A photoelectrochemical enzyme biosensor based on functionalized hematite microcubes for rutin determination by square-wave voltammetry.

A photoelectrochemical biosensing strategy for the highly sensitive detection of the flavonoid rutin was developed by synergizing the photoelectrocatalytic properties of hematite (α-Fe2O3) decorated with palladium nanoparticles (PdNPs) and the biocatalysis towards laccase-based reactions. The integration of α-Fe2O3.PdNPs with a polyphenol oxidase as a biorecognition element yields a novel biosensing platform. Under visible light irradiation, the photoactive biocomposite can generate a stable photocurrent, which was found to be directly dependent upon the concentration of rutin. Under the optimal experimental conditions, the cathodic photocurrent, measured at 0.33 V vs. Ag/AgCl, from the square-wave voltammograms presented a linear dependence on the rutin concentration within the range of 0.008-30.0 × 10-8 mol L-1 (sensitivity: 1.7 µA·(× 10-8 M-1)·cm-2), with an experimental detection limit (S/N = 3) of 8.4 × 10-11 mol L-1. The proposed biosensor device presented good selectivity towards rutin in the presence of various organic compounds and inorganic ions, demonstrating the potential application of this biosensing platform in complex matrices. This bioanalytical device also exhibited excellent operational and analytical properties, such as intra-day (standard deviation, SD = 0.21%) and inter-day (SD = 1.30%) repeatability, and long storage stability (SD = 2.80% over 30 days).Graphical abstract.

A luminescence study of the interaction of sulfobutylether-ß-cyclodextrin with rutin.

The luminol/sulfobutylether-ß-cyclodextrin (SBE(7M)-ß-CD) chemiluminescence (CL) system and the interaction of SBE(7M)-ß-CD/rutin were first described by flow injection (FI) CL method. It was found that SBE(7M)-ß-CD with luminol could form 1:1 complex online, which could accelerate the electrons transferring rate of excited 3-aminophthalate, giving the enhanced CL intensity of luminol. The enhancement of CL intensity was proportional to the concentrations of SBE(7M)- ß-CD with a linear range from 25 to 1750 µmol L⁻¹. It was also found that rutin could inhibit the CL intensity from luminol/SBE(7M)-ß-CD system, and the decrement of CL intensity was logarithm over the concentrations of rutin ranging from 0.1 to 100.0 nmol L⁻¹, giving the regression equation ΔI = 32.90lgC(rutin) + 16.26 (R² = 0.9952) with a detection limit of 0.03 nmol L⁻¹ (3σ). According to the proposed CL model, the binding constant (K(CD-R)) and the stoichiometric ratio of SBE(7M)-ß-CD/rutin complex were obtained as 1.6 × 106 L² mol⁻² and 2:1. The possible mechanism of luminol/SBE(7M)-ß- CD/rutin interaction was also discussed. The method was successfully applied to monitor rutin in human urine samples after ingesting SBE(7M)-ß-CD/rutin complex, with a total excretion of 68.8% within 8.0 h.

Pharmacokinetics and plasma protein binding of rutin deca (H-) sulfate sodium.

Rutin deca (H-) sulfate sodium (RDS) possesses very good activity as an inhibitor of the complement system of warm-blooded animals and HIV. An ion-pair coupled with solid-phase extraction technique (IP-SPE) was developed to extract RDS from rat plasma, urine, bile and protein solution samples. The assay was applied to pharmacokinetics of RDS, including plasma pharmacokinetics, excretion and protein binding studies. After i.v. 5, 20 and 100 mg x kg(-1) RDS via tail vein in rats, the plasma concentration-time profiles were fitted using 3P97 software. The average terminal half-life (t(1/2)) was 3.432 +/- 0.185 2 h. The relationship of dose and AUC of RDS was linear within the dosage range. This suggested that the disposition of RDS in rats belong to linear kinetics and the pharmacokinetic parameters of RDS were dose independent. After iv RDS 20 mg x kg(-1) in rats, the biliary excretion amount of parent drug amount was only 0.3181% +/- 0.2087% of given dosage, and the urinary excretion was 86.0% +/- 6.1% in 36 h. Ultrafiltration techniques were applied to determine the protein binding of RDS in plasma (from SD rat, Beagle dog and human), human serum albumin (HSA) and human alpha1-acid glycoprotein (AGP). The mean protein binding rate in plasma of SD rat, Beagle dog and human plasma of RDS were 80%-90%, in which the range of concentration of RDS was 5 to 100 microg x mL(-1). The protein binding to HSA was 85.7% +/- 1.3% and 14.0% +/- 3.2% to AGP.

[Effect of tobacco smoke on permeability of capillary of pregnant and non-pregnant rats]. / Wplyw dymu tytoniowego na przepuszczalnosc naczyn wlosowatych ciezarnych i nieciezarnych szczurów.

