RESUMO
Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 260-320 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections.
Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Helicobacter pylori/enzimologia , Isotiocianatos/farmacologia , Tiocianatos/farmacologia , Urease/antagonistas & inibidores , Antibacterianos/química , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Brassica/química , Relação Dose-Resposta a Droga , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/prevenção & controle , Helicobacter pylori/efeitos dos fármacos , Humanos , Isotiocianatos/química , Cinética , Testes de Sensibilidade Microbiana , Estrutura Molecular , Espectrofotometria Ultravioleta , Sulfóxidos , Tiocianatos/química , Fatores de Tempo , Urease/metabolismoRESUMO
Flavonoids are secondary plant products that are well represented in healthy diets because of ingestion of fruit, vegetables, herbs, and teas. Increased consumption is correlated with decreased risks of cardiovascular disease, cancer, and other chronic diseases. Certain flavonoids confer direct antioxidant protection to cells, others induce enzymes that protect cells against oxidative and other insults ("indirect antioxidants"), and others appear to be protective by both mechanisms. Hydroxylated flavones manifest substantial direct antioxidant activity but do not effectively induce cytoprotective enzymes. Methoxylated flavones that potently induce cytoprotective enzymes were evaluated to elucidate the structural prerequisites for effective chemoprotective agents: protecting healthy cells with minimal collateral toxicity. Flavones and flavanones methoxylated at the 5-position of the A-ring were among the most potent inducers of the cytoprotective NAD(P)H:quinone-oxidoreductase 1 (NQO1) in 3 different cell lines. Other flavones were equally potent inducers, but more toxic. Flavanones contain no Michael reaction center, yet some are potent inducers of NQO1, have low cytotoxicity, and inhibit LPS-stimulated iNOS activity, which suggests a redox mechanism of action rather than the Keap1/Nrf2/ARE mechanism by which so many of the classic inducers operate. Evaluation in vivo will reveal whether differential protective advantages support their possible evaluation in a cancer prevention setting.
Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Flavonoides/química , Flavonoides/farmacologia , Animais , Benzotiazóis/metabolismo , Células CACO-2 , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quimioprevenção , Humanos , Concentração Inibidora 50 , Modelos Lineares , Lipopolissacarídeos/efeitos adversos , Camundongos , NAD(P)H Desidrogenase (Quinona)/genética , NAD(P)H Desidrogenase (Quinona)/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Oxirredução , Relação Estrutura-Atividade , Ácidos Sulfônicos/metabolismoRESUMO
Sulforaphane [1-isothiocyanato-4-(methylsulfinyl)butane], a naturally occurring isothiocyanate derived from cruciferous vegetables, is a highly potent inducer of phase 2 cytoprotective enzymes and can protect against electrophiles including carcinogens, oxidative stress, and inflammation. The mechanism of action of sulforaphane is believed to involve modifications of critical cysteine residues of Keap1, which lead to stabilization of Nrf2 to activate the antioxidant response element of phase 2 enzymes. However, the dithiocarbamate functional group formed by a reversible reaction between isothiocyanate of sulforaphane and sulfhydryl nucleophiles of Keap1 is kinetically labile, and such modification in intact cells has not yet been demonstrated. Here we designed sulforaphane analogs with replacement of the reactive isothiocyanate by the more gentle electrophilic sulfoxythiocarbamate group that also selectively targets cysteine residues in proteins but forms stable thiocarbamate adducts. Twenty-four sulfoxythiocarbamate analogs were synthesized that retain the structural features important for high potency in sulforaphane analogs: the sulfoxide or keto group and its appropriate distance to electrophilic functional group. Evaluation in various cell lines including hepatoma cells, retinal pigment epithelial cells, and keratinocytes as well as in mouse skin shows that these analogs maintain high potency and efficacy for phase 2 enzyme induction as well as the inhibitory effect on lipopolysaccharide-induced nitric oxide formation like sulforaphane. We further show in living cells that a sulfoxythiocarbamate analog can label Keap1 on several key cysteine residues as well as other cellular proteins offering new insights into the mechanism of chemoprotection.
