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At least 667 records · Page 37Linked to original sources
PubMed2002

Parameters for the recovery of proteases from surimi wash water.

Proteases are important bioactive compounds that have many applications in food processing. In this study, laboratory scale experiments were performed to establish conditions for recovery of a heat stable, acid protease from Pacific whiting (Merluccius productus) surimi process water. Reduction of proteinaceous solids and recovery of protease activity was maximized when process water was pre-treated with acid (pH 4) followed by heat (60 degrees C). In addition, acid plus heat treatment of process water appeared to improve membrane flux and concentration of protease activity (10-fold) was achieved in half as much time as treatments using acidification but not heat. Neither purification nor concentration of protease was effective using either 300 and 1000 kDa ultrafiltration or 0.3 microm microfiltration membranes. However, concentration of protease using 50 kDa ultrafiltration membranes was successful in recovering about 80% of original protease activity. Results provide conditions for further investigations into pilot plant recovery of protease from surimi process water.

Endopeptidases↗
PubMed2002

Rose hip (Rosa canina L.) oil obtained from waste hip seeds by different extraction methods.

From the rose hip seed, which is generally a waste material, valuable oil can be obtained for medicinal use. Various extraction methods have been compared: traditional solvent extraction with ultrasound-, microwave-, sub- and supercritical fluid extraction (SFE). Unsaturated fatty acid (UFA: oleic-, linoleic- and linolenic acid; 16.25-22.11%, 35.94-54.75%, 20.29-26.48%) and polyunsaturated fatty acid (PUFA:linoleic- and linolenic acid) content were over 90% and 60% in the recovered oils. The oils contained different amounts of metals. The concentration of some metals, particularly iron in microwave oil (27.11 microg g(-1)) is undesirable from the aspect of stability. By traditional solvent extraction, oil was obtained in 4.85 wt/wt%. Subcritical FE appeared to be the best method for the recovery of rose hip oil with highest oil yield (6.68 wt/wt%), carotene- (145.3 microg g(-1)) and linoleic acid content (54.75%). Supercritical FE without organic solvent is suitable for mild recovery of oil. The oil was rich in UFA and PUFA (92.7% and 76.25%) and contained the lowest amount of carotene and pheophytin (36.3 and 45.8 microg g(-1)). Oil yield in most new extraction methods (microwave extraction, super- and subcritical FE) was higher than in the case of traditional Soxhlet extraction. The main benefit of supercritical FE with CO2 is the solvent free oil while in the case of other extractions evaporation of the solvent is needed. Although the content of bioactive compounds in oils was different, all oils may be appropriate for medicinal use.

Carbon Dioxide↗
PubMed2002

Pilot plant recovery of catheptic proteases from surimi wash water.

Recovery of bioactive compounds, such as proteolytic enzymes, from waste streams is a means to both recuperate value and reduce environmental pollution. Previously optimized lab-scale parameters for the recovery of a stable crude protease fraction from Pacific whiting (Merluccius productus) surimi wash water were tested using pilot plant equipment. Pretreatment of surimi wash water with 60 degrees C heat, acidification to pH 6, and centrifugation doubled ultrafiltration membrane flux and significantly improved protease purity by reducing a majority of the 35-205 kDa proteins. Concentrated crude protease obtained from wash water contained predominantly cathepsin L activity. Enzyme purity was increased about 100-fold, and yield was approximately 80%. Stability (frozen and freeze-dried protease) was maintained for 9 weeks at -80 degrees C. Freeze-dried preparations were also stable for 9 weeks at 4 and -15 degrees C. Successful application of pilot plant conditions allows for sufficient production of protease for further investigations into their applicability.

Animals↗
PubMed2003

Pharmaco-toxicological study of diterpenoids.

Azorella compacta, Azorella yareta and Laretia acaulis (Apiaceae) are native species from the high Andes Mountains, northeastern Chile, and they have being traditionally used to treat asthma, colds and bronchitis, illnesses with inflammation and pain as the main symptoms. Interestingly, there are no scientific reports available on their benefits or toxicity. This study was carried out with the purpose of validating the medicinal use of these species and to discover anti-inflammatory and analgesic new molecules. As a working hypothesis, we have proposed that these medicinal species contain bioactive compounds with anti-inflammatory and analgesic effects. In this context, azorellanol, 13-hydroxy-7-oxoazorellane and 7-deacetylazorellanol, three diterpenoids previously isolated only from these plants, were subjected to farmaco-toxicological evaluation. Their topical anti-inflammatory and analgesic activities along with acute toxicities or innocuosness were also investigated. Our results indicate the absence of toxic and side effects in mice. All compounds presented dose-related inhibition of pain. 13-hydroxy-7-oxoazorellane was the most potent analgesic but it was less effective than sodium naproxen, the reference drug. Azorellanol exhibited the highest topical anti-inflammatory potency on AA (arachidonic acid) and TPA (12-deoxyphorbol 13-tetradecanoate) induced oedema, and it effect was similar to the reference drugs (nimesulide and indomethacin). Probably, its mechanism of action could be explained through the inhibition to cyclo-oxygenase activity. Our results corroborate the anti-inflammatory and analgesic effects of these species, and it justifies their use in folk medicine.

