Beneficial and adverse effects of chemopreventive agents

Drug-food Interactions in the Era of Molecular Big Data, Machine Intelligence, and Personalized Health

The drug-food interaction brings forth changes in the clinical effects of drugs. While favourable interactions bring positive clinical outcomes, unfavourable interactions may lead to toxicity. This article reviews the impact of food intake on drug-food interactions, the clinical effects of drugs, and the effect of drug-food in correlation with diet and precision medicine. Emerging areas in drug-food interactions are the food-genome interface (nutrigenomics) and nutrigenetics. Understanding the molecular basis of food ingredients, including genomic sequencing and pharmacological implications of food molecules, helps to reduce the impact of drug-food interactions. Various strategies are being leveraged to alleviate drug-food interactions; measures including patient engagement, digital health, approaches involving machine intelligence, and big data are a few of them. Furthermore, delineating the molecular communications across dietmicrobiome- drug-food-drug interactions in a pharmacomicrobiome framework may also play a vital role in personalized nutrition. Determining nutrient-gene interactions aids in making nutrition deeply personalized and helps mitigate unwanted drug-food interactions, chronic diseases, and adverse events from their onset. Translational bioinformatics approaches could play an essential role in the next generation of drug-food interaction research. In this landscape review, we discuss important tools, databases, and approaches along with key challenges and opportunities in drug-food interaction and its immediate impact on precision medicine.

Exploring the recent trends in perturbing the cellular signaling pathways in cancer by natural products

Cancer is commonly thought to be the product of irregular cell division. According to the World Health Organization (WHO), cancer is the major cause of death globally. Nature offers an abundant supply of bioactive compounds with high therapeutic efficacy. Anticancer effects have been studied in a variety of phytochemicals found in nature. When Food and Drug Administration (FDA)-approved anticancer drugs are combined with natural compounds, the effectiveness improves. Several agents have already progressed to clinical trials based on these promising results of natural compounds against various cancer forms. Natural compounds prevent cancer cell proliferation, development, and metastasis by inducing cell cycle arrest, activating intrinsic and extrinsic apoptosis pathways, generating reactive oxygen species (ROS), and down-regulating activated signaling pathways. These natural chemicals are known to affect numerous important cellular signaling pathways, such as NF-B, MAPK, Wnt, Notch, Akt, p53, AR, ER, and many others, to cause cell death signals and induce apoptosis in pre-cancerous or cancer cells without harming normal cells. As a result, non-toxic “natural drugs” taken from nature’s bounty could be effective for the prevention of tumor progression and/or therapy of human malignancies, either alone or in combination with conventional treatments. Natural compounds have also been shown in preclinical studies to improve the sensitivity of resistant cancers to currently available chemotherapy agents. To summarize, preclinical and clinical findings against cancer indicate that natural-sourced compounds have promising anticancer efficacy. The vital purpose of these studies is to target cellular signaling pathways in cancer by natural compounds.

Determination of anticancer potential of a novel pharmacologically active thiosemicarbazone derivative in colorectal cancer cell lines

Thiosemicarbazones have received noteworthy attention due to their numerous pharmacological activities. Various thiosemicarbazone derivatives have been reported to play a key role as potential chemotherapeutic agents for the management of cancer. Herein, we aimed to establish the anticancer efficacy of novel thiosemicarbazone derivative C4 against colon cancer in vitro. The MTT viability assay identified C4 as a promising anticancer compound in a panel of cancer cell lines with the most potent activity against colon cancer cells. Further, anticancer potential of C4 was evaluated against HT-29 and SW620 colon cancer cell lines considering the factors like cell adhesion and migration, oxidative stress, cell cycle arrest, and apoptosis. Our results showed that C4 significantly inhibited the migration and adhesion of colon cancer cells. C4 significantly increased the intracellular reactive oxygen species (ROS) and induced apoptotic cell death. Cell cycle analysis revealed that C4 interfered in the cell cycle distribution and arrested the cells at the G2/M phase of the cell cycle. Consistent with these results C4 also down-regulated the Bcl-XL and Bcl-2 and up-regulated the caspase-3 expression. These findings introduced C4 as the potential anticancer agent against colon cancer.

Synthetic Diphenylacetylene-Based Retinoids Induce DNA Damage in Chinese Hamster Ovary Cells without Altering Viability

All-trans-retinoic acid (ATRA), the active metabolite of vitamin A, plays a pivotal role in cell differentiation, proliferation and embryonic development. It is an effective therapy for dermatological disorders and malignancies. ATRA is prone to isomerization and oxidation, which can affect its activity and selectivity. Novel diphenylacetylene-based ATRA analogues with increased stability can help to overcome these problems and may offer significant potential as therapeutics for a variety of cancers and neurodegenerative diseases, including amyotrophic lateral sclerosis. Here, we investigated the effects of these retinoids on cell viability and genotoxicity in the widely used model system of the rapidly proliferating Chinese hamster ovary cell line. DC360 is a fluorescent ATRA analogue and DC324 is a non-active derivative of DC360. EC23, DC525, DC540, DC645, and DC712 are promising analogues with increased bioactivity. The cytotoxic activity of the compounds was evaluated by ATP assay and DNA damage was tested by comet assay. No cytotoxicity was observed in the 10⁻⁶–10⁻⁵ M concentration range. All compounds induced DNA migration similar to ATRA, but DC324, DC360 and EC23 did so to a greater extent, particularly at higher concentrations. We believe that retinoid receptor-independent genotoxicity is a general characteristic of these compounds; however, further studies are needed to identify the molecular mechanisms and understand their complex biological functions.

Phytochemical Screening, Antioxidant and Sperm Viability of Nelumbo nucifera Petal Extracts

Sacred lotus (Nelumbo nucifera Gaertn.; N. nucifera) is a common ingredient in traditional medicine and Thai recipes. Its petal is an agricultural waste from stamen production. There are limitations in the used and pharmacological data of the petals resulting in more petals waste. The aims of this study were to investigate the phytochemical contents, antioxidant activity, and potential effects on sperm viability of aqueous (NAE) and ethanolic extracts (NEE) of both red and white N. nucifera petals. The white NAE had the highest total phenolics content, total tannins content and maximal antioxidant activity. The white NEE had the highest concentration of total flavonoids. Quercetin was a major flavonoid and was found in the aqueous extracts. Both red and white of NAE in the range of 0.22 to 1.76 mg/mL increased sperm viability. The white NAE was prominent in phytochemical content, antioxidant activity, and both red and white NAE effectively increased rat sperm viability in the in vitro model. The white NAE enhanced sperm viability by decreasing oxidative stress. It might be suggested that the N. nucifera petals have benefits for sperm viability health promotion and may increase the economic value of agricultural waste.

Toxicity of Saffron Extracts on Cancer and Normal Cells: A Review Article

BACKGROUND AND AIM

Medicinal plants have played an important role in human health since the Stone Age. According to WHO, 80% of Asian and African people rely on traditional medicine and medicinal plants to conserve their health. Saffron has received much attention among the herbal compounds related to cancer treatment.

METHODS

This review aims to provide an overview of in-vitro and in-vivo evaluation molecule mechanism for anti-tumor activity, cancer preventing and protective effects of saffron extract. The review is based on the available data accessible in PubMed, Science Direct, Google Scholar, Magiran.ir, and SID.ir databases.

