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Lipophilic Character (lipophilic + character)
Selected AbstractsEffect of plant phenolics, tocopherol and ascorbic acid on oxidative stability of pork pattiesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2009Lindsey Haak Abstract BACKGROUND: There is great interest in the use of naturally occurring antioxidants to delay oxidation in meat products. The effect of rosemary extract (RE), green tea extract (TE), tocopherol, trolox, ascorbic acid (AA) and ascorbyl palmitate (AP), at levels of 50,200 ppm of antioxidant components, on colour (CIE L*a*b*), lipid (TBARS) and protein oxidation (thiol groups) in fresh, frozen and cooked pork patties during illuminated chill storage was investigated. Individual components of RE and TE were also tested. RESULTS: RE, TE, AP, tocopherol and trolox equally inhibited lipid oxidation in fresh and frozen patties, whereas for cooked patties RE was most effective. AA stimulated lipid oxidation. No dose effect in the range of 50,200 ppm was found for fresh and frozen patties, whereas for cooked patties higher doses of RE and TE more efficiently prevented lipid oxidation. Protein oxidation was hardly influenced by antioxidant treatment. Colour stability decreased as follows: tocopherol, AA and AP > RE and TE > trolox. Antioxidant properties of the extracts and their major antioxidant components were comparable. CONCLUSION: The relative effect of the antioxidants depends on the oxidation parameter assessed, the applied dose and the hydrophilic/lipophilic character. Copyright © 2009 Society of Chemical Industry [source] Haematological, hepatic and renal alterations after repeated oral or intraperitoneal administration of monoisoamyl DMSA.JOURNAL OF APPLIED TOXICOLOGY, Issue 6 2002Abstract Monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA), a vicinal thiol chelator, is gaining recognition recently as a better chelator than meso 2,3-dimercaptosuccinic acid (DMSA) in decreasing heavy metal burden in tissues because of its lipophilic character. There is, however, little information available on the toxicological properties of this chelator after repeated administration in animals. In the present study, we investigated the dose-dependent effect of MiADMSA on various biochemical parameters suggestive of alterations in haem biosynthesis and hepatic, renal and brain oxidative stress after 21 days of repeated intraperitoneal (i.p.) or oral (p.o.) administration to rats. The concentration of essential metals in blood and soft tissues was determined along with histopathological observations of hepatic and renal tissues. The results suggest that MiADMSA administration had no effect on blood ,-aminolevulinic acid dehydratase activity. However, an increase in zinc protoporphyrin and a decrease in haemoglobin levels were noted in animals given MiADMSA i.p. A moderate increase in serum alkaline phosphatase suggested mild hepatotoxicity at the highest dose (100 mg kg,1, i.p.). This was confirmed by histopathological examinations, which identified basophilic stippling, granulation of the cytoplasm, haemorrhage and congestion. At the highest dose, levels of hepatic thiobarbituric acid reactive substance and oxidized glutathione were increased above those of control values. Levels of hepatic reduced glutathione were decreased. Taken together, these observations point to oxidative stress. In animals administered MiADMSA i.p. there was an increase in the brain malondialdehyde levels at the two higher doses (50 and 100 mg kg,1). Essential metal status revealed a significant effect of MiADMSA (p.o.) in increasing blood zinc while significantly decreasing the kidney zinc level. The most significant adverse effect of MiADMSA was on copper concentration, which showed significant depletion from almost all major organs. Magnesium levels in blood decreased but increased in liver of MiADMSA-administered rats. Histopathological observations of liver and kidneys suggest few moderate lesions. It can be concluded that repeated administration of MiADMSA is compromised with some mild toxic effect, particularly the loss of copper. The effects during oral administration are comparatively less pronounced than by the i.p. route. Copyright © 2002 John Wiley & Sons, Ltd. [source] Comparative evaluation of 99mTc-ethylene bis-l-cysteine and 99mTc-ethylene bis-l-,-homocysteine during reversed phase HPLC analysis and electrophoresis