Administration, Topical↗
PubMed2001

Superimposition-based protocol as a tool for determining bioactive conformations. II. Application to the GABA(A) receptor.

The natural templates (NT) superimposition method is used to determine the pharmacophoric requirements of the A subtype of the gamma-aminobutyric acid (GABA) receptor. Bioactive conformations for antagonists and agonists are found by superimposing them on a relatively rigid alkaloid bicuculline, which itself is a competitive antagonist at this ligand-gated ion channel receptor. As has been usual in the application of this modeling method, consideration of available experimental data is the cornerstone for obtaining realistic models. The identification of two substructural fragments of bicuculline permitted classification of the ligands. Analysis of the antagonists and agonists with respect to the two substructural fragments revealed two bioactive conformations of the highly flexible GABA molecule, one of which is extended with the nonhydrogenic atoms roughly coplanar torsional angles of -37 and -179 degrees at N-C-C-C and C-C-C-C (carboxyl), respectively. The second bioactive compound is clearly non planar (torsional angles of -81 and -109 degrees at N-C-C-C and C-C-C-C (carboxyl), respectively).

Bicuculline↗
PubMed2003

Plants, selenium and human health.

Selenium is an essential nutrient for animals, microorganisms and some other eukaryotes. Although selenium has not been demonstrated to be essential in vascular plants, the ability of some plants to accumulate and transform selenium into bioactive compounds has important implications for human nutrition and health, and for the environment. Selenium-accumulating plants provide unique tools to help us understand selenium metabolism. They are also a source of genetic material that can be used to alter selenium metabolism and tolerance to help develop food crops that have enhanced levels of anticarcinogenic selenium compounds, as well as plants that are ideally suited for the phytoremediation of selenium-contaminated soils.

Adaptation, Physiological↗
PubMed1999

An antitumor promoter from Moringa oleifera Lam.

In the course of studies on the isolation of bioactive compounds from Philippine plants, the seeds of Moringa oleifera Lam. were examined and from the ethanol extract were isolated the new O-ethyl-4-(alpha-L-rhamnosyloxy)benzyl carbamate (1) together with seven known compounds, 4(alpha-L-rhamnosyloxy)-benzyl isothiocyanate (2), niazimicin (3), niazirin (4), beta-sitosterol (5), glycerol-1-(9-octadecanoate) (6), 3-O-(6'-O-oleoyl-beta-D-glucopyranosyl)-beta-sitosterol (7), and beta-sitosterol-3-O-beta-D-glucopyranoside (8). Four of the isolates (2, 3, 7, and 8), which were obtained in relatively good yields, were tested for their potential antitumor promoting activity using an in vitro assay which tested their inhibitory effects on Epstein-Barr virus-early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). All the tested compounds showed inhibitory activity against EBV-EA activation, with compounds 2, 3 and 8 having shown very significant activities. Based on the in vitro results, niazimicin (3) was further subjected to in vivo test and found to have potent antitumor promoting activity in the two-stage carcinogenesis in mouse skin using 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and TPA as tumor promoter. From these results, niazimicin (3) is proposed to be a potent chemo-preventive agent in chemical carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Biopotentials of marine sponges from China oceans: past and future.

An extensive literature survey of over 17 Journals was carried out on Chinese sponges and their natural products in the period from 1980 to 2001. This review is thus intended to provide the first thorough overview of research on marine sponges from China Ocean territories. Information is provided about the rather-limited taxonomic study of Chinese marine sponges, with an analysis on their distribution and diversity. Research findings on the natural products and their bioactivity screening from Chinese sponges are summarized. The weaknesses, gaps and problems in the past R&D program of Chinese sponges are identified, which point to the future opportunities in exploiting these huge untapped sponge resources. The report is expected to serve as an entry point for understanding Chinese sponges and for furthering R&D on their bioactive compounds for new drug development.

