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At least 937 records · Page 52Linked to original sources
PubMed2007

Effects of 6-(methylsulfinyl)hexyl isothiocyanate on cyclooxygenase-2 expression induced by lipopolysaccharide, interferon-gamma and 12-O-tetradecanoylphorbol-13-acetate.

6-(methylsulfinyl)hexyl isothiocyanate (6-MITC) is a bioactive compound extracted from a typical Japanese spice, wasabi (Wasabia japonica (Miq.) Matsumura). In the present study, we found that 6-MITC suppressed the expression of cyclooxygenase-2 (COX-2) induced by lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), but did not suppress that induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), in murine macrophage RAW264. Molecular mechanisms were investigated by targeting the transcriptional factors including activator protein-1 (AP-1), CCAAT/enhancer-binding protein delta (C/EBPdelta), CRE-binding protein (CREB) and nuclear factor kappaB (NF-kappaB), which bind to the core element of COX-2 promoter. LPS induced activation of all of these factors and 6-MITC suppressed LPS-induced activation of AP-1, C/EBPdelta, CREB, but not NF-kappaB. IFN-gamma did not induce any activation of these factors, but 6-MITC suppressed IFN-gamma-induced COX-2 expression, suggesting that the upstream region of the core element is linked for this suppression. Finally, TPA stimulated the activation of CREB and AP-1, but 6-MITC did not block TPA-induced COX-2 expression. These results suggest that LPS, IFN-gamma and TPA regulate COX-2 expression through different mechanisms, and 6-MITC acts as a potent inhibitor of COX-2 expression induced by LPS or IFN-gamma.

Animals↗
PubMed2006

Quantitative study of soybean-induced changes in proliferation and programmed cell death in the intestinal mucosa of young rats.

The use of soybean in human and animal nutrition is limited because of high content of bioactive compounds: enzyme inhibitors, polyphenols, goitrogens, phytates, saponins, sugars, and agglutinins. The damage of intestinal mucosa structure was previously observed in animals fed soybean supplemented diets. Hence, the objectives of the presented study were to compare intensity of epithelium remodeling processes in different intestinal segments, and to evaluate the influence of the 1% of soybean dietary supplementation on the processes in intestinal mucosa. The experiment was performed on 30 Wistar rats fed AIN-93 based diets. Animals were divided randomly into three groups: control (CTRL), with 1% of raw soybean (RS) and with 1% of soaked and boiled soybean (BS). The samples of: duodenum (DUO), proximal jejunum (PROX), mid-jejunum (MID), distal-jejunum (DIST) and ileum (ILE) were collected. The following processes in these samples were evaluated: mitosis (Ki-67), apoptosis (Cpp32), autophagy (MAP I LC3) and DNA damage (p53). Present data show that modification of soybean by soaking and subsequent boiling markedly influences the enterocyte turnover in the small intestine mucosa. Increased mitotic ratio in the intestine of rats fed with boiled soybean masks the negative effects of soybean on the small intestine structure.

Animals↗
PubMed1991

The lyso-precursor of platelet-activating factor (lyso-PAF) in ischaemic myocardium.

While it has been postulated that lyso-PAF and PAF might contribute to structural and functional damage in myocardial ischaemia, there has been no clear evidence for the accumulation of these bioactive compounds in ischaemic myocardium. In open chest, anaesthetised dogs, the proximal left anterior descending coronary artery was ligated and myocardial samples from the central ischaemic and normal areas assayed for lyso-PAF, free arachidonic acid and PLA2 activity. Ischaemic myocardium contained 50 +/- 29% (SD) more lyso-PAF than non-ischaemic myocardium after 20 min ischemia (P less than 0.002; N = 8) and 53 +/- 39% more after 60 min (P less than 0.01; N = 8) but there was no difference after 10 min (N = 8). Free arachidonic acid significantly increased in ischaemic myocardium after 60 min (122 +/- 136%; P less than 0.05) while no increase in PLA2 activity was found in-vitro. Since lyso-phospholipids themselves damage cell membranes and, additionally, lyso-PAF is the precursor of PAF which has potent effects on platelets, leukocytes and small vessels, the increase in lyso-PAF in ischaemic myocardium could contribute to myocardial damage.

Acetylation↗
PubMedDate not supplied

[Pharmacological properties in vitro of various extracts of Mimosa tenuiflora (tepescohuite)].

