Neomycin-treated Rats Research Articles

MP12-13 A RAT MODEL TO STUDY THE ROLE OF GUT BACTERIA IN REGULATION OF URINARY CALCIUM

You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology I1 Apr 2017MP12-13 A RAT MODEL TO STUDY THE ROLE OF GUT BACTERIA IN REGULATION OF URINARY CALCIUM Ryan Chastain-Gross, Pedro Espino-Grosso, Paul Dominguez-Gutierrez, John Asplin, Vincent Bird, Saeed Khan, and Benjamin Canales Ryan Chastain-GrossRyan Chastain-Gross More articles by this author , Pedro Espino-GrossoPedro Espino-Grosso More articles by this author , Paul Dominguez-GutierrezPaul Dominguez-Gutierrez More articles by this author , John AsplinJohn Asplin More articles by this author , Vincent BirdVincent Bird More articles by this author , Saeed KhanSaeed Khan More articles by this author , and Benjamin CanalesBenjamin Canales More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.435AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Nephrolithiasis afflicts 1 in every 11 Americans, causing severe renal pain and reduction in quality of life. A majority of nephrolithiasis patients exhibit absorptive hypercalciuria (AH), a metabolic defect where intestinal absorption of dietary calcium is abnormally high. Prior genetics studies have not yielded a mechanism for this metabolic defect. Since there is a diverse microbial community in the human intestinal tract, with poorly defined effects on systemic health, we hypothesize that AH is mediated by changes in the intestinal microbial community that increase calcium absorption by intestinal epithelium. We test this by characterizing the urine chemistry and gut microbiota changes that occur in a rodent model upon administration of high doses of oral antibiotics. METHODS 6 week-old male and female Sprague-Dawley rats were evenly distributed in the following groups: control (n=12), chloramphenicol-treated (n=12) and neomycin-treated (n=12). All rats underwent pre-treatment urine and stool collection. Subsequently, control rats were provided sterile water ad libitum for 7 days; chloramphenicol and neomycin-treated rats received sterile water (ad libitum) containing 0.07% of their respective antibiotics for 7 days. Rats underwent post-treatment urine and stool collection. Pre- and post-treatment urinary calcium was assessed. Alterations in intestinal microbiota were characterized using 16S rRNA Illumina paired-end sequencing, followed by custom principal components analyses. RESULTS Gut microbial community structure was markedly different in both antibiotic treatment groups, compared to controls. Directly following antibiotic administration, neomycin-treated rats were colonized by high numbers of Sphingomonas species and showed a loss in Lactobacillus species; chloramphenicol-treated rats were highly colonized by Klebsiella species. Urinary calcium increased in both antibiotic treatment groups, and was most pronounced immediately after antibiotic administration. CONCLUSIONS Treatment with either neomycin or chloramphenicol significantly altered the gut microbiome compared to control rats. This is consistent with classical studies that suggested intestinal microbes may impact nutrient absorption, and that use of oral antibiotics may alter urinary concentrations of calcium. These data indicate that we have designed a model in which to further test the role of gut microbiota in modulating urinary calcium, and may provide a path to novel therapies for nephrolithiasis patients. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e149 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Ryan Chastain-Gross More articles by this author Pedro Espino-Grosso More articles by this author Paul Dominguez-Gutierrez More articles by this author John Asplin More articles by this author Vincent Bird More articles by this author Saeed Khan More articles by this author Benjamin Canales More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Intestinal Protective Effects of Herbal-Based Formulations in Rats against Neomycin Insult.

Disturbance in the gut microbial niche by antibiotics like neomycin produces gastrointestinal (GI) disorders. Here, we evaluated the impact of a mixture of extracts of three herbs (Atractylodis Rhizoma Macrocephalae, Massa Medicata Fermentata, and Dolichoris Semen) with known GI protective activities, either laboratory unfermented (herbal formulation-1 (HF-1)) or fermented/re-fermented (herbal formulation-2 (HF-2)) on neomycin-treated rats using a commercial Lactobacillus probiotic as a reference. Treatment with neomycin augmented stool water content, decreased fecal population of Lactobacillus spp., changed the histology of intestine without inducing inflammation, reduced the colonic expression of zonula occludens-1 (ZO-1) and claudin-1, and elevated the serum C-reactive protein (CRP) and interferon-gamma (IFN-γ) levels. Coadministration of either HF-2 or probiotic, but not HF-1, restored the fecal content of Lactobacillus spp., normalized the serum CRP level, and significantly increased the colonic expression of ZO-1 and claudin-1 in neomycin-treated rats. The combined treatment with any of the above agents ameliorated the histological changes of cecum and colon in neomycin-treated rats, and the magnitude of this effect was probiotic > HF-2 > HF-1. Our study revealed the intestinal protective effect of a mixture of three herbs against neomycin insult, which is mediated through multiple mechanisms and is potentiated upon prior fermentation/refermentation of the herbs.