From among 4200 chemical compounds contained in the tobacco smoke, nicotine and carbon monoxide are responsible for changes in the heart-vessel system to the greatest extent. Additionally, other toxic compounds, including the carcinogenic ones, have a significant impact on the biological activity in the tissues of blood vessels. A particularly complex picture of the detrimental impact of the tobacco smoke is presented in case of pregnant women, fetuses and newborns. The aim of the research was to assess the impact of tobacco smoke on the permeability of capillaries in different tissues of rats (lungs, brain, liver, kidneys) and testing of the potentially protective impact of rutine (3-rutinozide of quercetin). The research on the permeability of capillaries has been carried out applying Evans blue. The animals were divided into 8 research groups: pregnant animals--"control", "rutine", "tobacco smoke", "rutine+tobacco smoke", and non-pregnant animals--"control", "rutine", "tobacco smoke", "rutine+tobacco smoke". In the first stage of research (pregnant, non-pregnant-- groups: "rutine" and "rutine+tobacco smoke"), the water rutine solution in a dose of 40 mg/kg of body weight was administered. The non-pregnant and pregnant animals from groups "tobacco smoke" and "rutine+tobacco smoke" were exposed to tobacco smoke via inhalation (1500 mg CO/m3 of air) for 21 days. All the animals were injected with the water Evans blue solution in a dose of 30 mg/kg of body weight. After 30 minutes, the animals were killed by cutting the abdominal aorta, and lungs, brain, liver and kidneys were taken for further testing. The cotinine in the urine was determined by the HPLC method, using norephedrine as the internal standard, after the preceding extraction by means of the liquid-liquid technique. The concentration of cotinine in case of non-pregnant and pregnant females was respectively 11.8 +/- 1.9 pg/ml of urine and 12.0 +/- 2.5 microg/ml of urine. In case of the rats, which received the rutine, the concentration of rutine in the group of non-pregnant females was 9.3 +/- 1.0 microg/ml of urine, and in the group of the pregnant ones 8.5 +/- 1.1 microg/ml of urine. In the lungs of non-pregnant animals exposed to tobacco smoke, the decreased permeability of vessels for the albumin-Evans blue complex was proven. The administration of rutine to non-pregnant and pregnant animals did not exert influence on the permeability of vessels in lungs. A similar result was obtained for the lungs of rats receiving the rutine, as well as those exposed to tobacco smoke. In the brain tissue of non-pregnant and pregnant animals, a slight decrease in the content of Evans blue was declared as a consequence of tobacco smoke impact. In the groups receiving the rutine, this flavonoid was declared to influence the blood supply of the brain tissue, and the permeability of the vascular walls. In the liver tissue of animals inhaling the tobacco smoke, the permeability of vascular walls for albumin-Evans blue complex was increased. The rutine did not affect significantly the permeability of vessels, whereas the exposure of pregnant females, which received rutine, to smoke decreased the content of Evans blue in the liver tissue. In the tissues of all tested females, no significant differences between the control groups and groups exposed to tobacco smoke as well as rutine+tobacco smoke were detected. The obtained results do not indicate, however, that in case of chronic exposure to tobacco smoke, the rutine has insignificant protective meaning.

Absorption and urinary excretion of quercetin, rutin, and alphaG-rutin, a water soluble flavonoid, in rats.

Quercetin, rutin, alphaG-rutin (a water soluble flavonoid), and a mixture of rutin and alphaG-rutin were administered to rats by a single gastric intubation, and their absorption and urinary excretion were examined. The plasma and 24 h urinary levels of aglycons (quercetin and tamarixetin/isorhamnetin) were measured by HPLC after deconjugation with beta-glucuronidase/sulfatase treatment. alphaG-rutin was absorbed more rapidly than quercetin or rutin, and the plasma concentrations of quercetin and tamarixetin/isorhamnetin reached the highest peak level 30 min after dosing. Quercetin, rutin, and the mixture of rutin and alphaG-rutin showed the first peak level 8 h, 8 h, and 30 min after dosing, respectively. The area under the concentration-time curve (AUC) for quercetin in rats administered alphaG-rutin was approximately 4.5- and 2-fold higher than those in rats administered quercetin and rutin, respectively, and was almost the same as that in rats administered a mixture of rutin and alphaG-rutin. The highest 24 h urinary excretion was observed in alphaG-rutin-administered rats. These results suggest that alphaG-rutin is absorbed more efficiently than either quercetin or rutin and that a high plasma concentration can be maintained by supplying rutin and alphaG-rutin in combination.

Determination of hydrochlorothiazide and rutin in Chinese herb medicines and human urine by capillary zone electrophoresis with amperometric detection.

