This is the first comparative study on antimicrobial activity of essential oils (EOs) of six Achillea species (A. crithmifolia, A. distans, A. grandifolia, A. millefolium, A. nobilis, and A. ...lingulata) against ATCC and clinical microbial strains isolated from human swabs and on their toxicological potential on crustaceans. Oxygenated monoterpenes represented the major compound class in all six EOs, ranging from around 50 % (A. millefolium, A. nobilis, and A. lingulata) up to over 80 % (A. crithmifolia and A. grandifolia). Specific phytochemical profiles of the major volatiles were determined for each species. Still, borneol was the dominant compound in EOs of three yarrow species: A. distans, A. lingulata, and A. millefolium. Other major compounds were 1,8‐cineole in A. crithmifolia, camphor in A. grandifolia, and artemisia ketone in A. nobilis EO. Antimicrobial activities of EOs were examined by a microdilution method revealing inhibitory action against all 15 studied strains in the range of 0.07–20.00 mg/mL (MICs). High toxicity (LC50 <100 μg/mL) in Artemia salina acute toxicity bioassay was a shared characteristic, appearing in five out of six tested EOs, i. e., those isolated from A. lingulata, A. millefolium, A. distans, A. nobilis, and A. grandifolia. In both types of biological tests, A. lingulata EO has shown the highest and A. crithmifolia EO the lowest potential. The strongest activities, recorded for EO of A. lingulata, which was the only studied species from the section Anthemoideae, may be explained by its somewhat unusual chemical composition. According to the obtained results, the second dominant compound of this EO is γ‐palmitolactone, which may be a significant agent regarding the antimicrobial activity and toxicity to crustaceans, either on its own or in union with other components, and it may be a suitable topic for further research.
•A new natural product 5-phenylpentyl isothiocyanate (PhPeITC) was found in horseradish.•The first direct proof of the existence of a 5-phenylpentyl glucosinolate in nature.•PhPeITC and four related ...isothiocyanates were synthesised and extensively tested.•PhPeITC possesses spasmolytic activity 100 times more potent than papaverine.•Horseradish constituents showed significant cytotoxicity and antimicrobial activity.
Detailed analyses of horseradish autolysates led to the identification of a new natural product, 5-phenylpentyl isothiocyanate (PhPeITC). The structural assignment was corroborated by synthesis, and the identity unequivocally established by spectral means. The occurrence of PhPeITC is the first direct proof of the existence of a 5-phenylpentyl glucosinolate in the aerial parts of this species as one of the possible “mustard oil” precursors. To verify its possible contribution to the horseradish functional food status, horseradish above- and underground autolysates, together with five ω-phenylalkyl isothiocyanates were tested for their spasmolytic, cytotoxic and antimicrobial activities. Specifically, the cytotoxic effect on Caco-2, HeLa (cancer) and MDCK (non-cancer) cell lines was established. Additionally, the five tested ITCs exerted significant spasmolytic activity (on rat distal colon), with PhPeITC being almost 100 times more potent than papaverine. A non-selective antimicrobial activity of all ITCs was revealed in the case of 6 bacterial and 2 fungal strains.
This study focused on the essential oils (EOs) isolated from needles with twigs of three indigenous Balkan Abies species (A. alba, A. × borisii‐regis and A. cephalonica) regarding their chemical ...composition, antimicrobial activity and toxicity toward crustaceans and insects. Even though distinct phytochemical profiles of dominant volatiles were revealed for each species, β‐pinene and α‐pinene represented the first two major volatiles in all three EOs. Antimicrobial activity of EOs has shown inhibitory effect against all 17 studied strains (ATCC and respiratory isolates) in the range of 0.62–20.00 mg/mL (MICs). Further, all three EOs exhibited strong toxicity (LC50<100 μg/mL) in Artemia salina lethality bioassay, but with significant differences that depended on the EO type. Additionally, tested EOs have shown a certain level of toxicity against Drosophila melanogaster, mostly at the highest tested concentration (3 %) which caused significant prolongation of developmental time, larvicidal effect and pupal mortality. In the three biological assays performed, there was no observed inhibitory effect or weakest activity for A. alba EO. Further, A. cephalonica EO has shown the highest levels of antimicrobial activity and toxicity toward A. salina, while in relation to the insecticidal potential, A. cephalonica and A. × borisii‐regis EOs exhibited similar level of toxicity against D. melanogaster.
Neurotoxic thujones (α- and β-diastereoisomers) are common constituents of plant essential oils. In this study, we employed a statistical approach to determine the contribution of thujones to the ...overall observed behaviour-modulating and toxic effects of essential oils (Salvia officinalis L., Artemisia absinthium L., Thuja occidentalis L. and Tanacetum vulgare L.) containing these monoterpene ketones. The data from three in vivo neuropharmacological tests on rats (open field, light-dark, and diazepam-induced sleep), and toxicity assays (brine shrimp, and antimicrobial activity against a panel of microorganisms), together with the data from detailed chemical analyses, were subjected to a multivariate statistical treatment to reveal the possible correlation(s) between the content of essential-oil constituents and the observed effects. The results strongly imply that the toxic and behaviour-modulating activity of the oils (hundreds of constituents) should not be associated exclusively with thujones. The statistical analyses pinpointed to a number of essential-oil constituents other than thujones that demonstrated a clear correlation with either the toxicity, antimicrobial effect or the activity on CNS. Thus, in addition to the thujone content, the amount and toxicity of other constituents should be taken into consideration when making risk assessment and determining the regulatory status of plants in food and medicines.