RESULTS

Saffron has selective toxic and preventive effects on cancerous cells and without adverse effects on normal cells and prevents tumor formation. Saffron appears to reduce the toxic effects of anticancer drugs. Saffron has toxicity effects when used in high amounts, which are far greater than those  are used in human food culture.

CONCLUSIONS

Considering the observed effects of saffron on the removal of cancer cells, saffron extract can be used in the treatment and prevention of cancer after confirmation in human clinical trials. According to the high IC50 of saffron extracts in normal cells, its toxicity against non-cancerous cells is low and its use is safe. Besides, the studies suggested the cytotoxic effects of saffron on some of the  more cancers, including nervous system cancer and common cancers. Further studies are required to determine the effective dose and influence of mechanism of saffron in various animal type of cancers.

Crocetin and Crocin from Saffron in Cancer Chemotherapy and Chemoprevention

INTRODUCTION

Cancer is a disorder which has a powerful impact on the quality life and life expectancy despite the increase in drugs and treatments available for cancer patients. Moreover, many new therapeutic options are known to have adverse reactions without any improvement in outcome than before. Nowadays, natural products or plant derivatives are used as chemoprevention drugs and chemotherapy is the new approach that uses specific cell premalignant transformation in the malignant form. Natural substances derived from plants, such as polyphenols, flavonoids, carotenoids, alkaloids and others, can be biologically active and have a wide spectrum of effects. The protective effects of Saffron carotenoids (crocin and crocetin) have been extensively studied mainly for their antioxidant properties, however, they have various other biological activities including tumor growth inhibition with the induction of cell death.

METHODS

The relevant information on Saffron and its carotenoids was collected from scientific databases (such as PubMed, Web of Science, Science Direct). To identify all published articles in relation to saffron, crocin and crocetin, in different types of cancer, no language restriction has been used.

RESULTS

To date, crossing the words saffron and cancer, approximately 150 articles can be found. If crossing is made between crocin and cancer, approximately 60 articles can be found. With the crossing between crocetin and cancer, the number is approximately 55, while between carotenoids and cancer, the number exceeds 16.000 reports. In all the papers published to date, there are evidences that saffron and its carotenoids exert chemopreventive activity through anti-oxidant activity, cancer cells apoptosis, inhibition of cell proliferation, enhancement of cell differentiation, modulation of cell cycle progression and cell growth, modulation of tumor metabolism, stimulation of cell-to-cell communication and immune modulation.

CONCLUSION

Here, we have tried to offer an up-to-date overview of pre-clinical experimental investigations on the potential use of the main carotenoids of saffron in tumor models and focus the attention on the molecular mechanisms involved.

Secondary Metabolites Profiling of Acinetobacter baumannii Associated with Chili (Capsicum annuum L.) Leaves and Concentration Dependent Antioxidant and Prooxidant Properties

Secondary bioactive compounds of endophytes are inevitable biomolecules of therapeutical importance. In the present study, secondary metabolites profiling of an endophytic bacterial strain, Acinetobacter baumannii, were explored using GC-MS study. Presence of antioxidant substances and antioxidant properties in chloroform (CHL), diethyl ether (DEE), and ethyl acetate (EA) crude extracts of the endophytic bacteria were studied. Total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferrous ion chelating assay were evaluated. A total of 74 compounds were identified from the GC-MS analysis of the EA extract representing mostly alkane compounds followed by phenols, carboxylic acids, aromatic heterocyclic compounds, ketones, aromatic esters, aromatic benzenes, and alkenes. Among the two phenolic compounds, namely, phenol, 2,4-bis(1,1-dimethylethyl)- and phenol, 3,5-bis(1,1-dimethylethyl)-, the former was found in abundance (11.56%) while the latter was found in smaller quantity (0.14%). Moreover, the endophytic bacteria was found to possess a number of metal ions including Fe(II) and Cu(II) as 1307.13 ± 2.35 ppb and 42.38 ± 0.352 ppb, respectively. The extracts exhibited concentration dependent antioxidant and prooxidant properties at high and low concentrations, respectively. The presence of phenolic compounds and metal ions was believed to play an important role in the antioxidant and prooxidant potentials of the extracts. Further studies are suggested for exploring the untapped resource of endophytic bacteria for the development of novel therapeutic agents.

Sulforaphane: Its "Coming of Age" as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease

A growing awareness of the mechanisms by which phytochemicals can influence upstream endogenous cellular defence processes has led to intensified research into their potential relevance in the prevention and treatment of disease. Pharmaceutical medicine has historically looked to plants as sources of the starting materials for drug development; however, the focus of nutraceutical medicine is to retain the plant bioactive in as close to its native state as possible. As a consequence, the potency of a nutraceutical concentrate or an extract may be lower than required for significant gene expression. The molecular structure of bioactive phytochemicals to a large extent determines the molecule's bioavailability. Polyphenols are abundant in dietary phytochemicals, and extensive in vitro research has established many of the signalling mechanisms involved in favourably modulating human biochemical pathways. Such pathways are associated with core processes such as redox modulation and immune modulation for infection control and for downregulating the synthesis of inflammatory cytokines. Although the relationship between oxidative stress and chronic disease continues to be affirmed, direct-acting antioxidants such as vitamins A, C, and E, beta-carotene, and others have not yielded the expected preventive or therapeutic responses, even though several large meta-analyses have sought to evaluate the potential benefit of such supplements. Because polyphenols exhibit poor bioavailability, few of their impressive in vitro findings have been replicated in vivo. SFN, an aliphatic isothiocyanate, emerges as a phytochemical with comparatively high bioavailability. A number of clinical trials have demonstrated its ability to produce favourable outcomes in conditions for which there are few satisfactory pharmaceutical solutions, foreshadowing the potential for SFN as a clinically relevant nutraceutical. Although myrosinase-inert broccoli sprout extracts are widely available, there now exist myrosinase-active broccoli sprout supplements that yield sufficient SFN to match the doses used in clinical trials.

Indole-3-carbinol: a plant hormone combatting cancer

A diet rich in cruciferous vegetables such as cauliflower, broccoli, and cabbage has long been considered healthy, and various epidemiological studies suggest that the consumption of cruciferous vegetables contributes to a cancer-protecting diet. While these vegetables contain a vast array of phytochemicals, the mechanism by which these vegetables counteract cancer is still largely unresolved. Numerous in situ studies have implicated indole-3-carbinol, a breakdown product of the glucosinolate indole-3-ylmethylglucosinolate, as one of the phytochemicals with anti-cancer properties. Indole-3-carbinol influences a range of cellular processes, but the mechanisms by which it acts on cancer cells are slowly being revealed. Recent studies on the role of indole-3-carbinol in Arabidopsis opens the door for cross-kingdom comparisons that can help in understanding the roles of this important phytohormone in both plant biology and combatting cancer.

High Spicy Food Intake and Risk of Cancer: A Meta-analysis of Case-control Studies

Background:

Studies on the association between spicy food intake and cancer risk have reported inconsistent results. We quantitatively assessed this association by conducting a meta-analysis based on evidence from case–control studies.

