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Anti- Pseudomonas aeruginosa activity of hemlock ( Conium maculatum, Apiaceae ) essential oil



Conium maculatum is a nitrophilous weed belonging to the Apiaceae family and occurring in hedgerows, pastures, waste ground, along rivers and roadsides. Little is known on the chemistry and bioactivity of other secondary metabolites occurring in the plant. In the present work, we have analysed the chemical composition and antimicrobial activity of the essential oils hydrodistilled from leaves and inflorescenes of C. maculatum growing in Sicily, Italy. The composition of essential oils was achieved by gas chromatography-mass spectrometry (GC-MS) analysis, whereas the inhibitory effects on the growth of two Gram negative strains, namely Escherichia coli and Pseudomonas aeruginosa were assessed by two different analysis. The essential oils exhibited different chemical profiles (1-butylpiperidine and myrcene in the inflorescenes), (mostly (E)-caryophyllene in the leaves). The latter oil was particularly active in inhibiting the growth of P. aeruginosa. These results shed light on the possible application of hemlock essential oils as antimicrobial agents.
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Natural Product Research
Formerly Natural Product Letters
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Anti-Pseudomonas aeruginosa activity of hemlock
(Conium maculatum, Apiaceae) essential oil
Michela Di Napoli, Mario Varcamonti, Adriana Basile, Maurizio Bruno,
Filippo Maggi & Anna Zanfardino
To cite this article: Michela Di Napoli, Mario Varcamonti, Adriana Basile, Maurizio
Bruno, Filippo Maggi & Anna Zanfardino (2018): Anti-Pseudomonas�aeruginosa activity
of hemlock (Conium�maculatum,�Apiaceae) essential oil, Natural Product Research, DOI:
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Published online: 21 May 2018.
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Anti-Pseudomonas aeruginosa activity of hemlock (Conium
maculatum, Apiaceae) essential oil
MichelaDi Napolia, MarioVarcamontia, AdrianaBasilea, MaurizioBrunob,
FilippoMaggic and AnnaZanfardinoa
aDepartment of Biology, University of Naples “Federico II”, Naples, Italy; bDepartment of Biological, Chemical
and Pharmaceutical Science and Technology (STEBICEF), University of Palermo, Palermo, Italy; cSchool of
Pharmacy, University of Camerino, Camerino, Italy
Conium maculatum is a nitrophilous weed belonging to the Apiaceae
family and occurring in hedgerows, pastures, waste ground, along rivers
and roadsides. Little is known on the chemistry and bioactivity of other
secondary metabolites occurring in the plant. In the present work, we
have analysed the chemical composition and antimicrobial activity
of the essential oils hydrodistilled from leaves and inorescenes of C.
maculatum growing in Sicily, Italy. The composition of essential oils was
achieved by gas chromatography-mass spectrometry (GC-MS) analysis,
whereas the inhibitory eects on the growth of two Gram negative
strains, namely Escherichia coli and Pseudomonas aeruginosa were
assessed by two dierent analysis. The essential oils exhibited dierent
chemical proles (1-butylpiperidine and myrcene in the inorescenes),
(mostly (E)-caryophyllene in the leaves). The latter oil was particularly
active in inhibiting the growth of P. aeruginosa. These results shed light on
the possible application of hemlock essential oils as antimicrobial agents.
© 2018 Informa UK Limited, trading as Taylor & Francis Group
Conium maculatum; essential
oil; chemical composition;
antimicrobial activity
Received 12 March 2018
Accepted13 May 2018
CONTACT Filippo Maggi; Anna Zanfardino
Supplemental data for this article can be accessed at
1. Introduction
Conium maculatum L., also known as ‘cicuta, is a nitrophilous weed belonging to the Apiaceae
(Umbelliferae) family and occurring in hedgerows, pastures, waste ground, along rivers and
roadsides (Vetter 2004). The generic name comes from the Greek ‘Konas’, meaning ‘to whirl’
and alluding to the convulsions produced by its consumption, whereas the specic name
derives from the Latin maculatum’ alluding to the purple spots occurring on the stems (Vetter
2004). Hemlock is a biennial or, in favorable conditions, perennial plant with an erect stem,
120–180 cm tall, endowed with irregular purple spots, and alternate, tripinnate leaves.
