Drug screening identifies tazarotene and bexarotene as therapeutic agents in multiple sulfatase deficiency.

Multiple sulfatase deficiency (MSD, MIM #272200) results from pathogenic variants in the SUMF1 gene that impair proper function of the formylglycine-generating enzyme (FGE). FGE is essential for the posttranslational activation of cellular sulfatases. MSD patients display reduced or absent sulfatase activities and, as a result, clinical signs of single sulfatase disorders in a unique combination. Up to date therapeutic options for MSD are limited and mostly palliative. We performed a screen of FDA-approved drugs using immortalized MSD patient fibroblasts. Recovery of arylsulfatase A activity served as the primary readout. Subsequent analysis confirmed that treatment of primary MSD fibroblasts with tazarotene and bexarotene, two retinoids, led to a correction of MSD pathophysiology. Upon treatment, sulfatase activities increased in a dose- and time-dependent manner, reduced glycosaminoglycan content decreased and lysosomal position and size normalized. Treatment of MSD patient derived induced pluripotent stem cells (iPSC) differentiated into neuronal progenitor cells (NPC) resulted in a positive treatment response. Tazarotene and bexarotene act to ultimately increase the stability of FGE variants. The results lay the basis for future research on the development of a first therapeutic option for MSD patients.

Marmesin and Marmelosin Interact with the Heparan Sulfatase-2 Active Site: Potential Mechanism for Phytochemicals from Bael Fruit Extract as Antitumor Therapeutics.

Human heparan sulfatase-2 (HSULF-2) is an oncoprotein overexpressed in the surface of all types of tumor cells and its activity plays a critical role in cancer survival and progression. Our previous studies have shown that bael fruit extract, containing marmesin and marmelosin, inhibits the HSULF-2 activity and kills breast tumor cells, but the mechanism of these processes remains fairly known mainly because the HSULF-2's 3D structure is partially known. Herein, we aimed at providing an in silico molecular mechanism of the inhibition of human HSULF-2 by phytochemicals from bael fruit extract. Pharmacokinetic parameters of the main phytochemicals contained in the bael fruit extract, sequence-based 3D structure of human HSULF-2, and the interaction of bael fruit's phytochemicals with the enzyme active site was modeled, evaluated, and verified. Docking studies revealed marmesin and marmelosin as potential inhibitors with binding score -8.5 and -7.7 Kcal/mol; these results were validated using molecular dynamics simulations, which exhibited higher stability of the protein-ligand complexes. Taking together, with our earlier in vitro data, our computational analyses suggest that marmesin and marmelosin interact at the active site of HSULF-2 providing a potential mechanism for its inhibition and consequent antitumor activity by phytochemicals contained in the bael fruit extract.

Extracellular endosulfatase Sulf-2 harbors a chondroitin/dermatan sulfate chain that modulates its enzyme activity.

Sulfs represent a class of unconventional sulfatases which provide an original post-synthetic regulatory mechanism for heparan sulfate polysaccharides and are involved in multiple physiopathological processes, including cancer. However, Sulfs remain poorly characterized enzymes, with major discrepancies regarding their in vivo functions. Here we show that human Sulf-2 (HSulf-2) harbors a chondroitin/dermatan sulfate glycosaminoglycan (GAG) chain, attached to the enzyme substrate-binding domain. We demonstrate that this GAG chain affects enzyme/substrate recognition and tunes HSulf-2 activity in vitro and in vivo. In addition, we show that mammalian hyaluronidase acts as a promoter of HSulf-2 activity by digesting its GAG chain. In conclusion, our results highlight HSulf-2 as a proteoglycan-related enzyme and its GAG chain as a critical non-catalytic modulator of the enzyme activity. These findings contribute to clarifying the conflicting data on the activities of the Sulfs.

Engagement of phytoestrogens in breast cancer suppression: Structural classification and mechanistic approach.

