Antimutagenic effects of garlic extract on chromosomal aberrations

FEMA GRAS assessment of natural flavor complexes: Asafetida oil, garlic oil and onion oil

The Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) applies its procedure for the safety evaluation of natural flavor complexes (NFCs) to re-evaluate the safety of Asafetida Oil (Ferula assa-foetida L.) FEMA 2108, Garlic Oil (Allium sativum L.) FEMA 2503 and Onion Oil (Allium cepa L.) FEMA 2817 for use as flavoring in food. This safety evaluation is part of a series of evaluations of NFCs for use as flavoring ingredients conducted by the Expert Panel that applies a scientific procedure published in 2005 and updated in 2018. Using a group approach that relies on a complete chemical characterization of the NFC intended for commerce, the constituents of each NFC are organized into well-defined congeneric groups and the estimated intake of each constituent congeneric group is evaluated using the conservative threshold of toxicological concern (TTC) concept. Data on the metabolism, genotoxic potential and toxicology for each constituent congeneric group are reviewed as well as studies on each NFC. Based on the safety evaluation, Asafetida Oil (Ferula assa-foetida L.), Garlic Oil (Allium sativum L.) and Onion Oil (Allium cepa L.) were affirmed as generally recognized as safe (GRASa) under their conditions of intended use as flavor ingredients.

Radioprotective Potential of Nutraceuticals and their Underlying Mechanism of Action

Radiations are an efficient treatment modality in cancer therapy. Besides the treatment effects of radiations, the ionizing radiations interact with biological systems and generate reactive oxygen species that interfere with the normal cellular process. Previous investigations of synthetic radioprotectors have shown less effectiveness, mainly owing to some limiting effects. The nutraceuticals act as efficient radioprotectors to protect the tissues from the deleterious effects of radiation. The main radioprotection mechanism of nutraceuticals is the scavenging of free radicals while other strategies are involved modulation of signaling transduction of pathways like MAPK (JNK, ERK1/2, ERK5, and P38), NF-kB, cytokines, and their protein regulatory genes expression. The current review is focused on the radioprotective effects of nutraceuticals including vitamin E, -C, organosulphur compounds, phenylpropanoids, and polysaccharides. These natural entities protect against radiation-induced DNA damage. The review mainly entails the antioxidant perspective and mechanism of action of their radioprotective activities on a molecular level, DNA repair pathway, anti-inflammation, immunomodulatory effects, the effect on cellular signaling pathways, and regeneration of hematopoietic cells.

Types of garlic and their anticancer and antioxidant activity: a review of the epidemiologic and experimental evidence

Garlic, an Allium vegetable, contains rich flavonoids organosulfur compounds (OSCs) that have potent anticancer properties. The aim of the review is to provide an overview of the different types of garlic, their active compounds, and the potential anticancer benefits with a focus on antioxidant activity. Animal and cell line studies have provided convincing evidence that garlic and its organosulfur compounds inhibit carcinogenesis through a number of events including induction of apoptosis, inhibiting cellular proliferation, scavenging radical oxygen species (ROS), increasing the activities of enzymes such as glutathione S-transferase, and reducing tumor size. Epidemiological studies showed compelling evidence that garlic consumption is associated with decreased risk of colorectal cancer, but inconsistent evidence for stomach, breast, and prostate cancers. Studies also suggest that the presence and potency of garlic OSCs varies with respect to the preparation and form of garlic. Further epidemiological studies with information on garlic form consumed or preparation methods and molecular studies regarding its antioxidant mechanisms, such as increasing enzymatic and nonenzymatic antioxidants levels, are warranted.

Garlic (Allium sativum L.): A Brief Review of Its Antigenotoxic Effects

Traditional Medicine/Complementary and Alternative Medicine is a practice that incorporates medicine based on plants, animals, and minerals for diagnosing, treating, and preventing certain diseases, including chronic degenerative diseases such as obesity, diabetes, hypertension, atherosclerosis, and cancer. Different factors generate its continued acceptance, highlighting its diversity, easy access, low cost, and the presence of relatively few adverse effects and, importantly, a high possibility of discovering antigenotoxic agents. In this regard, it is known that the use of different antigenotoxic agents is an efficient alternative to preventing human cancer and that, in general, these can act by means of a combination of various mechanisms of action and against one or various mutagens and/or carcinogens. Therefore, it is relevant to confirm its usefulness, efficacy, and its spectrum of action through different assays. With this in mind, the present manuscript has as its objective the compilation of different investigations carried out with garlic that have demonstrated its genoprotective capacity, and that have been evaluated by means of five of the most outstanding tests (Ames test, sister chromatid exchange, chromosomal aberrations, micronucleus, and comet assay). Thus, we intend to provide information and bibliographic support to investigators in order for them to broaden their studies on the antigenotoxic spectrum of action of this perennial plant.