The role of the tissues and gut flora in the metabolism of [14C]homoprotocatechuic acid in the rat and rabbit.

Abstract The fate of orally administered [carboxy-14C]3, 4-dihydroxyphenylacetic (homoprotocatechuic) acid has been studied in normal and neomycin-treated rats and rabbits. In normal rats about 93% of the dose (0·1 g/kg) is excreted in 13 days after dosing, although 80% is excreted in the urine within 2 days. In neomycin-treated rats 100% of the 14C is excreted in 13 days, 95% being in the urine within 2 days. The urinary metabolites in 44 hr in normal rats were unchanged homoprotocatechuic acid (55% of the dose), homovanillic acid (19%), m-hydroxyphenylacetic acid (6·5%) and p-hydroxyphenylacetic acid (1·4%). In neomycin-treated rats, homoprotocatechuic acid (70%) and homovanillic acid (22%) were found but the other two metabolites were virtually absent. In normal and neomycin-treated rabbits, the 14C was excreted in the urine almost quantitatively in 9 days. The same metabolites as in rats were excreted, but there was more m-hydroxybenzoic acid (14%) and less homovanillic acid (6%). In neomycin-treated rabbits the excretion of m- and p-hydroxyphenylacetic acids was suppressed. In the rat, the metabolism of homoprotocatechuic acid, as far as methylation, dehydroxylation and decarboxylation (Scheline, 1967) is concerned, is qualitatively similar to that of protocatechuic acid (Dacre & Williams, 1968). In the rabbit, however, there is little, if any, decarboxylation. Whilst methylation is a reaction of the tissues, dehydroxylation and decarboxylation appear to be carried out by gut micro-organisms.

The role of the tissues and gut micro-organisms in the metabolism of [14C]protocatechuic acid in the rat. Aromatic dehydroxylation.

Abstract The fate of oral doses (0·1 g/kg) of [carboxy-14C]3, 4-dihydroxybenzoic (protocatechuic) acid in normal and neomycin-treated rats has been studied. In normal rats about 72% of the dose of 14C is excreted in 7 days (about 64% in urine and 8% in faeces) whereas in neomycin-treated rats 99% is excreted (87% in urine and 12% in faeces). In normal rats, the radioactive metabolites found in the urine excreted in 24 hr after dosing were protocatechuic acid (36%), vanillic acid (21%), m-hydroxybenzoic acid (2·1%), p-hydroxybenzoic acid (1·2%) and m-methoxybenzoic acid (2%). After neomycin-treatment protocatechuic acid (55%) and vanillic acid (22%) were found, but the other three were virtually absent. Incubation of [14C]protocatechuic acid with rat intestinal contents yielded 14CO2 and small amounts of m- and p-hydroxybenzoic acid. When [14C]protocatechuic acid was injected intraperitoneally into biliary cannulated rats about 13% appeared in the bile mainly as the 4-O-glucuronide of vanillic acid. It is concluded that, whilst the conjugation and methylation of protocatechuic acid occurs in the tissues of the rat, the dehydroxylation and decarboxylation of the acid is carried out by the gut micro-organisms.

Administration-route dependency of absorption of glycyrrhizin in rats: intraperitoneal administration dramatically enhanced bioavailability.

The pharmacokinetic behavior of glycyrrhizin after intravenous (i.v.), oral and intraperitoneal (i.p.) administration was compared in rats. The elimination half-life, total body clearance and volume of distribution at steady-state of glycyrrhizin were not significantly different among doses (2, 10 and 50 mg/kg i.v.). Glycyrrhizin was only detected in the plasma (maximum level: 1.3 micrograms/ml) after oral administration of 50 mg/kg. From comparison of the area under the plasma concentration-time curves after i.v. and oral administration of 50 mg/kg, the bioavailability of glycyrrhizin was estimated to be approximately 1%. Glycyrrhizin was stable for at least 3 h in gastric juice. The plasma concentration of glycyrrhizin after oral administration to neomycin-treated rats was not significantly different from that after administration to untreated rats. Furthermore, in in situ absorption study the cumulative ratio of glycyrrhizin in the mesenteric venous plasma after injection was only 1-2% of the dose. From these results, it appeared that the extremely low bioavailability by the oral route may be due to poor absorption of glycyrrhizin from the intestinal tract. On the other hand, the plasma concentration of glycyrrhizin rapidly increased after i.p. administration of doses of 2, 10 and 50 mg/kg, and reached a maximum level (4.7, 33.0 and 238.9 micrograms/ml, respectively) within 30 min. The bioavailability (65-90%) of glycyrrhizin after i.p. administration was enhanced dramatically. The i.p. route of administration may thus improve the bioavailability of glycyrrhizin.