Cancer is the world's devastating disease, and breast cancer is the most common reason for the death of women worldwide. Many synthetic drugs and medications are provided with their beneficial actions, but all of these have side effects and resistance problems. Natural remedies are coming forward to overcome the disadvantages of synthetic drugs. Among the natural categories, phytoestrogens having a structural similarity of mammalian oestradiol proves its benefit with various mechanisms not only in the treatment of breast cancer but even to prevent the occurrence of postmenopausal symptoms. Phytoestrogens are plant-derived compounds that were utilized in ancient medications and traditional knowledge for its sex hormone properties. Phytoestrogens exert pleiotropic effects on cellular signalling and show effects on estrogen-dependent diseases. However, because of activation/inhibition of steroid hormonal receptor ER-α or ER-ß, these compounds induce or inhibit steroid hormonal (estrogen) action and, therefore, have the potential to disrupt hormone (estrogen) signalling pathway. In this review, we have discussed and summarize the effect of certain phytoestrogens and their possible mechanisms that can substantiate advantageous benefits for the treatment of post-menopausal symptoms as well as for breast cancer.

Identification of metabolites and potential biomarkers of kratom in urine.

Mitragyna speciosa (kratom) is a drug that is increasingly used recreationally and "therapeutically", in the absence of medical supervision. The drug has been associated with a growing number of fatalities, and although its medicinal properties as an atypical opioid require further study, there are legitimate concerns regarding its unregulated use. Mitragynine is the most widely reported alkaloid within the plant, although more than forty other alkaloids have been identified. 7-Hydroxymitragynine is reported to have greater abuse liability due to its increased potency relative to mitragynine. In this report, biomarkers for mitragynine were investigated using liquid chromatography-quadrupole/time of flight mass spectrometry (LC-Q/TOF-MS). Speciociliatine and speciogynine were identified as alternative biomarkers, often exceeding the concentration of mitragynine in unhydrolyzed urine. 9-O-Demethylmitragynine and 7-hydroxymitragynine were identified in unhydrolyzed urine in 75% and 63% of the cases. Deconjugation of phase II metabolites using chemical hydrolysis was not suitable due to degradation of the Mitragyna alkaloids. Enzymatic hydrolysis was evaluated using three traditional glucuronidases, four sulfatases and four recombinant enzymes. Although enzymatic hydrolysis increased the concentration of 16-carboxymitragynine, it had nominal benefit for other metabolites. Deconjugation of urine was not necessary due to the abundance of parent drug (mitragynine), its diastereoisomers (speciociliatine and speciogynine) or metabolites (9-O-demethylmitragynine and 7-hydroxymitragynine).

The fallacy of enzymatic hydrolysis for the determination of bioactive curcumin in plasma samples as an indication of bioavailability: a comparative study.

BACKGROUND: Numerous health benefits have been demonstrated for curcumin which is extracted from turmeric (Curcuma longa L). However, due to its poor absorption in the free form in the gastrointestinal tract and rapid biotransformation, various formulations have been developed to enhance its bioavailability. Previous studies indicate that the free form of curcumin is more bioactive than its conjugated counterparts in target tissues. Most curcumin pharmacokinetics studies in humans designed to assess its absorption and bioavailability have measured and reported total (free plus conjugated) curcumin, but not free, bioactive curcumin in the plasma because enzymatic hydrolysis was employed prior to its extraction and analysis. Therefore, the bioavailability of free curcumin cannot be determined. METHODS: Eight human subjects (4 male, 4 female) consumed a single dose of 400 mg curcumin in an enhanced absorption formulation, and blood samples were collected over 6 h. Plasma was treated either with or without glucuronidase/sulfatase prior to extraction. Curcumin and its major metabolites were analyzed using HPLC-tandem mass spectrometry. In addition, the literature was searched for pharmacokinetic studies involving curcumin using PubMed and Google Scholar, and the reported bioavailability data were compared based on whether hydrolysis of plasma samples was used prior to sample analysis. RESULTS: Hydrolysis of blood plasma samples prior to extraction and reporting the results as "curcumin" obscures the amount of free, bioactive curcumin and total curcuminoids as compared to non-hydrolyzed samples. As a consequence, the data and biological effects reported by most pharmacokinetic studies are not a clear indication of enhanced plasma levels of free bioactive curcumin due to product formulations, leading to a misrepresentation of the results of the studies and the products when enzymatic hydrolysis is employed. CONCLUSIONS: When enzymatic hydrolysis is employed as is the case with most studies involving curcumin products, the amount of free bioactive curcumin is unknown and cannot be determined. Therefore, extreme caution is warranted in interpreting published analytical results from biological samples involving ingestion of curcumin-containing products. TRIAL REGISTRATION: ClinicalTrails.gov, trial identifying number NCT04103788 , September 24, 2019. Retrospectively registered.