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•The presence of thujones in essential oils is the reason for long-lasting concerns regarding their safety.•The impact of thujone content in four common essential oils on various aspects of their toxicity was evaluated.•Statistical analyses of the compositional/toxicity data disclosed constituent(s) responsible for the observed toxic actions.•Many constituents contribute to the overall toxicity of these oils or even surpass thujones in their cyto- and neurotoxicity.
Immortelle (Helichrysum italicum, Asteraceae) essential oil has been widely used in alternative medicine to accelerate wound healing, as well as in cosmetic products to stimulate skin regeneration ...and to reduce the appearance of wrinkles. It is also considered a natural and safe culinary spice that could also be applied in the food industry as a preservative in the future. The therapeutic efficacy of this oil changes with the natural variability of the composition. Herein we tested and mutually compared the antimicrobial and anti-inflammatory activities of four commercial immortelle oils differing in the relative amounts of marker compounds, i.e. neryl esters, α-pinene, γ- and ar-curcumenes, and β-diketones. The anti-inflammatory effect of selected chromatographic fractions, enriched in the aforementioned constituents, was evaluated by studying toxicity toward rat peritoneal macrophages, their nitric oxide production, myeloperoxidase, and arginase activities. Subsequently, the compositional and activity data were subjected to a multivariate statistical treatment to reveal the possible correlation(s) between the percentage of essential-oil constituents and the observed activities. The obtained results imply that immortelle oil efficiency as an antimicrobial and/or anti-inflammatory agent is most plausibly a result of a synergistic action between its constituents, and/or, rather unexpectedly, the presence of some minor constituents.
•Helichrysum italicum essential oil (EO) is used to promote wound healing.•Variations in the EO composition apparently affect its toxicity/bioactivity.•The tested EOs displayed strong antimicrobial and anti-inflammatory effects.•Unexpected links between the constituent amount and the toxicity were established.•Minor constituent presence and synergistic action define the modus operandi.
•The essential oils of four Pinus species from the Balkans were analyzed.•The total number of identified volatile constituents was 116.•Oils showed distinctive chemical profiles, antimicrobial and ...larvicidal activity.•According to both studied activities, oils can be arranged in the same order.
Comparative analysis of the chemical composition and biological activity of the essential oils from the needles of four Pinus species (P. mugo subsp. mugo, P. nigra subsp. nigra, P. sylvestris and P. peuce) from the central Balkans was performed. Although different chemical profiles of the dominant terpenes for each species were determined, essential oils were, generally, dominated by monoterpenes with α-pinene as one of the first two major volatiles. Tested oils showed inhibitory action against respiratory pathogenic bacterial strains, isolated from human swabs, in the range of 1.25–20.00mg/mL (MICs) and bactericidal effect (MBCs) at concentrations from 2.50 to 40.00mg/mL. Considering cell wall composition, there were no significant differences in sensitivity between Gram-positive and Gram-negative strains. In addition, the place of isolation did not provide evidences for higher susceptibility/resistance of the strains obtained from the particular infection site. On the other hand, toxicity of essential oils towards developing Drosophila melanogaster larvae was low, except P. mugo subsp. mugo oil, which did not show any signs of toxicity at concentrations up to 3%. Highest mortality of larvae and adults of D. melanogaster was noted for P. sylvestris essential oil with an estimated LC50 at the end of experiment (14days) of 2.78% with a 95% confidence interval of 2.15–3.42%. Short-term 96h LC50 values due to low mortality at larval stage could not be calculated for any oil and are expected to be much higher than 3%. According to the obtained antimicrobial activity and toxicity towards D. melanogaster, the oils can be arranged in the following order: P. sylvestris>P. peuce>P. nigra subsp. nigra>P. mugo subsp. mugo.
Carriage of
Clostridium
(
C.
)
difficile
in the intestinum of children, as well as its role in the disease (diarrhea) onset, is still controversial. The aim of this study is to investigate the ...community-acquired
Clostridium difficile
infection (CA-CDI) in Serbian pediatric population and to describe the basic clinical characteristics and risk factors for CA-CDI occurrence in Serbian pediatric population. The data obtained from 63 Serbian pediatric patients with CA-CDI and from control group of 126 children with community-acquired diarrhea, whose stool specimens were negative for
C. difficile
and toxins A/B, were mutually compared
.
