to observe if mutagenic activity can be correlated to the pungent properties of these six test compounds. However, due to toxicity and the observation that only capsaicin was mutagenic, using strain TA100 in the presence of S9 metabolic activation, it was not possible to deduce any relationship between mutagenicity and the test chemicals' pungent properties. Naturally occurring capsaicin, found in the spice Capsicum annum, was detected and quantified using thin layer and gas chromatographic techniques. The final objective was to detect the presence of antimutagenic factor(s) in C. annum that would suppress the mutagenicity of capsaicin. When the mutagenic capsaicin and 2-aminoanthracene were assayed in the presence of C. annum acetone extract, using strain TA100 with S9 metabolic activation, the mutagenic response of both the mutagens were reduced by approximately 50%. Assaying capsaicin and 2-aminoanthracene in the presence of chlorophyll, the mutagenic response of the two mutagens was reduced by less than 40%. From this observation it was inferred that chlorophyll can successfully suppress the mutagenicity activities of capsaicin and 2-aminoanthracene, together with other antimutagenic factors that were present in the acetone extract of C. annum.

Study on the carcinogenicity of tannic acid in F344 rats

The carcinogenicity of tannic acid, a compound that is used as a food additive, a clarifying agent and a refining agent, was examined in F344 rats of both sexes. Tannic acid was dissolved in distilled water at concentrations of 0.25 and 0.5%. The doses were selected on the basis of results from a 13-wk subchronic study. Groups of 50 male and 50 female rats were given one of these solutions ad lib. as their drinking water for up to 2 yr. The mean body weights of the treated males were essentially comparable with those of the controls, whereas treated females had lower mean body weights than the control group. A variety of tumours developed in all groups, including the control group, but all the neoplasms were histologically similar to those known to occur spontaneously in this strain of rats, and no statistically significant increase in the incidence of any tumour was found in the treated groups of either sex. Thus, it is concluded that, under the conditions of the experiment, tannic acid has neither carcinogenic potential in F344 rats nor modifying effects on spontaneous tumour development.

Comparison of the toxicity of cinnamaldehyde when administered by microencapsulation in feed or by corn oil gavage

The toxicity of cinnamaldehyde (CNMA) was compared after administration by gavage and in dosed feed. Rats and mice of both sexes received CNMA by daily corn oil gavage (for 2 wk), or in microencapsulated form in feed (2 wk for rats, 3 wk for mice). Feed formulations contained 0-10% CNMA microcapsules, equivalent to approximate daily doses of 0-3000 mg CNMA/kg body weight for rats and 0-10,000 mg CNMA/kg body weight for mice. Concentrations were chosen to deliver CNMA doses approximately equal to doses in the gavage study. Gavage doses of 2620 mg/kg/day and above in mice and 940 mg/kg/day and above in rats produced nearly 100% mortality; there were no deaths in animals receiving microencapsulated CNMA. Rats and mice receiving CNMA in feed showed a dose-related decrease in body weight gain, which was accompanied in rats by hypoplastic changes in reproductive organs and accessory sex glands. CNMA administration by either route caused hyperplasia of the forestomach mucosa. These results demonstrate that microencapsulation in feed can present a useful alternative to gavage dosing for repeated-dose or prolonged-exposure studies, in that (1) the toxic effects of CNMA were similar after gavage dosing and after administration in microencapsulated form in feed, (2) ingestion of chemical in the feed more closely approximates human exposures, and (3) microencapsulation allows the delivery of higher net doses of chemical, while avoiding the acutely toxic effects of a bolus dose.

Studies on trans-cinnamaldehyde. 1. The influence of dose size and sex on its disposition in the rat and mouse

The metabolism of trans-[3-14C]cinnamaldehyde was investigated in male and female Fischer 344 rats and CD1 mice at doses of 2 and 250 mg/kg body weight given by ip injection and in males at 250 mg/kg by oral gavage. Some 94% of the administered dose was recovered in the excreta in 72 hr in both species with most (75-81%) present in the 0-24-hr urine. Less than 2% of the administered dose was found in the carcasses at 72 hr after dosing. Urinary metabolites were identified by their chromatographic characteristics. In both species the major urinary metabolite was hippuric acid accompanied by 3-hydroxy-3-phenylpropionic acid, benzoic acid and benzoyl glucuronide. The glycine conjugate of cinnamic acid was formed to a considerable extent only in the mouse. The oxidative metabolism of cinnamaldehyde essentially follows that of cinnamic acid, by beta-oxidation analogous to that of fatty acids. Apart from the metabolites common to cinnamic acid and cinnamaldehyde, 7% of 0-24-hr urinary 14C was accounted for by two new metabolites in the rat and three in the mouse, which have been shown in other work to arise from a second pathway of cinnamaldehyde metabolism involving conjugation with glutathione. The excretion pattern and metabolic profile of cinnamaldehyde in rats and mice are not systematically affected by sex, dose size and route of administration. The data are discussed in terms of their relevance to the safety evaluation of trans-cinnamaldehyde, particularly the validity or otherwise of extrapolation of toxicity data from high to low dose.

Protection against radiation-induced mutagenesis at the hprt locus by spermine and N,N"-(dithiodi-2,1-ethanediyl)bis-1,3-propanediamine (WR-33278)

The polyamine spermine and the disulfide N,N"-(dithiodi-2,1-ethanediyl)bis-1,3-propanediamine (WR-33278) are structurally similar agents capable of binding to DNA. WR-33278 is the disulfide moiety of the clinically studied radioprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). Because of their reported structural and functional similarities, it was of interest to compare their effects on cell survival and mutation induction at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in Chinese hamster AA8 cells. WR-33278 and spermine (at concentrations of 0.01 and 0.001 mM) were electroporated into cells. Electroporation, 300 V and 125 microF, was performed either 30 min prior to or 3 h following exposure of cells to 750 cGy of ionizing radiation. Electroporation alone reduced cell survival to 75% but had no effect on hprt mutation frequency. The electroporation of either spermine or WR-33278 at concentrations greater than 0.01 mM was extremely toxic. The exposure of cells to both electroporation and irradiation gave rise to enhanced cell killing and mutation induction, with the sequence of irradiation followed 3 h later by electroporation being the more toxic protocol. Cell survival was only enhanced following electroporation of 0.01 mM of spermine and WR-33278 30 min prior to irradiation. Protection against radiation-induced hprt mutations was observed for both spermine and WR-33278 under all experimental conditions tested. Spermine at exposure concentrations of 0.01 and 0.001 mM administered 30 min before or 3 h after irradiation reduced mutation frequencies by factors of 2.2, 1.2, 1.9 and 2.2, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)