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Within the field of green chemistry, a noticeable results were obtained in the solvent-free synthesis of amide derivatives of naphthenic acids under microwave irradiation. Naphthenic acid amides, anilides, and morpholides were synthesized directly from free carboxylic acids and amines in the absence of solvent and catalyst under high-temperature heating in a closed-vessel system of microwave reactor. With this new and efficient method, different primary, secondary, and tertiary amide derivatives of naphthenic acids were obtained in good to excellent yields. Synthesized derivatives were assayed as plant rooting agents for their stimulative effects on the formation of adventitious roots in sunflower cuttings and susceptibility for growth stimulation of Pseudomonas sp. strains.

Summary Young plants of celery, parsley, parsnip and carrot, grown in nutrient solution, were treated with sodium naphthenate (10−7 mol dm−3), applying foliar and root treatments. Both treatments affected the root content of all investigated elements present in the nutrient solution, but in a different way, depending on the plant species. An average change (increase/decrease) in the contents of investigated essential elements was about 35%. Our experiments with naphthenate showed that this treatment may enhance the efficiency of essential elements uptake and increase its content in plants without changing concentration of these elements in the nutrient solution. Especially interesting results were obtained in the case of carrot, as increased contents were observed in the elements that are usually deficient in nutrition (Fe, Zn, Mn), whereas the other remained unchanged.

Aim: The aim of this study is to investigate the influence of bile salts, sodium cholate, sodium 12-ketocholate and sodium dehydrocholate, as excipients in ranitidine, aminophylline and phenobarbital tablets on dissolution rate. Methods: Four groups of tablets (control without bile salts and three investigational groups containing different bile salts) were prepared for three different drug substances: ranitidine, aminophylline and phenobarbital. Dissolution rate was measured. Results: Dissolution rate is increased significantly in all investigational groups comparing to the control group in all three drug substances. Discussion: Presented results are very favourable and encouraging in case of dissolution enhancing and should be further investigated, especially in drug substances that are classified in class II and IV as per Biopharmaceutical Classification System (BCS) classification. Conclusion: Bile acid salts are very promising excipients, proven to act as surfactants and as lubricants. Running title: Bile salts as excipients in ranitidine, aminophylline and phenobarbital tablets.

This work presents a study of the effect of foliar and root application of low concentrations (0.1–10 µM) of potassium naphthenate on the antioxidative status of cucumber (Cucumis sativus L.), assessed for both local and systemic organs. Changes in the contents of proline and glutathione indicate that the treatment of plants with potassium naphthenate can be characterized as a mild abiotic stress. The antioxidative system of cucumber plants is sensitive to such treatment, since organs directly exposed to the chemical showed a decrease in total antioxidant activities and an increase in peroxidation. In the organs that were not directly treated, an increase in the total antioxidative activity was observed only at the lowest naphthenate concentration while at higher concentrations this activity tended to decrease. As far as the activities of antioxidant enzymes (guaiacol peroxidase, superoxide dismutase, catalase) are concerned, the responses observed differed between enzymes for a given treatment, but showed similar trends within treated local and untreated systemic organs.

Naphthenic acids (NAs) are complex mixtures of cycloaliphatic and alkyl-substituted acyclic carboxylic acids whose overall characteristics are determined by the composition of the mixture. A complex mixture of NAs from a commercial fraction of atmospheric oil of the Vojvodina naphthenic crude "Velebit" (Serbia) was separated into narrower fractions on the basis of their acidity. Electrospray ionization mass spectrometry analysis of the fractions showed the occurrence of structural differentiation of acids. By extraction at pH 3-5, about 50% of the total mass of acids was separated, consisting predominantly of tricyclic and bicyclic structures. Acids of lower acidity, (about 22%), separated at pH 9 and 10, and their dominant constituents were acids with three, four and five rings. A correlation was found between the dominant structure and the biological activity of NAs of the fractions. The fraction extracted at pH 8, also with dominant bicyclic and tricyclic structures, showed the highest auxin and gibberellin activities.

Bile acids are amphiphilic molecules, which, in addition to their physiological role, have also acquired increasingly more important pharmacological applications. It has been shown that these compounds have a promoting effect on the transport of many drugs through the cell membrane. Pharmacodynamic studies showed that they exerted a significant effect on the analgesic action of lidocaine. This study is concerned with the determination of the constants of hydrogen-bonded complexes formed between the investigated bile acids and lidocaine. It was found that a prerequisite for forming such a complex is the existence of at least two OH groups or one OH group and one keto group in the bile acid molecule at an appropriate mutual distance. If a keto group is involved in lidocaine binding, the resulting complex has a larger equilibrium constant. A model – multiple linear regression equation – was constructed, relating the molecular descriptors to the equilibrium constant of hydrogen-bonded complex. It was also shown how the complex formed between lidocaine and bile acid influences the rate constant of the decrease of lidocaine concentration in the aqueous phase during its transfer to the chloroform solution of a bile acid. It was found that the complex formed between lidocaine and bile acids plays an important role in the appearance of the depot effect of lidocaine.

