Neda Mimica-Dukić

Antioxidant and hepatoprotective potential of essential oils of coriander (Coriandrum sativum L.) and caraway (Carum carvi L.) (Apiaceae).

Essential oils of Coriandrum sativum L. and Carum carvi L. fruits were analyzed by gas chromatography-mass spectrometry and assayed for their in vitro and in vivo antioxidant activity and hepatoprotective effect against carbon tetrachloride (CCl(4)) damage. The in vitro antioxidant activity was evaluated as a free radical scavenging capacity (RSC), measured as scavenging activity of the essential oils on 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) and OH radicals and effects on lipid peroxidation (LP) in two systems of induction. Some liver biochemical parameters were determined in animals pretreated with essential oils and later intoxicated with CCl(4) to assess in vivo hepatoprotective effect. Tested essential oils were able to reduce the stable DPPH(*) in a dose-dependent manner and to neutralize H(2)O(2), reaching 50% neutralization with IC(50) values of <2.5 microL/mL for Carvi aetheroleum and 4.05 microL/mL for Coriandri aetheroleum . Caraway essential oil strongly inhibited LP in both systems of induction, whereas coriander essential oil exhibited prooxidant activity. In vivo investigation conferred leak of antioxidative capacity of coriander essential oil, whereas the essential oil of caraway appeared promising for safe use in folk medicine and the pharmaceutical and food industries.

Essential Oil of Myrtus communis L. as a Potential Antioxidant and Antimutagenic Agents

The present study describes DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and antimutagenic properties of the essential oil of myrtle (Myrtus communis L.). Plant samples were collected from the two distant localities (southernmost and northern point) of the Montenegro coastline. Chemical profiles of the two samples were evaluated by GC-MS. In both of the samples monoterpenes were found to be the predominant compounds. Among them α-pinene, linalool, 1,8-cineole, and myrtenyl acetate were the major compounds. Significant differences between the samples were found in the ranges of α-pinene (14.7%–35.9%) and myrtenyl acetate (5.4%–21.6%). Both oils exhibited moderate DPPH scavenging activity, with IC50 values of 6.24 mg/mL and 5.99 mg/mL. The antimutagenic properties were assayed against spontaneous and t-BOOH-induced mutagenesis in Escherichia coli oxyR mutant IC202, a bacterial strain deficient in removing ROS. Reduction of the spontaneous mutagenesis in presence of myrtle EO was only slight, up to 13% at the highest concentration tested. When the oxidative mutagen was used, EO expressed higher reduction of mutagenesis, in a concentration dependent manner, with statistical significance for effect at the highest concentration tested (28%). Suppression of t-BOOH induced mutagenesis was correlated with the observed scavenging activity.

Phenolic Compounds in Field Horsetail (Equisetum arvense L.) as Natural Antioxidants

In this paper, the study of antioxidant activity and phenolic composition of three different extracts (EtOAc, n-BuOH and H2O) of field horsetail (Equisetum arvense L.) is presented. The antioxidant activity has been evaluated measuring the total reducing power (expressed by Ascorbate Equivalent Antioxidant Capacity - AEAC), inhibition of lipid peroxidation, and free radical scavenging capacity (RSC) towards 2,2-diphenyl-1-picrylhydrazyl (DPPH radical) and nitric oxide (NO), respectively. In addition, the total flavonoid content (TFC) and phenolic constituents of each extract have been determined. The results obtained show that the highest RSC regarding both DPPH and NO radicals is expressed by EtOAc extract (EC50=2.37 μg/mL and EC50=90.07 μg/mL, respectively), and the lowest by H2O extract (EC50=37.2 μg/mL and EC50>333.33 μg/mL, respectively). n-BuOH extract showed the highest total reducing power (AEAC=13.40 μg/mL). Differences in the phenolic composition of examined extracts are found comparing the HPLC chemical profiles. Although, isoquercitrin is the main flavonoid in both EtOAc and n-BuOH extracts, a considerable amount of di-E-caffeoyl-meso-tartaric acid was presented in the n-BuOH extract. In H2O extract high content of phenolic acids and low percentage of flavonoids were detected.

Quantitative determination of plant phenolics in Urtica dioica extracts by high-performance liquid chromatography coupled with tandem mass spectrometric detection

A method for quantification of 45 plant phenolics (including benzoic acids, cinnamic acids, flavonoid aglycones, C- and O-glycosides, coumarins, and lignans) in plant extracts was developed, based on reversed phase HPLC separation of extract components, followed by tandem mass spectrometric detection. The phenolic profile of 80% MeOH extracts of the stinging nettle (Urtica dioica L.) herb, root, stem, leaf and inflorescence was obtained by using this method. Twenty-one of the investigated compounds were present at levels above the reliable quantification limit, with 5-O-caffeoylquinic acid, rutin and isoquercitrin as the most abundant. The inflorescence extracts were by far the richest in phenolics, with the investigated compounds amounting 2.5-5.1% by weight. As opposed to this, the root extracts were poor in phenolics, with only several acids and derivatives being present in significant amounts. The results obtained by the developed method represent the most detailed U. dioica chemical profile so far.