Assuntos
Produtos Biológicos/química , Produtos Biológicos/farmacologia , Tiocianatos/química , Tiocianatos/farmacologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Proteínas do Citoesqueleto/metabolismo , Elétrons , Isotiocianatos , Proteína 1 Associada a ECH Semelhante a Kelch , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Estrutura Molecular , Óxido Nítrico/metabolismo , Pele/efeitos dos fármacos , Pele/metabolismo , Relação Estrutura-Atividade , Compostos de Sulfidrila/química , SulfóxidosRESUMO
Autism Spectrum Disorder (ASD) is one of the most common neurodevelopmental disorders with no drugs treating the core symptoms and no validated biomarkers for clinical use. The multi-functional phytochemical sulforaphane affects many of the biochemical abnormalities associated with ASD. We investigated potential molecular markers from three ASD-associated physiological pathways that can be affected by sulforaphane: redox metabolism/oxidative stress; heat shock response; and immune dysregulation/inflammation, in peripheral blood mononuclear cells (PBMCs) from healthy donors and patients with ASD. We first analyzed the mRNA levels of selected molecular markers in response to sulforaphane ex vivo treatment in PBMCs from healthy donors by real-time quantitative PCR. All of the tested markers showed quantifiability, accuracy and reproducibility. We then compared the expression levels of those markers in PBMCs taken from ASD patients in response to orally-delivered sulforaphane. The mRNA levels of cytoprotective enzymes (NQO1, HO-1, AKR1C1), and heat shock proteins (HSP27 and HSP70), increased. Conversely, mRNA levels of pro-inflammatory markers (IL-6, IL-1ß, COX-2 and TNF-α) decreased. Individually none is sufficiently specific or sensitive, but when grouped by function as two panels, these biomarkers show promise for monitoring pharmacodynamic responses to sulforaphane in both healthy and autistic humans, and providing guidance for biomedical interventions.
Assuntos
Transtorno do Espectro Autista/sangue , Transtorno do Espectro Autista/tratamento farmacológico , Isotiocianatos/uso terapêutico , Leucócitos Mononucleares/metabolismo , Transtorno do Espectro Autista/metabolismo , Células Cultivadas , Criança , Citocinas/sangue , Citocinas/metabolismo , Humanos , Inflamação/sangue , Inflamação/metabolismo , Leucócitos/metabolismo , Masculino , SulfóxidosRESUMO
Phase 2 detoxification enzymes protect against carcinogenesis and oxidative stress. Ginseng ( PANAX spp.) extracts and components were assayed for inducer activity of NQO1 (quinone reductase), a phase 2 enzyme, in Hepa1c1c7 cells. Ginseng extracts were analyzed for ginsenosides and panaxytriol. Korean red PANAX GINSENG extracts demonstrated the most potent phase 2 enzyme induction activity (76,900 U/g dried rhizome powder and 27,800 U/g for two similar preparations). The ginsenoside-enriched HT-1001 American ginseng ( PANAX QUINQUEFOLIUS) extract was the next most potent inducer, with activity of 15,900 U/g, followed by raw American ginseng root with activity of 8700 U/g. Neither a polysaccharide-enriched extract of American ginseng nor a commercial white PANAX GINSENG preparation showed any inducer activity. Pure ginsenosides showed no inducer activity. Protopanaxadiol and protopanaxatriol, deglycosylated ginsenoside metabolic derivatives, showed potent induction activity (approximately 500,000 U/g each). Synthetic panaxytriol was over 10-fold more potent (induction potency 5,760,000 U/g). There was no correlation between ginsenoside content and phase 2 enzyme induction. The most potent inducing red ginseng extract also had the highest panaxytriol content, 120.8 microg/g. We found that ginseng induced NQO1 and that polyacetylenes are the most active components.
Assuntos
NAD(P)H Desidrogenase (Quinona)/biossíntese , Panax , Extratos Vegetais/farmacologia , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Indução Enzimática , Humanos , Panax/químicaRESUMO
Leaves of the tropical tree Moringa oleifera are widely promoted in areas of chronic malnutrition as nutritional supplements for weaning infants and nursing mothers. Adoption, in these circumstances may hinge upon taste, which can vary greatly amongst cultivars. It is widely assumed that this taste variation is primarily germplasm-dependent, and results from the breakdown of glucosinolates to isothiocyanates. Leaves of 30 accessions, grown at a single field plot, were sampled 3 times over the course of a year. Taste, assessed in a masked protocol, was not related to glucosinolate content of the leaves.