The knowledge of the process of formation of molecular aggregates of bile acids in aqueous media and of the corresponding critical micellar concentrations (CMCs) is of great significance because of the biological importance of these compounds and their pharmacological applications. In view of this, the present study is concerned with the determination of CMCs of cholic and chenodeoxycholic acids and their keto derivatives at different temperatures with the aim to calculate the standard thermodynamic functions of micelle formation. Based on the molecular descriptors for tested compounds and entropy of micelle formation, the method of principal component analysis (PCA) allowed grouping of the behavior of tested molecules at 30, 50 and 70 degrees C. To one group belong cholic acid and its keto derivatives, the other group consisting of chenodeoxycholic and deoxycholic acids and their keto derivatives. For each group, the derived multiple linear regression equations of the entropy dependence on temperature contains different independent variables. A main difference between the two groups of tested bile acids is in the energy of dipole-dipole interaction, which appears to be temperature dependent, and in the case of the latter group comes into play as an independent variable already in the regression equation derived for 30 degrees C. The most remarkable changes of the descriptors with temperature were observed in the group of cholic acid and its derivatives.

Different multiple regression methods including forward stepwise multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS) have been applied to the modeling of partition coefficient (lipophilicity) of bile acids and their derivatives by means of 16 different descriptors obtained by using Alchemy package software and retention index RMo as an experimental estimation of lipophilicity. Retention indices for bile acids and their derivatives were determined by reversed phase high-performance thin layer chromatography on RP-18W bounded stationary phase with methanol–water in different volume proportions as mobile phase. The results achieved concerning the prediction of Log P are highly significant and consistent with the molecular structure of the compounds investigated. The sum of absolute values of the charges on each atom of the molecule, in electrons (SQ), the sum of absolute values of the charges on the nitrogens and oxygens in the molecule, in electrons (SQNO), specific polarizability of a molecule (SP), the third-order connectivity index (3χ) and molecular lipophilicity, seem to be dominant in the partition mechanism. In addition, regression models developed have allowed a correct estimation of the partition coefficients of cholic acid (Log PHA = 2.93; Log P A − = 2.02 ) as compared with reported experimental values (Log PHA = 2.02; Log P A − = 1.1 ).

This study investigated the effect of a commercial preparation of stevioside and a synthetic compound, sodium salt of monketocholic acid (MKC), administered per os (p.o.) and also adminstered via an osmotic pump, on glycemia in normoglycemic and diabetic Wistar rats. Diabetes was induced with alloxan, 100 mg/kg, i.p. Normoglycemic and diabetic rats were treated p.o. for five days either with physiological solution (1 ml/kg, controls), stevioside (20 mg/kg), MKC (4 mg/kg) and a combination of stevioside (20 mg/kg) and MKC (4 mg/kg). Apart from p.o. adminstration, stevioside and MKC were also administered via a subcutaneously (s.c.) implanted osmotic pump. During treatment and upon termination of the latter, glycemia was measured and the rats that were treated p.o. were subjected to the oral glucose tolerance test (OGTTT) at a dose of 1 g/kg. Following this animals were anesthetized with urethane (0.75 g/kg, i.p.) and killed by cardiopunction to determine C-peptide levels in the serum. In all three groups of normoglycemic rats highest decrease in glucose levels was observed on the fourth day of the experiment. The stevioside + MKC combination showed a stronger hypoglycemic effect compared to individual treatments with stevioside and MKC (3.73:4.80:4.73 mmol/L). In the group of diabetic rats that received both substances via the osmotic pump, the hypoglycemic action was also stronger compared to the individual treatments with stevioside and MKC (16.15:18.89:18.75 mmol/L). The treatment of healthy rats with both substances p.o. caused no statistically significant difference in glycemia, whereas in diabetic rats the combination of stevioside + MKC showed a statistically significant decrease in glycemia compared to control values. In both groups of rats, treatment with stevioside and MKC and their combination prevented an increase in glucose concentrations in the OGTT. Only the administration of stevioside by osmotic pump yielded a statistically significant increase in the concentrations of C-peptide in the serum of healthy rats. Compared to controls, the concentrations of C-peptide in diabetic rats were significantly higher after treatment with either stevioside or its combination with MKC, irrespective of the mode of administration.

