SEARCH · PubMed Health

Results for “GLUCOSIDES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources

PubMed2004

Minimization of photooxidative insult to calf lens protein irradiated with near UV-light in the presence of pigmented glucosides derived from human lens protein.

An aqueous solution of a pigmented glucoside associated with human lens protein, 2-amino-3-hydroxyacetophenone-O-beta-D-glucoside (AHA-Glc), was irradiated with near UV-light. The near UV-irradiated glucoside was shown to generate a much lower level of active species of molecular oxygen as compared to the level of the active species generated from the irradiated aglycon, 2-amino-3-hydroxyacetophenone (AHA). This result suggests that the glycon of the glucoside is functioning as a scavenger for active oxygen generated from the aglycon of the irradiated glucoside. Superoxide dismutase (SOD) was shown to remove a large portion of the active oxygen generated from the irradiated AHA, so the bulk of the active species generated is assumed to be superoxide anion. The small portion of active oxygen remains after removal of superoxide anion may include singlet oxygen. The photooxidation of tryptophan residues of calf alpha-crystallin irradiated with near UV-light in the presence of AHA-Glc or AHA was investigated to confirm the role that the glycon plays in diminution of the active species of oxygen generated through the photosensitized aglycon of the glucoside. A decrease with time in the fluorescence intensity of the tryptophan residues irradiated with AHA-Glc was shown to be much slower as compared to the time-dependent decrease with AHA, indicating that the photooxidation proceeds with an increase in accumulation of active oxygen generated through the aglycon and that the glycon of the glucoside deactivates the active species as it is formed in the photodynamic process. Similar effects have also been observed in calf lens crystallin irradiated with either 3-hydroxykynurenine-O-beta-D-glucoside (HKN-Glc) or 3-hydroxykynurenine (HKN). Furthermore, effects of near UV-irradiation on calf lens soluble protein in the presence of AHA-Glc or AHA were studied by monitoring changes in the SDS-PAGE profile of the irradiated protein. Near UV-irradiation with AHA-Glc was shown to bring about a slight change in cross-linking of the polypeptides, while irradiation with AHA was shown to give rise to a significant increase in cross-linking of the polypeptides. In conclusion, pigmented glucoside associated with human lens protein is not only a photosensitizer for near UV-light but also an anti-photooxidant to deactivate active oxygen formed through the in situ photosensitizer, in order that photooxidative insults to lens proteins may be minimized during aging.

Animals↗

PubMed1994

Mice, hamsters and guinea pigs differ in efficiency of pyridoxine-5'-beta-D-glucoside utilization.

Mice, hamsters and guinea pigs were studied to assess species variation in utilization of pyridoxine-5'-D-glucoside (PN-glucoside), a form of vitamin B-6 found in plants. Animals fed vitamin B-6-deficient or marginally supplemented diets [1 mg pyridoxine (PN)/kg] were given an oral dose of [3H]PN-glucoside plus [14C]PN. Urinary and fecal isotopic excretion was measured over 24 h and the distribution of B-6 vitamins in liver determined at the end of the 24-h period. Intestinal absorption was nearly complete, as very little (< 6%) of each isotope was excreted in the feces. In mice, hamsters and guinea pigs, 31.3, 31.5 and 9.5%, respectively, of urinary 3H was present as intact PN-glucoside. Incorporation into liver was reflected by 3H/14C ratios of hepatic vitamin B-6 as follows: mice, 0.39; hamsters, 0.73; guinea pigs, 1.49 (means for both diets). The intake of dietary vitamin B-6 had little effect on [3H]PN-glucoside metabolism. Guinea pigs displayed greater utilization of PN-glucoside than did mice, hamsters or rats (seen previously), although they may not be the best animal model for the study of PN-glucoside metabolism. Because the bioavailability of PN-glucoside in humans has been estimated to be 58% relative to PN, mice or hamsters, rather than guinea pigs or rats, would be better species for quantitative studies of PN-glucoside bioavailability and associated enzymatic processes.

Animals↗

PubMed1996

Pyridoxine 4'-alpha- and 5'-alpha-D-glucosides are taken up and metabolized by isolated rat liver cells.