Methods:

PubMed, EMBASE, and the Cochrane Library were searched for eligible publications. Combined odds ratios (ORs) with their 95% confidence interval (CI) were calculated using a random- or fixed-effects model. The methodological quality of the included articles was assessed using the Newcastle–Ottawa scale (NOS). All data were analyzed using STATA 11.0 software (version 11.0; StataCorp., College Station, TX, USA). Subgroup analyses were also performed with stratification by region, sex, number of cases, cancer subtype, source of the control group, and NOS score.

Results:

A total 39 studies from 28 articles fulfilled the inclusion criteria for the meta-analysis (7884 patients with cancer and 10,142 controls). Comparison of the highest versus lowest exposure category in each study revealed a significant OR of 1.76 (95% CI = 1.35–2.29) in spite of significant heterogeneity (P < 0.001). In the subgroup analyses, this positive correlation was still found for gastric cancer, different regions, different numbers of cases, different sources of the control group, and high-quality articles (NOS score of ≥ 7). However, no statistically significant association was observed for women, esophageal cancer, gallbladder cancer, or low-quality articles (NOS score of <7). No evidence of publication bias was found.

Conclusions:

Evidence from case–control studies suggested that a higher level of spicy food intake may be associated with an increased incidence of cancer despite significant heterogeneity. More studies are warranted to clarify our understanding of the association between high spicy food intake and the risk of cancer.

Chemopreventive and biological activities of Helicteres isora L. fruit extracts

Helicteres isora L. (H. isora) has been used in traditional medicine in Asia. This study was aimed to determine biological activities of H. isora fruit extracts. Chemopreventive effect was examined by cell proliferation assay and differentiation-inducing effect. Anti-inflammatory activity of extracts was studied on the levels of nitric oxide (NO), tumor necrosis factor alpha (TNF-α), production of prostaglandin E2 (PGE-2), and cyclooxygenas-2 (COX-2). Cell proliferation assay revealed that H. isora extracts and its major compound, rosmarinic acid, showed no cytotoxicity in THP-1 and RCM-1 cells. Methylthio acetic acid from Cucumis melo var.conomon used as a positive control and 80% ethanol extracts demonstrated significant cell differentiation induction. Hexane extract of H. isora could lower the levels of TNF-α, PGE-2, and NO in THP-1 cells with 51.61 ± 0.79%, 69.68 ± 0.017%, and 69.93 ± 9.41% inhibition, respectively. The highest inhibitory effect on COX-2 was obtained from dichloromethane extract. Dexamethasone inhibited the secretion of TNF-α with 95.82 ± 0.50% while celecoxib showed the inhibitory effect on COX-2 and PGE-2 with 100% and 99.86%, respectively. The ethanol extract showed the best antioxidant activity by DPPH and FRAP assays at IC₅₀ of 5.43 ± 1.01 μg/mL and 22.83 ± 0.13 mmol FeSO₄/g sample, respectively, while the positive control, trolox, showed the antioxidant activity with IC₅₀ and FRAP values at 4.08 ± 0.85 μg/mL and 10.84 ± 0.04 mmol FeSO₄/g sample, respectively. Taken together, H. isora possess chemopreventive and antioxidant activity. Further studies on in vivo activities of this plant are suggested.

Dose-Dependent Responses of I3C and DIM on T-Cell Activation in the Human T Lymphocyte Jurkat Cell Line

Indole-3-carbinol (I3C) and its dimer diindolylmethane (DIM) are bioactive metabolites of a glucosinolate, glucobrassicin, found in cruciferous vegetables. Both I3C and DIM have been reported to possess pro-apoptotic, anti-proliferative and anti-carcinogenic properties via modulation of immune pathways. However, results from these studies remain inconclusive since they lack thorough evaluation of these bioactives’ physiological versus pharmacological effects. In the present study, we investigated I3C and DIM’s dose-dependent effects on cytokines production in human T lymphocytes Jurkat cell line (Clone E6-1). The results showed that I3C and DIM pretreatment, at higher concentrations of 50 and 10 μM, respectively, significantly increased PMA/ionomycin-induced interleukin-2 (IL-2), interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) production, measured by real time polymerase chain reaction (RT-PCR) and enzyme linked immunosorbent assay (ELISA). As a plausible mechanism underlying such pronounced cytokine release, we found robust increase in downstream nuclear factor κB (NF-κB) and nuclear factor of activated T-cells 1 (NFAT1) signaling with I3C pretreatment, whereas DIM pretreatment only significantly induced NF-κB activation, but not NFAT1. We hypothesize that I3C/DIM pretreatment primes the T cells to become hyperresponsive upon PMA/ionomycin stimulation which in turn differentially induces two major downstream Ca²⁺-dependent inflammatory pathways, NF-κB and NFAT1. Our data show novel insights into the mechanisms underlying induction of pro-inflammatory cytokine release by pharmacological concentrations of I3C and DIM, an effect negligible under physiological conditions.

Impact of structural differences in carcinopreventive agents indole-3-carbinol and 3,3'-diindolylmethane on biological activity. An X-ray, ¹H-¹⁴N NQDR, ¹³C CP/MAS NMR, and periodic hybrid DFT study

Three experimental techniques (1)H-(14)N NQDR, (13)C CP/MAS NMR and X-ray and Density Functional Theory (GGA/BLYP with PBC) and Hirshfeld surfaces were applied for the structure-activity oriented studies of two phyto-antioxidants and anticarcinogens: indole-3-carbinol, I3C, and 3,3'-diindolylmethane, DIM, (its bioactive metabolite). One set of (14)N NQR frequencies for DIM (2.310, 2.200 and 0.110 MHz at 295K) and I3C (2.315, 1.985 and 0.330 MHz at 160K) was recorded. The multiplicity of NQR lines recorded at RT revealed high symmetry (chemical and physical equivalence) of both methyl indazole rings of DIM. Carbonyl (13)C CSA tensor components were calculated from the (13)C CP/MAS solid state NMR spectrum of I3C recorded under fast and slow spinning. At room temperature the crystal structure of I3C is orthorhombic: space group Pca21, Z=4, a=5.78922(16), b=15.6434(7) and c=8.4405(2)Å. The I3C molecules are aggregated into ribbons stacked along [001]. The oxygen atomsare disorderedbetween the two sites of different occupancy factors. It implies that the crystal is built of about 70% trans and 30% gauche conformers, and apart from the weak OH⋯O hydrogen bonds (O⋯O=3.106Å) the formation of alternative O'H⋯O bonds (O'⋯O=2.785Å) is possible within the 1D ribbons. The adjacent ribbons are further stabilised by O'H⋯O bonds (O'⋯O=2.951Å). The analysis of spectra and intermolecular interactions pattern by experimental techniques was supported by solid (periodic) DFT calculations. The knowledge of the topology and competition of the interactions in crystalline state shed some light on the preferred conformations of CH2OH in I3C and steric hindrance of methyl indole rings in DIM. A comparison of the local environment in gas phase and solid permitted drawing some conclusions on the nature of the interactions required for effective processes of recognition and binding of a given anticarcinogen to the protein or nucleic acid.

The impact of capsaicin intake on risk of developing gastric cancers: a meta-analysis

BACKGROUND

Reported associations of capsaicin with gastric cancer development have been conflicting. Here, we examine 10 published articles that explore these associations using 2,452 cases and 3,996 controls.

METHODS

We used multiple search strategies in MEDLINE through PubMed to seek for suitable articles that had case-control design with gastric cancer as outcome.