Sulfation mediates activity of zosteric acid against biofilm formation.

Zosteric acid (ZA), a metabolite from the marine sea grass Zostera marina, has attracted much attention due to its attributed antifouling (AF) activity. However, recent results on dynamic transformations of aromatic sulfates in marine phototrophic organisms suggest potential enzymatic desulfation of metabolites like ZA. The activity of ZA was thus re-investigated using biofilm assays and simultaneous analytical monitoring by liquid chromatography/mass spectrometry (LC/MS). Comparison of ZA and its non-sulfated form para-coumaric acid (CA) revealed that the active substance was in all cases the non-sulfated CA while ZA was virtually inactive. CA exhibited a strong biofilm inhibiting activity against Escherichia coli and Vibrio natriegens. The LC/MS data revealed that the apparent biofilm inhibiting effects of ZA on V. natriegens can be entirely attributed to CA released from ZA by sulfatase activity. In the light of various potential applications, the (a)biotic transformation of ZA to CA has thus to be considered in future AF formulations.

Pectin of Prunus domestica L. alters sulfated structure of cell-surface heparan sulfate in differentiated Caco-2 cells through stimulation of heparan sulfate 6-O-endosulfatase-2.

Although previous reports have suggested that pectin induces morphological changes of the small intestine in vivo, the molecular mechanisms have not been elucidated. As heparan sulfate plays important roles in development of the small intestine, to verify the involvement of heparan sulfate (HS) in the pectin-induced morphological changes of the small intestine, the effects of pectin from Prunus domestica L. on cell-surface HS were investigated using differentiated Caco-2 cells. Disaccharide compositional analysis revealed that sulfated structures of HS were markedly changed by pectin administration. Real-time RT-PCR showed that pectin upregulated human HS 6-O-endosulfatase-2 (HSulf-2) expression and markedly inhibited HSulf-1 expression. Furthermore, inhibition analysis suggested that pretreatment with fibronectin III1C fragment, RGD peptide, and ERK1/2 inhibitor suppressed pectin-induced HSulf-2 expression. These observations indicate that pectin induced the expression of HSulf-2 through the interaction with fibronectin, α5ß1 integrin, and ERK1/2, thereby regulating the sulfated structure of HS on differentiated Caco-2 cells.

Steady-state pharmacokinetics and tissue distribution of anthraquinones of Rhei Rhizoma in rats.

AIM OF THE STUDY: Rhei Rhizoma, the rhizome of Rheum palmatum L. (RP), is a popular herb in clinical Chinese medicine. RP is abundant in polyphenolic anthraquinones, which have been reported to show various beneficial bioactivities. This study investigated the pharmacokinetics and tissue distribution of anthraquinones following seven-dose administration of RP decoction to rats. MATERIALS AND METHODS: Six Sprague-Dawley rats were given 2.0 g/kg of RP twice daily for seven doses and blood samples were collected at designated time after the 7th dose. Another six rats were sacrificed at 30 min after the 7th dose and organs including liver, kidney, lung and brain were collected. Serum and tissue specimens were assayed by HPLC before and after hydrolysis with ß-glucuronidase and sulfatase, respectively. RESULTS: Pharmacokinetic analysis indicated that the anthraquinones in serum mainly presented as glucuronides/sulfates and contained higher ratio of sulfates when compared with single-dose administration of RP. Contrary to the finding in serum, tissue analysis discovered mainly free form of anthraquinone in most organs assayed, such as aloe-emodin and rhein in kidney, liver, lung; emodin in liver, lung; trace of chrysophanol in kidney and liver. In all brains, neither free forms nor their glucuronides/sulfates have been detected. CONCLUSIONS: The glucuronides/sulfates of anthraquinones were the major forms in bloodstream, whereas the free forms of most anthraquinones were predominant in kidney and liver.