Chemical Composition, Antioxidant and Antibacterial Properties of Achillea collina Becker ex Heimerl s.l. and A. pannonica Scheele Essential oils

The in vitro antioxidant and antimicrobial activities of two Achillea millefolium (Adanson) Koch s.l species essential oils (A. collina Becker ex Heimerl s.l. and A. pannonica Scheele, Asteraceae) originating from the Golija and Radan mountains (Serbia) were investigated. The chemical profiles of the essential oils were evaluated by GC-MS. Antioxidant activity was assessed as free radical scavenging capacity (RSC) towards 2,2-diphenyl-1-picrylhydrazil (DPPH) radicals, together with effects on lipid peroxidation (LP). Antibacterial activity was examined on 21 bacterial strains. Based on the chemical composition of the essential oil, A. collina s.l. from Mount Golija was classified as a chamazulene chemotype (tetraploid). The high percentage of oxygenated monoterpenes and absence of azulene in the essential oil obtained from A. pannonica from Radan pointing that this population is octaploid. Essential oil of A. pannonica expressed stronger antimicrobial activity on almost all tested bacteria. Furthermore, this essential oil expressed higher scavenging effects on DPPH radical (IC50 = 0.52 comparing to 0.62 μg/mL). Only in the LP evaluation, essential oil of A. collina s.l. from Golija exhibited stronger antioxidant activity (IC50 = 0.75 comparing to 2.12 μg/mL).

Antioxidant abilities of cultivated and wild species of garlic

The antioxidant abilities of cultivated and wild species of garlic were investigated. Huge quantities of malonyldialdehyde (MDA), superoxide (O2˙−) and hydroxyl (OH˙) radicals were observed in the above‐ground parts of plants examined. The highest quantities of O2˙− and OH˙ were observed in the above‐ground parts of wild Allium vienale L. where lipid peroxidation was also the highest. Carotenoid andvitamin C contents were the highest in leaves of cultivated Allium vienale L. where quantities of MDA, O2˙− and OH˙ were small indicating its high antioxidant ability.

Antimicrobial activity of Eucalyptus camaldulensis essential oils and their interactions with conventional antimicrobial agents against multi-drug resistant Acinetobacter baumannii.

ETHNOPHARMACOLOGICAL RELEVANCE Traditional herbal medicine has become an important issue on the global scale during the past decade. Among drugs of natural origin, special place belongs to essential oils, known as strong antimicrobial agents that can be used to combat antibiotic-resistant bacteria. Eucalyptus camaldulensis leaves are traditional herbal remedy used for various purposes, including treatment of infections. The aim of this study was to determine antimicrobial potential of two E. camaldulensis essential oils against multi-drug resistant (MDR) Acinetobacter baumannii wound isolates and to examine possible interactions of essential oils with conventional antimicrobial agents. MATERIALS AND METHODS Chemical composition of essential oils was determined by gas chromatography-mass spectrometry analysis (GC-MS). MIC values of essential oils against A. baumannii strains were estimated by modified broth microdilution method. The components responsible for antimicrobial activity were detected by bioautographic analysis. The potential synergy between the essential oils and antibiotics (ciprofloxacin, gentamicin and polymyxin B) was examined by checkerboard method and time kill curve. RESULTS The dominant components of both essential oils were spatulenol, cryptone, p-cimene, 1,8-cineole, terpinen-4-ol and β-pinene. The detected MICs for the E. camaldulensis essential oils were in range from 0.5 to 2 μl mL(-1). The bioautographic assay confirmed antibacterial activity of polar terpene compounds. In combination with conventional antibiotics (ciprofloxacin, gentamicin and polymyxin B), the examined essential oils showed synergistic antibacterial effect in most of the cases, while in some even re-sensitized MDR A. baumannii strains. The synergistic interaction was confirmed by time-kill curves for E. camaldulensis essential oil and polymyxin B combination which reduced bacterial count under detection limit very fast, i.e. after 6h of incubation. CONCLUSIONS The detected anti-A. baumannii activity of E. camaldulensis essential oils justifies traditional use of this plant. The proven E. camaldulensis essential oil synergistic interactions with conventional antibiotics could lead to the development of new treatment strategies of infections caused by MDR A. baumannii strains in the term of antibiotic dose reduction.

Erythema multiforme due to contact with weeds: a recurrence after patch testing.

