Adriana Trifan

Inhalation of coriander volatile oil increased anxiolytic–antidepressant-like behaviors and decreased oxidative status in beta-amyloid (1–42) rat model of Alzheimer's disease

The present study analyzed the possible anxiolytic, antidepressant and antioxidant proprieties of inhaled coriander volatile oil extracted from Coriandrum sativum var. microcarpum in beta-amyloid (1-42) rat model of Alzheimers disease. The anxiolytic- and antidepressant-like effects of inhaled coriander volatile oil were studied by means of in vivo (elevated plus-maze and forced swimming tests) approaches. Also, the antioxidant activity in the hippocampus was assessed using catalase specific activity and the total content of the reduced glutathione. The beta-amyloid (1-42)-treated rats exhibited the following: decrease of the locomotor activity, the percentage of the time spent and the number of entries in the open arm within elevated plus-maze test and decrease of swimming and immobility times within forced swimming test. Exposure to coriander volatile oil significantly improved these parameters, suggesting anxiolytic- and antidepressant-like effects. Moreover, coriander volatile oil decreased catalase activity and increased glutathione level in the hippocampus. Our results suggest that multiple exposures to coriander volatile oil can be useful as a mean to counteract anxiety, depression and oxidative stress in Alzheimers disease conditions.

Flavonoids as modulators of metabolic enzymes and drug transporters

Flavonoids, natural compounds found in plants and in plant‐derived foods and beverages, have been extensively studied with regard to their capacity to modulate metabolic enzymes and drug transporters. In vitro, flavonoids predominantly inhibit the major phase I drug‐metabolizing enzyme CYP450 3A4 and the enzymes responsible for the bioactivation of procarcinogens (CYP1 enzymes) and upregulate the enzymes involved in carcinogen detoxification (UDP‐glucuronosyltransferases, glutathione S‐transferases (GSTs)). Flavonoids have been reported to inhibit ATP‐binding cassette (ABC) transporters (multidrug resistance (MDR)–associated proteins, breast cancer–resistance protein) that contribute to the development of MDR. P‐glycoprotein, an ABC transporter that limits drug bioavailability and also induces MDR, was differently modulated by flavonoids. Flavonoids and their phase II metabolites (sulfates, glucuronides) inhibit organic anion transporters involved in the tubular uptake of nephrotoxic compounds. In vivo studies have partially confirmed in vitro findings, suggesting that the mechanisms underlying the modulatory effects of flavonoids are complex and difficult to predict in vivo. Data summarized in this review strongly support the view that flavonoids are promising candidates for the enhancement of oral drug bioavailability, chemoprevention, and reversal of MDR.

In Vitro Study on the Antioxidant Activity of a Polyphenol-Rich Extract from Pinus brutia Bark and Its Fractions

A crude hydromethanolic extract from Pinus brutia bark and its fractions (diethyl ether, ethyl acetate, n-butanol, and aqueous fractions) were studied with regard to their phenolic content and antioxidant activities. The total phenolics and proanthocyanidins in each extract were quantified by spectrophotometric methods; the polyphenolic profile was analyzed by RP-HPLC-DAD-ESI-MS. All extracts were tested with regard to their ability to scavenge free radicals (ABTS radical cation, superoxide and hydroxyl radicals), reduce ferric ions, and inhibit 15-lipoxygenase. P. brutia bark extracts had high phenolic contents (303.79±7.34-448.90±1.39 mg/g). Except diethyl ether extract, all other extracts contained proanthocyanidins ranging from 225.79±3.94 to 250.40±1.44 mg/g. Several polyphenols were identified by RP-HPLC-DAD-ESI-MS: taxifolin in diethyl ether extract, a taxifolin-O-hexoside, catechin, procyanidin dimers, and trimers in ethyl acetate extract. Except diethyl ether extract, all other extracts were effective scavengers of superoxide and hydroxyl radicals (EC₅₀=33.5±1.1-54.93±2.85 μg/mL and 0.47±0.06-0.6±0.0 mg/mL, respectively). All extracts had noticeable 15-lipoxygenase inhibitory effects (EC₅₀=22.47±0.75-34.43±2.25 μg/mL). We conclude that P. brutia bark is very promising for the dietary supplements industry due to its high free radical scavenging and 15-lipoxygenase inhibitory effects.