Animals↗
PubMed2002

Rapid pharmacokinetic screening for the selection of new drug discovery candidates using a generic isocratic liquid chromatography--atmospheric pressure ionization tandem mass spectrometry method.

A generic isocratic HPLC-APCI-MS-MS method has been developed for the determination of plasma concentrations of bioactive compounds for the selection of potential new drug discovery candidates. A 4.6 x 50 mm cyano phase column eluted with an acetonitrile/water mobile phase containing 20 mM ammonium acetate and 0.4% TFA produces retention times of 1 min or less for a wide range of compounds. This is a great advantage in new drug discovery where many compounds are analyzed once and eliminated. No time is consumed developing chromatographic conditions for each new compound. The mass spectrometer can be optimized and the samples can be processed and analyzed, all in the same day. Multiple assays can be run consecutively without changing the column or mobile phase between assays.

Atmospheric Pressure↗
PubMed2006

Tree nuts and the lipid profile: a review of clinical studies.

Tree nuts have a fatty acid profile that favourably affects blood lipids and lipoproteins. They are low in saturated fat and high in unsaturated fatty acids and are rich sources of other nutrients. An extensive database consistently shows total and LDL cholesterol-lowering effects of diets low in saturated fat and cholesterol and high in unsaturated fat provided by a variety of tree nuts. Collectively, a summary of studies conducted to date shows that tree nuts reduce LDL cholesterol by 3-19 % compared with Western and lower-fat diets. Nuts also contain many nutrients and bioactive compounds that appear to contribute to the favourable effects on lipids and lipoproteins--these include plant sterols, dietary fibre and antioxidants. Because of their unique nutrient profile, nuts can be part of a diet that features multiple heart-healthy foods resulting in a cholesterol lowering response that surpasses that of cholesterol-lowering diets typically used to reduce CVD risk.

Carya↗
PubMed2001

Immunomodulating effects of milks fermented by Lactobacillus helveticus and its non-proteolytic variant.

The effect of milks fermented by Lactobacillus helveticus and its non-proteolytic variant on mucosal and tumoral immunity was studied. Milks fermented by Lb. helveticus wild type or its non-proteolytic variant were administered orally to mice for different periods (3, 5 and 7 d). The immune response was assessed by analysing the activity of the peritoneal macrophages, the number of cells secreting IgA associated with the gut-associated lymphoid tissue and with the bronchial-associated lymphoid tissue. The number of cells was determined by direct immunofluorescence. The antitumour activity was monitored by studying the regression of the subcutaneously implanted fibrosarcomas. After 3 d feeding of milk fermented by Lb. helveticus wild type, the number of sIgA increased significantly at both the intestinal and bronchial levels, indicating that a cellular migration had occurred. This effect was not noticeable when milk fermented by Lb. helveticus Protease (-) was orally administered. Both fermented milks (wild type or its variant) exhibited an effect on the activity of the peritoneal macrophages, which might be indirectly correlated to the regression of the fibrosarcoma. Although the mechanism by which the lactic acid bacteria enhance the immune system is not clear, this study clearly suggests that the bioactive compounds released during milk fermentation might contribute to the immunoenhancing properties of these products. By releasing biopeptide, lactic acid bacteria have important implications in modulation of the host's immune response, more specifically its cellular immune response.

Adjuvants, Immunologic↗
PubMed2005

Effects of hormones and growth factors on TGF-beta1 expression in bovine mammary epithelial cells.

The decline of mammary epithelial cell (MEC) number during mammary gland involution in the cow is due to inhibition of proliferation and induction of apoptosis. Transforming growth factor-beta 1 (TGF-beta1) belongs to a group of intramammary auto/paracrine inhibitors of bovine MEC growth and inducers of apoptosis. However, the mechanism responsible for the regulation of TGF-beta1 expression in MEC is not known. The present study examined the effect of the hormones, growth hormone (GH), somatostatin (STS), 17-beta oestradiol (E2), progesterone (P4), as well as the growth factors, insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF), on TGF-beta1 expression in the bovine MEC lines, BME-UV1 and MAC-T. The model of apoptosis in bovine mammary gland in vitro was applied by reduction of fetal bovine serum (FBS) (from 10% to 2% or 0.5% FBS) in the cell environment to show the relationship between TGF-beta1 expression and apoptosis in bovine MEC. RT-PCR, Western blot and laser scanning cytometry (LSC) were used for analysis of TGF-beta1 transcript and protein level as well as apoptosis and cell cycle in examined MEC. In this model of apoptosis, FBS deficiency (mimicking the naturally occurring decline in the access of bioactive compounds and nutrients at the end of lactation and dry period) was associated with increased TGF-beta1 expression at the level of transcript and protein, induction of apoptosis and inhibition of cell cycle. Exogenous TGF-beta1, IGF-I, EGF and GH inhibited FBS-deficiency-stimulated TGF-beta1 expression. The suppressive effect of GH was reversed when cells were maintained longer in FBS-deficient medium. In general, STS, E2 and P4 increased TGF-beta1 expression. However, this effect was dependent on hormone concentration and cell line. BME-UV1 cells were much more responsive to the peptides, GH, STS, IGF-I and EGF, whereas MAC-T cells were more responsive to the steroid sex hormones: E2 and P4.