Effect of neomycin on the hydrolysis and toxicity of vicine and convicine in rats

This study in the rat established the effects that a broad-spectrum and poorly absorbed antibiotic, neomycin sulfate, had on the in vitro and in vivo hydrolysis of vicine and convicine by the intestinal microflora, and on vicine- and convicine-induced depletion of blood glutathione and the resulting toxicity. The in vitro studies demonstrated that digesta from the caecum and large intestine were highly effective in hydrolysing vicine and convicine, whereas digesta from the same sections of the gastro-intestinal tract of neomycin-treated rats were much less effective ( P < 0.0001). The in vivo studies showed that the total amount of vicine and convicine excreted in the urine and faeces was much greater in neomycin-treated rats compared with controls ( P < 0.05), indicating the ability of neomycin to increase the amount of glycosides, particularly that of vicine, excreted in the faeces. The ability of glycosides to decrease the concentration of glutathione in blood ( P < 0.05) and to increase rat mortality was greatly reduced in rats that were treated with neomycin, particularly in those treated ip with the toxin. Thus, the results demonstrated that neomycin reduced the rate at which vicine and convicine were hydrolysed in the lower section of the gastro-intestinal tract, and that neomycin treatment was associated with a reduced toxicity of the glycosides.

Hydrolysis of ochratoxin A by the microbial activity of digesta in the gastrointestinal tract of rats.

This study established the influence of dietary neomycin sulphate on the rate of hydrolysis of ochratoxin A (OA) by digesta from the intestine, and its effect on the excretion of OA and its hydrolyzed metabolite, alpha ochratoxin (O alpha), in the urine and feces of the rat. The first in vitro study demonstrated that digesta from the cecum and the large intestine were able to hydrolyze OA whereas digesta from the small intestine and stomach had very low hydrolytic activity against this substrate. Homogenates of the liver had no hydrolytic activity. The second in vivo study demonstrated that digesta from the large intestine and cecum of the neomycin treated rats was much less effective (P < 0.001) in promoting the hydrolysis of OA than digesta from the control rats. Neomycin when added directly to the in vitro system, however, did not affect the rate at which OA was hydrolyzed. In a third study, OA was administered in vivo to control and neomycin-treated rats. Rats fed the neomycin containing diet compared to those fed the control diet had a higher concentration (P < 0.005) of blood OA, and a greater cumulative excretion of OA plus O alpha over the entire 5 day collection period in the feces (P < 0.0001) and a corresponding decrease in the cumulative excretion of OA plus O alpha in the urine (P < 0.0001). Individually, there was a marked increase in cumulative fecal excretion of OA (P < 0.05) and a corresponding decrease in excretion of O alpha (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on Drug Metabolism by Use of Isotopes XXVII: Urinary Metabolites of Rutin in Rats and the Role of Intestinal Microflora in the Metabolism of Rutin

□ Analysis of urinary metabolites of orally administered rutin (I) labeled with deuterium ([2′,5′,6′-2H]rutin, rutin-d) was carried out by GLC-MS. In rat urine, 3-hydroxyphenylacetic acid (III), 3-me- thoxy-4-hydroxyphenylacetic acid (IV), 3,4-dihydroxyphenylacetic acid (V), 3,4-dihydroxytoluene (VI), and 3-(m-hydroxyphenyl)propionic acid (VIII) were identified as rutin metabolites and were differentiated from the corresponding endogeneous compounds. Unchanged I and quercetin (II) were not present in the urine. Rutin-d was injected intraperitoneally in rats, administered orally to neomycin-treated rats, and incubated in vitro with the intestinal contents of rats. The experiments suggested the involvement of intestinal microflora in the metabolism of orally administered I.