The in vitro biological effects of polar extracts of Mimosa tenuiflora (Willd.) Poir. trunk bark (tepescohuite) were studied. Ethyl acetate extract, with a high tannin content, inhibited the growth of different microorganisms. Alkaloids were particularly abundant in the butanol extract and this product strongly inhibited the intestinal peristalsis and produced contraction of uterine and gastric strips of rat and guinea pig. Saponins were detected in butanol and methanol extracts producing hemolysis. The screenings performed showed the diversity of bioactive compounds present in this plant product.

Alkaloids↗
PubMed1987

Occurrence of gastrin-releasing peptide-like and bombesin-like immunoreactivities in the epidermal sacciform gland cells of the clingfish Lepadogaster candollei.

Gastrin-releasing peptide (GRP)-like and bombesin (BOM)-like immunoreactivities were localized in the exocrine sacciform gland cells and in the surface epidermis of the clingfish Lepadogaster candollei with the use of previously characterized antibodies. The GRP-like and BOM-like peptides show resemblance to those immunohistochemically found in the dermal secretory products of the amphibian skin. The immunoreactive peptides tested in this study are unusual bioactive components of secretory sources of exocrine glands since these peptides were first demonstrated in cells of the neuroendocrine system. The results suggest that such bioactive compounds may exert regulatory activity in the absorptive processes of the skin epithelium and in influencing secretion release from exocrine complexes.

Animals↗
PubMed1986

Partial restoration of the lipopolysaccharide-induced proliferative response in splenic B cells from C3H/HeJ mice.

C3H/HeJ mice are hyporesponsive to the biologic effects of bacterial lipopolysaccharide (LPS), and their splenic B cells do not proliferate after exposure to LPS. The molecular basis of this hyporesponsiveness is unknown but it may result from defective membrane signal transduction after LPS binding. To examine this possibility, we added bioactive compounds in combination with LPS to C3H/HeJ B cell cultures in order to bypass the putative defect. The addition of PMA, monensin, or ionomycin, either alone or in combination, had no effect on C3H/HeJ B cell responses to LPS. In contrast, the addition of trypsin together with LPS resulted in a partial restoration of the proliferative response in C3H/HeJ splenic B lymphocytes. The maximal C3H/HeJ B cell response varied from 25 to 60% of the C3Heb/FeJ (LPS responder) B cell response. The trypsin-mediated enhancement of the LPS response was abrogated by pretreatment of the trypsin with the trypsin inhibitors DFP or TLCK. Pretreatment of the LPS with polymyxin B, which blocks lipid A-dependent reactions, also abrogated the trypsin effect. Because the C3H/HeJ B cell responds to all other B cell mitogens, we suggest that the defect is in an LPS-specific step and that the action of trypsin results in the restoration of the missing signal. At the present time the identity of this signal is not known, but the experiments described in this report provide a unique model to elucidate the basis of LPS hyporesponsiveness in splenic B cells from C3H/HeJ mice.

Adjuvants, Immunologic↗
PubMed1993

Endogenous natriuretic factors. 2: Characterization of natriuretic and vasopressive substances from human uremic urine.

It is our intention to isolate, purify, and characterize the putative low-molecular-weight "natriuretic hormone" responsible for extracellular fluid (ECF) homeostasis. Toward this end, we are purifying from human uremic urine, and identifying endogenous vasopressor and natriuretic compounds. Bioactive components from large volumes of pooled urine were purified by ultrafiltration (< or = 3 kDa), gel filtration chromatography, and sequential reverse-phase and normal-phase high-performance liquid chromatography (HPLC). After each HPLC step, the fractions were evaluated in vivo, were assayed for inhibition of Na+/K(+)-ATPase-mediated 86Rb+ uptake, and were checked for cross-reactivity with an anti-ouabain antibody. Fractions assayed in vivo were identified that induced natriuresis, altered mean arterial pressure, or increased plasma cyclic-GMP. Also, many fractions inhibited Na+/K(+)-ATPase and/or cross-reacted with anti-ouabain antibody. None of the in vitro assays correlates with natriuretic or pressor effects. This plethora of bioactivities, revealed only with increased sample purity, may account for much of the confusion and multiplicity of crude isolates claimed to be the putative hormone. Presently we are attempting to purify and identify these natriuretic materials. One of these, a 3-substituted indole, has been partially characterized.

Animals↗
PubMed1995

Genetic variability of the human SRD5A2 gene: implications for prostate cancer risk.