Naphthenic acids were isolated from gas oil fractions (distillation interval 168-290?C) of Vojvodina crude oil "Velebit", characterized and their biological activity evaluated by the biochemical changes in cuttings of Robinia pseudoacacia after treatment with naphthenate. The activities of IAA peroxidase, total peroxidases and amylase, as well as the contents of reducing sugars and total proteins, were determined in the basal parts of soft wood cuttings of black locust after treatment with sodium naphthenate or the sodium salt of 1-naphthaleneacetic acid (NAA), concentration 10-7 mol dm-3 for 3 or 6 h. High activities of IAA oxidase and amylase, together with a low activity of peroxidase (which is known as being stimulatory for the initiation and activation of primordia) were obtained after the three-hour treatment with sodium naphthenate. Six-hour treatment had an inhibitory effect on the examined biochemical markers. The effects of three- and six-hour treatments with NAA were between those of the corresponding treatment with naphthenic acids. .

Previous studies in our laboratory have shown that the semisynthetic bile acid derivative, sodium 3α,7α-dihydroxy-12-oxo-5β-cholanate (MKC), has hypoglycemic activity. The aim of this study was to investigate the relationship between the pharmacokinetics and hypoglycemic activity of MKC in healthy and diabetic rats. Groups of healthy and alloxan-induced diabetic rats were dosed intravenously (i.v.) and orally with MKC (4 mg/kg). Blood samples were taken before administration of the dose and at 20, 40, 60, 80, 120, 150, 180, 210 and 240 minutes post-dose. MKC serum concentration was measured by HPLC, and pharmacokinetic parameters determined using the WinNonlin program. The absolute bioavailability of MKC was found to be low in healthy and diabetic rats (29 and 23% respectively) and was not significantly different between the two groups. Mean residence time (MRT), volume of distribution (Vd) and half-life (t1/2) of MKC after oral administration were significantly lower in diabetic than in healthy rats (21, 31 and 29% respectively). After the i.v. dose, the change in blood glucose concentration was not significant in either healthy or diabetic rats. After the oral dose, the decrease in blood glucose concentration was significant, reaching a maximum decrease from baseline of 24% in healthy rats and 15% in diabetic rats. The results suggest that a first-pass effect is crucial for the hypoglycemic activity of MKC, indicating that a metabolite of MKC and/or interference with metabolism and glucose transport is responsible.

The influence of naphthenic acids (NAs) mixture and their narrow fractions (called NA pH 4, pH 8 and pH 10) onto permeability of beetroot cell membrane is examined. The results showed that the effect depends on treatment duration, concentration and NAs structure. Longer treatment of plant cell membranes with sodium naphthenate (Na-naph) resulted in the increase of membrane permeability (e.g. 4-hour treatment with Na-naph (C=100 μmol L-1) increased membrane permeability about 3 times, while prolongation of treatment to 24 hour resulted in the 18 times increasing of the effect). NAs in the concentration range from 0.1 to 10 μmol L-1 does not change membrane permeability, while membrane permeability is increasing linearly with concentration increasing from 10-100 μmol L-1. The strongest effect expressed fraction pH 8, where bi- and tricyclic carboxylic acids are the most abundant. These structures are predominant in the total NAs mixture as well. Thereby could be explained their closest, but a little bit weaker effect, comparing to NAs present in fraction pH 8. The effect of NAs onto beetroot cell membrane is between the effects of anionic (SDS and LS) and non-ionic surfactants (Triton X-100). [Projekat Ministarstva nauke Republike Srbije, br. 172006. i br. TR31036]

In this article, the methods of isolation and determination of bile acids are reviewed. Methods for separation of bile acids from cattle and pig bile are given in detail. Isolation of a mixture of cholic acid and deoxycholic acids from cattle bile and their subsequent purification are described. The isolation and purification of hyodeoxycholic acid and other components of pig bile are also included. Methods for the determination of bile acids in various biological samples are reviewed, including enzyme assays, radioimmunoassay, enzyme immunoassay and chromatographic methods. Among chromatographic methods, separation and determination of bile acids by thin-layer chromatography, gas chromatography and high performance liquid chromatography are reviewed. Particular attention is given to the use of high performance liquid chromatography since this has recently been the most commonly applied method for the separation and determination of bile acids.