RESULTS

The outcomes of our study shows protection (odds ratio [OR] 0.55, P = 0.003) and susceptibility (OR 1.94, P = 0.0004), both significant with low and medium-high intake of capsaicin, respectively, although under relatively heterogeneous conditions (P(heterogeneity) = <0.0001). Outlier analysis resulted in loss of overall heterogeneity (P = 0.14) without affecting the pooled ORs. Among the subgroups, low intake elicited protection in both Korean (OR 0.37) and Mexican (OR 0.63) populations while high intake rendered these subgroups susceptible (OR 2.96 and OR 1.57, respectively). These subgroup values were highly significant (P = 0.0001-0.01) obtained in heterogeneous conditions (P(heterogeneity) < 0.0001-0.04). The homogeneous (P(heterogeneity) = 0.27-0.37) H. pylori (OR 0.60 and 1.69) effects were highly significant (P < 0.001) in the low and medium-high intake analyses, respectively. Given outcomes from the tests of interaction, high capsaicin intake is significantly different from the protection that low consumption offers.

CONCLUSIONS

This meta-analysis implies moderation in capsaicin consumption in order to derive its protective benefits.

Evaluation of the effectiveness of Piper cubeba extract in the amelioration of CCl4-induced liver injuries and oxidative damage in the rodent model

Background. Liver diseases still represent a major health burden worldwide. Moreover, medicinal plants have gained popularity in the treatment of several diseases including liver. Thus, the present study was to evaluate the effectiveness of Piper cubeba fruits in the amelioration of CCl₄-induced liver injuries and oxidative damage in the rodent model. Methods. Hepatoprotective activity was assessed using various biochemical parameters like SGOT, SGPT, γ-GGT, ALP, total bilirubin, LDH, and total protein. Meanwhile, in vivo antioxidant activities as LPO, NP-SH, and CAT were measured in rat liver as well as mRNA expression of cytokines such as TNFα, IL-6, and IL-10 and stress related genes iNOS and HO-1 were determined by RT-PCR. The extent of liver damage was also analyzed through histopathological observations. Results. Treatment with PCEE significantly and dose dependently prevented drug induced increase in serum levels of hepatic enzymes. Furthermore, PCEE significantly reduced the lipid peroxidation in the liver tissue and restored activities of defense antioxidant enzymes NP-SH and CAT towards normal levels. The administration of PCEE significantly downregulated the CCl₄-induced proinflammatory cytokines TNFα and IL-6 mRNA expression in dose dependent manner, while it upregulated the IL-10 and induced hepatoprotective effect by downregulating mRNA expression of iNOS and HO-1 gene.

Attenuation of Carcinogenesis and the Mechanism Underlying by the Influence of Indole-3-carbinol and Its Metabolite 3,3'-Diindolylmethane: A Therapeutic Marvel

Rising evidence provides credible support towards the potential role of bioactive products derived from cruciferous vegetables such as broccoli, cauliflower, kale, cabbage, brussels sprouts, turnips, kohlrabi, bok choy, and radishes. Many epidemiological studies point out that Brassica vegetable protects humans against cancer since they are rich sources of glucosinolates in addition to possessing a high content of flavonoids, vitamins, and mineral nutrients. Indole-3-carbinol (I3C) belongs to the class of compounds called indole glucosinolate, obtained from cruciferous vegetables, and is well-known for tits anticancer properties. In particular, I3C and its dimeric product, 3,3'-diindolylmethane (DIM), have been generally investigated for their value against a number of human cancers in vitro as well as in vivo. This paper reviews an in-depth study of the anticancer activity and the miscellaneous mechanisms underlying the anticarcinogenicity thereby broadening its therapeutic marvel.

Vitamin supplement consumption and breast cancer risk: a review

BACKGROUND

Breast cancer is the most frequently diagnosed cancer globally, and studies provide contradictory results about the possible effects of vitamin supplementation to reduce cancer risk. Our aim was to conduct a review to better investigate whether vitamin supplements given orally modify breast cancer risk.

METHODS

We conducted a comprehensive, systematic bibliographic search of the medical literature to identify relevant studies. Case-control, cohort studies, and randomised controlled trials (RCTs) published up to August 2013 that reported cancer risk estimates for vitamin supplementation were included. For each study, we retrieved study characteristics, study population, exposure evaluation, and risk estimates.

RESULTS

We identified 26 studies (14 cohort, 11 case-control, and one RCT) and overall, we found 104 estimates. We grouped all the estimates into six supplementation categories: vitamin A and beta-carotene, B-group vitamins and folic acid, vitamin C, vitamin D, vitamin E, and multivitamins. Only a few studies showed a statistically significant association between the consumption of supplemental vitamins and the occurrence of breast cancer, and most of the significant estimates were found in case-control studies. The results found in prospective studies seem to be in the opposite direction.

CONCLUSION

The role of vitamin supplements in preventing breast cancer still remains unclear, considering our review. Although biologic mechanisms exist to support the anticancer effects of vitamins, there is no clear evidence for an effect in cancer prevention for vitamin supplements. Further investigations are warranted to elucidate the mechanisms by which vitamin supplementation can modify breast cancer development.

Redox cycling of endogenous copper by thymoquinone leads to ROS-mediated DNA breakage and consequent cell death: putative anticancer mechanism of antioxidants

Plant-derived dietary antioxidants have attracted considerable interest in recent past for their chemopreventive and cancer therapeutic abilities in animal models. Thymoquinone (TQ) is the major bioactive constituent of volatile oil of Nigella sativa and has been shown to exert various pharmacological properties, such as anti-inflammatory, cardiovascular, analgesic, anti-neoplastic, anticancer and chemopreventive. Although several mechanisms have been suggested for the chemopreventive and anticancer activity of TQ, a clear mechanism of action of TQ has not been elucidated. TQ is a known antioxidant at lower concentrations and most of the studies elucidating the mechanism have centered on the antioxidant property. However, recent publications have shown that TQ may act as a prooxidant at higher concentrations. It is well known that plant-derived antioxidants can switch to prooxidants even at low concentrations in the presence of transition metal ions such as copper. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Copper is an important metal ion present in the chromatin and is closely associated with DNA bases, particularly guanine. Using human peripheral lymphocytes and comet assay, we first show that TQ is able to cause oxidative cellular DNA breakage. Such a DNA breakage can be inhibited by copper-chelating agents, neocuproine and bathocuproine, and scavengers of reactive oxygen species. Further, it is seen that TQ targets cellular copper in prostate cancer cell lines leading to a prooxidant cell death. We believe that such a prooxidant cytotoxic mechanism better explains the anticancer activity of plant-derived antioxidants.

Aberrant crypt focus and fragile histidine triad protein in sporadic colorectal carcinoma

AIM: To characterize aberrant crypt focus (ACF) in adjoining mucosa in sporadic colorectal carcinoma and to evaluate fragile histidine triad (Fhit) protein and Ki67.

METHODS: ACF was identified grossly and classified histologically in 75 resected specimens. ACF was typed into hyperplastic ACF (HACF) and dysplastic ACF (DACF). Sections of ACF, carcinoma and normal colonic mucosa as control were studied for Fhit and Ki67 expressions by immunohistochemistry and were grouped according to staining intensity and the number of positive stained cells observed in different histological groups. Comparison was done between the different groups by Pearson’s χ² test and γ test for the ordinal data. P value < 0.05 was considered as significant.