Elevated dihydrotestosterone levels have been suggested to increase the risk of prostate cancer. The human SRD5A2 gene encodes the type II steroid 5 alpha-reductase, which converts testosterone to the more bioactive compound dihydrotestosterone. We have determined the distribution of a dinucleotide repeat in low-risk Asian-Americans, high-risk African-Americans, and intermediate-risk non-Hispanic Whites. We found this marker to be more polymorphic than previously reported, with some alleles being specific to African-Americans. Genetic variants of the SRD5A2 gene may play a role in predisposition to prostate cancer and in explaining the substantial racial/ethnic variability in risk.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1993

Endemic plants of Puerto Rico: brine shrimp lethality and antibacterial activity.

A total of 49 endemic plants of Puerto Rico were evaluated for their toxicological and antibacterial activities. The toxicological analysis was conducted with brine shrimp (Artemia salina Leach) lethality bioassay and the antibacterial screening was carried out by means of the agar diffusion test. In the toxicological bioassay, six plant extracts showed LC-50 values below 200 g/ml., indicating the potential presence of bioactive compounds. In the antibacterial screening, over 80% of the plant extracts displayed activity against gram positive bacteria, whereas only 6% of the extracts inhibited the growth of the gram negative bacteria.

Animals↗
PubMed1978

Polypeptide antibiotic 26a from Bacillus subtilis. I. Taxonomy and fermentative production.

In surface cultures on NK/2-Sym's medium, the isolate No. 26a of Bacillus subtilis from the intestinal tract of Galleria mellonella larvae produced three antibacterial substances which were separated by gel filtration on Sephadex G-25 column. The major bioactive compound named 26a had a close resemblance to bacitracin family of polypeptide antibiotics. Two minor active compounds, i.e. a bacteriolytic enzyme with endo-beta-N-acetylmuramidglycanohydrolase (EC. 3. 2. 1. 17) activity and other unidentified factor were usually synthetized in trace amounts. Maximum yield of 26a generally occurred after 120 hour incubation, when the producer reached the stationary growth phase and general sporulation of the bacterial cultures was found. The basal medium of NK/2-Sym supplemented by addition of manganese ions (10(-4) M), d-glucose (1%) and inorganic nitrogen beneficially resulted in antibiotic potency of the fermentation broth. The antibiotics produced by other isolates (Nos 5AK, 15 and 92) have been also analyzed and from their properties they can be tentatively classified as members of bacitracin group polypeptides. A possible role of the antibiotics produced by intestinal Bacillus spp in the formation process of typical gut microflora of G. mellonella is discussed.

Animals↗
PubMed1996

Trophic factors for the gastrointestinal tract.

GI trophic factors that influence the coordinated pre- and postnatal growth and development of the GI tract have been identified. Studies in animals and humans demonstrate that GI trophic factors can initiate cellular growth and expression of differentiated function, and they are important in adaptation and repair following injury. Systemically as well as enterally administered growth factors can stimulate GI growth and maturation, suggesting that trophic factors in the serum of neonates may modulate GI growth via receptors on the serosal membranes of enterocytes. GI trophic factors may be synthesized endogenously or provided postnatally in milk. GI trophic factors in human milk play an important role in regulating the adaptive functional changes that accompany the transition to postnatal enteral feedings. Although human milk growth factors do not appear to be essential for infant survival, the elevated risk of gastrointestinal-related illnesses in formula-fed as compared with breast-fed infants (diarrhea, necrotizing enterocolitis, colitis, Crohn's disease) suggest that bioactive compounds in human milk contribute to the apparent protective effect of breast feeding. GI trophic factors have the potential to be used therapeutically to enhance GI maturation and repair following injury. These applications may be particularly useful in the premature or postsurgical infant. Several issues require further research, including (1) the mechanism of action, (2) the efficacy of oral versus systemic administration, (3) characterization of the complex interactions between the various growth factors, because some appear to act synergistically, (4) the effect of exogenously administered growth factors on endogenous production of that factor, its receptor, or other growth factors, (5) the effect of growth factors upon tissues not directly associated with the GI tract, and (6) the determination of safe and effective upper limits.

Animals↗
PubMed1996

Microbial lipases: production and applications.