The biosynthesis of bile acids in mammalian liver and its regulation, together with the physiological role of bile acids, are reviewed in this article. Bile acids are biosynthesized from cholesterol in hepatocytes. Several steps are involved including epimerisation of the 3beta-hydroxyl group, reduction of the delta4 double bond to the 5beta-H structural arrangement, introduction of alpha-hydroxyl groups at C7 or C7 and C12 and, finally, oxidative degradation of the side chain by three carbon atoms. This gives the primary bile acids, cholic and chenodeoxycholic acids. Cholesterol-7alpha-hydroxylation is the rate determining step in the biosynthesis of cholic and chenodeoxycholic acids. Feedback regulation of cholesterol biosynthesis occurs by various mechanisms including termination of the synthesis of specific cytochromes P-450, modulation of specific cytosol proteins, short-term changes in the process of phosphorylation-dephosphorylation and changes in the capacity of the cholesterol pool as a substrate. Prior to being exported from the liver, bile acids are conjugated with glycine and taurine to produce the bile salts. After excretion into the intestinal tract, primary bile acids are partly converted to secondary bile acids, deoxycholic and lithocholic acids, by intestinal microorganisms. The majority of bile acids is absorbed from the intestinal tract and returned to the liver via the portal blood, so that only a small fraction is excreted in the feces. Bile acids returned to the liver can be reconjugated and reexcreted into the bile in the process of enterohepatic recycling. In addition to the physiological function of emulsifying lipids in the intestinal tract, bile acids are particularly important in respect of their ability to dissolve and transport cholesterol in the bile.

This article surveys chemical transformations of selected bile acids. Chemical transformations were initially carried out with the aim of determining the structure of bile acids. More recently they have been concerned with bile acid interconversions as well as with the synthesis of steroid hormones, vitamins and therapeutc agents. Studies of similarities and differences in the biosynthesis of bile acids from cholesterol have occupied many researches. However, this article reviews only papers dealing with the synthesis of potential intermediates in the biosynthesis of bile acids. Steroid hormones such as pregnenolone, progesterone and testosterone are synthesized from methyl thiodeoxycholate whereas cortisone is synthesized from methyl deoxycholiate. Numerous papers and patents devoted to the synthesis of ursodeoxycholic acid from cholic or chenodeoxycholic acid testify to its effectiveness in the treatment of cholelithiasis. Chenodeoxycholic acid appears to be an excellent precursor in the synthesis of steroid plant growth regulators, as well as in the synthesis of metabolites and vitamin D analogues. Chirality of bile acids has been exploited in the synthesis of cyclic and acyclic receptors and solvents. Cholic and deoxycholic acids have been used to create new macrocyclic structures which show different capacities to bind and transport other compounds. Another important trend in the chemistry of bile acids is their application in combinatorial chemistry.

Soybean (Glycine max L.) plants grown in nutrient solution were exposed to 1 mM Cd(NO3)2 for 24 h. Dynamics of distribution of cadmium among its different forms (water soluble, Ca-exchangeable and complexed) in the intercellular space and the ratio of the intercellular and intracellular cadmium in roots, stems and leaves were studied. In roots, in the beginning of treatment the largest portion of Cd was found in the intercellular space and 1 h later Cd content started to decrease, so that between 13- and 24-h treatment an equilibrium was reached in which about 70 % of Cd was found inside cells. In stems, already after 1-h treatment, the Cd concentrations in the cells and intercellular space were similar, the equilibrium being disturbed after 13 h, so that after 24-h treatment 80 % of Cd was found inside cells. In leaves, up to the 13 h Cd distribution showed fluctuation, after that equilibrium was reached, with 70 % of intracellular Cd. The highest contents of all Cd forms in the intercellular space was observed in roots.

Ova knjiga je namenjena studentima prve godine fakulteta na kojima hemija nije matična disciplina i predaje se kao jednosemestralni ili dvosemestralni predmet. S obzirom na to, udžbenik je napisan tako da postupno uvodi studenta u svet hemije kako bi predmet mogli pratiti i studenti koji nemaju dobro predznanje iz ove oblasti. Knjiga takođe može biti korisna nastavnicima hemije u osnovnim i srednjim školama koji imaju želju da osveže znanje kao i svim stručnjacima ne-hemičarima koji žele da prošire svoja znanja iz ove oblasti. Knjiga daje pregled modernih teorija o strukturi i promenama materije, najvažnijih naučnih metoda hemije sa akcentom na značaj i primenu hemije u životu savremenog čoveka.