Assuntos
Glucosinolatos/análise , Moringa oleifera/química , Extratos Vegetais/química , Folhas de Planta , Paladar , Suplementos Nutricionais , Glucosinolatos/metabolismo , Humanos , Isotiocianatos/metabolismo , Moringa oleifera/classificação , Projetos Piloto , Folhas de Planta/metabolismo , Especificidade da EspécieRESUMO
The tropical tree Moringa oleifera produces high yields of protein-rich leaf biomass, is widely used as a food source, contains an abundance of phytochemicals, and thus has great potential for chronic disease prevention and perhaps, treatment. We have developed and characterized standardized ways of preparing aqueous "teas" from moringa leaves to deliver precisely calibrated levels of phytochemicals for use in clinical trials. These phytochemicals, especially the glucosinolate glucomoringin and the isothiocyanate moringin, produced from it following hydrolysis by the enzyme myrosinase, provide potent anti-inflammatory and cytoprotective indirect antioxidant activity. The taste of both hot and cold teas is palatable without the need for flavor masking. These teas can be easily and reproducibly prepared in underserved tropical regions of the world where moringa is cultivated. Isothiocyanate yield from a cold extraction was rapid and essentially complete after 30 min and its anti-inflammatory potential is comparable to that of equimolar purified moringin. A preparation similar to this may be safe to consume with respect to its bacterial titer even after 48 h without refrigeration. Thus, facile delivery of moringa tea to both adults and children for clinical evaluation of their effects on such conditions as autism, diabetes, and hypertension, is now possible.
Assuntos
Glucosinolatos/administração & dosagem , Isotiocianatos/administração & dosagem , Moringa oleifera/química , Folhas de Planta/química , Administração Oral , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Bebidas , Glucosinolatos/química , Isotiocianatos/química , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Estrutura Molecular , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Células RAW 264.7RESUMO
We examined whether gastric acidity would affect the activity of myrosinase, co-delivered with glucoraphanin (GR), to convert GR to sulforaphane (SF). A broccoli seed and sprout extract (BSE) rich in GR and active myrosinase was delivered before and after participants began taking the anti-acid omeprazole, a potent proton pump inhibitor. Gastric acidity appears to attenuate GR bioavailability, as evidenced by more SF and its metabolites being excreted after participants started taking omeprazole. Enteric coating enhanced conversion of GR to SF, perhaps by sparing myrosinase from the acidity of the stomach. There were negligible effects of age, sex, ethnicity, BMI, vegetable consumption, and bowel movement frequency and quality. Greater body mass correlated with reduced conversion efficiency. Changes in the expression of 20 genes in peripheral blood mononuclear cells were evaluated as possible pharmacodynamic indicators. When grouped by their primary functions based on a priori knowledge, expression of genes associated with inflammation decreased non-significantly, and those genes associated with cytoprotection, detoxification and antioxidant functions increased significantly with bioavailability. Using principal components analysis, component loadings of the changes in gene expression confirmed these groupings in a sensitivity analysis.
Assuntos
Brassica , Suplementos Nutricionais , Glucosinolatos/administração & dosagem , Glicosídeo Hidrolases/administração & dosagem , Imidoésteres/administração & dosagem , Isotiocianatos/metabolismo , Omeprazol/administração & dosagem , Extratos Vegetais/administração & dosagem , Inibidores da Bomba de Prótons/administração & dosagem , Plântula , Sementes , Adulto , Idoso , Disponibilidade Biológica , Brassica/química , Suplementos Nutricionais/efeitos adversos , Interações Medicamentosas , Feminino , Ácido Gástrico/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Glucosinolatos/efeitos adversos , Glucosinolatos/isolamento & purificação , Glucosinolatos/metabolismo , Glicosídeo Hidrolases/efeitos adversos , Glicosídeo Hidrolases/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Imidoésteres/efeitos adversos , Imidoésteres/isolamento & purificação , Imidoésteres/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Masculino , Pessoa de Meia-Idade , Omeprazol/efeitos adversos , Oximas , Projetos Piloto , Extratos Vegetais/efeitos adversos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Inibidores da Bomba de Prótons/efeitos adversos , Plântula/química , Sementes/química , Sulfóxidos , Adulto JovemRESUMO
Inducible phase 2 enzymes constitute a primary line of cellular defense. The oleanane dicyanotriterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-onitrile (TP-225) is a very potent inducer of these systems. Topical application of TP-225 to SKH-1 hairless mice increases the levels of NAD(P)H-quinone acceptor oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO-1) and protects against UV radiation-induced dermal thickening. Daily topical treatments of 10 nmol of TP-225 to the backs of mice that were previously subjected to low-level chronic UVB radiation (30 mJ/cm(2)/session, twice a week for 17 weeks), led to 50% reduction in multiplicity of skin tumors. In addition, the total tumor burden of squamous cell carcinomas was reduced by 5.5-fold. The identification of new agents for protection against UV radiation-induced skin cancer and understanding of their mechanism(s) of action is especially important in view of the fact that human skin cancers represent a significant source of increasing morbidity and mortality.