Radioprotective Activity of Naturally Occurring Organosulfur Compounds

The radioprotective effects of naturally occurring sulfur compounds and isothiocyanates such as diallyl sulfide (DAS), diallyl disulfide (DADS), allyl methyl sulfide (AMS), allyl isothiocyanate (AITC) and phenyl isothiocyanate (PITC) have been investigated in whole body irradiated Swiss albino mice. Administration of these sulfur compounds could reduce the serum content of alkaline phosphatase (ALP), which was elevated after irradiation (23.9 ± 1.82 KA units). The elevated liver content of glutamate pyruvate transaminase (GPT) in control animals (76.2 ± 2.2 U/mL) after irradiation was significantly reduced in DAS (58.93 ± 4 U/mL) and AMS (55.7 ± 2.2 U/mL) treated animals. Elevated levels of lipid peroxides in serum and liver of irradiated control animals were also significantly reduced by treatment with these sulfur compounds. The glutathione (GSH) content in liver and intestinal mucosa was drastically reduced after irradiation. All the sulfur compounds and isothiocyanates could effectively enhance the GSH content of intestinal mucosa and liver. Findings at histopathological analysis of the intestine proved to be correlated with the above results.

Nutraceutic Potential of Two Allium Species and Their Distinctive Organosulfur Compounds: A Multi-Assay Evaluation

This study aimed to evaluate the biological activities of two Allium species (garlic and onion) as well as diallyl disulphide (DADS) and dipropyl disulphide (DPDS) as their representative bioactive compounds in a multi-assay experimental design. The genotoxic, antigenotoxic, and lifespan effects of garlic, onion, DADS, and DPDS were checked in Drosophila melanogaster and their cytotoxic, pro-apoptotic, and DNA-clastogenic activities were analyzed using HL60 tumoral cells. All compounds were non-genotoxic and antigenotoxic against H₂O₂-induced DNA damage with a positive dose-response effect and different inhibition percentages (the highest value: 95% for DADS) at all tested concentrations. Daily intake of Allium vegetables, DADS, or DPDS had no positive effects on flies' lifespan and health span. Garlic and DADS exerted the highest cytotoxic effects in a positive dose-dependent manner. Garlic and DADS exerted a DNA-internucleosomal fragmentation as an index of induced proapoptotic activity on HL60 cells. Allium vegetables and DADS were able to induce clastogenic strand breaks in the DNA of HL60 cells. This study showed the genomic safety of the assayed substances and their protective genetic effects against the hydrogen peroxide genotoxine. Long-term treatments during the whole life of the Drosophila genetic model were beneficial only at low-median concentrations. The chemo-preventive activity of garlic could be associated with its distinctive organosulfur DADS. We suggest that supplementary studies are needed to clarify the cell death pathway against garlic and DADS.

Physicochemical Characterization and Biological Activities of Black and White Garlic: In Vivo and In Vitro Assays

White and three types of black garlic (13, 32, and 45 days of aging, named 0C1, 1C2, and 2C1, respectively) were selected to study possible differences in their nutraceutic potential. For this purpose, garlic were physicochemically characterized (Brix, pH, aW, L, polyphenol, and antioxidant capacity), and both in vivo and in vitro assays were carried out. Black garlic samples showed higher polyphenol content and antioxidant capacity than the white ones. The biological assays showed that none of the samples (neither raw nor black garlic) produced toxic effects in the Drosophila melanogaster animal genetic model, nor exerted protective effects against H₂O₂, with the exception of the 0C1 black garlic. Moreover, only white garlic was genotoxic at the highest concentration. On the other hand, 0C1 black garlic was the most antigenotoxic substance. The in vivo longevity assays showed significant extension of lifespan at some concentrations of white and 0C1and 1C2 black garlic. The in vitro experiments showed that all of the garlic samples induced a decrease in leukemia cell growth. However, no type of garlic was able to induce proapoptotic internucleosomal DNA fragmentation. Taking into account the physicochemical and biological data, black garlic could be considered a potential functional food and used in the preventive treatment of age-related diseases. In addition, our findings could be relevant for black-garlic-processing agrifood companies, as the economical and timing costs can significantly be shortened from 45 to 13 days of aging.