Flowers are small and white, grouped in umbels with 12–16 rays which appear from June to
September. The fruit is an anise-like schizocarp, formed by two greyish-brown achenes bear-
ing ve ridges (Vetter 2004). The plant emits a mousy odour and has a bitter taste. The
notoriety of hemlock is linked to its historical use as poisoning, having been the cause of
the death of the famous Greek philosopher Socrates in 399 BC (De Boer 1950). Frequent
poisonings are reported in livestock that can be killed by respiratory paralysis (Panter et al.
1985). The hemlock toxicity is given by the presence of piperidine alkaloids (Vetter 2004).
These secondary metabolites, derived through the acetate pathway, act as chemical defense
against herbivore attacks (Panter et al. 1988a). Notably, eight main piperidine alkaloids are
produced by hemlock (Panter et al. 1985), with γ-conicein and coniine as the most abundant
and toxic compounds (Panter et al. 1988a, 1988b, 1988c). The alkaloid content in hemlock
is quite variable, depending on the plant organ, development stage and environmental and
climatic conditions, with the fruits usually being the richest part (López et al. 1999). Piperidine
alkaloids are generally accumulated in the secretory ducts occurring in the various organs
of hemlock along with essential oils (Corsi and Biasci 1998). Whereas many reports have
investigated the biosynthesis and structures of the former, only a few reports referred to the
volatile components of hemlock (Masoudi et al. 2006; Radulovic et al. 2008). Therefore, as a
continuation of our studies on the chemistry and bioactivity of medicinal and aromatic
plants occurring in Sicily (Casiglia et al. 2017; Pavela et al. 2017), here we report the antimi-
crobial properties of the essential oil obtained from inorescences and leaves of C. macula-
tum growing in Sicily against the two Gram negative strains.
2. Results and discussion
2.1. Essential oil analysis
A total of sixty volatile components were identied in the essential oils from inorescences
and leaves of C. maculatum, accounting for 80.7 and 82.2% of the total composition, respec
tively (Table S1). The two oils showed signicant dierences in the chemical prole as
detected by GC-MS (Figure S1). The essential oil from inorescences was characterized by
four chemical classes, namely monoterpene hydrocarbons (32.7%), volatile alkaloids (26.4%),
oxygenated sesquiterpenes (15.9%) and sesquiterpene hydrocarbons (15.2%). The major
components were 1-butylpiperidine (26.4%), myrcene (24.0%), (E)-caryophyllene (8.8%), (Z)-
β-ocimene (7.4%) and germacrene D (5.3%). It is worth to note the presence of some
unknown oxygen-containing sesquiterpenes having pseudo-molecular ion peak at m/z 214
[M + H]+ whose mass fragmentation is depicted in Figure S2. Also, the presence of com-
pounds involved in the attraction of pollinators (Pecetti and Tava 2000), such as the esters
octyl hexanoate (1.2%) and benzyl hexanoate (0.7%) was found in this essential oil and
conrmed what reported in a previous report (Radulovic et al. 2008). Finally, several alkanes
deriving from the hydrolysis of waxy coating of owers (Afshar et al. 2015) were found, with
n-tricosane (0.9%) and n-pentacosane (0.5%) as the most abundant ones. Interestingly, we
detected for the rst time the massive presence of a volatile alkaloid, i.e. 1-butylpiperidine
(Figure S3), a saturated piperidine alkaloid (Vetter 2004). On the other hand, the poisonous
coniine was not found, probably because it was linked to cations inside the vacuole of plant
cells, hence non-volatile under distillation. We assume that this volatile alkaloid may allow
plant to defend itself from herbivore feeding (Birkett et al. 2004). The essential oil from
hemlock leaves was dominated by sesquiterpenes hydrocarbons (64.2%) with oxygenated
sesquiterpenes (8.9%), monoterpene hydrocarbons (6.5%) and esters (4.7%), By far, the major
compound was (E)-caryophyllene (54.8%) (Figure S3) with minor contributions of germac-
rene D (4.2%), α-humulene (3.6%), myrcene (3.1%) and (Z)-β-ocimene (2.2%). Surprisingly,
here the alkaloid 1-butylpiperidine was detected in scant levels (0.1%) supporting its involve-
ment in the ower’s function. Also in this case we detected appreciable amounts (15.3%) of
two unknown compounds having pseudo-molecular ion peak at m/z 214 [M + H]+ (Figure
S2). Finally, we also found detectable amounts of esters, such as octyl hexanoate (1.5%) and
phenyl ethyl octanoate (1.2%), as well as alkanes like n-nonacosane (0.8%), n-pentacosane
(0.8%) and n-heptacosane (0.6%). Two reports described the chemical composition of hem-
lock essential oils from spontaneous plants growing in Serbia and Iran (Masoudi et al. 2006;
Radulovic et al. 2008). In both cases, the chemical proles reported were quite dierent from
those found in Sicilian hemlock. In the essential oil obtained from the Serbian population
the major volatile compounds were germacrene D (27.2%), (Z)-β-ocimene (14.3%), myrcene
(9.3%), (E)-β-ocimene (7.7%) and (E)-nerolidol (7.1%) in inorescences, and germacrene D
(41.0%), (E)-β-ocimene (22.3%) and (Z)-β-ocimene (7.1%) in leaves (Radulovic et al. 2008).