Assuntos
Heme Oxigenase-1/metabolismo , NADPH Desidrogenase/metabolismo , Neoplasias Induzidas por Radiação/tratamento farmacológico , Neoplasias Induzidas por Radiação/metabolismo , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/metabolismo , Triterpenos/administração & dosagem , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Citoproteção/efeitos dos fármacos , Feminino , Camundongos , Camundongos Pelados , NAD(P)H Desidrogenase (Quinona) , Neoplasias Induzidas por Radiação/etiologia , Neoplasias Induzidas por Radiação/patologia , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/patologia , Raios Ultravioleta/efeitos adversosRESUMO
Betulinic acid (BA), a pentacyclic triterpene isolated from birch bark and other plants, selectively inhibits the growth of human cancer cell lines. However, the poor potency of BA hinders its clinical development, despite a lack of toxicity in animal studies even at high concentrations. Here, we describe six BA derivatives that are markedly more potent than BA for inhibiting inducible nitric oxide synthase, activating phase 2 cytoprotective enzymes, and inducing apoptosis in cancer cells and in Bax/Bak(-/-) fibroblasts, which lack two key proteins involved in the intrinsic, mitochondrial-dependent apoptotic pathway. Notably, adding a cyano-enone functionality in the A ring of BA enhanced its cytoprotective properties, but replacing the cyano group with a methoxycarbonyl strikingly increased potency in the apoptosis assays. Higher plasma and tissue levels were obtained with the new BA analogues, especially CBA-Im [1-(2-cyano-3-oxolupa-1,20(29)-dien-28-oyl)imidazole], compared with BA itself and at concentrations that were active in vitro. These results suggest that BA is a useful platform for drug development, and the enhanced potency and varied biological activities of CBA-Im make it a promising candidate for further chemoprevention or chemotherapeutic studies.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Triterpenos/farmacologia , Animais , Antineoplásicos Fitogênicos/sangue , Antineoplásicos Fitogênicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Inflamação , Macrófagos/efeitos dos fármacos , Macrófagos/enzimologia , Masculino , Camundongos , NAD(P)H Desidrogenase (Quinona)/metabolismo , Óxido Nítrico/biossíntese , Triterpenos Pentacíclicos , Triterpenos/sangue , Triterpenos/química , Proteína X Associada a bcl-2/metabolismo , Ácido BetulínicoRESUMO
Taste drives consumption of foods. The tropical tree Moringa oleifera is grown worldwide as a protein-rich leafy vegetable and for the medicinal value of its phytochemicals, in particular its glucosinolates, which can lead to a pronounced harsh taste. All studies to date have examined only cultivated, domestic variants, meaning that potentially useful variation in wild type plants has been overlooked. We examine whether domesticated and wild type M. oleifera differ in myrosinase or glucosinolate levels, and whether these different levels impact taste in ways that could affect consumption. We assessed taste and measured levels of protein, glucosinolate, myrosinase content, and direct antioxidant activity of the leaves of 36 M. oleifera accessions grown in a common garden. Taste tests readily highlighted differences between wild type and domesticated M. oleifera. There were differences in direct antioxidant potential, but not in myrosinase activity or protein quantity. However, these two populations were readily separated based solely upon their proportions of the two predominant glucosinolates (glucomoringin and glucosoonjnain). This study demonstrates substantial variation in glucosinolate composition within M. oleifera. The domestication of M. oleifera appears to have involved increases in levels of glucomoringin and substantial reduction of glucosoonjnain, with marked changes in taste.
