Jelena S. Matejić

Biological activity of Pinus nigra terpenes-Evaluation of FtsZ inhibition by selected compounds as contribution to their antimicrobial activity

In the current work, in vitro antioxidant, antibacterial, and antifungal activites of the needle terpenes of three taxa of Pinus nigra from Serbia (ssp. nigra, ssp. pallasiana, and var. banatica) were analyzed. The black pine essential oils showed generally weak antioxidative properties tested by two methods (DPPH and ABTS scavenging assays), where the highest activity was identified in P. nigra var. banatica (IC50=25.08 mg/mL and VitC=0.67 mg (vitamin C)/g when tested with the DPPH and ABTS reagents, respectively). In the antimicrobial assays, one fungal (Aspergilus niger) and two bacterial strains (Staphylococcus aureus and Bacillus cereus) showed sensitivity against essential oils of all three P. nigra taxa. The tested oils have been shown to possess inhibitory action in the range from 20.00 to 0.62 mg/mL, where var. banatica exhibited the highest and ssp. nigra the lowest antimicrobial action. In order to determine potential compounds that are responsible for alternative mode of action, molecular docking simulations inside FtsZ (a prokaryotic homolog of tubulin) were performed. Tested compounds were the most abundant terpenoid (germacrene D-4-ol) and its structurally similar terpene (germacrene D), both present in all three essential oils. It was determined that the oxygenated form of the molecule creates stable bonds with investigated enzyme FtsZ, and that this compound, through this mechanism of action participates in the antimicrobial activity.

Total phenolic content, flavonoid concentration, antioxidant and antimicrobial activity of methanol extracts from three Seseli L. taxa

The present study describes the total phenolic content, concentrations of flavonoids and in vitro antioxidant and antimicrobial activity of methanol extracts from Seseli pallasii Besser, S. libanotis (L.) Koch ssp. libanotis and S. libanotis (L.) Koch ssp. intermedium (Rupr.) P. W. Ball, growing wild in Serbia. The total phenolic content in the extracts was determined using Folin-Ciocalteu reagent and their amounts ranged between 84.04 to 87.52 mg GA (gallic acid)/g. The concentrations of flavonoids in the extracts varied from 4.75 to 19.37 mg Qu (quercetin)/g. Antioxidant activity was analyzed using DPPH reagent. Antioxidant activity ranged from 0.46 to 4.63 IC50 (mg/ml) and from 1.98 to 2.19 mg VitC (vitamin C)/g when tested with the DPPH and ABTS reagents, respectively, using BHA and VitC as controls. The antimicrobial activity of the extracts was investigated using a micro-well dilution assay for the most common human gastrointestinal pathogenic bacterial strains: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, Salmonella enteritidis ATCC 13076, Bacillus cereus ATCC 10876, Listeria monocytogenes ATCC15313, Staphylococcus aureus ATCC 25923 and Candida albicans ATCC 10231. This finding suggests that Seseli species may be considered as a natural source of antioxidants and antimicrobial agents.

Plants of Genus Mentha: From Farm to Food Factory

Genus Mentha, a member of Lamiaceae family, encompasses a series of species used on an industrial scale and with a well-described and developed culture process. Extracts of this genus are traditionally used as foods and are highly valued due to the presence of significant amounts of antioxidant phenolic compounds. Many essential oil chemotypes show distinct aromatic flavor conferred by different terpene proportions. Mint extracts and their derived essential oils exert notable effects against a broad spectrum of bacteria, fungi or yeasts, tested both in vitro or in various food matrices. Their chemical compositions are well-known, which suggest and even prompt their safe use. In this review, genus Mentha plant cultivation, phytochemical analysis and even antimicrobial activity are carefully described. Also, in consideration of its natural origin, antioxidant and antimicrobial properties, a special emphasis was given to mint-derived products as an interesting alternative to artificial preservatives towards establishing a wide range of applications for shelf-life extension of food ingredients and even foodstuffs. Mentha cultivation techniques markedly influence its phytochemical composition. Both extracts and essential oils display a broad spectrum of activity, closely related to its phytochemical composition. Therefore, industrial implementation of genus Mentha depends on its efficacy, safety and neutral taste.

