Pharmacokinetics and metabolism of hydroxytyrosol, a natural antioxidant from olive oil.

3,4-Dihydroxyphenylethanol (DOPET) is the major o-diphenol detectable in extra virgin olive oil, either in free or esterified form. Despite its relevant biological effects, mainly related to its antioxidant properties, little data have been reported so far on its toxicity and metabolism. The aim of the present work is to evaluate DOPET toxicity and to investigate its molecular pharmacokinetics by using the (14)C-labeled diphenol. When orally administered to rats, the molecule does not show appreciable toxicity up to 2 g/kg b.wt. To identify and quantify its metabolites, [(14)C]DOPET has been synthesized and intravenously injected in rats. The pharmacokinetic analysis indicates a fast and extensive uptake of the molecule by the organs and tissues investigated, with a preferential renal uptake. Moreover, 90% of the administered radioactivity is excreted in urine collected up to 5 h after injection, and about 5% is detectable in feces and gastrointestinal content. The characterization of the labeled metabolites, extracted from the organs and urine, has been performed by high-pressure liquid chromatography analysis. In all the investigated tissues, DOPET is enzymatically converted in four oxidized and/or methylated derivatives. Moreover, a significant fraction of total radioactivity is associated with the sulfo-conjugated forms, which also represent the major urinary excretion products. On the basis of the reported results, an intracellular metabolic pathway of exogenously administered DOPET, implying the involvement of catechol-O-methyltransferase, alcohol dehydrogenase, aldehyde dehydrogenase, and phenolsulfotransferase, has been proposed.

Kinetics and mechanism of imazosulfuron hydrolysis.

Knowledge of the kinetics and pathways of hydrolytic degradation is crucial to the prediction of the fate and transport mechanism of chemicals. This work first describes the kinetics of the chemical hydrolysis of imazosulfuron, a new sulfonylurea herbicide, and evaluates the results to propose a degradation pathway. The hydrolysis of imazosulfuron has been studied in aqueous buffers both within the pH range 1.9-12.3 at ambient temperature (thermostated at 25 +/- 2 degrees C) and at pH 3.6 within the temperature range of 15-55 degrees C. The hydrolysis rate of imazosulfuron was characterized by a first-order kinetics, pH- and temperature-dependent, and accelerated by acidic conditions and higher temperatures. The calculated half-lives at pH 4.5 and 5.9 were 36.5 and 578 days, respectively. At pH 6.6, 7.4, 9.2, and 12.3 no significant change in imazosulfuron concentration was observed after 150 days. Half-lives were much lower at pH <4 (= imazosulfuron pK(a)), at which they ranged from 3.3 to 6.3 days. Moreover, a change in temperature from 15 to 25 degrees C in acidic conditions (pH 3.6) decreased the half-life of imazosulfuron by a factor of approximately 4.0; in any case, a 3-5-fold increase in the rate of hydrolysis was found for each 10 degrees C increase in temperature. In acidic conditions the only hydrolysis products were the two molecules resulting from the cleavage of the sulfonylurea bridge.

Degradation of imazosulfuron in soil.

Imazosulfuron, 1-(2-chloroimidazo[1,2-alpha]pyridin-3-ylsulfonyl)-3- (4,6-dimethoxypyrimidin-2-yl)urea, is a new post-emergence sulfonylurea herbicide applied once per growing season, highly active at low application levels, used to control most annual and perennial broad-leaf weeds and sedges in paddy rice (75-95 g AI ha-1) and turf (500-1000 g AI ha-1), and characterised by low mammalian toxicity. The degradation of imazosulfuron in a sandy loam soil (10-15 cm depth) has been investigated under aerobic and anaerobic laboratory conditions to evaluate its likely environmental fate. Test soils were treated with imazosulfuron in acetonitrile to give a final concentration of 0.2 mg kg-1 (100 g ha-1). The treated soils were extracted with methylene chloride + acetonitrile + 1 M ammonium hydroxide (4 + 15 + 1 by volume) and analysed by HPLC. Recoveries from spiked soils ranged from 80% to 95% (RSD 0.5-2.5%; n = 3) for imazosulfuron and its metabolites 2-chloroimidazo[1,2-alpha]pyridin-3-sulfonamide (IPSN), 1-(2-chloroimidazo[1,2-alpha]pyridin-3-ylsulfonyl)-3-(4-hydroxy-6- methoxypyrimidin-2-yl)urea (HMS) and 2-amino-4,6-dimethoxypyrimidine (ADPM). The limits of quantitation ranged from 0.001 mg kg-1 to 0.005 mg kg-1. Chemical cleavage of the sulfonylurea bond to give ADPM and IPSN was the main degradation pathway in aerobic conditions, whereas a remarkable production of HMS under anaerobic conditions suggested that degradation was due to micro-organisms which had the ability to demethylate imazosulfuron. In aerobic and anaerobic conditions, imazosulfuron disappeared from the soil with a half-life of approximately 70 (90% CL 62-75; r2 = 0.98) and 4 (90% CL 3.2-4.2; r2 = 0.97) days, respectively.

