Milica Cvijović

Synthesis and characterization of hexadentate cobalt(III) complexes with novel edta-type ligands Part 2. Circular dichroism of the trans(O5O6) and trans(O6) isomers of a cobalt(III) complex of 1,3-propanediamine-N,N′-diacetic-N,N′-di-3-propionic acid

Abstract Cobalt(III) complexes with the hexadentate ligand, 1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate ion (1,3-pddadp) were prepared, chromatographically separated into two geometrical isomers with respect to the NO chelate ring size [trans(O5O6) and trans(O6)], and resolved. The 1H NMR, electronic absorption and circular dichroism (CD) spectra were used to characterize the complexes. The splitting of the T1g(Oh) band of the trans(O6-[Co(1,3-pddadp)]− complex indicates that the tetragonal field is enhanced, relative to the fields in other [Co(edta)]− -type complexes reported. The (+)546-trans(O5O6)-[Co(1,3-pddadp)]− and (+)546-trans(O6)-[Co(1,3- pddadp)]− complexes with a positive CD peak at lowest energy in the first spin-allowed d-d absorption band region are tentatively assigned the Λ absolute configuration. Preliminary results of a crystallographic study of the Ktrans(O6)-[Co(1,3-pddadp)]·3H2O confirm the assignments of geometrical isomers of the complexes.

Phenolic Compounds and Biological Activity of Kitaibelia vitifolia

This study was aimed at evaluating the antioxidant activity and efficacy of the ethanolic extract of the endemic plant species Kitaibelia vitifolia in inhibiting the growth of selected fungi and bacteria. Antimicrobial activity was tested using the broth dilution procedure for determination of minimum inhibitory concentration (MIC). MICs were determined for eight selected indicator strains. The highest susceptibility to K. vitifolia ethanolic extract among the bacteria tested was exhibited by Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, and Klebsiella pneumoniae ATCC 13883 (MIC=15.62 μg/mL), followed by Escherichia coli ATCC 25922 and Proteus mirabilis ATCC 14153 (MIC=31.25 μg/mL), and Proteus vulgaris ATCC 13315 (MIC=62.50 μg/mL). Of the fungi, Candida albicans ATCC 10231 (MIC=15.62 μg/mL) showed the highest susceptibility, and Aspergillus niger ATCC 16404 (MIC=31.25 μg/mL) had the lowest. Results showed that K. vitifolia extract possesses antioxidant activity, with total antioxidant capacity of 75.45±0.68 μg of ascorbic acid/g and 50% inhibition concentration values of 47.45±0.55 μg/mL for 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, 35.35±0.68 μg/mL for inhibitory activity against lipid peroxidation, 95.25±0.52 μg/mL for hydroxyl radical scavenging activity, and 31.50±0.35 μg/mL for metal chelating activity. Total phenolics, flavonoids, condensed tannins, and gallotannins were 85.25±0.69 mg of gallic acid (GA)/g, 45.32±0.55 mg of rutin/g, 54.25±0.75 mg of GA/g, and 41.74±0.55 mg of GA/g, respectively. The phenolic composition of K. vitifolia extract was determined by high-performance liquid chromatography. Rosmarinic acid was found to be the dominant phenolic compound of the extract.

Studies on the complex formation equilibria in copper(II)- and nickel(II)-1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate solutions

Abstract The complex formation between copper(II) and nickel(II) ions and the title ligand (abbreviated as 1,3-pddadp) was studied by emf glass electrode and spectrophotometric measurements in 0.5 M (Na)NO 3 medium at 25°C. Within the concentration limits 1.0⩽[M] o ⩽ 10.0, 2.0 ⩽ [L] o ⩽ 20.0 (mM) (M = Cu or Ni, L = 1,3-pddadp) and 2.0⩽ -Iog[H + ] ⩽, 10.0, the experimental data were explained by the formation of the following complexes [CuH 2 L] (log β 1,2,1 = 22.32 ± 0.04); [CuHL] + (log β 1,1,1 = 19.03±0.06); [CuL] 2− (log β 1,0,1 = 14.96±0.06); [Cu(OH)L] 3− (log β 1,-1,1 = 3.40±0.08); [Ni(HL] − (log β 1,1,1 = 17.65±0.03); [NiL] 2− (log β 1,0,1 = 14.25±0.03) and [Ni(OH)L] 3− (log β 1,-1,1 = 3.30 ± 0.08). The complexes Na 2 [M(1,3-pddadp)] were synthesized and characterized by elemental analysis, visible and IR spectra. The structures of complexes are suggested.