Permeability of rosmarinic acid in Prunella vulgaris and ursolic acid in Salvia officinalis extracts across Caco-2 cell monolayers.

ETHNOPHARMACOLOGICAL RELEVANCE: Rosmarinic acid (RA), a caffeic acid-related compound found in high concentrations in Prunella vulgaris (self-heal), and ursolic acid (UA), a pentacyclic triterpene acid concentrated in Salvia officinalis (sage), have been traditionally used to treat inflammation in the mouth, and may also be beneficial for gastrointestinal health in general. AIM OF THE STUDY: To investigate the permeabilities of RA and UA as pure compounds and in Prunella vulgaris and Salvia officinalis ethanol extracts across human intestinal epithelial Caco-2 cell monolayers. MATERIALS AND METHODS: The permeabilities and phase II biotransformation of RA and UA as pure compounds and in herbal extracts were compared using Caco-2 cells with HPLC detection. RESULTS: The apparent permeability coefficient (P(app)) for RA and RA in Prunella vulgaris extracts was 0.2 ± 0.05 × 10(-6)cm/s, significantly increased to 0.9 ± 0.2 × 10(-6)cm/s after ß-glucuronidase/sulfatase treatment. P(app) for UA and UA in Salvia officinalis extract was 2.7 ± 0.3 × 10(-6)cm/s and 2.3 ± 0.5 × 10(-6)cm/s before and after ß-glucuronidase/sulfatase treatment, respectively. Neither compound was affected in permeability by the herbal extract matrix. CONCLUSION: RA and UA in herbal extracts had similar uptake as that found using the pure compounds, which may simplify the prediction of compound efficacy, but the apparent lack of intestinal glucuronidation/sulfation of UA is likely to further enhance the bioavailability of that compound compared with RA.

Plasma pharmacokinetics of catechin metabolite 4'-O-Me-EGC in healthy humans.

BACKGROUND: Tea is an infusion of the leaves of the Camellia sinensis plant and is the most widely consumed beverage in the world after water. Green tea contains significant amounts of polyphenol catechins and represents a promising dietary component to maintain health and well-being. Epidemiological studies indicate that polyphenol intake may have potential health benefits, such as, reducing the incidence of coronary heart disease, diabetes and cancer. While bioavailability of green tea bioactives is fairly well understood, some gaps still remain to be filled, especially the identification and quantification of conjugated metabolites in plasma, such as, sulphated, glucuronidated or methylated compounds. AIM OF THE STUDY: In the present study, we aimed to quantify the appearance of green tea catechins in plasma with particular emphasis on their methylated forms. RESULTS: After feeding 400 mL of green tea, 1.25% infusion to 9 healthy subjects, we found significant amounts of EC, EGC and EGCg in plasma as expected. EGC was the most bioavailable catechin, and its methylated form (4'-O-Me-EGC) was also present in quantifiable amounts. Its kinetics followed that of its parent compound. However, the relative amount of the methylated form of EGC was lower than that of the parent compound, an important aspect which, in the literature, has been controversial so far. The quantitative results presented in our study were confirmed by co-chromatography and accurate mass analysis of the respective standards. We show that the relative abundance of 4'-O-Me-EGC is ~40% compared to the parent EGC. CONCLUSION: 4'-O-Me-EGC is an important metabolite derived from catechin metabolism. Its presence in significant amounts should not be overlooked when assessing human bioavailability of green tea.