Uptake and metabolism of pyridoxine-4'-alpha-D-glucoside and pyridoxine-5'-alpha-D-glucoside by freshly isolated rat liver cells were studied using the membrane filtration method. The presence of the pyridoxine-alpha-glucosides at either 0.5 or 5.0 micromol/L had no inhibitory effect on the uptake of pyridoxine (0.5 micromol/L) by hepatocytes. The amount of pyridoxine-alpha-glucoside transported into the cells was only 10-12% of that of pyridoxine. The initial rates of uptake of the pyridoxine-alpha-glucosides were linear with concentrations up to 50 micromol/L. On entry into the cells, 78% of pyridoxine-5'-alpha-glucoside and 15% of the pyridoxine-4'-alpha-glucoside were hydrolyzed at the end of 60 min. Because pyridoxine-5'-alpha-glucoside is hydrolyzed readily and does not interfere with the transport of pyridoxine, the glucoside, if present in animal- or plant-derived foods, may be available as a source of vitamin B-6.

Animals↗

PubMed1990

Acyl glucuronidation and glucosidation of pranoprofen, a 2-arylpropionic acid derivative, in mouse liver and kidney homogenates.

The formation of acyl glucuronide and glucoside of 2-(5H-[1]benzopyrano[2,3-b]pyridin-7-yl)propionic acid (pranoprofen), an anti-inflammatory drug, was studied in homogenates and microsomes of mouse tissues by using S(+)-, R(-)- and RS(+/-)-pranoprofen. Acyl glucuronidation occurred mainly in the liver, whereas acyl glucosidation was predominant in the kidney. Furthermore, both conjugations occurred by enzymatic transfer of glucuronic acid of uridine diphosphate glucuronic acid (UDPGA) and glucose of uridine diphosphate glucose (UDPG) to pranoprofen, respectively. No conjugation reactions were observed in the lung, plasma or gut. The amount of conjugates in the liver and kidney increased by the prolongation of the incubation times and reached the maximum at 15-30 min for glucuronidation and 45 min for glucosidation. After that, both conjugates decreased with the lapse of time. Both acyl conjugates were the least stable in the liver, then in the kidney and the most stable in the plasma. In the liver, acyl glucoside was converted to acyl glucuronide and pranoprofen in the presence of UDPGA, but only a small amount of acyl glucuronide was changed to acyl glucoside in the kidney in spite of the presence of UDPG. In the kidney, acyl glucoside decreased relative to acyl glucuronide at increasing doses for both S(+)- and R(-)-pranoprofen, but the concentration of acyl glucoside was much higher for S(+)-pranoprofen than R(-)-enantiomer 1 h after the oral administration of S(+)- and R(-)-pranoprofen. No acyl glucoside was detected in the liver and plasma. Although only a small difference in acyl glucuronidation in the liver was observed between S(+)- and R(-)-enantiomers, acyl glucosidation in the kidney occurred more predominantly for S(+)-pranoprofen than for the R(-)-enantiomer.

Animals↗

PubMed1999

UV filter compounds in human lenses: the origin of 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid O-beta-D-glucoside.

PURPOSE: To investigate UV filter synthesis in the human lens, in particular the biosynthetic origin of the second most abundant UV filter compound, 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid O-beta-D-glucoside. METHODS: Human lenses were analyzed by high-performance liquid chromatography (HPLC) after separate incubation with 3H-tryptophan (3H-Trp), beta-benzoylacrylic acid, D,L-alpha-amino-beta-benzoylpropionic acid, or D,L-3-hydroxykynurenine O-beta-D-glucoside. The effect of pH on the model compound D,L-alpha-amino-beta-benzoylpropionic acid and D,L-3-hydroxykynurenine O-beta-D-glucoside was also investigated. RESULTS: UV filters were not detected in fetal lenses, despite a 5-month postnatal lens displaying measurable levels of UV filters. In adults no radiolabel was incorporated into 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid O-beta-D-glucoside after 3H-Trp incubations. Beta-benzoylacrylic acid was readily reduced in lenses. D,L-alpha-amino-beta-benzoylpropionic acid and D,L-3-hydroxykynurenine O-beta-D-glucoside slowly deaminated at physiological pH and were converted to beta-benzoylpropionic acid and 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid O-beta-D-glucoside, respectively, after lens incubations. CONCLUSIONS: UV filter biosynthesis appears to be activated at or near birth. Compounds containing the kynurenine side chain slowly deaminate, and in the lens, the newly formed double bond is rapidly reduced. These findings suggest that 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid O-beta-D-glucoside is derived from L-3-hydroxykynurenine O-beta-D-glucoside through this deamination-reduction process. The slowness of the deamination presumably accounts for the absence of incorporation of radiolabel from 3H-Trp into 4(2-amino-3-hydroxyphenyl)4-oxobutanoic acid O-beta-D-glucoside.