RESULTS: Age range was 40 to 86 years in males (mean = 43.36) and 45 to 70 years in females (mean = 56). HACF was identified in all cases studied in the non-tumorous colonic mucosa; ACF was observed as non-contiguous scattered foci, which supports the hypothesis of acquisition of single focus monoclonality by colonic epithelial cells in tumor generation. Twenty-four (32%) had DACF and were observed as closure to carcinoma foci. Intensity of Fhit expression: (1) HACF - 40% exhibited strong intensity, similar to normal, moderate in 36% and weak in 24%; (2) DACF - strong in 25%, moderate in 37.5% and weak in 37.5%; and (3) carcinoma - negative in 16%, strong in 43% and moderate and weak in 28.5% each. Significant difference was observed in intensity of the Fhit protein expressions by HACF and DACF (P < 0.05). Tumor in older patients showed a stronger Fhit intensity compared to younger patients (P = 0.036). Vegetarian diet intake and non-smokers showed stronger Fhit intensities. Advanced stage tumor, non-vegetarian diet and younger age was associated with loss of Fhit protein. Ki67 positivity was an extended crypt pattern in HACF and DACF showed extension up to the neck region of the crypts and surface epithelium. Carcinomas showed a marked increase in Ki67 expression (P < 0.05). Fhit protein had an inverse association with Ki67 expression.

CONCLUSION: Weaker Fhit intensity was associated with smoking, non-vegetarian diet intake and increasing Ki67 expression. Loss of Fhit protein expression is possibly influenced by environmental factors like smoking and non-vegetarian diet intake.

Crocetin: an agent derived from saffron for prevention and therapy for cancer

Cancer is one of the leading causes of death in the United States and accounts for approximately 8 million deaths per year worldwide. Although there is an increasing number of therapeutic options available for patients with cancer, their efficacy is time-limited and non-curative. Approximately 50-60% cancer patients in the United States utilize agents derived from different parts of plants or nutrients (complementary and alternative medicine), exclusively or concurrently with traditional therapeutic regime such as chemotherapy and/or radiation therapy. The need for new drugs has prompted studies evaluating possible anti-cancer agents in fruits, vegetables, herbs and spices. Saffron, a spice and a food colorant present in the dry stigmas of the plant Crocus sativus L., has been used as an herbal remedy for various ailments including cancer by the ancient Arabian, Indian and Chinese cultures. Crocetin, an important carotenoid constituent of saffron, has shown significant potential as an anti-tumor agent in animal models and cell culture systems. Crocetin affects the growth of cancer cells by inhibiting nucleic acid synthesis, enhancing anti-oxidative system, inducing apoptosis and hindering growth factor signaling pathways. This review discusses the studies on cancer preventive potential of crocetin and its future use as an anticancer agent.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Our systematic review has demonstrated that antioxidant supplements may increase mortality. We have now updated this review.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements for prevention of mortality in adults.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to February 2011. We scanned bibliographies of relevant publications and asked pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Random-effects and fixed-effect model meta-analyses were conducted. Risk of bias was considered in order to minimise the risk of systematic errors. Trial sequential analyses were conducted to minimise the risk of random errors. Random-effects model meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Seventy-eight randomised trials with 296,707 participants were included. Fifty-six trials including 244,056 participants had low risk of bias. Twenty-six trials included 215,900 healthy participants. Fifty-two trials included 80,807 participants with various diseases in a stable phase. The mean age was 63 years (range 18 to 103 years). The mean proportion of women was 46%. Of the 78 trials, 46 used the parallel-group design, 30 the factorial design, and 2 the cross-over design. All antioxidants were administered orally, either alone or in combination with vitamins, minerals, or other interventions. The duration of supplementation varied from 28 days to 12 years (mean duration 3 years; median duration 2 years). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (21,484 dead/183,749 (11.7%) versus 11,479 dead/112,958 (10.2%); 78 trials, relative risk (RR) 1.02, 95% confidence interval (CI) 0.98 to 1.05) but significantly increased mortality in a fixed-effect model (RR 1.03, 95% CI 1.01 to 1.05). Heterogeneity was low with an I(2)- of 12%. In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. Meta-regression analysis did not find a significant difference in the estimated intervention effect in the primary prevention and the secondary prevention trials. In the 56 trials with a low risk of bias, the antioxidant supplements significantly increased mortality (18,833 dead/146,320 (12.9%) versus 10,320 dead/97,736 (10.6%); RR 1.04, 95% CI 1.01 to 1.07). This effect was confirmed by trial sequential analysis. Excluding factorial trials with potential confounding showed that 38 trials with low risk of bias demonstrated a significant increase in mortality (2822 dead/26,903 (10.5%) versus 2473 dead/26,052 (9.5%); RR 1.10, 95% CI 1.05 to 1.15). In trials with low risk of bias, beta-carotene (13,202 dead/96,003 (13.8%) versus 8556 dead/77,003 (11.1%); 26 trials, RR 1.05, 95% CI 1.01 to 1.09) and vitamin E (11,689 dead/97,523 (12.0%) versus 7561 dead/73,721 (10.3%); 46 trials, RR 1.03, 95% CI 1.00 to 1.05) significantly increased mortality, whereas vitamin A (3444 dead/24,596 (14.0%) versus 2249 dead/16,548 (13.6%); 12 trials, RR 1.07, 95% CI 0.97 to 1.18), vitamin C (3637 dead/36,659 (9.9%) versus 2717 dead/29,283 (9.3%); 29 trials, RR 1.02, 95% CI 0.98 to 1.07), and selenium (2670 dead/39,779 (6.7%) versus 1468 dead/22,961 (6.4%); 17 trials, RR 0.97, 95% CI 0.91 to 1.03) did not significantly affect mortality. In univariate meta-regression analysis, the dose of vitamin A was significantly associated with increased mortality (RR 1.0006, 95% CI 1.0002 to 1.001, P = 0.002).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.

Cancer chemoprevention by carotenoids

Carotenoids are natural fat-soluble pigments that provide bright coloration to plants and animals. Dietary intake of carotenoids is inversely associated with the risk of a variety of cancers in different tissues. Preclinical studies have shown that some carotenoids have potent antitumor effects both in vitro and in vivo, suggesting potential preventive and/or therapeutic roles for the compounds. Since chemoprevention is one of the most important strategies in the control of cancer development, molecular mechanism-based cancer chemoprevention using carotenoids seems to be an attractive approach. Various carotenoids, such as β-carotene, a-carotene, lycopene, lutein, zeaxanthin, β-cryptoxanthin, fucoxanthin, canthaxanthin and astaxanthin, have been proven to have anti-carcinogenic activity in several tissues, although high doses of β-carotene failed to exhibit chemopreventive activity in clinical trials. In this review, cancer prevention using carotenoids are reviewed and the possible mechanisms of action are described.