Development of chiral liquid chromatography-tandem mass spectrometry isotope dilution methods for the determination of unconjugated and total S-equol in human plasma and urine.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for the determination of unconjugated and total (conjugated plus unconjugated) S-equol in human plasma and urine were developed and validated. The separation of R and S enantiomers was achieved with a Chiracel OJ-H column operated in a normal phase mode using ethanol/hexane mobile phase components. Ionization of S-equol by negative ion electrospray generated the [M-H](-) ion whose response was augmented by post-column addition of ammonium hydroxide. A triple stage quadrupole mass spectrometer was used to measure the ion current generated from the dissociative transitions m/z 241→m/z 121 (S-equol) and m/z 245→m/z 123 (equol-d(4)). The determination of total S-equol included an additional deconjugation step involving incubation of the sample with sulfatase and glucuronidase. Average recovery for both unconjugated and total S-equol was 85% with no observable matrix effects. Linearity was established for unconjugated S-equol from 0.025ng/mL to 10ng/mL (plasma) and 0.20ng/mL to 200ng/mL (urine). The average coefficient of variation and accuracy per occasion was within ±15% of the theoretical concentration of S-equol. The method was used to measure the pharmacokinetics of S-equol in human plasma after an oral administration of a single 20mg dose of S-equol to three normal healthy volunteers.

Genetic variation influences glutamate concentrations in brains of patients with multiple sclerosis.

Glutamate is the main excitatory neurotransmitter in the mammalian brain. Appropriate transmission of nerve impulses through glutamatergic synapses is required throughout the brain and forms the basis of many processes including learning and memory. However, abnormally high levels of extracellular brain glutamate can lead to neuroaxonal cell death. We have previously reported elevated glutamate levels in the brains of patients suffering from multiple sclerosis. Here two complementary analyses to assess the extent of genomic control over glutamate levels were used. First, a genome-wide association analysis in 382 patients with multiple sclerosis using brain glutamate concentration as a quantitative trait was conducted. In a second approach, a protein interaction network was used to find associated genes within the same pathway. The top associated marker was rs794185 (P < 6.44 x 10(-7)), a non-coding single nucleotide polymorphism within the gene sulphatase modifying factor 1. Our pathway approach identified a module composed of 70 genes with high relevance to glutamate biology. Individuals carrying a higher number of associated alleles from genes in this module showed the highest levels of glutamate. These individuals also showed greater decreases in N-acetylaspartate and in brain volume over 1 year of follow-up. Patients were then stratified by the amount of annual brain volume loss and the same approach was performed in the 'high' (n = 250) and 'low' (n = 132) neurodegeneration groups. The association with rs794185 was highly significant in the group with high neurodegeneration. Further, results from the network-based pathway analysis remained largely unchanged even after stratification. Results from these analyses indicated that variance in the activity of neurochemical pathways implicated in neurodegeneration is explained, at least in part, by the inheritance of common genetic polymorphisms. Spectroscopy-based imaging provides a novel quantitative endophenotype for genetic association studies directed towards identifying new factors that contribute to the heterogeneity of clinical expression of multiple sclerosis.

Exploration of composted cereal waste and poultry manure for soil restoration.

Poultry manure and fungal consortium developed by including fungi of genus Aspergillus, Trichoderma and Phanerochaete were evaluated separately to degrade high silica paddy straw. The quality evaluation of composted organic wastes after two months of decomposition revealed that poultry manure amended paddy straw compost had a C:N ratio of 13.06 and germination index of 132%, compared to 15.29 and 114% of its fungal inoculated counterpart. Supplementation of paddy straw with poultry manure was as effective as its bioaugmentation with fungal consortium. The incorporation of poultry manure @ 3 t ha(-1) (T3) and poultry manure amended paddy straw compost @ 3 t ha(-1)+N(60)P(40)K(30) (T4) separately to soil under rice crop for two consecutive years, resulted in improved microbial biomass and different enzymatic activities responsible for nutrient cycling. T3 and T4 treatments recorded a grain yield improvement of 54.87 and 79.26% respectively in 2007 and 79 and 80.2% respectively in 2008 compared to N(120)P(80)K(60).