In the current work, we found that children with CA-CDI display a significantly less severe disease clinical presentation than children with diarrheas of other origin. Lethal outcome was noted in two cases, but in children with severe underlying diseases (Crohn’s disease and leukemia). By using the multivariate statistical regression model, the following statistically significant risk factors for community-acquired
C. difficile
-associated diarrhea development were determined: previous application of laxatives (OR = 0.199, CI 0.55–0.79,
p
= 0.015), general antibiotic use during the previous 2 months (OR = 0.05, CI 0.02–0.17,
p
< 0.001), and specifically the use of penicillins (OR = 0.112, CI 0.04–0.31,
p
< 0.0001) and cephalosporins (OR = 0.16, CI 40.06–0.44,
p
< 0.0001). Antibiotics from the groups of cephalosporins and penicillins were found to be the most important independent risk factors. Laxative application plays a significant role in the community-acquired
Clostridium difficile
infections in children, with mechanisms that are not completely understood.
The effects of basil (Ocimum basilicum) and sage (Salvia officinalis) essential oils on selected virulence factors (biofilm formation, mature biofilm resistance, motility, and pyocyanin production) ...of Pseudomonas aeruginosa clinical isolates were evaluated in the present study for the first time. The two essential oils were chemically characterized by GC and GC-MS analyses. Linalool and (E)-anethole were found to be the main components of the investigated basil oil, while α-thujone and camphor were the major constituents of the studied sage essential oil. The oils inhibited biofilm formation up to 99.9% vs control, and significant reductions (74.7–99.9%) were also noted when the oils were applied to mature biofilms. Likewise, swimming, swarming, and twitching motility patterns were highly affected by both oils. The basil and sage oils reduced pyocyanin production by 13.32–55.6% and 5.0–58.7%, respectively. Thus, basil and sage essential oils are potentially highly efficient antipseudomonal agents that could be used against both acute and chronic infections.
•Basil and sage essential oils were chemically characterized and tested against P. aeruginosa.•Anti-biofilm experiments on P. aeruginosa isolates showed reductions up to 99.9%.•The oils eradicate all stages of biofilm development as well as mature biofilms.•The oils affected all motility types, and significantly reduced pyocyanin production.•Both essential oils are highly efficient anti-pseudomonal agents which decrease their virulence.
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•Eugenyl angelate and eugenyl 2-methylbutanoate are new compounds found in Anthemis segetalis essential oil.•A small combinatorial library comprised of the new compounds and related ...regioisomeric compounds was screened for toxicity.•New natural compounds have low toxicity against Artemia salina and low cytotoxicity against fibroblast and melanoma cells.•They are also weak antimicrobials and acetylcholinesterase inhibitors.•Intake of these esters in the form of A. segetalis botanical drug would not cause undesirable/adverse effects.
To determine the exact structure of previously tentatively identified minor essential-oil constituents of a Chamomile species (Antemis segetalis Ten. (Asteraceae)), we have synthesized a small combinatorial library of 54 regioisomeric allylmethoxyphenyl pentanoates and 2-pentenoates (49 completely new compounds). GC–MS in combination with 1D- and 2D-NMR analyses of the library compounds provided unambiguous data that led to a straightforward identification of the mentioned A. segetalis constituents as eugenyl angelate, 2-methylbutanoate and 3-methylbutanoate (0.21, 0.22, and 0.13mg/100g of fresh plant material, respectively). To assess the safety and potential beneficial pharmacological uses of these naturally occurring esters and several other library compounds (these were tested to provide relevant data for a SAR (structure–activity relationship) analysis), we have studied the effect of these compounds in several models of toxicity (acute toxicity against Artemia salina, cytotoxicity against two cell lines (fibroblast and melanoma)), as well as their acetylcholinesterase inhibitory and antibacterial activities. Anthemis segetalis constituents showed low to moderate activity in all tests. The obtained results suggest that the intake of these compounds in naturally available amounts, on their own, would probably not represent a risk to human health but the possible adverse interactions with the plant matrix should not be neglected.
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► Yarrow volatiles are more toxic to mice (LD50 853mg/kg) than thujone containing oils. ► Achillea umbellata constituents showed anxiolytic, analgesic and paralyzing activity. ► The ...oil is comprised of a rare monoterpene alcohol fragranol and its esters. ► A. umbellata oil exerts a different effect on prokaryotic and eukaryotic cells. ► Fragranol is believed to be the main carrier of the observed activity/toxicity.
Many plant species are used for medicinal purposes without the knowledge of their possible toxic effect. The ethnopharmacologically renowned genus Achillea L. (Asteraceae) is even more troublesome in this respect since different taxa are believed to have the same beneficial properties as A. millefolium. According to the median lethal i.p. dose (LD50=853mg/kg, mice), the volatiles of Achillea umbellata Sibth. et Sm. are more toxic than the thujone-containing essential oils (LD50>960mg/kg). A GC–MS analysis of A. umbellata oil revealed the presence of a series of fragranyl esters (six new natural products). The major constituents of this oil, the rare monoterpene alcohol fragranol and fragranyl acetate, and one more ester (benzoate), as well as the oil itself, showed antianxiety, analgesic and, in some instances, paralyzing properties at 50–150mg/kg but these are very likely sign of intoxication and not of possible beneficial effects of the plant volatiles. Testing of antimicrobial activity demonstrated that the oil possesses moderate activity against pathogenic microorganisms, but the effect of the oil differs in pro- and eukaryotic cells. According to the results obtained, fragranol may be considered as the main active principle responsible for the observed activity/toxicity.