Adsorption and desorption of imazosulfuron by soil.

Understanding and quantifying the adsorption and desorption of herbicides by soil is important for predicting their fate and transport in the environment. Here we report a study concerning the adsorption and desorption, by four different soils, of imazosulfuron, 1-(2-chloroimidazo[1,2-a]pyridin-3-ylsulfonyl)-3-(4, 6-dimethoxypyrimidin-2-yl)urea, a new sulfonylurea herbicide. Both phenomena are well-described by the Freundlich equation, which shows this herbicide to be little adsorbed by each of the four soils investigated. The Freundlich adsorption constants, K(f-ads), ranged from 1.46 to 3.02. Distribution coefficients between soil and water, Kd, measured on soils of different organic matter contents and pH values showed an important effect of these two parameters on imazosulfuron retention. The Freundlich desorption data indicated that a significant amount of the imazosulfuron sorbed is not easily desorbed. The desorption process showed an evident hysteresis phenomenon, which may contribute to the persistence of imazosulfuron in soil.

Liquid chromatographic determination of imazosulfuron in drinking water and in soil using ultraviolet detection.

Reversed-phase liquid chromatography (LC) is used to determine a relatively new sulfonylureic herbicide, imazosulfuron, 1-(2-chloroimidazo-[1,2-a] pyridin-3-ylsulfonyl)-3-(4,6-dimethoxy-2-pyrimidinyl)-urea (TH-913), in drinking water and in soil. TH-913 is extracted from water using solid-phase extraction on C18 bonded silica. Soil samples (20 g) are extracted with 300 ml of methanol-water (50:50) and the acidified extracts are transferred onto Sep-Pak C18 and processed as described for water samples. Off-line desorption is done with 20 ml of methanol-water (50:50). The eluate is evaporated to dryness, the residue dissolved in acetonitrile and analysed by LC with UV detection at 238 nm. The recoveries of TH-913 from water were over 95% (at 0.05 microg/l level) and from soil over 90% (at 0.005 mg/kg level).

Analysis of ACE inhibitor drugs by high performance liquid chromatography.

Seven angiotensin-converting-enzyme (ACE) inhibitors have been analyzed by HPLC. The influence of different organic modifiers and counter-ions in the eluent at different pH values have been investigated allowing the identification of the best experimental conditions for the analysis of these compounds. The sinergic effect of TEA and propanol in the eluents resulted as a critical factor to obtain satisfactory peak shapes and resolution.

Analysis of calcium channel blocking dihydropyridines and their degradation products by gas chromatography.

Seven dihydropyridine calcium blockers have been analyzed by GC. Simultaneous analysis has been performed both by an isothermal and a gradient method. Moreover, the proposed methods have been performed on the analysis of daylight exposed methanolic solutions of considered compounds; the ability of the systems in separate original compounds from daylight degradation products has been studied. The GC-MC spectra of photodegradation products are discussed.

High performance liquid chromatographic analysis of quinolone antibacterial agents.

Eleven quinolone antibacterials have been analyzed by HPLC. The effects of different pH values and organic modifiers on chromatographic behaviour are discussed. Moreover the influence on separation mechanism of different counter-ions at various concentrations in the eluent has been investigated. Two different chromatographic methods have been selected, that allow the simultaneous analysis of quinolones containing or not a piperazinyl moiety, respectively.