Essential Oils and Their Components as Modulators of Antibiotic Activity against Gram-Negative Bacteria

Gram-negative bacteria cause infections that are difficult to treat due to the emergence of multidrug resistance. This review summarizes the current status of the studies investigating the capacity of essential oils and their components to modulate antibiotic activity against Gram-negative bacteria. Synergistic interactions are particularly discussed with reference to possible mechanisms by which essential oil constituents interact with antibiotics. Special emphasis is given to essential oils and volatile compounds that inhibit efflux pumps, thus reversing drug resistance in Gram-negative bacteria. In addition, indifference and antagonism between essential oils/volatile compounds and conventional antibiotics have also been reported. Overall, this literature review reveals that essential oils and their purified components enhance the efficacy of antibiotics against Gram-negative bacteria, being promising candidates for the development of new effective formulations against Gram-negative bacteria.

Can phytochemicals be a bridge to develop new radioprotective agents

Various phytochemicals, mainly phenolic derivatives, have been screened for their radioprotective properties. This review summarizes the current knowledge in radioprotection using plant bioactive compounds with emphasis on two promising compounds, curcumin and genistein. Free radical scavenging abilities, maintaining cellular antioxidant status, modulation of DNA repair or prevention of DNA damages and anti-inflammatory activity are the main mechanisms involved in radioprotection exerted by phytochemicals. The chemical structure–activity relationship, the limits of existing research as well as the suggestions on further studies including clinical application are also discussed.

Helichrysum arenarium subsp. arenarium: phenolic composition and antibacterial activity against lower respiratory tract pathogens

The aim of this study was to investigate the phenolic content and antibacterial activity of the methanol extract from Helichrysum arenarium (L.) Moench subsp. arenarium inflorescences against lower respiratory tract pathogens (standard strains and clinical isolates). The extract was characterised by a total phenolic content of 160.17 mg/g. Several caffeic acid conjugates (chlorogenic acid and dicaffeoylquinic acids) and flavonoids (apigenin, naringenin, apigenin-7-O-glucoside and naringenin-O-hexosides) were identified as major constituents by HPLC-DAD-ESI-MS. Staphylococcus aureus ATCC 25923 was more susceptible to Helichrysum extract than Streptococcus pneumoniae ATCC 49619 (minimum inhibitory concentration [MIC] = 0.62 and 1.25 mg/mL, respectively). The extract exhibited similar antibacterial effects against methicillin-resistant S. aureus and penicillin-resistant S. pneumoniae clinical isolates (MIC = 2.5 mg/mL) displaying a higher activity against ampicillin-resistant Moraxella catarrhalis isolate (MIC = 0.15 mg/mL). The combination with ciprofloxacin exhibited additivity against both standard strains (fractional inhibitory concentration [FIC] index = 0.75 and 0.73) and S. aureus isolates (FIC index = 0.62) and synergy against S. pneumoniae isolates (FIC index = 0.5).

The Cardiovascular Effects of Cocoa Polyphenols—An Overview

Cocoa is a rich source of high-quality antioxidant polyphenols. They comprise mainly catechins (29%–38% of total polyphenols), anthocyanins (4% of total polyphenols) and proanthocyanidins (58%–65% of total polyphenols). A growing body of experimental and epidemiological evidence highlights that the intake of cocoa polyphenols may reduce the risk of cardiovascular events. Beyond antioxidant properties, cocoa polyphenols exert blood pressure lowering activity, antiplatelet, anti-inflammatory, metabolic and anti-atherosclerotic effects, and also improve endothelial function. This paper reviews the role of cocoa polyphenols in cardiovascular protection, with a special focus on mechanisms of action, clinical relevance and correlation between antioxidant activity and cardiovascular health.