Chemical Composition, Antioxidant and Antimicrobial Properties of Essential Oil and Extracts from Heracleum sphondylium L.

Abstract The present study describes chemical composition of essential oil, total phenolic and flavonoid content and in vitro antioxidant and antimicrobial activity of essential oil and various extracts from Heracleum sphondylium L. (Apiaceae). The essential oil isolated by hydrodistillation from the aerial parts was analyzed using combined GC and GC-MS. The dominant constituents in the oil were ar-curcumene (13.42%), β-sesquiphellandrene (11.91%) and β-bisabolene (10.11%). The total phenolic content in the extracts was determined using Folin-Ciocalteu reagent and their amounts ranged between 38.04 to 110.15 mg GA (gallic acid)/g. The concentrations of flavonoids in the extracts varied from 27.57 to 82.54 mg Qu (quercetin)/g. Antioxidant activity was analyzed using DPPH reagent. Antioxidant activity ranged from 2.50 to 24.16 IC 50 (mg/ml) and from 1.16 to 3.13 mg VitC (vitamin C)/g when tested with the DPPH and ABTS reagents, respectively. The antimicrobial activity of the essential oil and extracts was investigated using a micro-well dilution assay for the most common human gastrointestinal pathogenic microbial strains: Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus and yeast Candida albicans. The results showed that minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations of essential oil and extracts ranged from 1.56 mg/ml (for the most sensitive B. cereus) to above 50 mg/ml for S. enteritidis and E. coli. This finding suggests that H. sphondylium L. may be considered as a natural source of antioxidants and antimicrobial agents.

Chemical Composition of the Essential Oil of Geum Coccineum

The genus Geum with ca. 60 species in the family Rosaceae is primarily found in temperate or montane regions of Europe, Asia, North and South America, Africa, and New Zealand [1]. Geum coccineum is representative of the subendemic taxa and native to the Balkan region and Asia Minor [2]. Geum species are used in traditional medicine and exhibit antiviral, anti-inflammatory, anticoagulant, antidizziness (Meniere s syndrome), angiogenesis, and myogenesis activities [3–6]. Phytochemical studies on the Geum species have revealed the occurrence of many secondary metabolites, such as terpenoids, flavonoids, tannins, and phenylpropanoids [7–10]. To the best of our knowledge, there is no report in the literature on the chemical composition of the essential oil of Geum coccineum Sibth. et Sm. Aerial parts of Geum coccineum were collected in June 2013 from natural populations of Jablanica Mountain, Macedonia (41 13 44.33 N, 20 31 41.97 E, Elev. 1810 m). The plant material was authenticated by one of the authors (V. N. Randjelovic). A voucher specimen, with the accession number 16732, is deposited at the Herbarium of the Department of Botany, Faculty of Biology, University of Belgrade – Herbarium Code BEOU. Oil was obtained from air-dried aerial parts of the plant with 0.01% (w/w) yield by hydrodistillation for 4 h using a Clevenger-type apparatus. The oil analyses were performed simultaneously by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) systems. The GC analysis of the oils was carried out on a GC HP-5890 II apparatus equipped with a split-splitless injector, an HP-5MS capillary column (30 m 0.25 mm, 0.25 m film thickness) with helium as the carrier gas (1 mL/min), and a FID. Operating conditions: injector temperature 250 C and interface temperature 280 C, temperature program from 50 C (3 min) to 250 C at a rate of 3 C/min; volume injected, 1 L of the oil in ether (0.5%). GC/MS analyses, under the same gas-chromatograph conditions, were performed on an Agilent Technologies apparatus, Model GS 6890N, coupled with an MSD 5975C mass selective detector. The MS operating parameters were as follows: ionization potential 70 eV; ion source temperature 250 C; quadrapole 150 C, solvent delay 3.0 min, mass range 50–550 amu, and Em voltage 1435 V. Identification of the compounds was based on comparison of Kovats retention indexes (applying calibrated automated mass spectral deconvolution and identification system software (AMDIS ver. 2.64) in combination with selective ion analysis (SIA) resolution method [11]), comparison with the spectral data from the available literature [12], and comparison of their mass spectra with those from Wiley 275 and NIST/NBS libraries using various search engines. Relative retention indexes (RRI) were obtained by co-injection with an aliphatic hydrocarbons C7–C40 standard mixture. The results of GC and GC/MS analyses of the investigated oil are summarized in Table 1. Thirty-three compounds were identified, representing 97.4% of the total oil. The major component was phytol constituting 24.3% of the oil. Other significant compounds were myrtenal (13.4%), cis-myrtanol (9.6%), tricosane (9.2%) and palmitic acid (6.1%), while other constituents were present in less than 5%. The essential oil of the aerial part of Geum iranicum Khatamaz had palmitic acid (10.6%) and linoleic acid (9.6%) as the main constituents [13]. The major compounds in the oil of the roots and rhizomes of Geum kokanicum were eugenol (80.9%) and myrtenol (5.2%) [14].