Acrylates↗

PubMed2004

Uptake of quercetin and quercetin 3-glucoside from whole onion and apple peel extracts by Caco-2 cell monolayers.

Evidence suggests that regular consumption of fruits and vegetables may reduce the risk of chronic diseases, and phytochemicals from fruits and vegetables may be responsible for this health benefit. However, there is limited knowledge on the bioavailability of specific phytochemicals from whole fruits and vegetables. This study used Caco-2 cells to examine uptake of quercetin aglycon and quercetin 3-glucoside as purified compounds and from whole onion and apple peel extracts. Pure quercetin aglycon was absorbed by the Caco-2 cells in higher concentrations than quercetin 3-glucoside (p < 0.05). Caco-2 cells treated with quercetin 3-glucoside accumulated both quercetin 3-glucoside and quercetin. Caco-2 cells absorbed more onion quercetin aglycon than onion quercetin 3-glucoside (p < 0.05), and the percentage of onion quercetin absorbed was greater than that of pure quercetin, most likely due to enzymatic hydrolysis of quercetin 3-glucoside and other quercetin glucosides found in the onion by the Caco-2 cells. Caco-2 cells absorbed low levels of quercetin 3-glucoside from apple peel extracts, but quercetin aglycon absorption was not detected. Caco-2 cell homogenates demonstrated both lactase and glucosidase activities when incubated with lactose and quercetin 3-glucoside, respectively. This use of the Caco2 cell model appears to be a simple and useful system for studying bioavailability of whole food phytochemicals and may be used to assess differences in bioavailability between foods.

Biological Availability↗

PubMed1997

Cytosolic pyridoxine-beta-D-glucoside hydrolase from porcine jejunal mucosa. Purification, properties, and comparison with broad specificity beta-glucosidase.

During studies of the nutritional utilization of pyridoxine 5'-beta-D-glucoside, a major form of vitamin B6 in plants, we detected two cytosolic beta-glucosidases in jejunal mucosa. As expected, one was broad specificity beta-glucosidase that hydrolyzed aryl beta-D-glycosides but not pyridoxine beta-D-glucoside. We also found a previously unknown enzyme, designated pyridoxine-beta-D-glucoside hydrolase, that efficiently hydrolyzed pyridoxine beta-D-glucoside. These were separated and purified as follows: broad specificity beta-glucosidase 1460-fold and pyridoxine-beta-D-glucoside hydrolase 36,500-fold. Purified pyridoxine-beta-D-glucoside hydrolase did not hydrolyze any of the aryl glycosides tested but did hydrolyze cellobiose and lactose. Pyridoxine-beta-D-glucoside hydrolase exhibited a pH optimum of 5.5 and apparent molecular mass of 130 kDa by SDS-polyacrylamide gel electrophoresis and 160 kDa by nondenaturing gel filtration, in contrast to 60 kDa for native and denatured broad specificity beta-glucosidase. Glucono-delta-lactone was a strong inhibitor of both enzymes. Ionic and nonionic detergents were inhibitory for each enzyme. Conduritol B epoxide, a potent inhibitor of lysosomal acid beta-glucosidase, inhibited pyridoxine-beta-D-glucoside hydrolase but not broad specificity beta-glucosidase, but both were inhibited by the mechanism-based inhibitor 2-deoxy-2-fluoro-beta-D-glucosyl fluoride. Our findings indicate major differences between these two cytosolic beta-glucosidases. Studies addressing the role of vitamin B6 nutrition in regulating the activity and its consequences regarding pyridoxine glucoside bioavailability are in progress.