Lipases occupy a prominent place among biocatalysts and have a wide spectrum of biotechnological applications. Lipases are unique as they hydrolyse fats into fatty acids and glycerol at the water-lipid interface and can reverse the reaction in non-aqueous media. The stability of these enzymes in organic solvents have pushed them into the frontier areas of organic synthesis leading to the designing of novel drugs, surfactants, bioactive compounds and oleochemicals. In addition, lipase-catalysed trans-esterification and inter-esterification reactions have been exploited in the fat industry. Looking into the wide scenario of lipase applications, commercialization of lipase production is a prime area of interest for microbiologists, process engineers and biochemists. Research carried out in this field has revealed that microbes, especially fungi and bacteria, are the tools of choice for commercial production. Recently, the structure determination of a few microbial lipases has widened our knowledge about the unique mechanism of catalysis of this enzyme.

Animals↗
PubMed1997

Coral reefs, forests, and thermal vents: the worldwide exploration of nature for novel antitumor agents.

Nature has been a source of medicinal treatments for thousands of years, and plant-based systems continue to play an essential role in the primary health care of 80% of the world's population. Nature has provided many of the effective anticancer agents in current use, such as the microbially derived drugs, dactinomycin, bleomycin, and doxorubicin, and the plant-derived drugs vinblastine, irinotecan, topotecan, etoposide, and paclitaxel. The search for novel antitumor agents from natural sources continues with botanists, marine biologists, and microbiologists teaming up with chemists, pharmacologists, toxicologists, and clinicians in the investigation of coral reefs, rainforests, and deep subsurface thermal vents for novel bioactive compounds. The wealth of anticancer drugs of natural origin and critical aspects of the ongoing discovery and development process are discussed.

Animals↗
PubMed1998

S-Transnitrosation reactions are involved in the metabolic fate and biological actions of nitric oxide.

S-Nitrosothiols are a group of potent, bioactive compounds that form through the reaction of nitric oxide (NO) with thiols in the presence of oxygen. These compounds are naturally occurring in vivo, stabilize NO and potentiate its biological effects. S-Nitrosoglutathione is the most abundant intracellular S-nitrosothiol, and the kinetics for its formation favors de novo synthesis. In this analysis, we studied the formation of S-nitrosothiols by S-transnitrosation, or exchange of -NO for -H between sulfur atoms; we synthesized S-nitroso-glutathionyl-Sepharose 4B beads (SNO-4B) as a reagent with which to measure S-transnitrosation reactions. We detected a maximum of 1.57 +/- 0.24 pmol NO/bead (n = 5) after S-nitrosation of the beads with acidified nitrite. The stability of the S-NO bond was dependent on temperature, but not pH over the 5 to 9 range (except at pH 9 at 37 degrees ), with an estimated t1/2 of 30 hr at 22 degrees C and of approximately 2 wk at 4 degrees C. We demonstrated that SNO-4B transfers -NO to glutathione and to cysteine rapidly and in a pH-dependent manner. The initial rate of transfer of -NO from SNO-4B to glutathione at room temperature was 0.53, 3.03 and 5.14 microM/min at pH 5.0, 7.4 and 9.0, respectively (P < .05). Under the same conditions, the initial rate of -NO transfer to cysteine was 0. 72, 3.71 and 4.69 microM/min at pH 5.0, 7.4 and 9.0, respectively (P < .05). There was no appreciable S-transnitrosation between SNO-4B and bovine serum albumin. We further demonstrated that SNO-4B evokes significant vasodilator and platelet inhibitory responses in plasma-free systems and activates platelet soluble guanylyl cyclase. These data suggest a mechanism by which to explain the metabolic fate and distribution of NO among thiol pools in the vasculature, and implicate S-transnitrosation at the cell surface in NO signal transduction.

Animals↗
PubMed1998

Ovicidal activity of neem products (azadirachtin) against Culex tarsalis and Culex quinquefasciatus (Diptera: Culicidae).