[Investigation, identification and dosage of local anesthetics and antihistaminics in cosmetic products]. / Ricerca, identificazione e dosaggio di anestetici locali ed antistaminici in prodotti cosmetici.

A rapid and accurate reversed-phase HPLC method for separation and simultaneous quantitation of some local anesthetics, antihistamines and preservatives in skin cosmetics is described. The investigated compounds (procaine, lidocaine, mepivacaine, bupivacaine, benzocaine, brompheniramine, benzoic acid, methyl, ethyl and propyl p-hydroxybenzoate, o-phenylphenol) are extracted by ultrasonic treatment in methanol from cosmetic form. Methanol-aqueous orthophosphoric acid (pH 2.8) containing 0.9% dibutylamine has been used as eluent. The influence of different percentages of methanol on chromatographic behaviour has been studied using both isocratic conditions and gradient elution program. The gradient program allows a rapid resolution and quantitation also for acidic preservatives.

Relationships between octanol-water partition data, chromatographic indices and their dependence on pH in a set of beta-adrenoceptor blocking agents.

A thorough investigation on the dependence of octanol/water distribution coefficients (log D) of basic and amphiprotic beta-blocker drugs on pH and pKa values has been carried out. An attempt is made to clarify the factors which govern the chromatographic parameters (log k') in reversed-phase high performance liquid chromatography (RPLC) in terms of chemical structure and of distribution coefficients. The correlations between log D and log k' of different compounds show that the bulkiness and the branching of nitrogen substituent are controlling factors in RPLC measurements. Finally, an ion pair chromatographic system is considered for the prediction of octanol/water partition coefficients.

Traditional phytotherapy in the Roccamonfina volcanic group, Campania, southern Italy.

An investigation of the medicinal plants used in the Roccamonfina volcanic group is reported. The phytotherapy appears to be still utilized consistently; approx. 70 entities distributed among 39 different families are used. The chemical components and pharmacological behaviour of most of the species are very well known, however, an accurate phytochemical and pharmacological study seems necessary for some of them.

[The ratio of calcium carbonate/organic matrix in the valves of Mytilus galloprovincialis as an indication of marine pollution]. / Il rapporto carbonato di calcio/matrice organica nelle valve del Mytilus galloprovincialis come spia dell'inquinamento marino.

The CaCO3/organic matrix ratio, in the valves of Mytilus galloprovincialis, decreases when increases the degree of marine biological pollution. Its periodic measurement in the shells of Mollusca grown in the same area is, therefore, very useful for the analytical control of the sea environment. The method here proposed is very simple as CaCO3 amount is measured by weighting the valves ashes at 600 degrees C while organic matrix amount is calculated by difference between the weight of dry sample and that of its ashes.

[Enzymatic synthesis of taurine]. / Sintesi enzimatica della taurina.

In view of its interesting pharmacological and physiological functions, the enzymic synthesis of the taurine or the beta-aminoethan- alpha-sulfonic acid is described. This compound has been prepared by decarboxylation with rat heart homogenate and at room temperature of cysteic acid obtained by KMnO4 cysteine oxidation. The taurine prepared has been identified by paper and thin-layer chromatography with a taurine pure sample.

Chemical composition and anti-inflammatory activity of an alcoholic extract of Teucrium polium L.

In the Teucrium polium L. were identified, by gaschromatographic and spectroscopic techniques (1H-NMR and MS), beta-sitosterol, stigmasterol, campesterol, brassicasterol and clerosterol. In the aqueous phase of the alcoholic extract were identified glucose, fructose, raffinose and rhamnose by PC on Watmann paper Number 5. Anti-inflammatory activity was tested using male Wistar rats against carrageenin-induced paw oedema. All tested extract shown a sufficient pharmacological activity compared to that of indomethacine.

Phytotherapeutic profile of some plants used in folk medicine.

The effect of nine vegetable extracts was evaluated on the carrageenin-induced oedema in the rat. Our results show that the above extracts are able to exert - at different degree - a very marked decrease of the inflammed site related to the presence in the considered plants of several active biologically compounds as sterols and flavonoids. Preliminary chemical analysis of these vegetables are also reported.