On the other hand, the essential oil obtained from the aerial parts of Iranian hemlock showed
germacrene D (46.1%), (E)-caryophyllene (15.3%) and (E,E)-α-farnesene (10.1%) as the major
compounds (Masoudi et al. 2006). Therefore, the present work highlighted the presence of
new essential oil chemotypes for hemlock, characterized by 1-butylpiperidine in inores-
cences and (E)-caryophyllene in leaves. Notably, to the best of our knowledge, the alkaloid
1-butylpiperidine has never reported in C. maculatum so far. We assume that the geograph-
ical isolation of the Sicilian population with respect to the continental ones gave rise to its
chemical peculiarity.
2.2. Eect of C. maculatum essential oils on bacterial survival
The essential oils extracted from C. maculatum leaves and inorescences were tested against
two Gram negative strains: Escherichia coli DH5α and Pseudomonas aeruginosa PAOI which
represent a model strain and an opportunistic pathogen for plants, respectively. As shown
in Figure S4 A, the oil extracted from leaves was able to inhibit the P. aeruginosa growth,
forming an inhibition halo (about 250 AU/mL) almost comparable to the antibiotic colistin,
a polymyxin that acts on the bacterial membrane of Gram negative microorganisms used
as positive control in the experiment. Instead the other Gram negative indicator strain used
in this study, E. coli DH5α, was resistant to the treatment. The essential oil extracted from the
hemlock inorescences does not seem to have an equivalent antimicrobial activity. In Figure
S4 B is reported a quantitative analysis of inhibition halos. A more sensitive method to cal-
culate the eciency of antimicrobial activity is shown in Figure S5, where we demonstrate
that the activity of C. maculatum leaves extract is able to kill about seventy percent of P.
aeruginosa PAOI treated cells. In previous studies the antimicrobial activity of the major
volatile compound present in hemlock leaves, the (E)-caryophyllene, was demonstrated to
be directed against phytopathogens strains such as Pseudomonas syringae (Huang et al.
2012). In addition, caryophyllene rich essential oils are able to block or reduce the deterio-
ration of certain foodstus contaminated by Pseudomonas uorescens (Myszka et al. 2017).
Caryophyllene is able to enter inside the lipid bilayer of bacterial membrane causing loss of
its uidity and permeability, inhibition of respiration and alteration of transport processes
(Sikkema et al. 1994). Antimicrobial activities belonging to inorescences of hemlock were
not previously observed. Taking together results from this manuscript and from literature,
we can speculate that the antimicrobial molecules are produced as defense strategy in leaves
but not in the inorescences where attractor compounds for pollinators are instead
3. Conclusion
In this paper we demonstrate that C. maculatum essential oil is eective in preventing or
killing P. aeruginosa cells. Important future goals include the identication of antimicrobial
molecular mechanisms by which this oil counteracts bacterial growth. Thus, results of this
work give new insights into the potential application of hemlock essential oils as antimicro-
bial agent to combat pathogens dicult to eradicate and for the discovery of alternatives
to antibiotics.
Author Contributions
All authors planned and carried out the experimental work, discussed the results and com-
mented on the manuscript.