Assuntos
Antioxidantes/análise , Glucosinolatos/análise , Glicosídeo Hidrolases/análise , Moringa oleifera , Proteínas de Plantas/análise , Paladar/fisiologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Dessecação , Domesticação , Glucosinolatos/metabolismo , Glicosídeo Hidrolases/metabolismo , Humanos , Moringa oleifera/química , Moringa oleifera/classificação , Moringa oleifera/fisiologia , Extratos Vegetais/química , Folhas de Planta/química , Proteínas de Plantas/metabolismoRESUMO
Glucosinolates (GS) are metabolized to isothiocyanates that may enhance human healthspan by protecting against a variety of chronic diseases. Moringa oleifera, the drumstick tree, produces unique GS but little is known about GS variation within M. oleifera, and even less in the 12 other Moringa species, some of which are very rare. We assess leaf, seed, stem, and leaf gland exudate GS content of 12 of the 13 known Moringa species. We describe 2 previously unidentified GS as major components of 6 species, reporting on the presence of simple alkyl GS in 4 species, which are dominant in M. longituba. We document potent chemoprotective potential in 11 of 12 species, and measure the cytoprotective activity of 6 purified GS in several cell lines. Some of the unique GS rank with the most powerful known inducers of the phase 2 cytoprotective response. Although extracts of most species induced a robust phase 2 cytoprotective response in cultured cells, one was very low (M. longituba), and by far the highest was M. arborea, a very rare and poorly known species. Our results underscore the importance of Moringa as a chemoprotective resource and the need to survey and conserve its interspecific diversity.
Assuntos
Quimioprevenção/métodos , Doença Crônica/prevenção & controle , Glucosinolatos , Moringa/química , Moringa/classificação , Células Cultivadas , Citoproteção/efeitos dos fármacos , Glucosinolatos/química , Glucosinolatos/classificação , Glucosinolatos/isolamento & purificação , Glucosinolatos/farmacologia , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Moringa oleifera/química , Moringa oleifera/classificação , Filogenia , Fitoterapia/métodos , Extratos Vegetais/farmacologia , Folhas de Planta/química , Folhas de Planta/fisiologia , Sementes/químicaRESUMO
We have previously shown that broccoli sprouts are a rich source of chemopreventive isothiocyanates, which potently induce carcinogen-detoxifying enzymes and inhibit the development of mammary and skin tumors in rodents. However, the principal isothiocyanate present in broccoli sprout extracts, sulforaphane, not only induces carcinogen-detoxifying enzymes but also activates apoptosis and blocks cell cycle progression. In this article, we show that an aqueous extract of broccoli sprouts potently inhibits the growth of human bladder carcinoma cells in culture and that this inhibition is almost exclusively due to the isothiocyanates. Isothiocyanates are present in broccoli sprouts as their glucosinolate precursors and blocking their conversion to isothiocyanates abolishes the antiproliferative activity of the extract. Moreover, the potency of isothiocyanates in the extract in inhibiting cancer cell growth was almost identical to that of synthetic sulforaphane, as judged by their IC50 values (6.6 versus 6.8 micromol/L), suggesting that other isothiocyanates in the extract may be biologically similar to sulforaphane and that nonisothiocyanate substances in the extract may not interfere with the antiproliferative activity of the isothiocyanates. Further study showed that the isothiocyanate extract of broccoli sprouts activated the mitochondria-mediated apoptosis pathway and halted cells in S and M phases. Cell cycle arrest was associated with down-regulation of Cdc25C and disruption of mitotic spindles. These data show that broccoli sprout isothiocyanate extract is a highly promising substance for cancer prevention/treatment and that its antiproliferative activity is exclusively derived from isothiocyanates.