Protective Effects of Fullerene C60 Nanoparticles and Virgin Olive Oil against Genotoxicity Induced by Cyclophosphamide in Rats

The potential effects of the fullerene C₆₀ nanoparticle (C₆₀) as well as virgin olive oil (VOO) against the cyclophosphamide- (CP-) induced cytotoxic and mutagenic effects were evaluated by two main methods: molecular intersimple sequence repeat (ISSR) assay and cytogenetic biomarkers. Thirty adult male rats were divided to five groups (control, CP, C₆₀, CP + C₆₀, and CP + VOO). CP was i.p. injected with a single dose of 200 mg/kg; C₆₀ and VOO were given orally (4 mg/kg dissolved in VOO and 1 ml, resp.) in alternative days for 20 days. The ISSR analysis revealed an increased in the DNA fragmentation level for liver and heart tissues represented by 21.2% and 32.6%, respectively, in the CP group. The DNA polymorphism levels were modulated and improved in CP + C₆₀ (8.9% and 12%) and CP + VOO (9.8% and 12.7%) for hepatic and cardiac tissues, respectively. The bone marrow cytogenetic analysis revealed that C₆₀ and VOO had significantly decreased the frequency of CP-induced chromosomal aberrations (chromosomal ring, deletion, dicentric chromosome, fragmentation, and polyploidy). Fullerene C₆₀ and VOO have ability to reduce DNA damage and decrease chromosomal aberrations. In conclusion, fullerene C₆₀ and VOO have protective effects against the CP-induced mutagenicity and genotoxicity. Fullerene C₆₀ and VOO open an interesting field concerning their potential antigenotoxic agents against deleterious side effects of chemotherapeutics.

Hepatoprotective and antioxidant effects of single clove garlic against CCl4-induced hepatic damage in rabbits

Background

The increase in demand and consumption of single clove garlic or ‘Solo garlic’ (Allium sativum) has resulted in an increase in research on its therapeutic properties. The present study aims to evaluate the antioxidant activities, oxidant-scavenging efficiency and preventive effects of SCG (single clove garlic) and MCG (multi clove garlic) on CCl₄-induced acute hepatotoxicity in male rabbits.

Methods

For this purpose, rabbits were orally administered with 3 ml of CCl₄ /kg of body weight, followed by 0.8 g of MCG or SCG/kg twice a week for three successive weeks. Oxidative hepatotoxicity was then assessed.

Results

SCG extracts exhibited higher antioxidant capacity than the MCG extract. Scavenging ability of SCG showed significant (p < 0.05) elevation against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals in comparison to MCG. In addition, total phenolic content of SCG was significantly elevated (p < 0.001), thereby suggesting that the composition of garlic storage constituents varies with the number of cloves present. CCl₄-induced hepatotoxicity demonstrated histological changes including severe damage in the structure of liver tissues which correlated well to oxidative stress levels. Simultaneously, administration of SCG resulted in a significant reduction of serum alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TB) levels in addition to improvement in some histological parameters. Low levels of lipid peroxidation (malondialdehyde, MDA) (p < 0.001), along with a huge reduction in peroxidase (POx) (p < 0.001) revealed protection against oxidative toxicity in the liver homogenate. Higher levels of catalase (CAT) (p < 0.001) and superoxide dismutase (SOD) (p < 0.05) when compared to the MCG test (TM) group indicates that removal of H₂O₂ is based on CAT activity in SCG test (TS) group rather than the POx activity demonstrated in the former group.

Conclusion

The present study indicates that SCG possesses more protective ability than MCG against CCl₄-induced liver injury and might be an effective alternative medicine against acute oxidative liver toxicity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1916-8) contains supplementary material, which is available to authorized users.