Aromatic Plants from Western Balkans: A Potential Source of Bioactive Natural Compounds

Documentation of traditionally used aromatic and medical plants has been carried out in many European countries over the last several years. Over the last decade, the Western Balkans has become the area of a huge number of ethnobiological field studies. Many of those focused on Balkans ethnobotany are linked to the long and ongoing history of gathering and trading local wild aromatic and medicinal plants from this territory into Western European markets. But only less than a half percent of these have been studied for their chemical composition and medicinal value. The most investigated aromatic species in this area belongs to the few biggest families: Asteraceae, Apiaceae, Lamiaceae and Rosaceae. Medicinal value of plants lies in some chemical substances that produce physiological action on the human body, which leads to positive effect on health. Essential oils are secondary metabolites which are the most examined, as well as various plant extracts. Isolation and identification of the compounds in combination with its biological screening can considerably contribute to plant studies. Also, application of new activities and novel techniques for susceptibility testing provide better knowledge of wild growing medicinal plants as potential sources of biological agents and justified their traditional uses.

Chemical Composition of the Essential Oil of Geum rhodopeum

were collected in June 2010 at Prestojceva mahala (Cemernik Mountain-42 44 45.43N, 22 18 40.01 E, Elev. 1339 m). The plant material was authenticated by one of the authors (V. N. Randjelovic). A voucherspecimen, with the accession number 16680, is deposited at the Herbarium of the Department of Botany, Faculty of Biology,University of Belgrade – Herbarium Code BEOU.Oil was obtained from air-dried aerial parts of the plant with 0.01% (w/w) yield by hydrodistillation for 4 h using aClevenger-type apparatus. The oil analyses were performed simultaneously by gas chromatography (GC) and gaschromatography-mass spectrometry (GC-MS) systems. The GC analysis of the oils was carried out on a GC HP-5890 IIapparatus equipped with a split-splitless injector, an HP-5MS capillary column (30 m 0.25 mm, 0.25 m film thickness) withhelium as the carrier gas (1 mL/min), and FID. Operating conditions: injector temperature 250 C and interface temperature280 C, temperature program from 50 C (3 min) to 250 C at a rate of 3 C/min. Volume injected, 1 L of the oil in ether (0.5%).GC/MS analyses, under the same gas-chromatograph conditions, were performed on an Agilent Technologies apparatus,Model GS 6890N coupled with a mass selective detector MSD 5975C. The MS operating parameters were as follows: ionizationpotential 70 eV; ion source temperature 250 C; quadrapole 150 C, solvent delay 3.0 min, mass range 50–550 amu, Em voltage1435 V.Identification of the compounds was based on comparison of Kovats retention indexes (applying calibrated automatedmass spectral deconvolution and identification system software (AMDIS ver. 2.64) in combination with selective ion analysis(SIA) resolution method [11]), comparison with the spectral data from the available literature [12], and comparison of theirmass spectra to those from Wiley 275 and NIST/NBS libraries using various search engines. Relative retention indexes (RRI)were obtained by co-injection with an aliphatic C