The study describes the rooting effect of naphthenates and their fractions on in vitro grown Robinia pseudoacacia L. shoots. Natural naphthenic acids have been isolated by alkaline extraction from middle fraction of crude oil type “Velebit” from Vojvodina, characterized and fractionated. Black locust shoot bases were immersed in ACM medium [Ahuja, 1984] without agar supplemented with either 10, 50 or 100 µM of basic naphthenate preparation, naphthenate fractions obtained by extraction at different pHs (pH 2, pH 4, pH 7 and pH 9), or indole3-butyric acid (IBA). Treated shoots have been then grown on hormone-free medium for four weeks. Significant differences among test treatments were recorded during the third and the fourth week of in vitro cultivation. Final evaluation was performed on the basis of rooting percentage after four weeks of cultivation. The highest rooting percentage (>70%) was achieved after the treatment with solution containing 50 µM of IBA. However, treatment with 10 µM of naphthenate preparation achieved also positive effect on rooting (>60%). Average rooting percentage in the control treatment was just 45%. Our results with black locust confirm previous results gained with some other agricultural and forest tree species that naphthenates have the potential to stimulate rooting in shoots and cuttings. Rad opisuje efekat naftenata na ožiljavanje mikroizbojaka bagrema in vitro. Naftenske kiseline su izolovane baznom ekstrakcijom iz srednje frakcije sirove nafte tipa “Velebit”, koja je opisana u ranijim radovima. Donji deo mikroizbojka je uronjen jedan minut u tečni ACM medijum [Ahuja, 1984] u koji je dodato 10, 50 ili 100 µM osnovne mešavine natrijum-naftenata ili njenih pojedinih frakcija dobijenih ekstrakcijom na različitim pH (pH 2, pH 4, pH 7 ili pH 9), odnosno 10, 50, 100 µM ili 1g/l indol-3-buterne kiseline (IBA). Kontrolni tretman je činio ACM medijum bez ispitivanih aktivnih materija. Tretirani mikroizbojci su zatim gajeni na čvrstoj ACM podlozi bez hormona. Značajne razlike među ispitivanim tretmanima su zabeležene tokom treće i četvrte nedelje uzgoja u in vitro uslovima. Konačna ocena je izvedena na osnovu procenta ožiljavanja nakon četiri nedelje uzgoja. Najviši procenat ožiljavanja je postignut rastvorom sa 10 µM natrijum naftenata, nakon čega je ostvaren značajan pozitivan efekat na procenat ožiljavanja (>60%) u odnosu na kontrolni tretman (oko 45%). Rezultati do kojih smo došli kod bagrema potvrđuju ranije rezultate koji su dobijeni kod poljoprivrednih i šumskih drvenastih vrsta o mogućnosti stimulacije ožiljavanja mikroizbojaka i reznica solima naftenskih kiselina.

A comparative study was carried out on the effect of molybdenum (Mo), nickel (Ni), cadmium (Cd), and lead (Pb) using concentrations of 1×10− 7, 1×10− 5, and 1×10− 3 mol dm− 3, on the metabolism of nitrogen and proteins in young pea plants (Pisum sativum L. ‘NS Lim’). The highest concentrations of the investigated metals were noted to suppress the development of the aboveground parts and roots. The smallest inhibiting effect was observed in the presence of Ni, which at lowest concentration produced a stimulating effect; Pb and Cd had a similar effect. The most pronounced inhibition was caused by Mo, which decreased the growth of the roots and aboveground parts by 50% and 35%, respectively. An increase in concentration of heavy metals in the medium resulted in their increased accumulation in both the plant roots and aboveground parts. The largest accumulation in the aboveground parts was observed for Ni and Mo, followed by Cd, and least for Pb. Nitrate and protein metabolism decreased according to the order...

The lipophilic character of bile acids and their glyco- and tauro-conjugates was studied. The classical RMo values were measured by means of reversed thin-layer chromatography using a mixture of methanol–water as the solvent system and compared with the factors scores obtained by principal component analysis based also onto the TLC-retention data. The reliability of the factor scores values as lipophilic indices are shown by their high correlation with the classical RMo values. In addition, a better correlation was observed between scores corresponding to the first principal components and the partition coefficients (log P) of bile acids. Finally, the “lipophilicity chart” described by the first two components has the effect of separating compounds from each other most effectively from the congeneric aspect point of view.

Nitrate content, activities of nitrate reductase and glutamine synthetase, soluble protein content, and proportion of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) protein in total proteins were measured in leaves of Beta vulgaris L. plants affected by nickel, cadmium, and molybdenum in concentrations of 10-4, 10-2, and 1 mM. The most harmful effect on the above mentioned parameters had Cd, less harmful Ni, whereas Mo stimulated the investigated parameters. The proportion of RuBPCO protein showed a high tolerance to heavy metals.

Activities of superoxide-dismutase, catalase and peroxidase and pigment content in leaves of wheat inoculated with Azotobacter chroococcum strains and supplied with different amounts of nitrogen were investigated. Inoculation with Azotobacter and higher nitrogen concentration caused an increase in all examined parameters.