Bioactive compounds contained in the seed kernel and other parts of the neem tree (Azadirachta indica A. Juss) have been found to show insecticidal activities and other effects in many species of insects. These activities include antifeedancy, growth regulation, fecundity suppression, male sterility, oviposition repellency, changes in biological fitness such as loss of flying ability, immunodepression, enzyme inhibition, splitting of biological rhythms, and so forth. We investigated the ovicidal effects of various formulations of azadrirachtin (AZ) against the mosquitoes Culex tarsalis Coquillett and Culex quinquefasciatus Say. The formulations tested were wettable powder Azad WP10, emulsifiable concentrate Azad EC4.5, and technically pure AZ. The ovicidal activity of the test neem products was influenced by concentration of AZ, age of the egg rafts, and age of the neem preparations. Other factors such as formulation and mosquito species were also involved in the degree of ovicidal activity. When the egg rafts were deposited directly in fresh neem suspension and left there for 4 h before transfer to untreated water, 1 ppm of AZ produced almost 100% mortality in eggs. When egg rafts aged for 0, 4, 8, 12, and 24 h were exposed to 10 ppm neem suspensions for 36 h, the ovicidal activity was only attained in the egg rafts deposited directly (0 h old) in the neem suspension, not in those with ages of 4-24 h. On aging, depending on the formulations and mosquito species, the neem suspensions at 1 ppm completely lost ovicidal activity within 7-20 days. The egg rafts of Cx. quinquefasciatus were more susceptible to the test neem products than those of Cx. tarsalis. The formulated neem products were more persistent and effective than the technical AZ. The wettable powder (WP) formulation was slightly more persistent and effective than the emulsifiable concentrate (EC). The ovicidal activity of the neem products against mosquitoes from the current research clearly demonstrated the potential of neem products as possible ovicides against Culex mosquitoes.

Animals↗
PubMed1998

[The auto- and endocrine function of the adipose tissue. Significance for metabolic complications in obesity].

The present review discusses recent research showing adipose tissue to be highly metabolically active, producing and releasing many different bioactive compounds besides free fatty acids (FFA) such as tumor necrosis factor alpha (TNF alpha), leptin, acetylation stimulating protein (ASP), plasminogen activator inhibitor-1 (PAI-1), cholesterol ester transfer protein (CETP), prostaglandins and oestrogens. Most of these compounds have autocrine effects on the adipose cells and they are presumably involved in the physiological regulation of blood flow, growth and metabolism of the adipose tissue. When the adipose tissue becomes enlarged, as seen in association with obesity, it has now been shown that several of the compounds produced in the adipose tissue (TNF, PAI-1, CETP etc.) may be directly involved in the pathogenesis of some of the complications commonly seen in association with obesity such as insulin resistance, hypertension, enhanced thrombogenesis, and premature atherosclerosis.

Adipose Tissue↗
PubMed1999

Polymorphic expression of the glutathione S-transferase P1 gene and its susceptibility to Barrett's esophagus and esophageal carcinoma.

Factors determining individual susceptibility to esophageal cancer or premalignant Barrett's epithelium are still largely unclear. An imbalance between phase I drug metabolism [e.g., cytochrome P450 (CYP)] and phase II detoxification [e.g., glutathione S-transferase (GST)] may contribute to the development of these diseases. Polymorphic variants in the CYP1A1 gene were described leading to increased levels of bioactive compounds, whereas polymorphisms in GST genes often resulted in impaired detoxification. We studied the frequencies of polymorphic variants in CYP1A1, GSTP1, GSTT1, and GSTM1 genes in 98 patients with Barrett's epithelium and 34 patients with esophageal cancer. The results were compared with those obtained from 247 healthy blood donors. DNA was extracted, and PCR-RFLP methods were used to detect genetic polymorphisms. Chi2 analysis, Spearman rank correlation, and Wilcoxon rank sum tests were used for statistical evaluation. Polymorphisms in CYP1A1, GSTM1, and GSTT1 occurred at an equal frequency in patients and controls. Occurrence of the polymorphic GSTP1b variant in the GSTP1 gene resulted in a significantly lower GST enzyme activity (P < 0.05), and GSTP1b was found significantly more often in patients with Barrett's epithelium (70%; P < 0.001) and patients with esophageal adenocarcinoma (76%; P = 0.005), as compared to healthy blood donors (41%). In conclusion, presence of the GSTP1b allele leads to lower GST enzyme activity levels and, consequently, impaired detoxification. This most important esophageal GST isoform may, therefore, contribute to the development of Barrett's epithelium and adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Mechanisms by which garlic and allyl sulfur compounds suppress carcinogen bioactivation. Garlic and carcinogenesis.

Overall, a host of studies provides compelling evidence that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. These studies reveal that the benefits of garlic are not limited to a specific species, to a particular tissue, or to a specific carcinogen. Several mechanisms are likely to account for this protection. Notable among these is a depression in nitrosamine formation and a reduction in carcinogen bioactivation. The benefits provided by garlic must be viewed as part of the entire diet, since several dietary constituents can influence the degree of protection. More than one compound is responsible for the anticancer properties associated with garlic. Future research should focus on how genetic variability and daily environmental factors influence the anticancer benefits attributed to garlic and its allyl sulfur components.

Allyl Compounds↗