Zoran Maksimović

Preliminary assay on the antioxidative activity of Maydis stigma extracts

Antioxidative effects of Maydis stigma methanolic extracts were studied on the level of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured spectrophotometrically by the TBA-test. The most significant inhibition of lipid peroxidation was observed when methanolic extracts of fully developed, mature corn silk were applied. The same test, performed after fractionation of the most active extract, showed that most of the activity was concentrated in fractions with moderate lipophilicity, containing phenolic acids, flavonoid aglyca and resembling monosides.

Essential Oil of Stachys officinalis (L.) Trevis. Lamiaceae from Montenegro

Abstract The aerial parts of Stachys officinalis(L.) Trevis., collected from Velika Greda locality at Durmitor mountain (Montenegro), contained 0.5% of essential oil. Using GC and GC/MS, 32 constituents were identified. A mixture of isocaryophyllene and β-caryophyllene (22.9 %) was identified as its principal component.

Essential Oil of Wild Growing Mentha pulegium L. from Yugoslavia

Abstract The essential oil of Mentha pulegium L., Lamiaceae was obtained by steam distillation of the herb, collected during the period of full flowering, when 0.2% was gained. The analysis of its chemical composition was performed using GC and GC/MS. Twenty-two components (89.9% of the total oil) were identified. The principal one was menthone (30.9%), while the other important were pulegone (14.1%) and neomenthol (13.8%) and caryophyllene oxide (9.0%).

Antibacterial activity of Veronica montana L. extract and of protocatechuic acid incorporated in a food system.

This study was designed to evaluate the antibacterial activity of the Veronica montana L. water extract and its main phenolic compound, protocatechuic acid. The antibacterial activity was determined by microdilution assay against six strains of Gram-positive and Gram-negative bacteria. Listeria monocytogenes was the most sensitive of the tested bacterial species. Antibacterial preserving properties of protocatechuic acid were also evaluated after its incorporation in cream cheese, using L. monocytogenes as commonly cheese contaminant. The compound successfully inhibited L. monocytogenes development in cream cheese, at room temperature and in refrigerator (25°C and 4°C, respectively), after 3days of inoculation. Sensory evaluation was carried out in order to validate the mentioned food system. A possible mode of action of the tested compound towards bacterial cells was assessed and appears to be direct lysis of pathogenic cytoplasmic membrane. Prediction of pharmacokinetic properties was also performed using computational analyzes. The obtained results can serve as an important platform for the development of effective natural preservatives.

CHEMICAL COMPOSITION OF TWO WILD SPECIES OF THE GENUS SALVIA L. FROM YUGOSLAVIA: SALVIA AETHIOPIS AND SALVIA VERTICILLATA

Abstract We compared two wild Salvia species found in Yugoslavia: S. aethiopis L. and S. verticillata L. Both oils contained β-caryophyllene as main constituent (27.5% and 13.3%, respectively), but differed by the presence of germacrene D (10.9%) andcaryophyllene oxide (6.4%) in the first, and γ-muurolene (10.3%) and trans-chrysanthenol (6.1%) in the second.

Chemical composition and antimicrobial activity of Thymus pannonicus All. (Lamiaceae) essential oil

This paper presents the results of a study on chemical composition and antimicrobial activity of Thymus pannonicus All. (Lamiaceae) essential oil from Vojvodina province (north of Serbia). The investigated oil was hydrodistilled from a flowering plant and analysed by GC and GC-MS. Fifty-three constituents were identified (>97% of total oil), with geranial (41.42%, w/w) and neral (29.61%, w/w) as the most prominent. The antimicrobial activity of the oil was evaluated using agar disc diffusion and broth microdilution method against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, two strains of Klebsiella pneumoniae and two strains of Candida albicans. The essential oil exhibited antimicrobial activity to varying degrees against all tested strains. The maximum activity of T. Pannonicus oil was observed against E. coli, S. aureus and both tested strains of C. Albicans (MIC = 50 µ/ml, each). Moderate activity was observed against P. aeruginosa and one of the tested strains of K. Pneumoniae (MIC = 200 µ/ml), while E. faecalis and the other strain of K. Pneumoniae expressed a higher degree of resistance (MIC > 200 µ/ml). This study confirms that essential oil of T. pannonicus possesses remarkable in vitro antimicrobial activity against several medicinally important pathogens. This is attributable to lemon-scented citral, a mixture of geranial and neral, which has well-documented antimicrobial activity against a range of bacteria and fungi.

Essential oil of the herb of Stachys recta L., Lamiaceae from Serbia.

Abstract The aerial parts of wild Stachys recta L., Lamiaceae, collected in the vicinity of Nis (Southern Serbia) during the full blooming stage, contained only 0.014% of essential oil. Using GC and GC/MS, 32 components were identified, predominantly alcohols and adequate oxides. The major constituent was 1-octen-3-ol (19.7%). The other important components were caryophyllene oxide, humulene oxide and nerolidol, but present in significantly lower amounts (4.6%, 3.8% and 3.6%, respectively).

Composition of the Essential Oil of Nepeta rtanjensis Diklic et Milojevic, Lamiaceae from Serbia

Abstract The essential oil from the aerial parts of Nepeta rtanjensis Diklic et Milojevic, Lamiaceae was obtained by steam distillation of the herb, collected in full blooming stage, with an average yield of 0.3%. Nineteen constituents (95-0% of the total oil) were identified by mass spectrometry. The principal one was 4aα,7α,7aβ-nepetalac-tone (86.4%), along with 2-methoxy-p-cresol (1.5%), α-pinene (1.4%) and 1,4-dimethyl-benzene (1.0%). All the others were present in quantities below 1%.

Composition of Essential Oil of Artemisia campestris L. from Serbia

Abstract The essential oil yield from the aerial parts of A. campestris was 0.2% (mL/g dried plant). The oil was analyzed using GC and GC/MS and 38 compounds were identified. The principal components were sesquiterpene alcohols: spathulenol (9.2%) and 4-hydroxy-9-epi-β-caryophyllene (3.0%); and monoterpene hydrocarbons: β-pinene (9.1%), α-pinene (3.4%), limonene (2.5%) and germacrene D (3.3%).

Antioxidant activity of yellow dock (Rumex crispus L., Polygonaceae) fruit extract

The methanol extract of ripe Rumex crispus L. fruits was evaluated for its antioxidant potential by assays for ferric‐reducing antioxidant power (FRAP), DPPH‐free radical scavenging activity (DPPH) and the influence on lipid peroxidation in liposomes (LP). Considerable activity was observed in all test systems (FRAP: 9.9 mmol Fe2+/g; DPPH IC50: 3.7 μg/mL; LP IC50: 4.9 μg/mL), comparable to that of BHT (FRAP: 8.0 μg/mL; DPPH IC50: 19.4 μg/mL; LP IC50: 3.5 μg/mL), but lower than the activity of ascorbic acid, rutin and quercetin, used as positive control substances. The in vivo effects were evaluated in several hepatic antioxidant systems (activities of LPx, GSH‐Px, Px, CAT and XOD, as well as GSH content), after treatment with the studied yellow dock extract in different doses, or in combination with carbon tetrachloride (CCl4). Pretreatment with the R. crispus extract inhibited CCl4‐induced oxidative stress by decreasing LPx and increasing GSH content in a dose dependent manner, bringing the levels of antioxidant enzymes to near control values. Copyright