Genotoxicity of a thiosulfonate compound derived from Allium sp. intended to be used in active food packaging: In vivo comet assay and micronucleus test

Components of Allium species have antimicrobial and antioxidant properties. A commercial Allium sp. extract (Proallium AP(®)), of which the main constituent is propyl thiosulphinate oxide (PTSO), is being used in the development of active food packaging. In previous in vitro genotoxicity studies, PTSO, in the presence of metabolic activation, increased the appearance of micronuclei (MN). We assessed the genotoxicity PTSO in rats following oral administration (doses: 5.5, 17.4, and 55mg/kg). The comet assay in liver and stomach (OECD 489) and the MN assay in bone marrow (OECD 474) were carried out. After necropsy, histopathological examinations of the liver and the stomach were performed. The results revealed no in vivo genotoxicity and the histopathological analysis showed only slight modifications, such as increased glycogen storage in the liver and a degenerative process in stomach, with vacuolization of cell membranes, only at the highest dose. Therefore, the present work confirms that this compound is not genotoxic and could be considered as a natural alternative to synthetic preservatives used in the food packaging industry.

Protective effect of diallylsulphide against mercuric chloride-induced hepatic injury in rats

The present study was undertaken to evaluate the effect of diallylsulphide (DAS) against mercuric chloride (HgCl₂)-induced oxidative stress in rat livers. Rats were randomly divided into four groups of six rats each and exposed to HgCl₂ (50 mg/kg/body weight (b.w.)) intraperitoneally and/or DAS (200 mg/kg/b.w.) by gavage. HgCl₂ administration enhanced alanine aminotransferase (AST) and aspartate aminotransferase (ALT) levels (p < 0.05) with reduction in the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). However, treatment with DAS markedly attenuated HgCl₂-induced biochemical alterations in liver and serum transaminases (AST and ALT; p < 0.05). Further, biochemical results were confirmed by histopathological changes as compared to HgCl₂-intoxicated rats. Histopathology of liver also showed that administration of DAS significantly reduced the damage generated by HgCl₂ The present study suggests that DAS shows antioxidant activity and plays a protective role against mercury-induced oxidative damage in the rat livers.

Assessment of anti-mutagenic, anti-histopathologic and antioxidant capacities of Egyptian bee pollen and propolis extracts

Bee pollen and propolis are popular, traditional health foods. The objective of the current study was to investigate the anti-mutagenic, anti-histopathologic and antioxidant effects among water extracts of Egyptian bee pollen (WEBP) and brown powder of water-soluble derivative propolis (WSDP) on cisplatin (CDDP) induced hepatic, renal, testicular and genotoxicity in male albino mice (Mus muscullus), in addition to their effects on the oxidant/antioxidant status in the tested organs. Hepatic, renal and testicular dysfunctions were evaluated histologically; while genotoxicity and cytotoxicity were evaluated by the bone marrow chromosomal aberration assay and mitotic index, respectively. Moreover, oxidative stress was explored via determination of lipid peroxidation, catalase activity and the concentration of the reduced form of glutathione. The treatment of mice with WEBP and WSDP at doses 140 and 8.4 mg/kg b. wt./day, respectively for 14 days simultaneously with CDDP (2.8 mg/kg b. wt.) resulted in significant protection. The positive control animals taken CDDP alone showed toxic histological and genetical manifestations (at P < 0.05) accompanied with an elevated content of peroxidized lipid and lowered catalase activity and glutathione concentration in the homogenate of liver, kidney and testis tissues (at P < 0.001). These toxic side effects in all tested organs were greatly ablated with a significant reduction in lipid peroxidation level and elevation in catalase activity and glutathione concentration (P < 0.001) when using both WEBP and WSDP. On the basis of the present assays, Bee pollen appears more potent in exerting an ameliorative effect and this effect was more pronounced in testis.