Nine sugar beet lines were grown in a glasshouse on chernozem soil watered to 35, 50 and 65 % of maximal soil water capacity. After 12 d, plant water potential, net photosynthetic rate, contents of soluble proteins, DNA and RNA, proportion of ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) protein, and carbonic anhydrase activity were measured. As soil moisture decreased, the leaf water potential and net photosynthetic rate decreased. DNA and RNA content and carbonic anhydrase activity decreased under moderate drought, and increased with severe drought. RUBISCO protein proportion did not change significantly under decreased soil moisture, while the total soluble protein content decreased.

Serbian soybean genotype Ana was gamma irradiated at doses of 1, 2, 4, and 10 kGy in order to evaluate the influence of gamma irradiation on isoflavone (genistein, daidzein, and their glycosides genistin and daidzin) contents and hydroxyl radical scavenging effect (HRSE). The increase in genistin and daidzin contents as well as antioxidant activities was observed especially at doses of 4 and 10 kGy. Results were also compared with our previous results relating to total phenol content (TPC), DPPH radical scavenger capacity (DPPH RSC), and ferric reducing antioxidant power (FRAP). Our results indicated that doses up to 10 kGy improve the antioxidant activities of soybean and also nutritional quality with respect to isoflavone content. All results were analyzed by multivariate techniques (correlation matrix calculation and autoscaling transformation of data). Significant positive correlations were observed between genistin, daidzin, DPPH RSC, and HRSE.

In young sugar beet plants cadmium suppressed the activity of nitrate reductase, glutamine synthetase and glutamate dehydrogenase, whereas sulphur exhibited a protective role towards activity of these enzymes, except of glutamine synthetase. Protein synthesis was suppressed in the absence of S in nutrient medium; the lowest level was at 10-3 M Cd2+. Chloroplast pigment contents were increased by S while Cd2+, even in the lowest concentration, (10−5 M) showed a repressive effect. The highest concentrations of Cd2+ (10−3 M) caused a decrease in dry mass, whereas S induced its increase. Nitrate content was increased in the presence of Cd2+ and decreased by increased concentration of S.

The work is concerned with the effect of low concentrations (10−7 mol dm−3) of sodium naphthenate on total content of Cd and its particular forms in the intercellular space and inside cells, as well as on some physiological and biochemical parameters of young soybean plants grown in the presence of 1 mmol dm−3 solution of cadmium chloride. Presence of naphthenate reduced in average by 40 % content total and intracellular Cd in root, stem and leaves and alleviated the harmful effect of Cd on activity of nitrate reductase and content of photosynthetic pigments.

A novel multi-step synthesis of 3α,12α-dihydroxy-23a,23b-dihomo-5β-cholan-24-oic acid (23a,23b-dihomodeoxycholic acid) (5) has been achieved from methyl 3α,12α-dihydroxy-5β-cholanoate (1). Reduction of compound 1 with LiAlH 4 in dry ether gave the corresponding alcohol 2 in 83 % yield. Selective esterification of compound 2 with tosyl chloride in dry piridine at 0-5 °C for 12 h afforded the 3α,12α-dihydroxy-5β-24-cholanyl tosylate (3) in 64 % yield. The reaction of the tosyl derivative 3 with sodium diethyl malonate gave compound 4 which was first subjected to hydrolysis under basic conditions, followed by decarboxylation under acidic conditions to afford 3α,12α-dihydroxy-5β-23a,23b-dihomocholan-24-oic acid in 84 % yield.

In order to investigate the effect of phytohormones exogenous auxins on the level of the mechanical injury induced oxidative stress, intensity of lipid peroxidation (LP) was measured in rootstocks of cherry softwood cuttings. Basal parts of the cuttings and leaves of five rootstocks (Mahaleb 1 and 2, Gisela 5, European ground cherry (EGC) and “Oblačinska” sour cherry) were sampled 0, 2, 4 and 6 days after cutting. Cuttings were treated with 0.5% solutions of three auxins: α-naphthylacetic acid (NAA), indolebutyric acid (IBA) and combination of these two (INCIT K). Results obtained for the LP intensity varied depending on the rootstock, plant organ and auxin applied. The best LP-lowering effect of auxins occurred in all genotypes when treated with NAA. In the leaves, the LP peaked on the 2nd day while the best LP-lowering effect was recorded in European ground cherry rootstocks on the 4th day, independently of auxin applied. The highest MDA production in leaves was recorded in Mahaleb 2 and European ground cherry rootstocks treated with IBA (60-90% higher then control) two days after the cuttings were made. It has been established that in the most of the rootstocks examined auxins showed lowering effect on LP which points to their positive effect, not only on rooting of softwood cuttings, but on their antioxidant protection system, as well.