Animals↗

PubMed2006

Growth inhibitory activity of cucurbitacin glucosides isolated from Citrullus colocynthis on human breast cancer cells.

Our aim was to study the effects of cucurbitacin glucosides extracted from Citrullus colocynthis leaves on human breast cancer cell growth. Leaves were extracted, resulting in the identification of cucurbitacin B/E glucosides. The cucurbitacin glucoside combination (1:1) inhibited growth of ER(+) MCF-7 and ER(-) MDA-MB-231 human breast cancer cell lines. Cell-cycle analysis showed that treatment with isolated cucurbitacin glucoside combination resulted in accumulation of cells at the G(2)/M phase of the cell cycle. Treated cells showed rapid reduction in the level of the key protein complex necessary to the regulation of G(2) exit and initiation of mitosis, namely the p34(CDC2)/cyclin B1 complex. cucurbitacin glucoside treatment also caused changes in the overall cell morphology from an elongated form to a round-shaped cell, which indicates that cucurbitacin treatment caused impairment of actin filament organization. This profound morphological change might also influence intracellular signaling by molecules such as PKB, resulting in inhibition in the transmission of survival signals. Reduction in PKB phosphorylation and inhibition of survivin, an anti-apoptosis family member, was observed. The treatment caused elevation in p-STAT3 and in p21(WAF), proven to be a STAT3 positive target in absence of survival signals. Cucurbitacin glucoside treatment also induced apoptosis, as measured by Annexin V/propidium iodide staining and by changes in mitochondrial membrane potential (DeltaPsi) using a fluorescent dye, JC-1. We suggest that cucurbitacin glucosides exhibit pleiotropic effects on cells, causing both cell cycle arrest and apoptosis. These results suggest that cucurbitacin glucosides might have therapeutic value against breast cancer cells.

Blotting, Western↗

PubMed2006

Glucosides from MBOA and BOA detoxification by Zea mays and Portulaca oleracea.

Incubation of Zea mays cv. Nicco seedlings with 6-methoxybenzoxazolin-2(3H)-one (MBOA) led to a minor detoxification product hitherto only found in Poaceae. This new compound was identified as 1-(2-hydroxy-4-methoxyphenylamino)-1-deoxy-beta-glucoside 1,2-carbamate (1) (methoxy glucoside carbamate) and represents an analogue to the previously described 1-(2-hydroxyphenylamino)-1-deoxy-beta-glucoside 1,2-carbamate (glucoside carbamate) from benzoxazolin-2(3H)-one (BOA). In Portulaca oleracea var. sativa cv. Gelber treatment with BOA resulted in further unknown detoxification products, which were not synthesized in detectable amounts after BOA absorption in all other species tested. Compound 1 easily undergoes decay into BOA-5-O-glucoside (2). Z. mays seedlings, known to produce BOA-6-O-Glc on incubation with BOA, are able to transform BOA-5-OH into BOA-5-O-glucoside (2). Besides the known compounds, maize contained a formerly unseen product that accumulated during late stages of the detoxification process. It was isolated and identified as 1-(2-hydroxyphenylamino)-6-O-malonyl-1-deoxy-beta-glucoside 1,2-carbamate (3) (malonyl glucoside carbamate).

Benzoxazoles↗

PubMed1981

Cryptic operon for beta-glucoside metabolism in Escherichia coli K12: genetic evidence for a regulatory protein.