Animals↗
PubMed2005

Biological effects of milk proteins and their peptides with emphasis on those related to the gastrointestinal ecosystem.

The protein fraction of milk contains several components with physiological significance for the development of the newborn. Among them, immunomodulatory peptides and lactoferrin exemplify the complexity of biologically active substances of milk. Immunomodulatory peptides have latent activity within the native protein and are generated after proteolysis during gastrointestinal transit. Once they are generated, they modulate mucosal immunity, possibly by guiding the local immune system until it develops its full functionality. Lactoferrin is another milk bioactive compound with nutritional and health promoting properties; it modulates the microbial intestinal environment, displays anti-microbial activity against various pathogens and stimulates the establishment of beneficial microflora. The following overview focuses on the importance of immunomodulatory peptides and lactoferrin for the maturation of intestine and immune system that are functionally immature in the newborn.

Animals↗
PubMed1992

Rates of peptide proteolysis measured using liquid chromatography and continuous-flow fast atom bombardment mass spectrometry.

An immobilized digestive enzyme assay, which has been used to determine whether orally administered peptide drugs are hydrolyzed by the digestive system, was applied to the measurement of rates of proteolysis of biologically active peptides. In this study, the rates of hydrolysis by trypsin and chymotrypsin of the pressor agent angiotensin II, the peptide hormone [Arg8]vasopressin, and the peptide drug [deamino-Cys1,D-Arg8]vasopressin were measured. Enzyme immobilization prevented autolytic proteolysis and provided a stable enzyme preparation during the assays. For rate determinations, the disappearance of substrate was measured over time by using either flow injection continuous-flow fast atom bombardment (FAB) mass spectrometry with selected ion monitoring or reversed-phase high-performance liquid chromatography (HPLC) with UV absorbance detection. Compared to the HPLC method, continuous-flow FAB was faster, provided more confident identification of the analyte because molecular weight data was obtained, and could be used for all enzymatic reactions instead of only those in which complete chromatographic resolution of substrate from proteolytic fragments was obtained. The in vitro proteolytic rates measured for the vasopressins were compared to data from rat bioassays and confirmed that the limiting factor in the oral bioavailability of [Arg8]vasopressin was rapid hydrolysis by trypsin in the intestinal lumen. The more bioactive compound, [deamino-Cys1,D-Arg8]vasopressin, was more stable to chymotryptic digestion and completely resistant to trypsinization.

Amino Acid Sequence↗
PubMed2006

Detection of FITC-cortisol via modulated supraparticle lighthouses.

Hormones are important bioactive compounds in blood and tissue that vary in concentration in response to stress and certain disease states. Establishing the changes in physiological hormone concentrations over time can lead to more effective diagnoses and perhaps a better understanding of the evolution of stress and disease. To monitor concentration over time, the sampling must be rapid and noninvasive; specimens such as saliva that require little effort to collect are preferred. However, more sensitive assay techniques are needed when compared to blood analysis since free hormone concentration in saliva is only a small fraction of the concentration in circulating blood. In this work, magnetic field-induced structures of paramagnetic particles are used as a solid substrate to demonstrate improved detection limits for a separation-free assay of cortisol. Once formed, the structures are subjected to a rotating magnetic field and this leads to two important features. First is the ability to utilize frequency and phase filtering (lock-in amplification) for the signal generated from surface-bound labeled species. Second is the improved mass transport of the antigen to the surface of the rotating structures. These two unique capabilities result in a quantifiable signal at a relatively low target antigen concentration. This method has been demonstrated with the detection of fluorescein isothiocyanate-labeled cortisol (FITC-cortisol) at a concentration of 300 pM.