The oxidative stress and antioxidant systems in soybean leaves and roots infected with plant pathogen Aspergillus niger were studied following treatment with different concentrations of cholic acid. Several oxidative stress parameters were analyzed: production of superoxide (O2 ·−) and hydroxyl radicals (·OH), lipid peroxidation (LP), and superoxide dismutase (SOD; EC 1.15.1.1) activity, as well as the content of reduced glutathione (GSH). Results showed that inoculation with A. niger led to the increase of O2 ·− production and GSH quantities in leaves and ·OH in roots. The highest activity of SOD occured in infected plants treated with cholic acid in concentrations of 40 and 60 mg L−1 which ultimately led to a decrease in O2 ·− production. Inoculation with Aspergillus in combination with elevated cholic acid concentrations also increased ·OH production which is correlated with increased LP. These results may support the idea of using cholic acid as an elicitor to trigger hypersensitive response in plant cells. Use of cholic acid may also actively contribute to soybean plants defense response against pathogen attack.

The main goal of this study was to estimate the lipophilicity and investigate the molecular mechanism of retention of bile acids and their derivatives in order to find an objective manner of quantitative comparison of different chemically bonded stationary phases for high performance TLC in terms of their (dis)similarities. Highly significant correlations were obtained between different experimental indices of lipophilicity (R(M0), S and the scores corresponding to the first principal component) estimated on CN(F254s) and RP-18(F254s) and some computed log P values that combine electronic and topological aspects. The most statistically significant quantitative structure-property relationship models, using descriptors from Dragon software, multiple linear regression and genetic algorithm, were also obtained in the case of CN(F254s) and RP-18(F254s) stationary phases. Cross-validation suggests a good reliability of the results. The contribution of 2D and 3D descriptors, which are related to atomic mass, together with reactivity parameters such as polarizability and electronegativity seem to control the chromatographic mechanism (lipophilicity) on all stationary phases.

Recent findings regarding the physiological transport mechanisms and metabolism of bile acids have led to an increased interest in their synthetic derivatives, especially as transmucous transporters. The aim of this study was to examine the influence of the synthetic sodium salt of monoketocholic acid (Na-MKHA) on the hypolipidemic activity of lovastatin. The effects of a 7 days administration of lovastatin (20 mg/kg b.w.) (experimental group 1,n=5) and a combination of lovastatin (20 mg/kg b.w.) and Na-MKHA (2 mg/kg b.w.) (experimental group 2,n=5) in group of healthy and diabetic male Wistar rats were investigated. The animals in the control group of healthy (n=5) and diabetic (n=5) rats were treated with physiological saline (10 ml/kg b.w.) per os twice a day. In the healthy rats, lovastatin increased the low density lipoprotein (LDL) (32.14%) and non-high density lipoprotein (HDL) (15.38%) cholesterol and decreased HDL cholesterol levels (9.89%), and also increased the investigated atherogenic ratios. Na-MKHA significantly potentiated lovastatin activity, and its effects on the LDL (p

The critical micellar concentration (CMC) values of keto derivatives of cholic acid (3alpha,12alpha-dihydroxy-7-oxo-5beta-cholanoic acid, 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholanoic acid, 12alpha-hydroxy-3,7-dioxo-5beta-cholanoic acid, 3alpha-hydroxy-7,12-dioxo-5beta-cholanoic acid, 3,7,12-triketo-5beta-cholanoic acid) and cholic acid itself, were determined. Replacement of hydroxyl groups in cholic acid molecule with keto groups yields the derivatives whose CMC values increase with increase in the number of keto groups introduced. The CMCs of derivatives with the same number of keto groups but at different positions do not differ significantly. The relationship between the number of keto groups in the molecule of cholic acid keto derivatives and CMC value can be described by the following equation: CMC=43 number of keto groups+14.667. The effect of NaCl concentration on CMC increases with increase in the number of keto groups.

An overview of the structure and the origin of naturally occurring bile acids is given. Most naturally occurring bile acids belong to the 5beta-series, with hydroxyl groups in the A, B, and C ring of the steroid system. Hydroxyl groups are mostly found at the C3, C6, C7, C12 and C23 positions and are a- rather than beta-oriented. In most bile acids, the A/B ring junction is cis (5beta-series). However, the A ring can be usually present in the more stable (chair) or less stable (boat) conformation. Both B/C and C/D ring junction are trans. With respect to the angular C19-methyl group, the hydrogen atoms at C5 and C8 are cis-oriented whereas those at C9 and C14 are trans-oriented. The archetypal bile acid is 5beta-cholanic acid (3) from which all other C24 bile acids can be derived. In addition to the bile acids with 24 carbons, some naturally occurring C27 bile acids have been identified including di-, tri- and tetra-hydroxy derivatives of coprostanic acid isolated from bile of several reptile species. The most dominant bile acids and their natural sources are given and a selection of naturally occurring bile acids with unusual structures which have been mostly isolated from the bile of reptiles and amphibians is described.