Effect of neomycin on amino acid uptake and on synthesis and release of lipoproteins by rat intestine.

The in vitro uptake and incorporation of amino acids into proteins and lipoproteins, and release of lipoproteins by intestinal segments of control and rats treated with neomycin or its N-methylated and N-acetylated derivatives (1 mg/10 g body weight for 8 days) was investigated. The intestine of the neomycin-treated rats contained a greater amount of water within the epithelial cells (81.6 ± 6.2% vs. 89.3 ± 6.8%, P &lt; 0.01) and it exhibited a significantly greater uptake of amino acid radioactivity per weight of tissue proteins (1.9 ± 0.2% vs. 2.6 ± 0.3%, P &lt; 0.001). The fraction of the amino acid radioactivity incorporated into tissue proteins was not affected by the respective treatments. The distribution of the radioactivity associated with tissue lipoproteins, however, was markedly affected by neomycin. The radioactivity of tissue low density lipoproteins (LDL) and high density lipoproteins (HDL) of the neomycin-treated rats was much lower than that of the controls. This difference could be accounted for by the release of a greater proportion of LDL and HDL radioactivity in the incubation medium. Release of LDL and HDL radioactivity was inversely related to the molecular weights of these lipoproteins. The effects of neomycin were reproduced by its N-methylated derivative which is devoid of antibiotic activity but retains the polycationic properties of neomycin. The N-acetylated derivative which is devoid of both antibiotic and polycationic properties was without effect. These findings suggest that the observed effects may be related to the polycationic properties of neomycin and that they are independent of its antibiotic activity.

Contamination of rat urine with gut flora using all-glass metabolism cages for collection of urine and faeces.

In rat urine collected in all-glass metabolism cages, at least four strains of intestinal microflora were found: two types of E. coli, Enterobacter cloaceae and Proteus vulgaris. The number of bacteria of each strain increased with time. 2. The pH of the urine increased from 6-9 after 24 h to 8-95 after 120 h. The pH of the urine of neomycin-treated rats remained nearly constant over a period of two days. 3. Nitroreductase activity was present in the rat urine. Added p-nitrobenzoic acid was reduced within the first 24 h. Nitroreductase activity in the urine of neomycin-treated rats was significantly lower than in the urine of normal rats, during the second 24-h period only. 4. Collection of urine at -10 degrees prevented the consequences of contamination.

Biliary excretion of mestranol in the female rat: effect of neomycin pretreatment on enterohepatic recirculation.

The biliary excretion of 4-carbon 14-mestranol and of its metabolites after ip and intraduodenal administration was determined in neomycin-treated rats. 3 hours after administration 39% of the ip dose and 72-75% of the intraduodenal dose of mestranol had been excreted. 4 hours after the intraduodenal administration of metabolic conjugates of mestranol there was a marked decrease in the excretion of mestranol conjugates in neomycin-treated animals compared with controls. This lower excretion rate may reflect a decrease in deconjugation. It appears that intestinal microflora may be in part responsible for the hydrolysis of conjugated mestranol and its metabolites.

Aromatization of shikimic acid in the rat and the role of gastrointestinal micro-organisms.

rats. Ether extraction of such samples at pH5.0 showed them to contain at least 98 % of the radioactivity in a conjugated form. Bile containing the labelled conjugates was diluted with 0.9% NaCl such that ~ 1 O O O d.p.s. was administered to each animal. Biliary excretion of radioactivity was again expressed as a percentage of this dose. Experimental rats received neomycin sulphate orally (100mg in 0.2ml of water) twice daily for 4 days and once on the fifth day 1-2 h before the experiment. Fig. 1 shows the observed rates of biliary excretion of mestranol after intraperitoneal and intraduodenal administration. Biliary excretion is rapid in both cases, but far more so for intraduodenal administration. Reference to the mean bile-flow rates given in Fig. 1 shows that after 3 h 35-39 % of the intraperitoneal and 72-75 % of an intraduodenal mestranol dose had been excreted in the bile. The results suggest that an active transport mechanism may be involved in the absorption of mestranol across the wall of the intestine. The biliary excretion of radioactivity after intraduodenal administration of metabolic conjugates of mestranol into normal and neomycin-treated rats is shown in Fig. 2. In addition the rate of excretion after administration of conjugated bile plus the 8-glucuronidase inhibitor saccharolactone is shown. After 4h a significant decrease in the rate of excretion of radioactivity was observed in both cases compared with controls. This lower excretion rate can be interpreted as reflecting a decrease in the rate of deconjugation, since the absorption of the free steroids and their subsequent biliary excretion is rapid (see curve for intraduodenal administration, Fig. 1). It seems on this evidence that the gut microflora are responsible (in part) for the hydrolysis of conjugated mestranol and its metabolites. The fact that recirculation is not totally prevented in neomycin-treated animals is not surprising, since neomycin does not suppress all groups of gastro-intestinal microorganisms (e.g. Bacteriodes; Finegold et al., 1965) and there is likely to be a contribution from hydrolytic enzymes of tissue origin. Preliminary incubations in vitro have shown that rat caecal micro-organisms are capable of extensive deconjugation of biliary conjugates of mestranol.