Disclosure statement
No potential conict of interest was reported by the authors.
This work was supported by grant from MIUR-ITALY PRIN2015 ‘Top-down and Bottom-up approach in
the development of new bioactive chemical entities inspired on natural products scaolds’ (Project
N. 2015MSCKCE_003).
Filippo Maggi
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... In the frame of our ongoing research on Mediterranean species belonging to the Apiaceae family [36][37][38][39][40][41], we analyzed the chemical composition of the flower EO of a Sicilian accession of R. segetum, not investigated so far, and evaluated its insecticidal activity on a panel of insect species of high economic importance, i.e., the lymphatic filariasis vector Culex quinquefasciatus Say (Diptera: Culicidae)-for which the development of novel and sustainable control tools is urgently needed [37,42]-the common housefly, Musca domestica L. (Diptera: Muscidae), which is a noxious insect being able to transmit a large number of microbial pathogens [43], and the African cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), which is currently considered one of the most polyphagous moth species attacking highly diverse crops tropic and sub-tropic regions, and is listed as an A2 quarantine pest [44]. For mosquitoes and moths, the third larval instar was targeted, while for houseflies we examined the EO toxicity on adults, assessing the potential difference in EO effectiveness on male and female flies. ...
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Several species of the family Apiaceae are aromatic herbs that produce essential oils usable on an industrial scale for pharmaceutical, cosmetic, and food purposes. In particular, some essential oils, such as green insecticides for example, may replace synthetic insecticides, keeping most of their efficacy and avoiding environmental pollution or human poisoning. In the present study, we explored the insecticidal potential of Ridolfia segetum (L.) Moris essential oil (EO) against three different pests: Culex quinquefasciatus Say, Musca domestica L., and Spodoptera littoralis (Boisduval). For this purpose, the EO was obtained by hydrodistillation of flowers and its composition was achieved by gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). This EO was rich in α-phellandrene (49.3%), β-phellandrene (9.2%), terpinolene (20.7%), and piperitenone oxide (5.9%). Concerning the mosquitocidal efficacy, the EO showed noteworthy toxicity against C. quinquefasciatus 3rd instar larvae, with a LC50 = 27.1 µL L−1 and LC90 = 42.5 µL L−1. Regarding M. domestica, a different toxicity of the R. segetum EO was found on male and female flies, calculating LD50 values of 10.5 and 50.8 µg adult−1, respectively. The EO was also toxic to S. littoralis 3rd instar larvae, achieving LD50 and LD90 values of 37.9 and 99.6 µg larva−1, respectively. Overall, this flower EO, extracted from a traditional Sicilian food plant, merits further investigation for the development of green insecticide formulations to be used in real world conditions, pending a careful assessment of non-target toxicity on beneficial organisms.
... The presence of antimicrobial molecules in the essential oil extracted from A. secundiramea leaves and flowers was detected using Kirby-Bauer assay [7,8] against Escherichia coli DH5α, P. aeruginosa PAOI, or S. aureus ATCC 6538P strains. ...
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Anthemis secundiramea is a perennial herb native widespread throughout the Mediterranean basin. The oil obtained from the flowers of this plant has antimicrobial properties against gram-positive and -negative bacteria, and inhibits the biofilm formation. The extract of A. secundiramea also has antioxidant activity—increasing the activity of different enzymes (SOD, CAT, and GPx). Surprisingly, in the oil extracted from the flowers, there is a single molecule, called (+)-(E)-chrysanthenyl acetate: This makes the A. secundiramea flowers extract extremely interesting for future topical, cosmetic, and nutraceutical applications.