Is comfrey root more than toxic pyrrolizidine alkaloids? Salvianolic acids among antioxidant polyphenols in comfrey (Symphytum officinale L.) roots

Comfrey root preparations are used for the external treatment of joint distortions and myalgia, due to its analgesic and anti-inflammatory properties. Up to date, key activity-determining constituents of comfrey root extracts have not been completely elucidated. Therefore, we applied different approaches to further characterize a comfrey root extract (65% ethanol). The phenolic profile of comfrey root sample was characterized by HPLC-DAD-QTOF-MS/MS. Rosmarinic acid was identified as main phenolic constituent (7.55 mg/g extract). Moreover, trimers and tetramers of caffeic acid (isomers of salvianolic acid A, B and C) were identified and quantified for the first time in comfrey root. In addition, pyrrolizidine alkaloids were evaluated by HPLC-QQQ-MS/MS and acetylintermedine, acetyllycopsamine and their N-oxides were determined as major pyrrolizidine alkaloids in the comfrey root sample. Lastly, the antioxidant activity was determined using four assays: DPPH and ABTS radicals scavenging assays, reducing power assay and 15-lipoxygenase inhibition assay. Comfrey root extract exhibited significant antioxidant activities when compared to known antioxidants. Thus, comfrey root is an important source of phenolic compounds endowed with antioxidant activity which may contribute to the overall bioactivity of Symphytum preparations.

Computational Aids for Assessing Bioactivities

Abstract Bioactivity assessment requires test systems, which are often representative for phenomena in the human body or other target organisms, like microbes. They involve the acquisition of signals, mainly spectrophotometric, or luminometric, in parallel experiments (e.g., microtitre plates) from different concentrations of the test samples and the comparison to blanks and positive controls. In such complex settings, computational aids are needed for the handling, storage, sorting, and visualization of the data and to help to apply suitable mathematical or statistical models to interpret and evaluate the findings and correlate data sets and signals of different origins. In the case of bioactivity assessment of natural products, the complexity of the multicompound mixture in natural extracts and fractions requires computational tools on different levels of the scientific challenge, such as text and data mining, in silico screening by target-ligand docking, as well as chemometrics and multivariate data analysis.

Antibacterial activity of traditional spices against lower respiratory tract pathogens: combinatorial effects of Trachyspermum ammi essential oil with conventional antibiotics

The aim of this study was to investigate the effects of ajowan essential oil (AjEO)/thymol and antibiotics combinations against three standard strains and six resistant clinical isolates of major respiratory bacteria (Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae). The broth microdilution method was conducted to determine the minimum inhibitory concentrations (MIC) of essential oil/thymol and antibiotics. The checkerboard method was used to investigate the interactions between the essential oil/thymol and antibiotics by means of the fractional inhibitory concentration index (FICI). The chemical composition of essential oil was also analysed by GC–MS and GC‐FID. Thymol (50·75%), γ‐terpinene (25·94%) and p‐cymene (18·31%) were identified as major constituents of the oil. The most sensitive organisms to ajowan volatile oil were Strep. pneumoniae bacteria (MIC = 0·125–0·5 mg ml−1). Synergistic effects were observed with AjEO/thymol and amoxicillin combinations on methicillin‐resistant Staph. aureus clinical isolates (FICI = 0·37–0·50) and with essential oil and ciprofloxacin combinations against P. aeruginosa ATCC 27853, Staph. aureus ATCC 25923 and penicillin (P)‐resistant Strep. pneumoniae bacteria (FICI = 0·37–0·50). Combination of thymol and ciprofloxacin produces synergistic effects only against P. aeruginosa ATCC 27853 and P‐resistant Strep. pneumoniae clinical isolate (FICI = 0·46–0·49).