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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.

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.

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.

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. .

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 divergent synthesis of two new muscarine analogues bearing the (5 S )-dioxolanyl isosteric group was achieved starting from d -glucose, enabling access to libraries of potential muscarinic agonists or antagonists. The key step of the synthesis involved a regioselective epoxide ring opening in 2,5:3,4-dianhydro derivatives 5 and 15 with LiAlH 4 , whereby the natural stereochemistry of (+)-muscarine ( 1 ) and (−)- allo -muscarine ( 2 ) was efficiently established.

To study the scavenger properties four naphthenic methyl esters were synthesized. The abilities of the compounds to act as radical scavengers were investigated in an experimental epinephrine/adrenochrome model using enzymic and non-enzymic systems. We found that our particular compounds exhibited radical scavenger activity and superoxide-dismutase activity inhibition. Investigated compounds also showed physiological activity. In the auxin test one compound induced elongation of the wheat coleoptile by 35%.

A stereospecific synthesis of (+)-muscarine iodide (1) has been achieved starting from D-glucose as a chiral precursor. The key steps of the synthesis involved a stereospecific cyclization of 3,5-di-O-mesyl derivative 3 into the 2,5-anhydride 4, the stereospecific catalytic hydrogenation of unsaturated derivative 6, and the C-4 epimerization of alcohol 12 by Mitsunobu reaction.

A simple one-pot esterification and selective 3α-acetylation of cholic and deoxycholic acid with selected esters of acetic acid (ethyl, propyl and butyl) in the presence of catalytic amount of 4-toluenesulfonic acid and water has been described. The yields of the obtained esters varied in range of 74-95%.

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.

A simple one-pot esterification and selective 3α-acetylation of cholic and deoxycholic acid with selected esters of acetic acid (ethyl, propyl and butyl) in the presence of catalytic amount of 4-toluenesulfonic acid and water has been described. The yields of the obtained esters varied in range of 74-95%.

The study describes the effect of naphthenates and their fractions on rooting of in vitro grown Sequoia sempervirens (Lamb. ex D. Don) Endl. shoots. Natural naphthenic acids have been isolated by alkaline extraction from the middle gas fraction of the crude oil. Sequoia sempervirens shoots (1 cm in length) were grown on Murashige and Skoog (1962) (MS) medium supplemented with either total naphthenate preparation, naphthenate fractions obtained by extraction on different pH (pH 2, pH 4, pH 7 and pH 9), or indole-3-butyric acid (IBA) in different concentrations (twenty treatments tested). The rooting testing was based on number and total length of roots formed after four weeks of in vitro growth. Similarly to total length of roots, the highest number of roots per explant (approximate to 7) was achieved in medium containing 50 mu M of the naphthenate fraction extracted at pH 2 and in medium containing 50 mu M of the fraction extracted at pH 9. That is triple higher than in the control and significantly better than in the best IBA-treatment (50 mu M IBA), where five roots per explants in average were formed. Similar to the results obtained for some agricultural and tree forest species, our results with Sequoia sempervirens confirm the possibility of rooting stimulation by naphthenates.

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.

A novel stereospecific synthesis of (+)-muscarine and (+)-epi-muscarine has been achieved by utilizing d -glucose as a chiral precursor. The key steps of the synthesis involved stereospecific cyclization of 3,5-di-O-sulfonyl- d -glucofuranose derivatives into the corresponding 2,5-anhydrides, and stereospecific hydrogenation of 2,5-anhydro- l -threo-hex-2-enose ethylene acetal derivatives, thus providing an access to divergent intermediates for the preparation of both target molecules in a fully stereospecific manner.

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.