COMPOSITION AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS OF SOME MEDICINAL AND SPICE PLANTS

An examination was made on the chemical composition and antimicrobial activity of four medicinal plants Carum carvi, Coriandrum sativum, Hyssopus officinalis, and Eucalyptus globulus, the first three of which are also used as culinary spice herbs. Carum carvi L. and Coriandrum sativum L. belong to the Apiacea family. In traditional medicine, Carum carvi is used in the form of a tea as a digestive and diuretic [1]. Coriandrum sativum has been used since ancient times; it was found in pharaonic tombs where it was used for embalming, and there is mention of it in the Bible. It is used as a medicine against flatulence and as a diuretic [1], and it also has an anticonvulsive effect [2]. The essential oils of these two plants are used as spices in preparing food. Hyssopus officinalis L. and Eucalyptus globulus Lab. belong to the Lamiaceae and Myrtaceae families, respectively, and they are used in folk medicine to treat respiratory diseases [1]. The aim of this paper was to determine the chemical composition of the essential oils of the said plants and examine their activity against the growth of bacteria (Staphylococcus aureus ATCC 25923, Streptococcus haemolyticus group A, Escherichia coli ATCC 25922, Enterecoccus faecalis ATCC 29212, and Pseudomonas aeruginosa ATCC 27853), and fungi (Candida albicans ATCC 10231). Eucalyptus globulus was collected at the Montenegrin Coast and all the rest of the plants were grown in the fields of Vojvodina (Northern Serbia). The essential oils were obtained from the fruits of Carum carvi and Coriandrum sativum and the leaves of Hyssopus officinalis and Eucalyptus globulus by the steam distillation method following Procedure III of the Yugoslav Pharmacopoeia [3]. The GC and GC/MS analyses were used for determination of the essential oil composition. Percentages of the main components of the essential oils investigated are given in Table 1. The essential oils of the plants examined are of different chemical compositions, and monoterpenes are distributed the most. By comparison of the composition of the essential oils of the plants mentioned with the literature data [4] and [5], it was concluded that it was dependent on the geographic region and plant growing conditions. The antimicrobial activity of the essential oils of the plants investigated was determined by the disc-diffusion method [6] and [7]. Tables 2 gives MIC (minimum inhibitory concentration) values and inhibition zone diameters for three different essential oil concentrations. The inhibition zone diameters were compared with the reference antibiotics, as shown in the tables. As Enterecoccus faecalis ATCC 29212and Pseudomonas aeruginosa ATCC 27853 were not inhibited by the essential oils of the plants mentioned, their results are not given in the Tables. The broadest inhibitory activity spectrum was exhibited by the essential oils of Carum carvi and Hyssopus officinalis, and the narrowest one by Eucalyptus globulus. The antimicrobial activity of certain oils (Carum carvi, Hyssopus officinalis, and Eucalyptus globulus) against Staphylococcus aureus ATCC 25923 was higher than or equal to the reference value. A pronounced activity against Candida albicans ATCC 10231 was also expressed by all the essential oils with the exception of the essential oil of Hyssopus officinalis.

Biological activities of phenolic compounds and ethanolic extract of Halacsya sendtneri (Boiss) Dőrfler

The objective of this study was to evaluate the efficacy of the ethanolic extract of endemic plant Halacsya sendtneri in inhibiting the growing of the test fungi and bacteria as well as to determine its genotoxic potential and toxicity using the Allium anaphase-telophase assay. Minimum inhibitory concentrations (MIC) were determined for 15 indicator strains of pathogens, representing both bacteria and fungi. The highest susceptibility to the ethanolic extract of H.sendtneri was exhibited by Pseudomonas glycinea (FSB4), (MIC=0.09 mg/ml) among the bacteria, and by Phialophora fastigiata (FSB81), (MIC=1.95 mg/ml) among the fungi. The composition of H. sendtneri extracts was also determined using HPLC analysis. Rosmarinic acid was found to be the dominant phenolic compound. The Allium anaphase-telophase genotoxicity assay revealed that the ethanolic extract of H. sendtneri at concentrations of 31.5 mg/l and below does not produce toxic or genotoxic effects. This is the first report of chemical constituents, genotoxic and antimicrobial activities of the endemic species, H. sendtneri.

Statistical optimization of an RP-HPLC method for the determination of selected flavonoids in berry juices and evaluation of their antioxidant activities

An isocratic RP-HPLC method for the separation and identification of selected flavonoids (quercetin, rutin, luteolin-7-O-glucoside, kaempferol and kaempferol-3-O-glucoside) in commercial berry juices (blackcurrant, blueberry, red raspberry and cherry) was developed with the aid of central composite design and response surface methodology. The optimal separation conditions were a mobile phase of 85:15 (% v/v) water-acetonitrile, pH 2.8 (adjusted with formic acid), flow rate 0.5 mL min-1 and column temperature 35°C. The obtained levels of bioflavonoids (mg per 100 mL of juice) were as follows: for quercetin, ca. 0.21-5.12; for kaempferol, ca. 0.05-1.2; for rutin, ca. 0.4-6.5; for luteolin-7-O-glucoside, ca. 5.6-10.2; and for kaempferol-3-O-glucoside, ca. 0.02-0.12. These are considerably lower than the values in fresh fruits. Total phenolic, flavonoid and anthocyanin contents were determined spectrophotometrically. Total flavonoid content varied as follows: blackcurrant > blueberry > red raspberry > cherry. The antioxidant activity of juice extracts (DPPH and ABTS methods) expressed as IC50 values varied from 8.56 to 14.05 mg L-1 . These values are ~2.5-3 times lower than quercetin, ascorbic acid and Trolox®, but compared with rutin and butylhydroxytoluene, berries show similar or better antioxidant activity by both the DPPH and ABTS methods.