Assuntos
Apoptose/efeitos dos fármacos , Brassica , Ciclo Celular/efeitos dos fármacos , Mitocôndrias/fisiologia , Extratos Vegetais/farmacologia , Caules de Planta/química , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Cinética , Mitocôndrias/efeitos dos fármacos , Fitoterapia , Fase S/efeitos dos fármacos , Neoplasias da Bexiga UrináriaRESUMO
SCOPE: The isothiocyanate sulforaphane (SF) from broccoli is one of the most potent known inducers of the cytoprotective phase 2 response. Its role in a host of biochemical pathways makes it a major component of plant-based protective strategies for enhancing healthspan. Many nutritional supplements are now marketed that purport to contain SF, which in plants exists as a stable precursor, a thioglucoside hydroxysulfate. However, SF in pure form must be stabilized for use in supplements. METHODS AND RESULTS: We evaluated the stability and bioavailability of two stabilized SF preparations-an α-cyclodextrin inclusion (SF-αCD), and an SF-rich, commercial nutritional supplement. SF-αCD area-under-the-curve peak serum concentrations occurred at 2 h, but six of ten volunteers complained of mild stomach upset. After topical application it was not effective in upregulating cytoprotective enzymes in the skin of SKH1 mice whereas pure SF was effective in doing so. Both of these "stabilized" SF preparations were as potent as pure SF in inducing the cytoprotective response in cultured cells, and they were more stable and as bioavailable. CONCLUSION: Our studies of a stabilized phytochemical component of foods should encourage further examination of similar products for their utility in chronic disease prevention and therapy.
Assuntos
Anticarcinógenos/farmacologia , Brassica/química , Isotiocianatos/farmacologia , Tiocianatos/farmacologia , Animais , Disponibilidade Biológica , Suplementos Nutricionais , Glucosinolatos/farmacologia , Humanos , Imidoésteres/farmacologia , Camundongos , Oximas , Compostos Fitoquímicos/metabolismo , Sulfóxidos , alfa-Ciclodextrinas/metabolismoRESUMO
Aerobic life, UV solar radiation, genetic susceptibility, and immune status contribute collectively to the development of human skin cancers. In addition to direct DNA damage, UV radiation promotes the generation of reactive oxygen intermediates that can cause oxidative damage and inflammation, and ultimately lead to tumor formation. Treatment of murine and human keratinocytes with the isothiocyanate sulforaphane elevated phase 2 enzymes and glutathione and protected against oxidant toxicity. Topical application of sulforaphane-containing broccoli sprouts extracts induced the phase 2 response in mouse skin in vivo. Sulforaphane inhibited cytokine-dependent (gamma-interferon or lipopolysaccharide) induction of iNOS in RAW 264.7 macrophages. The UV-radiation-induced skin carcinogenesis in "initiated high-risk mice" was substantially inhibited by broccoli sprout extracts containing sulforaphane. After completion of the UV irradiation schedule (30 mJ/cm(2)/session twice a week for 20 weeks), groups of approximately 30 mice were treated topically on their backs (5 days a week for 11 weeks) with broccoli sprout extract containing either the equivalent to 0.3 micromol (low dose) or 1.0 micromol (high dose) sulforaphane, respectively. At this time point, the tumor incidence had reached 100% in the control mice. Tumor burden, incidence, and multiplicity were reduced by 50% in the animals that received the high dose of protector. Tumor incidence and multiplicity did not differ between the low dose-treated and the control groups, but the low dose treatment resulted in a substantial reduction of the overall tumor burden. Thus, topical application of sulforaphane-containing broccoli sprout extracts is a promising strategy for protecting against skin tumor formation after exposure to UV radiation.