A Mechanistic Approach for Modulation of Arsenic Toxicity in Human Lymphocytes by Curcumin, an Active Constituent of Medicinal Herb Curcuma longa Linn

Chronic exposure of humans to high concentrations of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, blackfoot disease and a high risk of cancer. Arsenic induces single strand breaks, DNA-protein crosslinks and apurinic sites in DNA, which are prerequisites for induction of cancer. Amelioration of such damages with natural compounds could be an effective strategy to combat arsenic toxicity. Curcumin is the active ingredient of turmeric, a common household spice, which is a rich source of polyphenols and this compound has been extensively studied as a chemopreventive agent against many types of cancer. The present study investigates whether curcumin could counteract the DNA damage caused by arsenic as assessed by single cell gel electrophoresis (SCGE) using peripheral blood lymphocytes, from healthy donors. It was observed that DNA damage induced by arsenic could be efficiently reduced by curcumin and the effect was more pronounced when lymphocytes were pre-incubated with curcumin prior to arsenic insult. Arsenic caused DNA damage by generation of reactive oxygen species (ROS) and enhancement of lipid peroxidation levels. Curcumin counteracted the damage by quenching ROS, decreasing the level of lipid peroxidation and increasing the level of phase II detoxification enzymes like catalase, superoxide dismutase and glutathione peroxidase. Curcumin also enhanced the DNA repair activity against arsenic induced damage. The expression of polymerase, a repair enzyme, was found to be highly elevated when arsenite induced damaged cells were allowed to repair in presence of curcumin. Results indicate that curcumin has significant role in confronting the deleterious effect caused by arsenic, which could be an economic mode of arsenic mitigation among rural population in West Bengal, India.

Comparison between efficacy of allicin and fluconazole against Candida albicans in vitro and in a systemic candidiasis mouse model

The efficacy of allicin compared with fluconazole in alleviating systemic Candida albicans infections was evaluated both in vitro and in vivo through a systemic candidiasis mouse model. Determination of in vitro minimum inhibitory concentrations (MICs) for different C. albicans isolates revealed that both allicin and fluconazole showed different MICs that ranged from 0.05 to 12.5 μg mL(-1) and 0.25 to 16 μg mL(-1) , respectively. A time-kill study showed a significant effect of allicin (P<0.01) against C. albicans, comparable to that of fluconazole. Scanning electron microscopy observation revealed that, similar to fluconazole, allicin produced structural destruction of C. albicans cell surface at low MIC and lysis or puncture at high MIC concentrations. Treatment of BALB/c mice systemically infected with C. albicans showed that although the allicin treatment (at 5 mg kg(-1) day(-1) ) was slightly less efficacious than fluconazole treatment in terms of the fungal load reduction and host survival time, it was still effective against C. albicans in terms of mean survival time, which increased from 8.4 to 15.8 days. These results demonstrate the efficacy of anticandidal effects of allicin both in vitro and in an animal model of candidiasis and affirm the potential of allicin as an adjuvant therapy to fluconazole.

Silibinin exerts sustained growth suppressive effect against human colon carcinoma SW480 xenograft by targeting multiple signaling molecules

PURPOSE

Earlier, we reported the strong preventive efficacy of silibinin against colorectal cancer (CRC), but its usefulness against established CRC or effect of its withdrawal on CRC growth remained unknown. Present study focused on these important issues by employing two different treatment protocols in advanced human CRC SW480 xenograft in nude mice.

METHODS

In the first treatment protocol, silibinin was fed for 28 days (200 mg/kg body weight, 5 days/week) to mice with growing SW480 xenograft; thereafter, tumor growth was monitored for additional 3 weeks without silibinin treatment. In the second protocol, silibinin treatment was started after 25 days of SW480 cells injection (established tumors), and tumor growth was studied 4 days, 8 days and 16 days after silibinin treatment.

RESULTS

In both treatment protocols, silibinin had strong and sustained inhibitory effect on xenograft growth. Detailed xenograft analyses showed that silibinin, in both treatment protocols, exerts anti-proliferative, pro-apoptotic and anti-angiogenic effects. Further, silibinin reduced the expression of β-catenin and phospho-GSK3β in xenograft tissues. Silibinin also targeted signaling molecules involved in CRC proliferation and survival (cyclin D1, c-Myc and survivin) as well as angiogenesis regulators (VEGF and iNOS).

CONCLUSIONS

Collectively, these findings substantiate silibinin's therapeutic efficacy against CRC, advocating its translational potential.

Aloe vera as a functional ingredient in foods

The main scientific discoveries on Aloe vera published mainly in the last three decades are presented in this work. After describing Aloe from a botanical point of view, the papers related with the chemical composition of different parts of the leaf of Aloe, particularly those in which the gel is described and are presented in a synthetic manner. The chemical analyses reveal that Aloe gel contains mannose polymers with some glucose and other sugars, among which the most important is Acemannan. Besides these, other components such as glycoproteins, enzymes, amino acids, vitamins, and minerals are described. Different factors also affecting the chemical composition of the gel, such as species and variety, climatic and soil conditions, cultivation methods, processing and preservation, are enumerated and discussed. On the other hand, the main therapeutic applications have been revised and the possible damaging effects of Aloe are also commented upon. A special emphasis is placed on the biologically active compounds or groups of compounds responsible for the therapeutic applications and which are their action mechanisms. The paper concludes that more research is needed to confirm the therapeutic and beneficial effects and to definitively clarify the myth surrounding Aloe vera. A general view on the problem of the commercialization and establishment of the quality and safety of Aloe products in the food industry has been offered here. The main points and European regulations that need to be considered regarding the quality control of prepared Aloe products are presented in this paper.

Factors to consider in the use of stem cells for pharmaceutic drug development and for chemical safety assessment

Given the reality of the inadequacies of current concepts of the mechanisms of chemical toxicities, of the various assays to predict toxicities from current molecular, biochemical, in vitro and animal bioassays, and of the failure to generate efficacious and safe chemicals for medicines, food supplements, industrial, consumer and agricultural chemicals, the recent NAS Report, "Toxicity Testing in the 21st Century: A Vision and a Strategy", has drawn attention to a renewed examination of what needs to be done to improve our current approach for better assessment of potential risk to human health. This "Commentary" provides a major paradigm challenge to the current concepts of how chemicals induce toxicities and how these various mechanisms of toxicities can contribute to the pathogenesis of some human diseases, such as birth defects and cancer. In concordance with the NAS Report to take "... advantage of the on-going revolution in biology and biotechnology", this "Commentary" supports the use of human embryonic and adult stem cells, grown in vitro under simulated "in vivo niche conditions". The human being should be viewed "as greater than the sum of its parts". Homeostatic control of the "emergent properties" of the human hierarchy, needed to maintain human health, requires complex integration of endogenous and exogenous signaling molecules that control cell proliferation, differentiation, apoptosis and senescence of stem, progenitor and differentiated cells. Currently, in vitro toxicity assays (mutagenesis, cytotoxicity, epigenetic modulation), done on 2-dimensional primary rodent or human cells (which are always mixtures of cells), on immortalized or tumorigenic rodent or human cell lines do not represent normal human cells in vivo [which do not grow on plastic and which are in micro-environments representing 3 dimensions and constantly interacting factors]. In addition, with the known genetic, gender, and developmental state of cells in vivo, any in vitro toxicity assay will need to mimic these conditions in vitro. More specifically, while tissues contain a few stem cells, many progenitor/transit cells and terminally differentiated cells, it should be obvious that both embryonic and adult stem cells would be critical "target" cells for toxicity testing. The ultimate potential for in vitro testing of human stem cells will to try to mimic a 3-D in vitro micro-environment on multiple "organ-specific and multiple genotypic/gender "adult stem cells. The role of stem cells in many chronic diseases, such as cancer, birth defects, and possibly adult diseases after pre-natal and early post-natal exposures (Barker hypothesis), demands toxicity studies of stem cells. While alteration of gene expression ("toxico-epigenomics") is a legitimate endpoint of these toxicity studies, alteration of the quantity of stem cells during development must be serious considered. If the future utility of human stem cells proves to be valid, the elimination of less relevant, expensive and time-consuming rodent and 2-D human in vitro assays will be eliminated.

