Ivanka Stoilova

Composition and Antioxidant Activities of the Essential Oil of Cinnamon (Cinnamomum zeylanicum Blume) Leaves from Sri Lanka

Abstract The composition of the volatiles from leaves of Cinnamomum zeylanicum Blume from Sri Lanka was studied by GC-FID and GC-MS. The basic component of the oil was found to be eugenol (74.9%), followed by β-caryophyllene (4.1%), benzyl benzoate (3.0%), linalool (2.5%), eugenyl acetate (2.1%) and cinnamyl acetate (1.8%). The essential leaf oil from cinnamon demonstrated scavenger activity against the DPPH radical at concentrations which are lower than the concentrations of eugenol, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). This essential cinnamon oil showed also a significant inhibitory effect on hydroxyl radicals and acted as an iron chelator. Cinnamon leaf oil efficiently inhibited the formation of conjugated dienes and the generation of secondary products from lipid peroxidation at a concentration equivalent to that of the standard BHT.

Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism

The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%) and β-pinene (5.0%). The antioxidant capacity of the essential oil was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) radical cation scavenging, hydroxyl radical (ОН•) scavenging and chelating capacity, superoxide radical (•O2−) scavenging and xanthine oxidase inhibitory effects, hydrogen peroxide scavenging. The antioxidant activity of the oil attributable to electron transfer made juniper berry essential oil a strong antioxidant, whereas the antioxidant activity attributable to hydrogen atom transfer was lower. Lipid peroxidation inhibition by the essential oil in both stages, i.e., hydroperoxide formation and malondialdehyde formation, was less efficient than the inhibition by butylated hydroxytoluene (BHT). In vivo studies confirmed these effects of the oil which created the possibility of blocking the oxidation processes in yeast cells by increasing activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx).

Composition and Antimicrobial Activity of Ginger Essential Oil from Vietnam

Abstract The chemical composition of essential oils obtained by water and steam distillation of ginger from Vietnam was investigated. The yield of the essential oils was 2.05% and 2.1%, respectively. The main components of the essential oil obtained by water distillation were ar-cucumene (11.7 %) and β-bisabolene (4.1 %), and of the essential oil obtained by steam distillation were ar-curcumene (12.6 %), α-zingiberene (10.3 %), β-bisabolene (8.1 %) and β-sesquiphellandrene (7.4 %). The antimicrobial effect of both essential oils from ginger was studied according to the agar diffusion cup method. The test microorganisms used were the Gram-positive bacteria Bacillus pumilus, Bacillus subtilis, Staphylococcus epidermidis and Staphylococcus aureus; Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli and Salmonella abony; the yeast Saccharomyces cerevisiae and Candida albicans and the fungi Penicillium sp., Aspergillus niger, Botrytis cinerea and Rhizopus nigricans. The essential oil had a weak effect on the Gram-positive and Gram-negative bacteria and had a substantial fungicidal effect on the fungi under study.

Decolorization of Industrial Dyes by Immobilized Mycelia of Trametes Versicolor

ABSTRACT The aim of this study was to compare the decolorization of several of the most utilized synthetic dyes in textile applications by immobilized white-rot fungus Trametes versicolor. Different immobilization methods for achieving maximum decolorization were explored. The initial dye concentration was 125 mg/L and the immobilized preparation concentration was 10% (w/v). Different degrees of decolorization were observed. Different operational stability of the immobilized preparations was accomplished. Increase of the immobilized preparation concentration up to 30% (w/v) was investigated. The study was performed in two stages: simulated incubation in a ‘batch’ reactor and trickle-bed continuous flow reactor During the decolorization process, laccase activity was detected. The dye-decolorizing activity of the immobilized culture was found to be associated with the processes of biodegradation, bio-oxidation and biosorption.

Low Temperature Extraction of Essential Oil Bearing Plants by Liquefied Gases. 6. Barks from Cinnamon (Cinnamomum zeylanicum Nees)

Abstract The chemical composition of extract from the barks of cinnamon (Cinnamomum zeylanicum Nees) produced by extraction with 1,1,1,2-tetrafluoroethane was analyzed using GC and GC-MS. The main compounds (concentration higher than 3 %) of extract were: cinnamal (77.3 %) and coumarin (4.3 %). The studied extract demonstrated antimicrobial activity against pathogenic and spoilage microorganisms from clinical and food isolates belonging to species Sta-phylococcus aureus, Staphylococcus epidermidis, Salmonella abony, Escherichia coli and Candida albicans. The extract was inactive against some of the most resistible bacteria belonging to genus Pseudomonas. The produced cinnamon extract demonstrated higher antioxidant activity against DPPH radical in comparison with other plant extracts produced by low temperature extraction with tetrafluorethane.

Phytochemical Constituents and In Vitro Anti-Diabetic Properties of Ziziphus jujubа (Rhamnaceae) Fruits

In the current study the phytochemical profile of 70% ethanol extract of Ziziphus jujubа (Rhamnaceae), cultivated in Bulgaria has been investigated. The fruit extract contained numerous phytochemicals, such as triterpenes, phenolic acids and flavonoids. Five triterpenes, 11 phenolic acids and 5 flavonoids have been identified. The fruit extract had a total phenolic content of 21.62 ± 0.0265 mg/g and total flavonoid content 1.34 ± 0.017 mg/g dried extract. Among the triterpenes with the highest concentration was the betulinic acid 20943.17±527.06 μg/g dried extract, rosmarinic acid (1174.26±29.55 μg/g) among the phenolic acids, followed by myricetin (214.61±5.40 μg/g) as a representative of flavonoids and rutin 3 046.89±76.68 among the quercetin glycosides. The inhibitory effect of Z. jujubа fruit extract has been investigated on the key enzymes linked to diabetes α-glucosidase and α-amylase. In order to evaluate the type of inhibition a LineweaverBurk plot was produced. The results obtained from the enzyme kinetic studies exhibited a mixed noncompetitiveuncompetitive type of inhibition on α-glucosidase and mixed competitive-non-competitive type of inhibition on α-amylase. Besides that the obtained results proved high inhibition of α-glucosidase (79.46% at 1.33 mg.ml extract) and moderate inhibition of α-amylase (39.10% at 0.666 mg.ml extract concentration). These results suggest the possible use of fruits of Z. jujubа in the management of diabetes mellitus.