The Apiaceae Lindl. (=Umbelliferae Juss.), which includes several economical important vegetables, herbs, and spices, is one of the most numerous plant family. Umbelliferous crops (namely anise, fennel, carrot, coriander, parsley, etc.) are also valuable sources of botanical flavoring agents and fragrances. In addition, Apiaceae species yield a wide variety of distinctive specialized metabolites (i.e, volatile phenylpropanoids, furanocoumarins, sesquiterpene coumarins, polyacetylenes, and phthalides), some of them been described as uncommon natural phytochemicals exclusive of the family, which offers a great potential for bioprospection. Numerous studies have pointed out the outstanding biological activity of extracts and several classes of phytochemicals from Apiaceae species. Emphasis has been given to essential oils (EOs) and their constituents activities, most likely because this type of plant added value product benefits from a larger acceptance and application potential in integrated pest management (IPM) and integrated vector management (IVM) programs. Several species of the family offer a variety of unique compounds with great potential as biopesticidal and/or synergizing agents. Investigations covering their activity toward agricultural pests and phytopathogens have increased in the last years, nevertheless the interest remains strongly focus on arthropod species, predominantly those acting as vectors of human diseases. From our survey, it is patent the gap of knowledge concerning the potential molluscicidal properties of Apiaceae extracts/phytochemicals, as well as their herbicidal activities against invasive plant species. In this review, we propose to highlight the potential of Apiaceae species as suitable sources of bioactive phytochemicals with great relevance within the frame of plant-based pesticides R&D, and will discuss their applicability in real-world scenarios considering the recent developments regarding the design of stable formulations incorporating Apiaceae bioactive products. We expect that this review will encourage researchers to consider undervalued Apiaceae species as alternative sources of bioactive compounds and will give a contribute to the field by suggesting new research topics.
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In the present study, the chemical compositions of the essential oils from roots, stems, leaves and fruits of Foeniculum vulgare subsp. piperitum collected in Sicily were evaluated by GC and GC-MS. The main components of the roots were terpinolene (33.15%), γ-terpinene (12.18%) and fenchyl acetate (11.23%). Stems and leaves were very rich in α-phellandrene (36.85% and 41.59%, respectively) and β-phellandrene (19.68% and 25.79%, respectively), whereas the main components of fruits were terpinolene (20.10%) and limonene (17.84%) These results were compared with those of the EOs of the same vegetative parts of Foeniculum vulgare subsp. vulgare, collected in the same station and in the same days. The oils of F. vulgare subsp. vulgare showed completely different compositions, with estragole, (E)-anethole and α-pinene as main compounds, clearly indicating the differentiation of the two subspecies. Our results were also compared with those reported in literature for other accessions of Foeniculum vulgare subsp. piperitum
EFV12 is a small bioactive peptide produced by Lactobacillus gasseri SF1109, a human intestinal isolate with probiotic features. In this study, EFV12 antimicrobial and anti-inflammatory properties are characterised. In particular, we propose a possible mechanism of action for EFV12 involving bacterial membranes targeting. Moreover, we show that this small peptide is able to bind lipopolysaccharides (LPS) and to counteract its inflammatory insult preventing LPS action on Toll-like receptor 4, thus interfering with extracellular signal-regulated kinase, p38 and Jun N-terminal kinase, mitogen-activated protein kinases signalling pathways. Altogether these observations suggest that the bioactive peptide EFV12 is a good candidate to promote L. gasseri induced gut homeostasis and counteracting intestinal pathogens.
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Many cyclic hydrocarbons, e.g. aromatics, cycloalkanes, and terpenes, are toxic to microorganisms. The primary site of the toxic action is probably the cytoplasmic membrane, but the mechanism of the toxicity is still poorly understood. The effects of cyclic hydrocarbons were studied in liposomes prepared from Escherichia coli phospholipids. The membrane-buffer partition coefficients of the cyclic hydrocarbons revealed that these lipophilic compounds preferentially reside in the membrane. The partition coefficients closely correlated with the partition coefficients of these compounds in a standard octanol-water system. The accumulation of hydro carbon molecules resulted in swelling of the membrane bilayer, as assessed by the release of fluorescence self-quenching of fluorescent fatty acid and phospholipid analogs. Parallel to the expansion of the membrane, an increase in membrane fluidity was observed. These effects on the integrity of the membrane caused an increased passive flux of protons and carboxyfluorescein. In cytochrome c oxidase containing proteoliposomes, both components of the proton motive force, the pH gradient and the electrical potential, were dissipated with increasing concentrations of cyclic hydrocarbons. The dissipating effect was primarily the result of an increased permeability of the membrane for protons (ions). At higher concentrations, cytochrome c oxidase was also inactivated. The effective concentrations of the different cyclic hydrocarbons correlated with their partition coefficients between the membrane and aqueous phase. The impairment of microbial activity by the cyclic hydrocarbons most likely results from hydrophobic interaction with the membrane, which affects the functioning of the membrane and membrane-embedded proteins.