Escherichia coli K12 does not metabolize beta-glucosides such as arbutin and salicin because of lack of expression of the bglBSRC operon, which contains structural genes for transport (bglC) and hydrolysis (bglB) of phospho-beta-glucosides. Mutants carrying lesions in the cis-acting regulatory site bglR metabolize beta-glucosides as a consequence of expression of this cryptic operon (Prasad and Schaefler 1974). We isolated mutations promoting beta-glucoside metabolism that were unlinked to bglR; some of these mutations were shown to be amber. All of them were mapped at 27 min on the E. coli K12 linkage map and appeared to define a single gene, for which we propose the designation bglY. Utilization of beta-glucosides in bglY mutants appeared to be a consequence of expression of the bglBSRC operon, since bglB bglR and bglB bglY double mutants had the same phenotype. All bglY mutations analyzed were recessive to the wild-type bglY+ allele. Phospho-beta-glucosidase B and beta-glucoside transport activities are inducible in bglY mutants, as they are in bglR mutants. Metabolism of beta-glucosides in both bglR and bglY mutants required cyclic AMP. We propose that bglY encodes a protein acting as a repressor of the bglBSRC operon, active in both the presence and absence of beta-glucosides, whose recognition site would be within the bglR locus.

Carrier Proteins↗

PubMed1988

Metabolic utilization of pyridoxine-beta-glucoside in rats: influence of vitamin B-6 status and route of administration.

[3H]5'-O-(beta-D-glucopyranosyl) pyridoxine (PN-glucoside) and [14C]pyridoxine (PN) were administered orally or intraperitoneally to vitamin B-6-adequate or -deficient rats. Analysis of intestinal contents and feces indicated effective intestinal absorption of PN-glucoside relative to PN. There was greater retention of 14C than 3H in the liver and carcass regardless of the route of administration of the radiolabeled vitamins. There was no major difference in the relative distribution of 3H and 14C among the vitamin B-6 metabolites in the liver between the treatment groups, and no [3H]PN-glucoside was detected in any of the livers. For all groups, the majority of the 3H administered was detected in the urine within 24 h. Less excretion of both 3H and 14C in the urine was observed for the deficient rats. There was no major difference in the relative proportion of urinary [3H]PN-glucoside or [3H]4-PA between rats fed or injected with the radiolabeled vitamins. These results indicate that vitamin B-6 status influences the clearance of metabolites derived from PN and PN-glucoside, as well as the clearance of intact PN-glucoside. Vitamin B-6 status, however, has little or no effect on the utilization of PN-glucoside. This study also suggests that the intestine is the primary site of the limited conversion of PN-glucoside to biologically active PN in the rat.

Administration, Oral↗

PubMed1988

Incomplete utilization of pyridoxine-beta-glucoside as vitamin B-6 in the rat.

This research was conducted to determine the bioavailability of 5'-O-(beta-D-glucopyranosyl) pyridoxine (PN-glucoside) during chronic administration in a depletion-repletion bioassay. PN-glucoside was found previously to constitute a major portion of the total vitamin B-6 in many foods of plant origin. Following a 14-d depletion period, rats were fed diets containing graded levels of either free pyridoxine (PN) or PN-glucoside for 17 d. Slope ratio analysis of dose-response curves, on the basis of growth and plasma pyridoxal 5-phosphate (PLP) concentration, indicated 10-34% utilization of PN-glucoside relative to the molar response to PN. Erythrocyte aspartate amino-transferase (AspAT) activity and urinary 4-pyridoxic acid concentration were lower and the stimulation of AspAT activity by exogenous PLP was greater for rats fed PN-glucoside than for those fed PN, which indicated reduced vitamin B-6 nutriture in response to PN-glucoside. A constant 7-9% of the ingested PN-glucoside was detected in urine in intact form at all dosage levels. These results provide further evidence of incomplete bioavailability of PN-glucoside and indicate that its extent of utilization is not influenced by its level of dietary intake.

Administration, Oral↗

PubMed1992

Pyridoxine-5'-beta-D-glucoside affects the metabolic utilization of pyridoxine in rats.