In this paper, capillary zone electrophoresis with amperometric detection (CZE-AD) was firstly applied to the simultaneous determination of rutin (RT) and hydrochlorothiazide (HCT) in compound Chinese herb medicines and human urine samples. The two analytes could be perfectly analyzed within 12 min and showed significant current responses at carbon electrode under the optimum conditions. It was found that the linear range of HCT was from 2.0 x 10(-6) to 1.0 x 10(-4) mol l(-1) and that of RT was from 1.0 x 10(-6) to 1.0 x 10(-4) mol l(-1). Their sensitivity was determined by linear regression and calculated as 7.02 x 10(4) and 2.17 x 10(5) nA l mol(-1), respectively, and their detection limits were 5.0 x 10(-7) and 2.0 x 10(-7) mol l(-1), respectively (S/N=3). Above results demonstrated that this method was of high sensitivity, good repeatability, high selectivity and could be used in metabolic kinetics studies of medicines. Satisfactory results were obtained when this method was used to simultaneously analyze the amounts of RT and HCT in one general compound Chinese herb medicine-Zhen Ju jiang Ya Pian and human urine samples.

Chemiluminescence investigation of detection of rutin in medicine and human urine using controlled-reagent-release technology.

A novel continuous-flow sensor based on chemiluminescence (CL) detection was developed for the determination of rutin in pharmaceutical preparations and human urine by controlled-reagent-release technology. The analytical reagents involved in the CL reaction, including luminol and hexacyanoferrate(III), were both immobilized on an anion-exchange column in a flow-injection system. The CL signal produced by the reaction between luminol and hexacyanoferrate(III), which were eluted from the column through sodium phosphate injection, was decreased in the presence of rutin. CL intensity was inhibited by rutin; the decrement of CL intensity was linear over the logarithm of the rutin concentration range of 1.0-400 ng x mL(-1), and the detection limit was 0.35 ng x mL(-1) (3 sigma). The whole process, including sampling and washing, could be completed in 1.5 min with a relative standard deviation of <3.5%. The flow sensor showed remarkable stability and could be easily reused >450 time; the sensor proposed was applied successfully to the determination of rutin in pharmaceutical preparations and human urine.

Urinary excretion of hydroxycinnamates and flavonoids after oral and intravenous administration.

The urinary recoveries of the hydroxycinnamates, ferulic acid (3-methoxy, 4-hydroxy cinnamic acid), and chlorogenic acid (the quinic acid ester of 3,4-dihydroxycinnamic acid), and three structurally related flavonoids were studied in the rat. For the latter, the aglycone quercetin was compared with its 3-glucoside (isoquercitrin) and 3-rhamnoglucoside (rutin). Doses of 50 mg/kg were administered via the oral and intravenous routes and urine collected over the subsequent 24-h period. Reverse phase HPLC with photo-diode array detection was used to analyze the unchanged compound and their metabolites excreted in the urine. Ferulic acid and isoquercitrin were orally absorbed (5.4 and 0.48% of administered dose, respectively) and are therefore bioavailable. In contrast, neither unchanged chlorogenic acid, rutin, quercetin, nor the conjugated metabolites in the form of glucuronide or sulphate were detected in the urine after oral dosing. All the flavonoids studied produced low total urinary recoveries after intravenous administration, 9.2% for quercetin-3-rhamnoglucoside, 6.7% for the 3-glucoside, and 2.4% for the aglycone, indicating that extensive metabolism to low molecular weight compounds or excretion via other routes may be occurring. Overall it can be stated that renal excretion is not a major pathway of elimination for intact flavonoids and hydroxycinnamates in the rat.

Serum concentrations of rutoside metabolites after oral administration of a rutoside formulation to humans.

In the present study a highly specific and sensitive method by gas chromatography-mass spectrometry has been established for the determination of the blood levels of four metabolites of 5,7,3',4'-tetrahydroxyflavonol-3-rutinoside (rutoside, rutin), i.e. 3,4-dihydroxytoluene (DHT), 3-hydroxyphenylacetic acid (mPHAA), 3,4-dihydroxyphenylacetic acid (DHPAA), and 3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid, HVA) after the oral administration of rutoside to healthy volunteers. By the established method the pharmacokinetics in the blood and the urinary excretion of those metabolites were investigated. Blood levels of DHT, mHPAA, DHPAA, and HVA started to increase at 4 to 8 h after the oral dosage of the rutoside formulation, Esberiven (further active ingredient: coumarin). At 8 to 12 h post-administration, blood levels reached a maximum level which was 2- to 3-fold the time 0 level. Blood levels decreased gradually afterwards and returned to the original level at 20 to 35 h. The sum of the four metabolites was at a maximum value at 8 h which then returned to the initial levels at 35 h yielding a half-life of 11 h. Total urinary excretion of metabolites was 50.5% of the dose in 48 h.

Studies on drug metabolism by use of isotopes XXVI: Determination of urinary metabolites of rutin in humans.

Determination of urinary metabolites of orally administered rutin and rutin-2',5',6'-d3 in humans was carried out by TLC and GLC-mass spectrometry. In human urine, 3-hydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxytoluene, and beta-m-hydroxyphenylhydracrylic acid were identified as rutin metabolites. Unchanged rutin and quercetin were not present in urine.