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volatiles in this species has been investigated, with par- ticular regard to their attractiveness for honey bees, Flower volatile compounds of alfalfa (Medicago sativa L.) are Apis mellifera, (Kauffeld et al., 1969; Loper and Waller, involved in attractiveness to pollinating insects, and thus influence 1970; Loper and Lapioli, 1971; Kauffeld and Sorensen, the first three flowerings of the growing season, during which alfalfa color. pollination was expected to take place. Confirming previous evidence, As pointed out by Dafni and Neal (1997), the flower temporal patterns of emanation were observed, with a sharp increase is a morphological unit not necessarily corresponding from the flowering in May to those in July and August and a strong to a functional unit of the pollination process (a ''polli- time-of-day effect during the two summer flowerings (burst of volatiles nation unit''). If flowers in inflorescences are small and around midday). The marked seasonal effect appeared somewhat the inflorescence is compact, the insects may perceive related to temperature increase while the daily variation of emanation
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The compn. of leaf and flower essential oils of Conium maculatum from Serbia was detd. [on SciFinder(R)]
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Flowers have a high risk of pathogen attack because of their rich nutrient and moisture content, and high frequency of insect visitors. We investigated the role of (E)-β-caryophyllene in floral defense against a microbial pathogen. This sesquiterpene is a common volatile compound emitted from flowers, and is a major volatile released from the stigma of Arabidopsis thaliana flowers. Arabidopsis thaliana lines lacking a functional (E)-β-caryophyllene synthase or constitutively overexpressing this gene were challenged with Pseudomonas syringae pv. tomato DC3000, which is a bacterial pathogen of brassicaceous plants. Flowers of plant lines lacking (E)-β-caryophyllene emission showed greater bacterial growth on their stigmas than did wild-type flowers, and their seeds were lighter and misshapen. By contrast, plant lines with ectopic (E)-β-caryophyllene emission from vegetative parts were more resistant than wild-type plants to pathogen infection of leaves, and showed reduced cell damage and higher seed production. Based on in vitro experiments, (E)-β-caryophyllene seems to act by direct inhibition of bacterial growth, rather than by triggering defense signaling pathways. (E)-β-Caryophyllene thus appears to serve as a defense against pathogens that invade floral tissues and, like other floral volatiles, may play multiple roles in defense and pollinator attraction.
The effective management of insect pests and vectors still represents a major challenge in current entomology. Culex quinquefasciatus Say is a key vector of lymphatic filariasis, Rift Valley fever, West Nile, St. Louis encephalitis and Western equine encephalitis virus. Recently, the importance of the eco-friendly control of C. quinquefasciatus larval population using plant-borne biopesticides, including essential oils (EOs), has been stressed. Spodoptera littoralis (Boisd.) also known as tobacco cutworm, is one of the most destructive moth agricultural pests in tropic and sub-tropic regions. Despite the fact that sea fennel (Crithmum maritimum L., Apiaceae) is considered as a promising biosaline crop, its potential for commercial cultivation has not yet been exploited. Notably, it has been reported that in coastal marine environments insect pests stay away from sea fennel plants. This aromatic plant is endowed with secretory structures as ducts and vittae storing volatile compounds. In the present study, the chemical composition of sea fennel essential oils from three different EO accessions, namely France (Brittany), Central and South Italy (Marche and Sicily regions) have been analysed by gas chromatography-mass spectrometry (GC–MS), and their toxicity against larvae of Cx. quinquefasciatus and S. littoralis was evaluated. Selected pure compounds from the essential oils mentioned above were also tested. The essential oils showed notable variability in chemical composition, being dominated by dillapiole and γ-terpinene (French EO), limonene and γ-terpinene (central Italy EO) and thymol methyl ether and γ-terpinene (Sicilian EO). As found out, the significantly most efficient essential oils were obtained from the seeds and aerial parts of plants of the French region. For these EOs, LD50 values were estimated as 62.3 and 71.7 μg/larva for S. littoralis, respectively, and LC50 as 13.7 and 15.6 μl/L for C. quinquefasciatus larvae, respectively. γ-Terpinene and myristicin were the most effective on C. quinquefasciatus larvae showing LC50 values< 17 μl/L. Overall, these findings shed light on the insecticidal potential of C. maritimum EO against mosquitoes and agricultural pests, allowing to identify the most effective chemotype, and to stimulate cultivation of this species as a source of botanical insecticides.