A major form of vitamin B-6 in plant-derived foods is pyridoxine-5'-beta-D-glucoside. Previous studies have shown that pyridoxine-5'-beta-D-glucoside is poorly available as a source of vitamin B-6 in rats and is partially utilized in humans. This research was conducted to determine whether unlabeled pyridoxine-5'-beta-D-glucoside affects the metabolic utilization of simultaneously administered isotopically labeled pyridoxine in rats. Three groups of rats (n = 6) were administered a single oral dose of 0, 36 or 72 nmol of unlabeled pyridoxine-5'-beta-D-glucoside along with 166.5 MBq (240 nmol) of [14C]pyridoxine. Twenty-four hours after administration of the dose the rats were killed, and the isotopic distribution of vitamin B-6 metabolites in liver and urine was determined. Urinary 14C and hepatic 14C-labeled pyridoxine phosphate and pyridoxal phosphate were directly related to pyridoxine-5'-beta-D-glucoside dose. Hepatic 14C, 14C-labeled pyridoxal, pyridoxine and pyridoxamine, and the concentration of urinary [14C]4-pyridoxic acid, relative total urinary 14C, were inversely proportional to the dose of pyridoxine-5'-beta-D-glucoside. These results provide evidence that pyridoxine-5'-beta-D-glucoside quantitatively alters the metabolism and in vivo retention of [14C]pyridoxine and that pyridoxine-5'-beta-D-glucoside may retard the utilization of nonglycosylated forms of vitamin B-6.

Administration, Oral↗

PubMed2000

Soy isoflavone aglycones are absorbed faster and in higher amounts than their glucosides in humans.

Isoflavones are contained in soybean or soy foods in two chemical forms, i.e., aglycones and glucosides. We investigated the difference in the absorption of soy isoflavone aglycones and glucosides in humans. After a single, low dose intake (0.11 mmol), the highest isoflavone concentrations in plasma were reached 2 and 4 h after ingestion of aglycones and glucosides, respectively; subjects were four men (41 y old) and four women (45 y old). The highest plasma concentration after aglycone intake was more than two times greater than that after glucoside ingestion. In a similar manner, we then compared the plasma isoflavone concentration profiles after intake of a single, high dose of isoflavones (1.7 mmol) in eight subjects (four men, 40 y old; four women, 47 y old) and found the highest plasma concentration after aglycone intake was more than five times higher than that after glucoside intake. In both high and low dose intake tests, the plasma concentration of genistein was significantly higher than that of daidzein despite the similar levels of intake. After long-term (4 wk) intakes (0.30 mmol/d), we also measured the plasma concentration of isoflavones (eight men, 45 y old). After 2 and 4 wk, these concentrations remained >100% higher after ingestion of aglycones than of glucosides. The isoflavone aglycones were absorbed faster and in greater amounts than their glucosides in humans. Isoflavone aglycone-rich products may be more effective than glucoside-rich products in preventing chronic disease such as coronary heart disease.

Absorption↗

PubMed2001

Octyl glucoside induced formation of the molten globule-like state of glutamate dehydrogenase.

The interaction between n-octyl-beta-D-glucopyranoside (octyl glucoside) and bovine liver glutamate dehydrogenase (GDH) was studied using techniques including equilibrium dialysis, UV-spectrophotometry, circular dichroism (CD), fluorescence energy transfer and extrinsic spectrofluorometry in 50 mM sodium phosphate buffer solution (pH 7.6). The equilibrium dialysis experiment showed a higher binding of octyl glucoside to GDH that induces up to 80% enzyme inhibition in 20 mM octyl glucoside solution. The CD study indicated that GDH retains its secondary structure in the presence of octyl glucoside, but loses a degree of its tertiary structure by acquiring a more extended tertiary structure. Measurement of the binding of a hydrophobic fluorescent probe, 1-anilino-naphthalene-8-sulfonate (ANS), to GDH revealed that the binding of ANS to GDH is increased in the presence of octyl glucoside, a finding that may be interpreted in terms of the increment of surface hydrophobic patch(es) of GDH because of its binding to octyl glucoside. Fluorescence energy transfer studies also showed more binding of the reduced coenzyme (NADH) to GDH and the Lineweaver-Burk plots (with respect to NADH) indicate the existence of substrate inhibition in the presence of octyl glucoside. These observations are aimed at explaining the formation of the molten globule-like structure of GDH, which is induced by a non-ionic detergent such as octyl glucoside.