Effects of garlic on Schistosoma mansoni harbored in albino mice: molecular characterization of the host and parasite

Garlic has been used for its health benefits for thousands of years. Modern research confirmed many of the healing properties of garlic, including its antiparasitic activity. This study was designed to evaluate the antischistosomal action of garlic through detecting the changes in DNA profile of Schistosoma mansoni worms and the infected mouse. Forty mice were subcutaneously infected with ~200 Schistosoma mansoni cercariae/mouse. Infected mice were divided into four equal groups: non-treated, prophylactic, therapeutic, and continuously-treated. Non-infected control and garlic-treated groups were assigned for the sake of comparison. Garlic extract (50mg/kg bw/mouse) was given orally, day after day, at a fixed daytime. Seven weeks post-infection, adult schistosomes were recovered by perfusion and the livers of the mice were excised out and were processed for DNA extraction and Random Amplification of Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR). The results showed that garlic exerted no major changes in the genome of schistosomes. Nevertheless, that schistosomal infection induced genetic alterations in the DNA of mice, and garlic was able to ameliorate such alterations to a great extent.

Antigenotoxic and anticytotoxic effect of camel milk in mice treated with cisplatin

Camel milk (CM) has good nutritive value, in addition to its antigenotoxic and anticytotoxic effects. Therefore the aim of this investigation was to evaluate the capacity of CM to inhibit the micronucleated polychromatic erythrocytes (MnPCEs) in the bone marrow and improve the mitotic activity produced by cisplatin. Cisplatin is one of the most widely used antineoplastic drugs in the treatment of cancer. The 70 adult male Swiss albino mice were divided into seven groups:Gr. I: treated with distilled water and considered as a control group.Gr. II: treated with camel milk (33 ml/kg, b.w).Gr. III: treated previously with cisplatin (0.5 mg/kg, b.w).Gr. IV: treated with camel milk and followed after 2 h. with cisplatin (33 ml/kg → 0.5 mg/kg, b.w).Gr. V: treated with camel milk and cisplatin at the same time (33 ml/kg + 0.5 mg/kg, b.w).Gr. VI: treated with an acute single dose of cisplatin (2.5 mg/kg, b.w).Gr. VII: treated with camel milk prior and followed with an acute single dose of cisplatin (33 ml/kg → 2.5 mg /kg, b.w). The animals were sacrificed 24 h after cisplatin injection. The pretreatment with CM dose caused a significant decrease (P < 0.001) in the frequency of MnPCEs and increase (P < 0.001) in the mitotic index (MI) induced by cisplatin when compared with the groups treated with cisplatin alone. The possible explanation for the antigenotoxic and anticytotoxic effects observed in the pretreatment with CM is ascribed to its contents. In conclusion, from the findings we suggest that this milk has some antioxidant effect, and the antigenotoxic mechanism of this milk needs to be explored further before their use during cisplatin chemotherapy.

Treatment of mice with stem bark extract ofAphanamixis polystachyareduces radiation-induced chromosome damage

PURPOSE

Normal tissue radiosensitivity is the major limiting factor in radiotherapy of cancer. The use of phytochemicals may reduce the adverse effects of radiation in normal tissue. The effect of ethyl acetate fraction of Aphanamixis polystachya (EAP) was investigated on the radiation-induced chromosome damage in the bone marrow cells of Swiss albino mice exposed to various doses of gamma-radiation.

MATERIALS AND METHODS

The mice were divided into two groups, one group was exposed to 0, 1, 2, 3, 4 or 5 Gy of gamma-radiation, while another group received 7.5 mg/kg body weight (BW) of EAP 1 h before exposure to 0, 1, 2, 3, 4 or 5 Gy of gamma-radiation. Various asymmetrical chromosome aberrations were studied in the bone marrow cells of mice at 12, 24 or 48 h post-irradiation. To understand the mechanism of action of the free radical scavenging activity of 0, 5, 10, 20, 30, 40, 50, 60 or 70 microg/ml EAP, assays were carried out in vitro.

RESULTS

Irradiation of mice to different doses of gamma radiation caused a dose dependent elevation in the frequency of aberrant cells and chromosome aberrations like chromatid breaks, chromosome breaks, dicentrics, acentric fragments and total aberrations at all the post-irradiation times studied. The maximum asymmetrical aberrations were scored at 24 h post-irradiation except chromatid breaks that were highest at 12 h post-irradiation. A maximum number of polyploid and severely damaged cells (SDC) were recorded at 24 h post-irradiation in the SPS+irradiation group. Treatment of mice with 7.5 mg/kg BW of EAP before exposure to 1-5 Gy of whole body gamma-radiation significantly reduced the frequencies of aberrant cells and chromosomal aberrations like acentric fragments, chromatid and chromosome breaks, centric rings, dicentrics and total aberrations at all post-irradiation scoring times (p<0.01). The EAP showed a concentration dependent scavenging of hydroxyl, superoxide, 2,2'-diphenyl-1-picryl hydrazyl (DPPH) radicals and the 2,2-azino-bis-3-ethyl benzothiazoline-6-sulphonic acid (ABTS) cation radicals in vitro. EAP treatment also reduced lipid peroxidation in bone marrow cells in a concentration dependent manner.