Glycine- and proline-rich glycoprotein regulates the balance between cell proliferation and apoptosis for ACF formation in 1,2-dimethylhydrazine-treated A/J mice

The objective of this study was to investigate the chemopreventive potentials of glycine- and proline-rich glycoprotein (SNL glycoprotein, 150-kDa) isolated from Solanum nigrum Linne on formation of colonic aberrant crypt foci (ACF) induced by 1,2-dimethylhydrazine (DMH, 20 mg/kg) in A/J mice. Administration of SNL glycoprotein inhibited phosphorylation of extracellular signal-regulated kinase (ERK), expression of colonic proliferating cell nuclear antigen (PCNA), and frequency of colonic ACF in DMH-stimulated mice colon carcinogenesis. In addition, SNL glycoprotein increased expression of cyclin-dependent kinase inhibitors (p21(WAF/Cip1) and p27(Kip1)), whereas reduced expression of precursor form of apoptosis-related proteins [pro-caspase-3 and pro-poly(ADP-ribose)polymerase (PARP)] in the mice. Interestingly, the results in this study revealed that SNL glycoprotein has suppressive effects on activity of nuclear factor-kappa B (NF-kappaB), whereas it has stimulatory effect on the expression of p53, accompanying inhibitory effects on expression of NF-kappaBp50, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha in DMH-stimulated ACF formation. Also, SNL glycoprotein has inhibitory effects on the formation of thiobarbituric acid reactive substances (TBARS), on the production of inducible nitric oxide (NO), and on the release of lactate dehydrogenase (LDH) in the mice plasma. Collectively, our findings in this study suggest that SNL glycoprotein has chemopreventive activity via modulation of cell proliferation and apoptosis in DMH-treated A/J mice.

p21/Cip1 and p27/Kip1 Are essential molecular targets of inositol hexaphosphate for its antitumor efficacy against prostate cancer

Inositol hexaphosphate (IP6) causes G(1) arrest and increases cyclin-dependent kinase inhibitors p21/Cip1 and p27/Kip1 protein levels in human prostate cancer (PCa) DU145 cells lacking functional p53. However, whether cyclin-dependent kinase inhibitor I induction by IP6 plays any role in its antitumor efficacy is unknown. Herein, we observed that either p21 or p27 knockdown by small interfering RNA has no considerable effect on IP6-induced G(1) arrest, growth inhibition, and death in DU145 cells; however, the simultaneous knockdown of both p21 and p27 reversed the effects of IP6. To further confirm these findings both in vitro and in vivo, we generated DU145 cell variants with knockdown levels of p21 (DU-p21), p27 (DU-p27), or both (DU-p21+p27) via retroviral transduction of respective short hairpin RNAs. Knocking down p21 or p27 individually did not alter IP6-caused cell growth inhibition and G(1) arrest; however, their simultaneous ablation completely reversed the effects of IP6. In tumor xenograft studies, IP6 (2% w/v, in drinking water) caused a comparable reduction in tumor volume (40-46%) and tumor cell proliferation (26-28%) in DU-EV (control), DU-p21, and DU-p27 tumors but lost most of its effect in DU-p21+p27 tumors. IP6-caused apoptosis also occurred in a Cip/Kip-dependent manner because DU-p21+p27 cells were completely resistant to IP6-induced apoptosis both in cell culture and xenograft. Together, these results provide evidence, for the first time, of the critical role of p21 and p27 in mediating the anticancer efficacy of IP6, and suggest their redundant role in the antiproliferative and proapoptotic effects of IP6 in p53-lacking human PCa cells, both in vitro and in vivo.

Estimation of tolerable upper intake level (UL) of active aloe

It has been reported that an active aloe polysaccharide isolated from Aloe barbadensis Miller exerted various pharmacological effects, such as anti-inflammatory, wound healing, anti-hepatitis, anti-gastric ulcer, and anti-tumorigenicity in animals. Adverse health effects of aloe are of concern in humans. Therefore, this study was conducted to investigate a tolerable upper intake level (UL) of active aloe or a maximal allowable daily intake (ADImax) of active aloe based on 4-wk oral toxicity investigation in ICR mice. An active aloe was daily administered to male and female ICR mice for 4 wk at different dose levels (0, 120, 600, 3000, or 15,000 mg/kg body weight [bw]). All animals were sacrificed at the end of the experiment and changes of body weight, food consumption, organ weights, and hematological and biochemical parameters were recorded. In this study, no changes in clinical signs, urinalysis, or hematological or biochemical analysis were observed. In females, a dose-dependent quantitative decrease in albumin (ALB) levels was observed, but it was not significant, due to wide interindividual variations. A significant decrease in male kidney weight was observed from the 120-mg/kg to the 15,000-mg/kg bw treatment groups, and blood urea nitrogen (BUN) levels were also quantitatively lower. A dose-dependent reduction in the body weight of females was also observed, which might be related to less food consumption. Based on the reduced kidney weights in males, the lowest-observed-adverse-effect level (LOAEL) of an active aloe was estimated to be 120 mg/kg bw in male ICR mice, and the UL or ADImax was 0.4 mg/kg bw/d [(120 mg/kg bw/d)/(100 for safety factor) x (3 for modifying factor)], or 24 mg for a 60-kg adult (24 mg x 200 = 4.8 g of aloe gel/d/adult), assuming that consumers utilize active aloe for a month. Data showed that an active aloe did not induce any remarkable subacute toxic effects, but decreased male kidney weights, which requires further investigation.

Risk assessment of soybean-based phytoestrogens

Koreans generally consume high quantities of soybean-based foods that contain a variety of phytoestrogens, such as, daidzein, zenistein, and biochalin A. However, phytoestrogens are considered to be potential endocrine-disrupting chemicals (EDC), which interfere with the normal function of the hormonal and reproductive systems. Therefore, dietary exposure to soybean-based phytoestrogens is of concern for Koreans, and comparative dietary risk assessments are required between Japanese (high consumers) versus Americans (low consumers). In this study, a relative risk assessment was conducted based upon daily intake levels of soybean-based foods and phytoestrogens in a Korean cohort, and the risks of photoestrogens were compared with those posed by estradiol and other EDC. Koreans approximately 30-49 yr of age consume on average a total of 135.2 g/d of soy-based foods including soybean, soybean sauce, soybean paste, and soybean oil, and 0.51 mg/kg body weight (bw)/d of phytoestrogens such as daidzein and genistein. Using estimated daily intakes (EDI) and estrogenic potencies (EP), margins of safety (MOS) were calculated where 0.05 is for estradiol (MOS value <1, considered to exert a positive estrogenic effect); thus, MOS values of 1.89 for Japanese, 1.96 for Koreans, and 5.55 for Americans indicate that consumption of soybean-based foods exerted no apparent estrogenic effects, as all MOS values were all higher than 1. For other synthetic EDC used as reference values, MOS values were dieldrin 27, nonylphenol 250, butyl benzyl phthalate 321, bisphenol A 1000, biochanin A 2203, and coumesterol 2898. These results suggest that dietary exposure to phytoestrogens, such as daidzein and genistein, poses a relatively higher health risk for humans than synthetic EDC, although MOS values were all greater than 1.