Anilino Naphthalenesulfonates↗

PubMed1991

A specific, high-affinity binding site for the hepta-beta-glucoside elicitor exists in soybean membranes.

The presence of a specific binding site for a hepta-beta-glucoside elicitor of phytoalexin accumulation has been demonstrated in soybean microsomal membranes. A tyramine conjugate of the elicitor-active hepta-beta-glucoside was prepared and radiolabeled with 125I. The labeled hepta-beta-glucoside-tyramine conjugate was used as a ligand in binding assays with a total membrane fraction prepared from soybean roots. Binding of the radiolabeled hepta-beta-glucoside elicitor was saturable, reversible, and with an affinity (apparent Kd = 7.5 x 10(-10) M) comparable with the concentration of hepta-beta-glucoside required for biological activity. A single class of hepta-beta-glucoside binding sites was found. The binding site was inactivated by proteolysis and by heat treatment, suggesting that the binding site is a protein or glycoprotein. Competitive inhibition of binding of the radiolabeled hepta-beta-glucoside elicitor by a number of structurally related oligoglucosides demonstrated a direct correlation between the binding affinities and the elicitor activities of these oligoglucosides. Thus, the hepta-beta-glucoside-binding protein fulfills criteria expected of a bona fide receptor for the elicitor-active oligosaccharin.

Binding Sites↗

PubMed1990

Stereoselective acyl glucuronidation and glucosidation of pranoprofen, a 2-arylpropionic acid derivative, in mice in vivo.

Following the oral administration of RS(+/-)-pranoprofen to mice at a dose of 25 mg/kg, 10.7% of the acyl glucuronide and 46.4% of the acyl glucoside of pranoprofen were excreted in the urine within 24 h. The recovery of acyl glucoside in the urine decreased relative to that of acyl glucuronide at increasing doses (100, 200 mg/kg). Following the oral administration of S(+)-pranoprofen to mice at a dose of 25 mg/kg, 5.0% of the acyl glucuronide and 56.5% of the acyl glucoside were excreted in the urine within 24 h, while 10.8% of the acyl glucuronide and 13.9% of the acyl glucoside were excreted after the oral administration of R(-)-pranoprofen, respectively. The absolute configuration of the aglycone of acyl glucuronide was almost R(-)-enantiomer (92.5-96.1%) in the 0-24 h urine, whereas that of acyl glucoside contained 15.3-24.7% of S(+)-enantiomer after the oral administration of R(-)-pranoprofen. On the other hand, only the S(+)-isomer was found as the aglycone of both acyl glucuronide and glucoside after the oral administration of S(+)-pranoprofen. The present results showed that stereoselective conjugation was observed in glucosidation in mice. Nevertheless, a dose-dependent shift in glucuronidation and glucosidation was found for both the administrations of S(+)- and R(-)-enantiomers as well as RS(+/-)-pranoprofen. Also a chiral inversion of R(-)-enantiomer to S(+)-antipode may occur slightly but significantly in mice.

Administration, Oral↗

PubMed1992

Enzymatic synthesis of glucoside derivatives of validamine and valienamine.

alpha- And beta-glucoside derivatives of validamine and valienamine were prepared by enzymatic transglucosidation using alpha- and beta-glucosidase of Rhodotorula lactosa. The structures of these derivatives have been elucidated by 13C- and 1H-nuclear magnetic resonance spectral analysis. Thus, 7-alpha-glucoside, 7-alpha-isomaltoside, and 4-alpha-glucoside of validamine and 7-alpha-glucoside, 7-alpha-isomaltoside, 4-alpha-glucoside, and 4-alpha-isomaltoside of valienamine were obtained from maltose and validamine or valienamine using alpha-glucosidase. 7-beta-glucoside, 2-beta-glucoside, and 4-beta-glucoside of validamine or valienamine were obtained from cellobiose and validamine or valienamine using beta-glucosidase. These derivatives were tested for alpha-glucosidase inhibitory activity on rat small intestinal glycosidases.

Animals↗