Equipment Design↗
PubMed2003

Site-specific observation of acyl intermediate processing in thiotemplate biosynthesis by fourier transform mass spectrometry: the polyketide module of yersiniabactin synthetase.

Complex arrays of thioester bound intermediates are present on 100-700 kDa enzymes during the biogenesis of diverse types of pharmacophores and natural product drugs. These multidomain enzymes, known as nonribosomal peptide synthetases and polyketide synthases (NRPSs and PKSs, respectively), synthesize from simple, physiologically available substrates bioactive compounds that can be further tailored by a host of modifying domains (e.g., methylation, cyclization, and epimerization) to increase the complexity of the mature final product. Interrogation of such covalent intermediates using mass spectrometry (MS) presents an underutilized method for understanding the covalent catalysis executed by NRPS and PKS enzymes. For the PKS module (205 kDa) from the yersiniabactin (Ybt) gene cluster of Yersinia pestis, limited proteolysis afforded a key 11 kDa peptide from the acyl-carrier protein (ACP) domain upon which at least five covalent intermediates could be detected (42, 70, 86, 330, and 358 Da). The isotopic resolution achieved by Fourier transform mass spectrometry (FTMS) allowed for the incorporation of substrates with stable isotopes to confirm the structural assignments of three intermediates (86, 330, and 358 Da) on the Ybt biosynthetic pathway to within 1 Da. Approximately 75% of the enzyme capacity is lost to unproductive decarboxylation of malonyl-S-ACP partly constraining the 1.4 min(-)(1) rate of Ybt production in vitro. Acyl transfer to the ACP domain (on the Ybt pathway) was promoted by a factor of approximately 10 over unproductive CO(2) loss in the presence of the cosubstrate S-adenosylmethionine (SAM), with S-adenosylhomocysteine unable to restore the condensation yield observed with SAM. The data are consistent with Claisen condensation from KS to the ACP carrier site being reversible, with the absence of downstream methylation providing more opportunity for unproductive CO(2) loss. Extension of such FTMS-based studies will allow the direct visualization of multiple intermediates in determining the catalytic order of events and kinetics of NRPS and PKS systems.

Acyl Carrier Protein↗
PubMed2006

Chemoenzymatic design of acidic lipopeptide hybrids: new insights into the structure-activity relationship of daptomycin and A54145.

The acidic lipopeptides, including the clinically approved antibiotic daptomycin, constitute a class of structurally related branched cyclic peptidolactones and peptidolactams synthesized by nonribosomal peptide synthetases (NRPSs). In this study, the excised peptide cyclases from A54145 and daptomycin NRPSs were shown to be able to catalyze the macrocyclization of peptide thioester substrates, which were chemically produced by solid phase peptide synthesis. Applying this chemoenzymatic strategy, we generated derivatives of A54145 and daptomycin as well as hybrid molecules of both compounds. Bioactivity determination of the derived cyclic molecules revealed new insights into the structure-activity relationship of the acidic lipopeptide family. The general importance of several amino acid positions, including two conserved aspartic acid residues, was confirmed to be substantial for antibiotic potency. As a robust macrocyclization catalyst, the peptide cyclase excised from A54145 synthetase is the first cyclase of a branched cyclic lipopeptide, which catalyzes both macrolactonization and macrolactamization. The results presented herein illustrate the advantages of combining organic synthesis with natural product biosynthetic enzymes to explore the interplay between structural features and biological activity.

Amino Acid Sequence↗
PubMedDate not supplied

Application of a MTT assay for screening nutritional factors in growth media of primary sponge cell culture.

Marine sponges (Porifera) are producers of the largest variety of bioactive compounds among benthic marine organisms. In vitro culture of marine sponge cells has been proposed for the sustainable production of these pharmacologically interesting compounds from marine sponges but with limited success. The development of a suitable growth medium is an essential prerequisite for sponge cells grown in vitro. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was adapted to screen for potential nutritional factors in formulating a growth medium for primary cell culture of Suberites domuncula. In 96-well plates, the effects of nutritional factors including glutamine, pyruvate, iron citrate, silicon, RPMI 1640, and Marine Broth 2216 on the viable cell density were examined in primary cell culture of S. domuncula 36 h after inoculation. Ferric iron (Fe(3+)) and pyruvate were found to significantly improve cell viability in a dose-dependent manner. Silicon and glutamine showed limited improvements at certain concentrations. The supplement of RPMI 1640 and Marine Broth 2216 did not increase cell viability. As a result, several improved media able to maintain higher cell viability in a short-term culture of primary sponge cells could be formulated.

Animals↗