Metabolism and pharmacokinetics of anthraquinones in Rheum palmatum in rats and ex vivo antioxidant activity.

Anthraquinones are a major group of polyphenols in the rhizome of Rheum palmatum L. (RP). This study investigated the metabolism and pharmacokinetics of anthraqinones in RP decoction in rats. The concentrations of four anthraquinones including aloe-emodin, rhein, emodin, chrysophanol, and their glycosides in the decoction were quantitated by HPLC before and after acid hydrolysis with the results indicating that the anthraquinones mainly existed as the glycoside form except for rhein. Rats were orally administered RP decoction and blood samples were assayed by HPLC before and after treatments with sulfatase and beta-glucuronidase. It was found that the glucuronides of aloe-emodin, rhein, emodin and chrysophanol were predominant in the blood, whereas their aglycones were not detected except for rhein. In conclusion, the anthraquinones were subject to a rapid and extensive conjugation metabolism in rats and the serum metabolites of RP exhibited a potential free radical scavenging effect on AAPH-induced hemolysis at pharmacologically relevant concentrations.

Chromatographic analysis and decomposition product characterization of compound SR16157 (NSC 732011).

SR16157 (21-(2-N,N-diethylaminoethyl)oxy-7alpha-methyl-19-norpregna-1,3,5(10)-triene-3-O-sulfamate) is a novel, dual-acting estrone sulfatase inhibitor currently in preclinical development for use in breast cancer therapy. The compound has a dual mechanism of action: the sulfamate-containing parent compound SR16157 inhibits estrogen biosynthesis by irreversibly inhibiting the enzyme estrone sulfatase. The phenolic metabolite, SR16137, generated by the sulfatase enzyme is a potent antiestrogen in breast tissues and has beneficial effects in bone and the cardiovascular system. As part of the ongoing preclinical studies, an HPLC assay method has been developed and validated for SR16157. The assay method is specific, accurate (recovery=99.4-101.1), linear (r(2)> or =0.9999), precise (intraday R.S.D.< or =1.1%, intermediate R.S.D.< or =0.8%), and sensitive (limit of detection=1.0 microg/ml). It separates SR16157 from its impurities and forced decomposition products, which have been characterized by LC coupled with mass and UV spectral data. Major decomposition pathways are hydrolysis, hydroxylation, and oxidation.

Comparison of oral bioavailability of genistein and genistin in rats.

Genistein (GT) is an isoflavone from Leguminosae and has received much attention as a phytoestrogen. Genistin is a glycoside form of GT (genistein-7-O-beta-D-glucopyranoside, GT-glu) is mainly found in soy-derived foods. In this study, we examined the pharmacokinetic properties and bioavailability of GT in rats and compared with those of GT-glu. In order to characterize and compare the pharmacokinetics of GT and GT-glu, these compounds were administered intravenously and orally. The plasma concentration of GT was determined by HPLC after enzymatic hydrolysis. After oral administration of GT with various doses (4, 20, 40 mg/kg), the bioavailability of GT was 38.58, 24.34 and 30.75%, respectively. The T(max), C(max) and AUC(0-infinity) of GT after oral administration of GT (40 mg/kg), were 2h, 4876.19 ng/ml, 31,269.66 ng h/ml, respectively. When smaller amount of GT was administered, the faster T(max) was observed. Oral administration of GT-glu resulted in longer T(max), lower C(max), and greater bioavailability than that of GT. The pharmacokinetic parameters of GT following oral administration of GT-glu (64 mg/kg as GT-glu, 40 mg/kg as GT) were obtained as follows: 8h (T(max)), 3763.96 ng/ml (C(max)), 51,221.08 ng h/ml (AUC(0-infinity)) and 48.66% (absolute bioavailability), respectively. These results indicate that the oral bioavailability of GT-glu is greater than that of GT.

