Antimutagenic compounds and their possible mechanisms of action

K. Safety assessment of a standardized polyphenolic extract of clove buds: Subchronic toxicity and mutagenicity studies

Despite the various reports on the toxicity of clove oil and its major component eugenol, systematic evaluations on the safety of polyphenolic extracts of clove buds have not been reported. Considering the health beneficial pharmacological effects and recent use of clove polyphenols as dietary supplements, the present study investigated the safety of a standardized polyphenolic extract of clove buds (Clovinol), as assessed by oral acute (5 g/kg b.wt. for 14 days) and subchronic (0.25, 0.5 and 1 g/kg b.wt. for 90 days) toxicity studies on Wistar rats and mutagenicity studies employing Salmonella typhimurium strains. Administration of Clovinol did not result in any toxicologically significant changes in clinical/behavioural observations, ophthalmic examinations, body weights, organ weights, feed consumption, urinalysis, hematology and clinical biochemistry parameters when compared to the untreated control group of animals, indicating the no observed-adverse-effect level (NOAEL) as 1000 mg/kg b.wt./day; the highest dose tested. Terminal necropsy did not reveal any treatment-related histopathology changes. Clovinol did not show genotoxicity when tested on TA-98, TA-100 and TA-102 with or without metabolic activation; rather exhibited significant antimutagenic potential against the known mutagens, sodium azide, NPD and tobacco as well as against 2-acetamidoflourene, which needed metabolic activation for mutagenicity.

Comparing the functional components, SOD-like activities, antimutagenicity, and nutrient compositions of Phellinus igniarius and Phellinus linteus mushrooms

Many species of the genus Phellinus possess beneficial properties, including antioxidant, immune-enhancing, and antimutagenic effects. Phenolic compounds and polysaccharides are two kinds of bioactive compounds; however, few studies have compared the differences between Phellinus igniarius and Phellinus linteus in their functional components, functional activities, and nutrient compositions. Herein, the proximate compositions and microelements of the fruiting body of P. igniarius and P. linteus were determined. The fruiting body of P. igniarius and P. linteus were extracted by boiling water [water extract of P. igniarius (WEPI) and P. linteus (WEPL)]. The contents of total phenolics and polysaccharides, as well as superoxide dismutase (SOD)-like and antimutagenic activities of WEPI and WEPL, were compared. We found that WEPI was rich in phenolics and polysaccharides and had higher SOD-like activity than WEPL. Nutrient compositions were mainly different in minerals, whereas anitmutagenicity was similar. All of these results suggested that P. igniarius has greater potential for the development of antioxidant and immunomodulating food products than P. linteus.

Antimutagenic Compounds of White Shrimp (Litopenaeus vannamei): Isolation and Structural Elucidation

According to the World Health Organization, cancer is the main cause of mortality worldwide; thus, the search of chemopreventive compounds to prevent the disease has become a priority. White shrimp (Litopenaeus vannamei) has been reported as a source of compounds with chemopreventive activities. In this study, shrimp lipids were extracted and then fractionated in order to isolate those compounds responsible for the antimutagenic activity. The antimutagenic activity was assessed by the inhibition of the mutagenic effect of aflatoxin B1 on TA98 and TA100 Salmonella tester strains using the Ames test. Methanolic fraction was responsible for the highest antimutagenic activity (95.6 and 95.9% for TA98 and TA100, resp.) and was further separated into fifteen different subfractions (M1-M15). Fraction M8 exerted the highest inhibition of AFB1 mutation (96.5 and 101.6% for TA98 and TA100, resp.) and, after further fractionation, four subfractions M8a, M8b, M8c, and M8d were obtained. Data from (1)H and (13)C NMR, and mass spectrometry analysis of fraction M8a (the one with the highest antimutagenic activity), suggest that the compound responsible for its antimutagenicity is an apocarotenoid.

Antimutagenicity and induction of antioxidant defense by flavonoid rich extract of Myrcia bella Cambess. in normal and tumor gastric cells

ETHNOPHARMACOLOGICAL RELEVANCE

The Brazilian "Cerrado" is an important source of natural products, such as Myrcia bella Cambess (MB, also known as "mercurinho"). MB leaves are popularly used for the treatment of diabetes and gastrointestinal disorders; however, only its hypoglycemic activity has been experimentally described.

AIM OF THE STUDY

Because MB is used to treat gastrointestinal disorders, the present study characterized biological activities of hydroalcoholic MB extract in human normal and tumor gastric cells.