Assuntos
Neoplasias Induzidas por Radiação/prevenção & controle , Extratos Vegetais/farmacologia , Protetores contra Radiação/farmacologia , Neoplasias Cutâneas/prevenção & controle , Tiocianatos/farmacologia , Raios Ultravioleta/efeitos adversos , Animais , Anticarcinógenos/farmacologia , Ensaio Cometa , DNA/efeitos da radiação , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Feminino , Glutationa/metabolismo , Humanos , Isotiocianatos , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Camundongos , Camundongos Pelados , NAD(P)H Desidrogenase (Quinona) , NADPH Desidrogenase/metabolismo , Neoplasias Induzidas por Radiação/metabolismo , Neoplasias Induzidas por Radiação/patologia , Óxido Nítrico Sintase Tipo II/metabolismo , Estresse Oxidativo , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , SulfóxidosRESUMO
Residents of Qidong, People's Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of aflatoxin-contaminated foods, and are exposed to high levels of phenanthrene, a sentinel of hydrocarbon air toxics. Cruciferous vegetables, such as broccoli, contain anticarcinogens. Glucoraphanin, the principal glucosinolate in broccoli sprouts, can be hydrolyzed by gut microflora to sulforaphane, a potent inducer of carcinogen detoxication enzymes. In a randomized, placebo-controlled chemoprevention trial, we tested whether drinking hot water infusions of 3-day-old broccoli sprouts, containing defined concentrations of glucosinolates, could alter the disposition of aflatoxin and phenanthrene. Two hundred healthy adults drank infusions containing either 400 or < 3 micromol glucoraphanin nightly for 2 weeks. Adherence to the study protocol was outstanding; no problems with safety or tolerance were noted. Urinary levels of aflatoxin-N(7)-guanine were not different between the two intervention arms (P = 0.68). However, measurement of urinary levels of dithiocarbamates (sulforaphane metabolites) indicated striking interindividual differences in bioavailability. An inverse association was observed for excretion of dithiocarbamates and aflatoxin-DNA adducts (P = 0.002; R = 0.31) in individuals receiving broccoli sprout glucosinolates. Moreover, trans, anti-phenanthrene tetraol, a metabolite of the combustion product phenanthrene, was detected in urine of all participants and showed a robust inverse association with dithiocarbamate levels (P = 0.0001; R = 0.39), although again no overall difference between intervention arms was observed (P = 0.29). Understanding factors influencing glucosinolate hydrolysis and bioavailability will be required for optimal use of broccoli sprouts in human interventions.
Assuntos
Aflatoxinas/urina , Anticarcinógenos/farmacologia , Brassica/química , Adutos de DNA/urina , Glucosinolatos/farmacologia , Fenantrenos/urina , Adulto , Aflatoxinas/metabolismo , Idoso , Bebidas , Disponibilidade Biológica , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/prevenção & controle , Feminino , Humanos , Hidrólise , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/prevenção & controle , Masculino , Pessoa de Meia-Idade , PlacebosRESUMO
We review herein the basis for using dietary components to treat and/or prevent Helicobacter pylori infection, with emphasis on (a) work reported in the last decade, (b) dietary components for which there is mechanism-based plausibility, and (c) components for which clinical results on H pylori amelioration are available. There is evidence that a diet-based treatment may reduce the levels and/or the virulence of H pylori colonization without completely eradicating the organism in treated individuals. This concept was endorsed a decade ago by the participants in a small international consensus conference held in Honolulu, Hawaii, USA, and interest in such a diet-based approach has increased dramatically since then. This approach is attractive in terms of cost, treatment, tolerability, and cultural acceptability. This review, therefore, highlights specific foods, food components, and food products, grouped as follows: bee products (eg, honey and propolis); probiotics; dairy products; vegetables; fruits; oils; essential oils; and herbs, spices, and other plants. A discussion of the small number of clinical studies that are available is supplemented by supportive in vitro and animal studies. This very large body of in vitro and preclinical evidence must now be followed up with rationally designed, unambiguous human trials.
Assuntos
Laticínios , Infecções por Helicobacter/dietoterapia , Helicobacter pylori/crescimento & desenvolvimento , Mel , Óleos Voláteis , Plantas Comestíveis , Probióticos , Animais , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/prevenção & controle , Humanos , Fitoterapia , EspeciariasRESUMO
Glucoraphanin from broccoli and its sprouts and seeds is a water soluble and relatively inert precursor of sulforaphane, the reactive isothiocyanate that potently inhibits neoplastic cellular processes and prevents a number of disease states. Sulforaphane is difficult to deliver in an enriched and stable form for purposes of direct human consumption. We have focused upon evaluating the bioavailability of sulforaphane, either by direct administration of glucoraphanin (a glucosinolate, or ß-thioglucoside-N-hydroxysulfate), or by co-administering glucoraphanin and the enzyme myrosinase to catalyze its conversion to sulforaphane at economic, reproducible and sustainable yields. We show that following administration of glucoraphanin in a commercially prepared dietary supplement to a small number of human volunteers, the volunteers had equivalent output of sulforaphane metabolites in their urine to that which they produced when given an equimolar dose of glucoraphanin in a simple boiled and lyophilized extract of broccoli sprouts. Furthermore, when either broccoli sprouts or seeds are administered directly to subjects without prior extraction and consequent inactivation of endogenous myrosinase, regardless of the delivery matrix or dose, the sulforaphane in those preparations is 3- to 4-fold more bioavailable than sulforaphane from glucoraphanin delivered without active plant myrosinase. These data expand upon earlier reports of inter- and intra-individual variability, when glucoraphanin was delivered in either teas, juices, or gelatin capsules, and they confirm that a variety of delivery matrices may be equally suitable for glucoraphanin supplementation (e.g. fruit juices, water, or various types of capsules and tablets).