Objective: Kundmannia sicula is an herbaceous plant belonging to the family Apiaceae and is distributed in the Mediterranean coastal areas where it occurs in arid places. In this work, we have analysed the essential oil distilled from the aerial parts of K. sicula from Sicily (Italy) and its biological activity. Methods: GC-MS was used to analyze the chemical composition, whereas its antioxidant capacity and cytotoxicity on three human tumour cells (A375, MDA MB-231 and HCT 116) were evaluated by DPPH, ABTS, FRAP and MTT methods, respectively. Result: The essential oil resulted very rich of the sesquiterpene hydrocarbon germacrene D (81.2%). Moreover, the K. sicula oil displayed relevant scavenging activity towards the ABTS radical (IC50 values of 14.5 μg/ml) and noteworthy antiproliferative effects on tumour cell lines (IC50 values in the range 21.59–31.94 μg/ml). Conclusion: Results of this study may support uses of K. sicula as a natural source of germacrene D to be exploited on an industrial level.
Pseudomonas fluorescens are able to cause the biodeterioration process of fresh-cut lettuce via the indole-3-acetic acid (IAA)-dependent type III secretion system (TTSS). The application of pepper EOs of proven of anti-IAA and anti-TTSS activities into salad dressing can reduce the organoleptic deterioration of fresh-cut leafy vegetables during storage. In this work, the influence of black and white pepper EOs on IAA production and on TTSS gene expression in P. fluorescens KM06 was examined. The black and white pepper EOs and β-caryophyllene at concentrations below the sub-MICs altered (i.e., 78%, 94%, and 90%, respectively) the IAA production in a 72 h old culture of P. fluorescens KM06. All the test agents significantly reduced the mRNA levels of the TTSS gene (−0.106, −0.428, and −0.448 for black pepper EO, white pepper EO and β-caryophyllene, respectively) (p < 0.05). In model in situ experiments, the supplementation of the salad dressing with sub-MIC doses of β-caryophyllene-rich white and black pepper EOs also markedly inhibited bacterial IAA production (by 81% and 73%, respectively) and the IAA-related TTSS gene expression (by −0.880 and −0.680, respectively) (p < 0.05). β-Caryophyllene-rich pepper EO seems to be a promising candidate to minimize or arrest the organoleptic deterioration of lettuce salad.
Phytochemical investigations of Alchemilla persica Rothm. growing in Iran were performed taking into account both the volatile and polar constituents. The hydrodistilled essential oil was analysed by GC-MS that revealed the presence of alkanes (27.8%), diterpenoids (19.6 %) and sesquiterpene hydrocarbons (17.1%) as the major constituents, while tannins and flavonol glycosides were identified as the most abundant constituents of the methanol extract by HPLC-MS. A. persica can be a valuable source of ellagitannins and polyphenols.
The composition of the essential oils from three Umbelliferae species of Iran—Dorema aucheri Boiss., which is endemic to Iran, Seseli libanotis (L.) W. D. Koch var. armeniacum Bordz. and Conium maculatum L.—obtained by hydrodistillation were analyzed by GC and GC[sol ]MS. -Eudesmol (31.2%) and δ-cadinene (10.9%) were the main components among the 35 constituents characterized in Dorema aucheri, representing 89.2% of the total components detected. Twenty-five compound were identified in the oil of Seseli libanotis, repesenting 90.6% of the total oil with acorenone (35.5%) as the major constituents. The oil of Conium maculatum was characterized by higher amount of germacrene D (46.1%), β-caryophyllene (15.3%) and (E,E)--farnesene (10.1%) among the 17 components comprising 91.0% of the total oil detected. All oils were richer in sesquiterpenes than monoterpenes. Copyright © 2006 John Wiley & Sons, Ltd.
In this paper histochemical investigations of the secretory structures ofConium maculatumL., are described that discriminated between ducts and vittae. The localization of alkaloids in seedlings, vegetative organs, flowers, and in the mericarp (during its development from ovary to full maturity), was achieved using specific histochemical tests.Copyright 1998 Annals of Botany Company