ZPDC glycoprotein inhibits inflammation-related cytokine and protein via nuclear factor-kappa B in dextran sulfate sodium-stimulated ICR mouse

The purpose of this study is to investigate the anti-inflammatory potentials of a 24-kDa glycoprotein isolated from Zanthoxylum piperitum DC fruit (ZPDC glycoprotein) in dextran sulfate sodium (DSS)-stimulated ICR mouse colitis. ZPDC glycoprotein was administered to mice at 10 and 20 mg/kg for 7 days and then the mice were co-treated with 5% DSS for another 7 days in presence of ZPDC glycoprotein and killed on day 15. The results showed that ZPDC glycoprotein has inhibitory effects on levels of disease activity index and large intestine shortening in DSS-treated mice. In addition, ZPDC glycoprotein suppresses the formation of thiobarbituric acid reactive substances, production of inducible nitric oxide, and release of lactate dehydrogenase in DSS-treated mice plasma. Interestingly, we found that consumption of ZPDC glycoprotein (20 mg/kg) significantly inhibited the expressions of interleukin-1beta and tumor necrosis factor-alpha, inducible nitric oxide synthase, and cyclooxygenase-2 via modulation of transcriptional activity of nuclear factor-kappa B in DSS-treated mice colon. Collectively, these results suggest that ZPDC glycoprotein is useful for prevention of inflammatory gastrointestinal diseases.

Systematic review: primary and secondary prevention of gastrointestinal cancers with antioxidant supplements

BACKGROUND

The evidence on whether antioxidant supplements prevent gastrointestinal cancers is contradictory.

AIM

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

METHODS

Using the Cochrane Collaboration methodology, we reviewed the randomized trials comparing antioxidant supplements with placebo or no intervention on the occurrence of gastrointestinal cancers. We searched electronic databases and reference lists until October, 2007. Our outcome measures were gastrointestinal cancers, overall mortality and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence intervals (CI) based on random-effects and fixed-effect models meta-analyses.

RESULTS

We identified 20 randomized trials (211,818 participants) assessing beta-carotene, vitamin A, vitamin C, vitamin E, and selenium. The trial quality was generally high. The antioxidant supplements were without a significant effect on the occurrence of gastrointestinal cancers (RR 0.94, 95% CI 0.83-1.06, I(2) = 54.0%). The heterogeneity seemed to be explained by bias risk (low-bias risk trials RR 1.04, 95% CI 0.96-1.13 compared to high-bias risk trials RR 0.59, 95% CI 0.43-0.80, test of interaction P < 0.0005) and type of antioxidant supplement (beta-carotene potentially increasing and selenium potentially decreasing cancer risk). Antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (RR 1.02, 95% CI 0.97-1.07, I(2) = 53.5%) but significantly increased mortality in a fixed-effect model meta-analysis (RR 1.04, 95% CI 1.02-1.07).

CONCLUSIONS

We could not find evidence that the studied antioxidant supplements prevented gastrointestinal cancers. On the contrary, they seem to increase overall mortality.

Antioxidant supplements for preventing gastrointestinal cancers

BACKGROUND

Oxidative stress may cause gastrointestinal cancers. The evidence on whether antioxidant supplements are effective in preventing gastrointestinal cancers is contradictory.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

SEARCH STRATEGY

We identified trials through the trials registers of the four Cochrane Review Groups on gastrointestinal diseases, The Cochrane Central Register of Controlled Trials in The Cochrane Library (Issue 2, 2007), MEDLINE, EMBASE, LILACS, SCI-EXPANDED, and The Chinese Biomedical Database from inception to October 2007. We scanned reference lists and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing antioxidant supplements to placebo/no intervention examining occurrence of gastrointestinal cancers.

DATA COLLECTION AND ANALYSIS

Two authors (GB and DN) independently selected trials for inclusion and extracted data. Outcome measures were gastrointestinal cancers, overall mortality, and adverse effects. Outcomes were reported as relative risks (RR) with 95% confidence interval (CI) based on random-effects and fixed-effect model meta-analysis. Meta-regression assessed the effect of covariates across the trials.

MAIN RESULTS

We identified 20 randomised trials (211,818 participants), assessing beta-carotene (12 trials), vitamin A (4 trials), vitamin C (8 trials), vitamin E (10 trials), and selenium (9 trials). Trials quality was generally high. Heterogeneity was low to moderate. Antioxidant supplements were without significant effects on gastrointestinal cancers (RR 0.94, 95% CI 0.83 to 1.06). However, there was significant heterogeneity (I(2) = 54.0%, P = 0.003). The heterogeneity may have been explained by bias risk (low-bias risk trials RR 1.04, 95% CI 0.96 to 1.13 compared to high-bias risk trials RR 0.59, 95% CI 0.43 to 0.80; test of interaction P < 0.0005), and type of antioxidant supplement (beta-carotene potentially increasing and selenium potentially decreasing cancer risk). The antioxidant supplements had no significant effects on mortality in a random-effects model meta-analysis (RR 1.02, 95% CI 0.97 to 1.07, I(2) = 53.5%), but significantly increased mortality in a fixed-effect model meta-analysis (RR 1.04, 95% CI 1.02 to 1.07). Beta-carotene in combination with vitamin A (RR 1.16, 95% CI 1.09 to 1.23) and vitamin E (RR 1.06, 95% CI 1.02 to 1.11) significantly increased mortality. Increased yellowing of the skin and belching were non-serious adverse effects of beta-carotene. In five trials (four with high risk of bias), selenium seemed to show significant beneficial effect on gastrointestinal cancer occurrence (RR 0.59, 95% CI 0.46 to 0.75, I(2) = 0%).

AUTHORS' CONCLUSIONS

We could not find convincing evidence that antioxidant supplements prevent gastrointestinal cancers. On the contrary, antioxidant supplements seem to increase overall mortality. The potential cancer preventive effect of selenium should be tested in adequately conducted randomised trials.

Immunomodulatory activity of plant residues on ovine neutrophils

Neutrophils play an essential role in host defense and inflammation. Plants have long been used to improve the immune function, but for most of them specific investigations on animal health are lacking. In the present study, water and hydroethanolic extracts from 11 plant wastes have been screened on immune responses of ovine neutrophils. Eight sheep clinically healthy, not lactating, non-pregnant were selected and used for the experiment. Freshly isolated neutrophils were incubated with the extracts of the residues at increasing doses, and then they were tested for adhesion and superoxide production induced with PMA. The residues of Larix decidua, Thymus vulgaris, Salix alba, Sinupret, Helianthus annuus, Mangifera indica modulated the neutrophil immune functions, moreover, Larix decidua, Thymus vulgaris and Salix alba presented the highest anti-inflammatory activity.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival.

OBJECTIVES

To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials.

SEARCH STRATEGY

We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials).

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.