Erythema multiforme (EM) as a complication of patch testing (PT) is rare. A 52‐year‐old woman with a 13‐year history of episodes of EM, after contact with weeds during home gardening, had had no recent history of herpes simplex, other infection, drug ingestion or vaccination. On examination, EM lesions were distributed on the exposed skin. 5 weeks after complete resolution, PT and photopatch testing (PPT) were done with fresh plants she brought in. She was PT with a standard series and the Hermal‐Trolab plants, woods, tars, balsams and flavors series. Intradermal testing, with a 3 + reaction to mixed weed pollens, was done 3 weeks later. Specific IgE to weed pollens class 1 (CAP‐Pharmacia) was detected. Eczematous PT reactions were obtained with fresh leaves: common chickweed (Stellaria media Caryophyllaceae), dandelion (Taraxacum officinale Compositae), field‐milk thistle (Sonchus arvensis Compositae) and white clover (Trifolium repens Leguminosae). Photoaggravation was seen to common chickweed and dandelion. Positive PT was also seen with alantolactone. By the 4‐day reading, a typical EM had commenced, coming up to quite the same extent as seen on admission. There was no photosensitivity (UV skin tester, K. Waldmann). In the essential oil obtained from common chickweed, thin layer chromatography (TLC) revealed the well‐known contact allergens borneol, menthol, linalool, 1,8‐cineole, and other terpenes such as epoxy‐dehydro‐caryophyllene, monoterpene alcohol‐ester and caryophyllene. Up to now, no data on essential oil in Stellaria media (common chickweed) have been reported. It can be concluded that EM developed due to contact with weeds, and recurred after patch testing. Neither blistering nor eczematous lesions have been seen on her skin, making this case very unusual. As far as the world literature is concerned, this is only the 4th report of EM developing in association with patch testing.

Synergistic effect of Myrtus communis L. essential oils and conventional antibiotics against multi-drug resistant Acinetobacter baumannii wound isolates.

Acinetobacter baumannii is a rapidly emerging, highly resistant clinical pathogen with increasing prevalence. In recent years, the limited number of antimicrobial agents available for treatment of infections with multi-drug resistant (MDR) strains reinforced tendency for discovery of novel antimicrobial agents or treatment strategies. The aim of the study was to determine antimicrobial effectiveness of three Myrtus communis L. essential oils, both alone and in combination with conventional antibiotics, against MDR A. baumannii wound isolates. The results obtained highlighted the occurrence of good antibacterial effect of myrtle oils when administered alone. Using checkerboard method, the combinations of subinhibitory concentrations of myrtle essential oils and conventional antibiotics, i.e. polymixin B and ciprofloxacine were examined. The results proved synergism among M. communis L. essential oils and both antibiotics against MDR A. baumannii wound isolates, with a FIC index under or equal 0.50. Combination of subinhibitory concentrations of essential oils and ciprofloxacin most frequently reduced bacterial growth in synergistic manner. The similar has been shown for combination with polymyxin B; furthermore, the myrtle essential oil resulted in re-sensitization of the MDR wound isolates, i.e. MICs used in combination were below the cut off for the sensitivity to the antibiotic. Time-kill curve method confirmed efficacy of myrtle essential oil and polymyxin B combination, with complete reduction of bacterial count after 6h. The detected synergy offers an opportunity for future development of treatment strategies for potentially lethal wound infections caused by MDR A. baumannii.

Chemical Composition of Essential Oil and Leaf Anatomy of Salvia bertolonii Vis. and Salvia pratensis L. (Sect. Plethiosphace, Lamiaceae)

The taxonomical relationship between Salvia pratensis and S. bertolonii has been unclear for a long time. Salvia bertolonii has alternatively been considered a synonym, a subspecies, a problematic subspecies and a form of Salvia pratensis. However, both these two species are sometimes used in traditional medicine instead of sage (Salvia officinalis) or as an adulteration for the same drug. In order to confirm the status of S. bertolonii, together with the potential identification characteristics for differentiation from sage, both taxa were analyzed through the analysis of their essential oils, together with the micromorphological characteristics of the leaf surface and the anatomy and morphology of the leaves. The obtained results show that there are clear differences in the quantity of essential oil (0.073% for S. pratensis and 0.0016% for S. berolonii). The major compound in the essential oil of S. pratensis was E-caryophyllene (26.4%) while in S. berolonii essential oil caryophyllene oxide was the major component (35.1%). The micromorphological differences are also pronounced in the leaf indumentum (density and distribution of certain types of non-glandular and glandular trichomes). Clear distinction between the investigated Salvia species is also observed in the leaf anatomy (in S. pratensis leaves are thinner, palisade tissue is made of 1-2 layers of cells, and leaves of S. bertolonii are characterized by 2-3 layers of palisade tissue cells, and consequently thicker).