Assuntos
Brassica/química , Glucosinolatos/administração & dosagem , Glicosídeo Hidrolases/administração & dosagem , Imidoésteres/administração & dosagem , Isotiocianatos/urina , Adulto , Disponibilidade Biológica , Suplementos Nutricionais , Sistemas de Liberação de Medicamentos , Feminino , Glucosinolatos/farmacocinética , Glicosídeo Hidrolases/metabolismo , Humanos , Imidoésteres/farmacocinética , Isotiocianatos/farmacocinética , Masculino , Pessoa de Meia-Idade , Oximas , Extratos Vegetais/análise , Extratos Vegetais/farmacocinética , Plântula/metabolismo , Sementes/metabolismo , SulfóxidosRESUMO
Glucosinolates are anionic, hydrophilic plant secondary metabolites which are of particular interest due to their role in the prevention of cancer and other chronic and degenerative diseases. The separation and purification of glucosinolates from a variety of plant sources (e.g. seeds of broccoli, arugula and the horseradish tree), was achieved using high-speed counter-current chromatography (HSCCC). A high-salt, highly polar system containing 1-propanol-acetonitrile-saturated aqueous ammonium sulfate-water (1:0.5:1.2:1), was run on a semi-preparative scale and then transferred directly to preparative scale. Up to 7 g of a concentrated methanolic syrup containing about 10% glucosinolates was loaded on an 850-ml HSCCC column, and good separation and recovery were demonstrated for 4-methylsulfinylbutyl, 3-methylsulfinylpropyl, 4-methylthiobutyl, 2-propenyl and 4-(rhamnopyranosyloxy)benzyl glucosinolates. Multiple injections (5 to 6 times) were performed with well-preserved liquid stationary phase under centrifugal force. Pooled sequential runs with broccoli seed extract yielded about 20 g of its predominant glucosinolate, glucoraphanin, which was produced at > 95% purity and reduced to powdered form.
Assuntos
Distribuição Contracorrente/métodos , Glucosinolatos/isolamento & purificação , Extratos Vegetais/química , Brassica/química , Brassicaceae/química , Moringa oleifera/química , Sementes/químicaRESUMO
Over 60 different samples comprising 35 distinct honeys were evaluated for their ability to induce mammalian phase 2 detoxication enzymes using a microtiter plate assay of quinone reductase (QR) induction with murine hepatoma cells in microtiter plates. This assay has been used extensively to identify and isolate a variety of natural and synthetic inducers from plants. All 35 honeys examined induced elevations of mammalian QR activity ranging from 153 to 2155 units/g with a mean of 630 and a median of 417 units/g. The concentrations for doubling the QR activity (CD) of certain of the prominent flavonoids found in honey were also assessed (pinostrobin, 0.5 microM; pinocembrin, 110 microM; chrysin, 25 microM) and compared to those of related, more commonly described flavonoids such as quercetin (2.7 microM) and myricetin (58 microM). On the basis of the extremely high QR inducing potency of one of these compounds, pinostrobin (5-hydroxy-7-methoxyflavanone), a bioassay-guided search was conducted which revealed a dietary source of pinostrobin, Boesenbergia pandurata (fingerroot), with extraordinarily high ability to induce mammalian phase 2 detoxication enzymes. Although the QR inducing activity of buckwheat honeys was 2155 +/- 951 units/g (n = 8 samples), which is less than 10% of the average values obtained from fresh broccoli, the potency of fingerroot rhizomes (ca. 110,000 units/g) is even higher than that of broccoli and the potencies of fingerroot oil and powdered rhizome (ca. 500,000 units/g) rival that of broccoli sprouts.