CONCLUSION

Our study demonstrates that EAP protects mouse bone marrow cells against radiation-induced chromosomal aberrations and this reduction in radiation-induced chromosome damage may be due to free radical scavenging and reduction in lipid peroxidation. The radioprotection by EAP is best comparable to that of protection demonstrated by the grape fruit flavonone, naringin, in our earlier studies in mouse bone marrow cells.

The inhibitory effects of garlic and Panax ginseng extract standardized with ginsenoside Rg3 on the genotoxicity, biochemical, and histological changes induced by ethylenediaminetetraacetic acid in male rats

Ethylenediaminetetraacetic acid (EDTA) is widely used in food and other industries to sequester metal ions and to prevent their disadvantageous effects. The objective of the current study was to evaluate the protective effect of Panax ginseng extract standardized with ginsenoside Rg3 (ginsenoside Rg3 content was 3.6% w/w, i.e., 36 microg/mg P. ginseng extract) and garlic against EDTA-induced biochemical, genotoxic, and histological changes in rats. Forty male rats were divided into eight treatment groups and treated for 7 days as follows: the control group, the group treated with EDTA (20 mg/kg b.w) and the groups treated with P. ginseng extract (20 mg/kg b.w), garlic (5 mg/kg b.w), P. ginseng plus garlic alone or in combination with EDTA. In vivo bone marrow micronucleus test and random amplified polymorphism DNA-PCR (RAPD-PCR) method were performed to assess the antigenotoxic effect of both protective agents. The results indicated that EDTA administration caused a significant decrease in the serum biochemical parameters and antioxidant enzymes activity. The administration also increased lipid peroxidation and the incidence of micronucleated polychromatic erythrocytes (MnPCEs), caused appearance of some changes in polymorphism band patterns, and induced different histopathological lesions in the livers, kidneys, and testis. Treatment with P. ginseng, garlic alone or plus EDTA significantly improved all the tested parameters. Moreover, P. ginseng extract was found to be more effective than garlic in restoring the parameters that were altered by EDTA.

Inhibition of carcinogen-induced DNA damage in rat liver and colon by garlic powders with varying alliin content

The present study was designed to investigate the protective efficiency of three garlic powders, obtained from bulbs grown in soils with different levels of sulfur fertilization, against DNA damage. Increasing fertilization of soil resulted in an increased alliin content of the powders. Garlic powders were administered to rats for 2 weeks (5% of the diet) and their antigenotoxic effects were examined in the liver and the colon using the comet assay. Consumption of the different garlic powders induced a 35-60% reduction in DNA damage induced by N-nitrosodimethylamine (NDMA) in rat liver. Increased alliin content of the garlic powder was associated strongly with a proportional decrease in NDMA induced DNA alteration. DNA damage induced by aflatoxin B1 in the liver or by 1,2-dimethylhydrazine in the colon were also decreased strongly by the three garlic powders but these decreases were not correlated to the alliin content of the garlic powders. Feeding garlic powders did not modify the genotoxic activity of the direct-acting carcinogen methylnitrosourea in the colon. Part of our results supports evidence that fertilization can have an impact on the protective capacity of garlic bulbs.

Modulatory effects of diallyl sulfide against testosterone- induced oxidative stress in Swiss albino mice

AIM

To investigate the protective effect of diallyl sulfide (DAS), a constituent of garlic, against testosterone-induced oxidative stress in male Swiss albino mice.

METHODS

The animals were given low (250 mg/animal) and high dose (500 mg/animal) of DAS in corn oil for 7 days along with testosterone (5 mg/kg body weight, i.p.). At the end of the study period, the prostate and the liver were dissected to determine various antioxidant enzyme levels (catalase, superoxide dismutase, glutathione reductase, glutathione-s-transferase) and lipid peroxidation.