Ethanolic extracts of black cohosh (Actaea racemosa) inhibit growth and oestradiol synthesis from oestrone sulphate in breast cancer cells.

Extracts of black cohosh (Actaea racemosa) and soy are used as 'natural' alternatives to conventional hormone replacement therapy (HRT) and there is some evidence that soy may protect against breast cancer by inhibiting the production of active oestrogens. This study compares the action of ethanolic extracts of black cohosh (BCE) and genistein on growth and enzyme activity in MCF-7 and MDA-MB-123 breast cancer cells. BCE inhibited growth at the two highest doses tested, i.e. 50 and 100 microg/ml, whilst genistein stimulated growth in the oestrogen receptor positive (ER(+)) MCF-7 cells, but at high doses it inhibited growth in both cell lines. BCE did not affect the conversion of androstenedione to oestradiol and only the highest doses (50 and 100 microg/ml) significantly inhibited the conversion of oestrone to oestradiol in MDA cells. In contrast, BCE induced a dose-dependent inhibition of the conversion of oestrone sulphate to oestradiol in both cell lines, whilst in human granulosa lutein (GL) cells enzyme activity was only inhibited at the highest dose of BCE. Genistein had no significant effect on enzyme activity in breast cancer cells and like BCE only the highest doses (10 and 50 microM) inhibited enzyme activity in human GL cells. In vivo genistein may have growth stimulatory effects on breast tissue but BCE not only inhibits growth but inhibits the conversion of oestrone sulphate to active oestradiol, considered by some, to be the preferred pathway of oestradiol synthesis in breast tissue.

Dietary supplementation of resveratrol suppresses colonic tumour incidence in 1,2-dimethylhydrazine-treated rats by modulating biotransforming enzymes and aberrant crypt foci development.

Diet-induced changes in the activities of bacterial enzymes are known to play a role in colon cancer development. Resveratrol has been implicated as a protective agent in carcinogenesis. In the present study, the effect of resveratrol on the activities of faecal and colonic biotransforming enzymes such as beta-glucuronidase, beta-glucosidase, beta-galactosidase, mucinase, nitroreductase and faecal sulfatase activity was assessed. The total number of aberrant crypt foci and their distribution in the proximal, medial and distal colon were observed in 1,2-dimethylhydrazine (DMH)-induced rats (group 3) and other treatment groups (groups 4-6). DMH (0.02 g/kg body weight) was given subcutaneously once a week for 15 consecutive weeks, and the experiment was terminated at 30 weeks. DMH-treated rats showed elevated levels of cancer-associated bacterial enzyme activities, whereas on resveratrol supplementation in three different regimens, rats showed lowered activities. Resveratrol supplementation throughout the experimental period (group 6) exerted a more pronounced effect (P < 0.01) by modulating the development of aberrant crypt foci and the activities of bacterial enzymes than did the other treatment regimens (groups 4 and 5). Thus, the present results demonstrate the inhibitory effect of resveratrol on DMH-induced colon carcinogenesis in rats.

Endocrine-disrupting chemicals as modulators of sex steroid synthesis.

Endocrine-disrupting chemicals (EDCs) are typically identified as compounds that can interact with oestrogen or androgen receptors and thus act as agonists or antagonists of endogenous hormones. Growing evidence shows that they may also modulate the activity/expression of steroidogenic enzymes. These are expressed not only in the adrenal glands and gonads but also in many tissues that have the ability to convert circulating precursors into active hormones. In this way, EDCs may impact both on sexual differentiation and development and on hormone-dependent cancers. This review summarizes the evidence for EDCs as modulators of steroidogenic enzymes, identifies the structure/activity relationship in terms of inhibiting specific enzyme activity, questions whether experimental observations can equate with natural in vivo exposure or dietary intake of EDCs, and finally looks at the mechanisms through which these chemicals may disrupt normal steroidogenesis. In summarizing the evidence, the question of whether or not the dietary intake of these endocrine disrupters could pose a threat to human sexual development and health will be addressed.