Metabolism of myricetin and related compounds in the rat. Metabolite formation in vivo and by the intestinal microflora in vitro.

1. The metabolism of a group of polyphenols related in structure to myricetin (3,5,7,3',4',5'-hexahydroxyflavone), including myricetin, myricitrin, 3,4,5-trihydroxyphenylacetic acid, delphinidin, robinetin, tricetin, tricin, malvin and 5,7-dihydroxy-3',4',5'-trimethoxyflavone, has been studied both in vivo after oral administration to the rat and in vitro in cultures of micro-organisms derived from the intestine of the rat. 2. It was shown that the rat intestinal microflora are able to degrade compounds of this group to the ring-fission products observed in urine after oral administration of the specific flavonoid. 3. All flavones and flavonols possessing free 5- and 7-hydroxyl groups in the A ring and a free 4'-hydroxyl group in the B ring gave rise to ring-fission products that included 3',5'-dihydroxyphenylacyl derivatives. 4. The metabolites 3,5-dihydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 3,5-dihydroxyphenylpropionic acid and 3-hydroxyphenylpropionic acid were isolated and identified by chromatographic and spectral methods. 5. On anaerobic incubation in a thioglycollate medium it was shown that intestinal micro-organisms can effect cleavage of glycosidic bonds, ring fission of certain flavonoid molecules showing 3',4',5'-trihydroxyphenyl substitution and dehydroxylation of certain flavonoid metabolites. 6. The urinary excretion of the metabolites 3,5-dihydroxyphenylacetic acid and 3-hydroxyphenylacetic acid was completely abolished when neomycin-treated rats were used.

Excretory and metabolic studies of isopropyl N-(3-chlorophenyl)carbamate in the rat

The excretion and metabolic fate of [ 14C]isopropyl N-(3-chlorophenyl)carbamate (alkyl[ 14C]-CIPC) and isopropyl N-(3-chloro-[ 14C]phenyl)carbamate (ring[ 14C]-CIPC) was investigated in the rat after both intraperitoneal and oral dosage. The 4-day urinary excretion after administration of alkyl- and ring-labelled compounds was about 50 and 85% of the administered radioactivity, respectively, and with the alkyl-labelled compound 17–20% of the administered radioactivity appeared in the respired air. Studies with neomycin-treated rats indicated that hydrolysis of the carbamate link occurred systemically in the animal rather than in its intestine, and in vitro studies suggested that the site of hydrolysis might be the liver. The 6-hr biliary excretion of radioactivity accounted for 40% of an intravenous dose.

Studies with uraemic serum on the renal transport of hippurates and tetraethylammonium in the rabbit and rat: effects of oral neomycin.

1. The depression of p-aminohippurate and o-iodohippurate transport induced by uraemic serum in rabbit and rat renal cortex in vitro was confirmed. At the same time no change in oxygen consumption was observed. 2. The transport of the tetraethylammonium ion was unimpaired by uraemic serum from man or rat. 3. When sera from neomycin-treated uraemic rats were incubated with rabbit renal cortex, the uptakes of p-aminohippurate and of o-iodohippurate were 50% higher than when sera from untreated uraemic rats were used. 4. In rat uraemic serum, the levels of hippuric and indole acetic acids are markedly elevated. Administration of neomycin causes a substantial reduction in these levels. 5. The implications of these observations upon the impaired renal transport of hippurates produced by uraemic serum is discussed.