RESULTS

In testosterone treated mice, depleted antioxidant enzyme level was accompanied with enhancement in lipid peroxidation in prostate and liver. DAS significantly restored the testosterone-induced antioxidant enzymes and lipid peroxidation in the both organs. These changes appear to be mediated by the antioxidant-enhancing effects of DAS.

CONCLUSION

The results of the present study suggest that DAS is effective in exerting antioxidant effects by inhibiting testosterone-induced oxidative stress and might be helpful in preventing prostate cancer.

Cancer chemoprevention with garlic and its constituents

Advance metastasized cancers are generally incurable; hence an effort to prolong the process of carcinogenesis through chemoprevention has emerged consistent with this notion. In recent years, a considerable attention has been placed to identify naturally occurring chemopreventive substances capable of inhibiting, retarding or reversing the process of carcinogenesis. A number of phenolic substances, particularly those present in dietary and medicinal plants, have been shown to possess substantial anticarcinogenic and antimutagenic activities. Epidemiological observations and laboratory studies, both in cell culture and animal models have indicated anticarcinogenic potential of garlic and its constituents, which has been traditionally used for varied human ailments around the world. Chemical analysis has indicated that protective effects of garlic appear to be related to the presence of organosulfur compounds mainly allyl derivatives. Several mechanisms have been presented to explain cancer chemopreventive effects of garlic-derived products. These include modulation in activity of several metabolizing enzymes that activate and detoxify carcinogens and inhibit DNA adduct formation, antioxidative and free radicals scavenging properties and regulation of cell proliferation, apoptosis and immune responses. Recent data show that garlic-derived products modulate cell-signaling pathways in a fashion that controls the unwanted proliferation of cells thereby imparting strong cancer chemopreventive as well as cancer therapeutic effects. This review discusses mechanistic basis of cancer chemopreventive effects of garlic-derived products, their implication in cancer management and ways and means to take these agents from bench to real life situations.

Antimutagenicity of selenium-enriched rice on mice exposure to cyclophosphamide and mitomycin C

The in vivo antimutagenicity of Se-enriched rice was evaluated by bone marrow micronucleus and testicle chromosomal aberrations assay in mice exposed to cyclophosphamide (CP) and mitomycin C (MMC). Regular rice did not alter the occurrence of chemical-induced mutation. However, the addition of Se-enriched rice or selenite significantly inhibited the incidence of CP-induced micronuclei and MMC-induced chromosomal aberration in mice and the effect was dose-dependent. Providing selenite or Se-enriched rice also significantly increased the activity of glutathione peroxidase in liver and the selenium concentration in blood compared to regular rice. No significant differences were found in mice body weight gain. These results revealed the antimutagenic potential of Se-enriched rice against chemical-induced mutation.

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Modulation of altered hepatic foci induction by diallyl sulphide in Wistar rats

Diallyl sulphide (DAS) is a sulphur-containing volatile compound present in garlic (Allium sativum). It has been shown to inhibit a number of chemically induced forms of cancer in experimental animals. The present study demonstrates the inhibitory effect of DAS on the development of diethylnitrosamine (DEN) initiated and 2-acetyl-aminofluorene (2-AAF) promoted preneoplastic altered hepatic foci (AHF) in Wistar rats. AHF were scored and analysed by quantitative stereology using the Image Analysis system from frozen liver sections stained for biological markers, namely glutathione S-transferase, placental form (GST-P), gamma-glutamyl transpeptidase (GGT), adenosine triphosphatase (ATPase), glucose-6-phosphatase (G6 Pase) and alkaline phosphatase (AlkPase). DAS-supplemented rats were found to restore the near-normal levels of enzymes GST-P and GGT when exposed to DEN and 2-AAF. DAS administration following DEN and 2-AAF exposure led to the restoration of enzymic activity of ATPase, G6 Pase and AlkPase, as evident by number and area of the foci. These findings suggest the protective role of DAS in rat hepatocarcinogenesis, by suppressing DEN- and 2-AAF-induced AHF development.