MATERIALS AND METHODS

Cytotoxic, antiproliferative, genotoxic and protective effects were evaluated, as well as the effects of the MB extract on gene expression.

RESULTS

The MB extract induced cytotoxicity in tumor cells at lower concentrations compared with normal cells as assessed by the MTT assay. Moreover, the MB extract induced necrosis based on acridine orange/ethidium bromide staining. An antiproliferative effect was evidenced through an arrest in the G2/M phase detected by flow cytometry and a decrease in the nuclear division index using the cytokinesis-block micronucleus cytome assay. Cells treated with MB extract combined with doxorubicin (DXR) showed increased NUBDs, which may be related to the gene amplification of CCND1. Antimutagenic effects were also observed and may be associated with the antioxidant activities detected using the CM-H2DCFDA probe.

CONCLUSIONS

Our findings showed the following: (a) high concentrations of MB induced cytotoxicity and cell death by necrosis; (b) its antiproliferative effect was associated with G2/M arrest; and (c) its antioxidant activity could be responsible for the observed antimutagenic effects and for protective effects against gastrointestinal disorders previously described to MB. Although these effects are not specific to normal or tumor cells, they provide a panel of biological activities for further exploration.

Diaryl sulfide analogs of combretastatin A-4: Toxicogenetic, immunomodulatory and apoptotic evaluations and prospects for use as a new chemotherapeutic drug

Combretastatin A-4 exhibits efficient anti-cancer potential in human tumors, including multidrug-resistant tumors. We evaluated the mutagenic, apoptotic and immunomodulatory potential of two diaryl sulfide analogs of combretastatin A-4, 1,2,3-trimethoxy-5-([4-methoxy-3-nitrophenyl]thio)benzene (analog 1) and 1,2,3-trimethoxy-5-([3-amino-4-methoxyphenyl]thio)benzene (analog 2), as well as their association with the anti-tumor agent cyclophosphamide, in Swiss mice. Such evaluation was achieved using the comet assay, peripheral blood micronucleus test, splenic phagocytosis assay, and apoptosis assay. Both analogs were found to be genotoxic, mutagenic and to induce apoptosis. They also increased splenic phagocytosis, although this increase was more pronounced for analog 2. When combined with cyclophosphamide, analog 1 enhanced the mutagenic and apoptotic effects of this anti-tumor agent. In contrast, analog 2 did not enhance the effects of cyclophosphamide and prevented apoptosis at lower doses. These data suggest that analog 1 could be an adjuvant chemotherapeutic agent and possibly improve the anti-neoplastic effect of cyclophosphamide. Additionally, this compound could be a candidate chemotherapeutic agent and/or an adjuvant for use in combined anti-cancer therapy.

Preliminary mutagenicity and genotoxicity evaluation of selected arylsulfonamide derivatives of (aryloxy)alkylamines with potential psychotropic properties

Determination of the mutagenic and genotoxic liability of biologically active compounds is of great concern for preliminary toxicity testing and drug development. In this study, we focused on the evaluation of the mutagenic and genotoxic effects of selected arylsulfonamide derivatives of aryloxyethyl piperidines and pyrrolidines (1-8), classified as 5-HT7 receptor antagonist with antidepressant and procognitive properties, using in silico and in vitro methods: the Vibrio harveyi assay and the SOS/umu-test (umuC Easy CS test). Finally, the antimutagenic potential of tested compounds was evaluated with the V. harveyi assay. It was demonstrated that none of the examined compounds produced a positive response in in vitro assays and these results were in line with in silico prediction. Additionally, all the tested compounds demonstrated various antimutagenic potential, with compound 1 (5-chloro-N-((1-(2-phenoxyethyl)piperidin-4-yl)methyl)thiophene-2-sulfonamide) being the most active against NQNO-induced mutagenicity.

Genotoxicity and Antigenotoxicity Studies of Traditional Medicinal Plants: How Informative and Accurate are the Results?

Genotoxicity and antigenotoxicity studies of (traditional medicinal) plants are important from a risk assessment point of view and in the search for new medication against, for example, cancer. It is clear yet that attention should be paid to a number of aspects that may influence the outcome of a study and to which often no or insufficient attention is paid. A short overview is given of such aspects that deserve more attention.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation and fate: an example of the coordinate contribution of lipid oxidation and Maillard reaction to the production and elimination of processing-related food toxicants

Major chemical reactions dealing with carbonyl chemistry in foods (Maillard reaction and lipid oxidation) play a role in PhIP formation and fate, pointing to this and analogous heterocyclic aromatic amines as outcomes of this chemistry.