The role of bile acids in pharmacotherapy is reviewed in this article. The therapeutic use of bile has been recognized since ancient times. Previously bile acids were the standard treatment for gallstones where chenodeoxycholic acid and ursodeoxycholic acid were effective in promoting the dissolution of cholesterol gallstones. Today their therapeutic role looks set to expand enormously. Bile acids as absorption promoters have the potential to aid intestinal, buccal, transdermal, ocular, nasal, rectal and pulmonary absorption of various drugs at concentrations that are non-toxic. Keto derivatives of cholic acid, such as 3a,7a,dihydroxy-12-keto-5alpha-cholic acid (sodium salt and methyl ester) are potential modifiers of blood-brain barrier transport and have been shown to promote quinine uptake, enhance the analgesic effect of morphine and prolong the sleeping time induced by pentobarbital. They have also been shown to be hypoglycaemic. Bile acids as therapeutic agents have the potential to produce beneficial effects in sexually transmitted diseases, primary biliary cirrhosis, primary sclerosing cholangitis, gallstones, digestive tract diseases, cystic fibrosis, cancer and diabetes.

After treatment with increased quantities of nitrogen and Azotobacter strains, activities of antioxidant enzymes superoxide dismutase, peroxidase and catalase, content of chlorophylls and carotenoids, soluble proteins and dry matter in leaves of sugar beet increased.

It is possible to carry out the isolation of native nucleic acids from higher plants by basically different phenoldetergent methods. Considering the nature of biological material, extraction of native NA proved sometimes to be relatively easy while at other times it requires particular treatment. This paper deals with various procedures for the isolation of native NA from young (7-days old) and older (15-days old) sunflower leaves (Helianthus annuus). It was found that the common procedures for the isolation of native NA from plant meterial couldn’t be successfully applied for the analyses of sunflower leaves. An extremely satisfactory extraction and preparation quality was obtained through isolation of NA from young leaves by the method Konarev and Tjuterev (1970). However, it couldn’t be applied for the isolation of NA from older leaves, as the extraction of DNA is very poor, indicating significantly stronger bonds between DNA and proteins in young leaves, which, of course, contain free DNA too. The most convenient extraction of NA from both young and old leaves has been obtained by the modified method of Konarev and Tjuterev, where extraction is occuring in an alkali media (pH 7.6), and the last reextraction at higher temperature (65 °C) in an acidic media (pH 6.0). Preparations yield obtained by this procedure was satisfactory and the characteristic values for quality were in the range of values for native NA.

The influence of long-term water deficit on photosynthesis, electron transport and carbon metabolism of sunflower leaves has been examined. Water deficit was imposed from flower bud formation up to the stage of full flowering in the field on two sunflower hybrids with different drought tolerance. CO 2 assimilation and stomatal conductance of the intact leaves, determined at atmospheric CO 2 and full sunlight (1500-2000 μmol quanta m -2 s -1 ), decreased with water deficit. Maximum quantum efficiency of PSII (F v /F m ) and relative quantum yield of PSII (Φ II ) determined under similar experimental conditions, did not change significantly in severely stressed leaves. The strong inhibition of the plateau region of the light response curve, determined at high CO 2 (5%) in water-deficient sunflower leaves, indicates that photosynthesis is also limited by non-stomatal factors. The decreased slope and the plateau of the CO 2 response curves show that the capacity of carboxylation and RuBP regeneration decreased in severely stressed intact leaves. Rubisco specific activity decreased in severely stressed leaves, but Rubisco content increased under prolonged drought. The increase of Rubisco content was significantly higher in leaves of the drought-tolerant sunflower hybrid indicating that a higher Rubisco content could be one factor in conferring better acclimation and higher drought tolerance.

This study examined the effect of the structure and concentration of cholic acid and its keto derivatives on the local analgesic action of lidocaine in rats, measured by an analgesimetric method. The increase in bile acid concentrations in the administered lidocaine solution increased the duration of local anesthesia. It was found that the introduction of keto groups into the cholic acid molecule yielded derivatives with lower promotory action, i.e. decreased the duration of local anesthesia. The biochemical parameters investigated indicated that the keto derivatives of cholic acid exhibited no toxicity compared to that of cholic acid itself.