at various pH conditionsJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 4 2001K.O. Mang'era Ethylene bis- L -,-homocysteine (L,L -EH) differs from ethylene bis- L -cysteine (L,L -EC) in having an extra methylene group between each pair of amine and carboxyl groups. The objective of this study was to determine the effect of the extra methylene groups on the characteristics of the complex of these compounds with technetium-99m during analysis by reversed phase HPLC and by electrophoresis at various pH values. Up to pH 5.5, 99mTc- L,L -EH exhibits a substantially longer retention time during reversed phase HPLC than 99mTc- L,L -EC, suggesting a more lipophilic character for 99mTc- L,L -EH under these conditions. On the other hand, 99mTc- L,L -EH clearly possesses a higher negative charge in the pH range 3-6.5 as shown by the markedly greater migration towards the anode in electrophoresis experiments. A rational explanation for these seemingly opposing observations can not yet be offered. Copyright © 2001 John Wiley & Sons, Ltd. [source] The First Potent Subtype-Selective Retinoid X Receptor (RXR) Agonist Possessing a 3-Isopropoxy-4-isopropylphenylamino Moiety, NEt-3IP (RXR,/,-dual agonist)CHEMMEDCHEM, Issue 5 2008Kayo Takamatsu Abstract Retinoid X receptor (RXR) agonists (rexinoids) are attracting much attention for their use in treatment of cancers, including tamoxifen-resistant breast cancer and taxol-resistant lung cancer, and metabolic disease. However, known RXR agonists have a highly lipophilic character. In addition, no subtype-selective RXR agonists have been found. We previously reported an RXR,-preferential agonist 4-[N -methanesulfonyl- N -(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)amino]benzoic acid (6,a). The RXR agonistic activity is much less than that of well-known RXR agonists. To develop potent, less-lipophilic, and subtype-selective RXR agonists, we created new RXR agonists possessing alkoxy and isopropyl groups as a lipophilic domain of the common structure of well-known RXR agonists. As a result, compounds possessing branched alkoxy groups, 6-[N -ethyl- N -(3-isopropoxy-4-isopropylphenyl)amino]nicotinic acid (NEt-3IP: 7,a) and 6-[N -ethyl- N -(3-isobutoxy-4-isopropylphenyl)amino]nicotinic acid (NEt-3IB: 7,c), showed RXR agonistic activity as potent as, or more potent than, the activities of representative RXR agonists. Moreover, NEt-3IP (7,a) was found to be the first RXR,/,-selective (or RXR,/,-dual) agonist. Being potent, less lipophilic, and having RXR subtype-selective activity, NEt-3IP (7,a) is expected to become a new drug candidate and to be a useful biological tool for clarifying each RXR subtype function. [source] Lipophilicity affects the pharmacokinetics and toxicity of local anaesthetic agents administered by caudal blockCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2004Alejandro A Nava-Ocampo Summary 1.,Drugs administered into the epidural space by caudal block are cleared by means of a process potentially affected by the lipophilic character of the compounds. 2.,In the present study, we examined the relationship between the octanol,water partition coefficient (log Poct) and the time to reach the maximum plasma drug concentration (tmax) of lignocaine, bupivacaine and ropivacaine administered by caudal block in paediatric patients. We also examined the relationship between log Poct and the toxicity of these local anaesthetic agents in experimental models. The tmax and toxicity data were obtained from the literature. 3.,Ropivacaine, with a log Poct of 2.9, exhibited a tmax of 61.6 min. The tmax of lignocaine, with a log Poct of 2.4, and bupivacaine, with a log Poct of with 3.4, were approximately 50% shorter than ropivacaine. At log Poct of approximately 3.0, the toxicity of these local anaesthetic agents was substantially increased. The relationship between log Poct and the convulsive effect in dogs was similar to the relationship between log Poct and the lethal dose in sheep. 4.,With local anaesthetic agents, it appears that the relationship between log Poct and drug transfer from the epidural space to the blood stream is parabolic, being the slowest rate of transference at log Poct 3.0. Toxicity, due to plasma availability of these local anaesthetic agents, seems to be increased at log Poct equal or higher than 3.0 secondary to the highest transfer from plasma into the central nervous system. [source] | ||||||||||