Vera Ćirin-Novta

Effect of cholic acid and its keto derivatives on the analgesic action of lidocaine and associated biochemical parameters in rats.

SummaryThis 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.

Critical micellar concentrations of keto derivatives of selected bile acids: Thermodynamic functions of micelle formation

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.

A Divergent Synthesis of (+)-Muscarine and (+)-epi-Muscarine from d-Glucose

Abstract 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.

Divergent synthesis of two novel muscarine analogues from D-glucose

Abstract 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.

Scavenger Properties of Synthetic Naphthenic Methyl Esters

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%.

The Increased Content of Micronutrients in Celery, Carrot, Parsnip and Parsley Plants after Treatment with Sodium Naphthenate

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.

Foliar and root treatments of cucumber with potassium naphthenate: Antioxidative responses

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.