The Effect of Oral Neomycin Therapy Following Whole-Body X-Irradiation of Rats

This study was designed to examine the beneficial effects of oral antibiotic treatment with neomycin following total-body X-irradiation of Sprague-Dawley rats. Survival times of irradiated, neomycin-treated male rats were compared with those of irradiated, untreated controls. Eleven selected radiation exposures, beginning at 700 R and extending in increments to 2500 R, were used. Thirty-day lethality was also evaluated at and below exposures of 1100 R. Neomycin treatment resulted in a significant prolongation of the mean survival times of irradiated animals at exposures between 800 R and 1500 R. At exposures between 1500 R and 2500 R, a small but consistent prolongation of mean survival time resulted. For exposures between 700 R and 1100 R, the 30-day lethality was consistently lower for the neomycin-treated rats. It is suggested that postirradiation treatment with oral neomycin, administered every 12 hours, can effect an increase in the mean survival time of whole-body X-irradiated rats.

Hexosamine metabolism I. The absoption and metabolism, in vivo, of orally administered d-glucosamine and [formula omitted] in the rat

1. 1. 1 M solutions containing d-[1- 14C]glucosamine, N- acetyl- d -[1- 14 C] glucosamine , N-[1- 14 C] acetyl- d-glucosamine or d-[1- 14C]glucose were administered to rats by stomach tube. The adsorption coefficients of d-[1- 14C]glucosamine and N- acetyl- d -[1- 14 C] glucosamine were similar in animals treated with neomycin (0.0062±0.007) and 0.068±0.016 mmole per 100 g of body wt. per h, respectively.) In rats not treated with neomycin, glucosamine but not acetylglucosamine was apparently degraded by the intestinal flora and the absorption coefficient was increased to 0.104±0.017 mmole per 100 g of body wt. per h. The absorption coefficients of these amino sugars were much less than that of glucose (0.0831 mmole per 100 g of body wt. per h). 2. 2. Although radioactivity from adsorbed d-[1- 14C]glucosamine, N- acetyl- d [1- 14 C] glucosamine and N-[1- 14 C] acetyl- d-glucosamine was found primarily in tissue hexosamines, appreciable amounts of radioactivity were also demonstrated within 3 h in the hexose and amino acid fractions of liver and small intestinal tissue. The relative distribution of radioactivity among hexosamine, hexose and amino acid fractions of these tissues was approximately the same after 3 h whether N-[1- 14 C]- acetyl- d-glucosamine or N- acetyl- d -[1- 14 C] glucosamine was administered. 3. 3. The only radioactive monosaccharide detected in significant amount in the urine was the administered radioactive glucosamine or acetylglucosamine. 4. 4. After 3 h, exhaled CO 2 contained approx. 4% of the absorbed radioactivity from d-[1- 14C]glucosamine in neomycin-treated rats. In rats not treated with neomycin, approx. 19% of the absorbed radioactivity from d-[1- 14C]glucosamine, 9% of the absorbed radioactivity from N- acetyl- d -[1- 14 C] glucosamine and 30% of the absorbed radioactivity from N-[1- 14 C] acetyl- d-glucosamine were exhaled within 3 h as CO 2. The latter observation suggests that an appreciable amount of the N- acetyl- d-glucosamine was deacetylated.

URINARY PRODUCTS FROM QUERCETIN IN NEOMYCIN-TREATED RATS.

Abstract In order to learn whether urinary m -hydroxyphenyl acids are mainly microbial in orgin, following the oral administration of quercetin the phenolic acid content of urine from neomycin-treated rats has been compared with that of urine from rats not treated with neomycin. The three acids, 3,4-dihydroxyphenylacetic, homovanillic, and m -hydroxyphenylacetic, occurring characteristically in the urine from untreated rats following quercetin feeding, were not found in urine from neomycin-treated rats fed quercetin. However, dihydroferulic, p -hydroxyphenylpropionic, and p -hydroxybenzoic acids, and tentatively, isovanillic acid, were identified in the urine of the treated rats. None of these compounds was found in urine from neomycin-treated rats which were not fed queercetin. Several compounds whose identification has not been achieved have also been found, but no m -hydroxyphenyl acid have been identified thus far. These results strengthen the evidence for previous suggestions by others that urinary m -hydroxyphenyl acids appear to be primarily bacterial metabolites of certain dietary precursors, including flavonoid compounds.

913. Urinary metabolic products of quercetin: Nakagawa, Y., Shetlar, M. R. & Wender, S. H. (1965). Urinary products from quercetin in neomycin-treated rats. Biochim. biophys. Acta97, 233

913. Urinary metabolic products of quercetin: Nakagawa, Y., Shetlar, M. R. & Wender, S. H. (1965). Urinary products from quercetin in neomycin-treated rats. Biochim. biophys. Acta97, 233