Antigenotoxic potential of certain dietary constituents

The human diet contains a variety of compounds that exhibit chemopreventive effects towards an array of xenobiotics. In the present study, the antigenotoxic potential of selected dietary constituents including Diallyl sulfide (DAS), Indole-3-carbinol (I3C), Curcumin (CUR), and Black tea polyphenols (BTP) has been evaluated in the Salmonella typhimurium reverse mutation and mammalian in vivo cytogenetic assays. In addition, the anticlastogenic effect of the above dietary constituents was identified towards Benzo(a)pyrene (BaP) and cyclophosphamide- (CP) induced cytogenetic damage in mouse bone marrow cells. The induction of BaP and CP induced chromosomal aberrations, micronuclei formation, and sister chromatid exchanges (SCEs) were found to be inhibited in a dose-dependent manner by DAS, I3C, CUR, and BTP. Thus the study reveals the antimutagenic potential of these dietary compounds towards BaP- and CP-induced genotoxicity in microbial and mammalian test systems.

Inhibition of clastogenicity of benzo[a]pyrene and of its trans-7,8-dihydrodiol in mice in vivo by fruits, vegetables, and flavonoids

In the in vivo mouse bone marrow micronucleus assay, homogenates of spinach, artichoke, peaches, and blue grapes as well as commercial concentrates of these vegetables and fruits reduced induction of micronuclei by benzo[a]pyrene (BaP) by 43-50%. Concentrates of strawberries (31% reduction) and of cauliflower (20% reduction) were less potent. Inhibition of genotoxicity by spinach and peaches was not caused by any delay in maturation of micronucleated erythrocytes as shown by experiments with sampling times of 24, 48, and 72 h after dosing of BaP. Pre-treatment of the mice with spinach 48, 24, and 12h before application of BaP resulted in a 44% reduction of micronuclei while peaches generated only a marginal effect. A post-treatment procedure administering spinach or peaches 6h after dosing of BaP did not indicate any protective effects. When trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BaP-7,8-OH) was applied for induction of micronuclei spinach and peaches reduced the number of micronuclei by 55 and 48%, respectively. Pre-treatment of mice with spinach 96, 72, and 60 h before sacrifice caused a decline of hepatic 7-ethoxyresorufin-O-dealkylase (EROD) and of 7-pentoxyresorufin-O-dealkylase (PROD) activities by factors of 2.2 and 1.4, respectively. However, statistical significance was not reached. On the other hand, peaches had no influence on hepatic EROD or PROD activities. The flavonoids quercetin and its glucoside isoquercitrin, administered orally in doses of 0.03 mmol/kg body weight simultaneously with intraperitoneally given BaP, reduced the number of micronuclei in polychromatic erythrocytes of the bone marrow of mice by 73 and 33%. Ten-fold higher concentrations, however, reversed the effects with a particular strong increase observed with isoquercitrin (+109%; quercetin: +16%).

Inhibitory effect of fruit extracts on P-glycoprotein-related efflux carriers: an in-vitro screening

In this study, standardized food extracts were screened for their possible inhibitory effect on the P-glycoprotein (P-gp)-mediated efflux of 3H-ciclosporin A (CsA) using the in-vitro Caco-2 model. CsA is commonly used as a substrate for P-gp-related efflux carriers and is characterized by a polarity in transport, the absorptive transport being much lowerthan the secretorytransport (polarityfactor: PF approximately 7). Of the 68 tested, nine extracts showed a decreased efflux of CsA (< 75% of the reference value) and were retained for further experiments on the bidirectional transport of CsA across Caco-2 monolayers. Results of these experiments showed that strawberry, orange, apricot and mint extract exert an inhibitory effect on intestinal P-gp-related functionality (PF < 4.2). The effect of apricot extract was also studied on the bidirectional transport of talinolol, a specific P-gp substrate; inclusion of 1%, v/v, in the apical compartment of Caco-2 monolayers resulted in a significantly reduced polarity in the transport of talinolol (PF reference = 15.5; PF in the presence of apricot extract = 2.5). This study suggests that co-administration of fruit extracts might be a conceptually safe and useful strategy to enhance the intestinal absorption of P-gp substrates. More research is necessary to characterize the impact of this inhibition on P-gp-related efflux mechanisms in other absorption models (in-vitro and in-vivo) and to identify the compounds that are responsible for this inhibitory effect.