Analytical Method for Quantifying Monoterpenoids (p-Cymene and Myrcene) in Nanoemulsions Using High-Performance Liquid Chromatography.

BACKGROUND: Myrcene and cymene, aromatic monoterpenes found in plants and essential oils, possess distinctive aromatic qualities. However, their volatility and limited solubility pose challenges in precise handling and formulation. Meanwhile, nanoemulsions emerge as promising drug delivery systems, improving the bioavailability and stability of these active ingredients. OBJECTIVE: This article aimed to develop an HPLC method for the quantification of two monoterpenoids, p-cymene and myrcene, in nanoemulsions. METHOD: The method used a Phenomenex® Synergi™ Fusion-RP column (150 mm × 4.6 mm id, 4 µm particle size) on an HPLC system with isocratic elution. The mobile phase was composed of acetonitrile and water (60:40, v/v) and was validated in terms of specificity, linearity, accuracy, precision, robustness, and selectivity. RESULTS: The method provided accurate and precise results with a correlation coefficient of 0.999 and RSD values of less than 2%. The method can be used for quality control of nanoemulsions containing these monoterpenoids and as a reference for future studies on their efficacy and stability. CONCLUSIONS: The study demonstrates the feasibility of using HPLC for the quantification of monoterpenoids in nanoemulsions and its potential as a quality control tool for nanoemulsion-based drug delivery systems. HIGHLIGHTS: The method's accuracy, precision, and reliability, as evidenced by high correlation coefficients and low RSD values, underscore its suitability for ensuring the consistent formulation of these monoterpenoid-containing nanoemulsions, while also serving as a reference point for future research endeavors in this field.

Biological Activities and Chemical Composition of Essential Oil from Hedyosmum purpurascens (Todzia)-An Endemic Plant in Ecuador.

Hedyosmum purpurascens is an endemic species found in the Andes of Ecuador and it is characterized by its pleasant smell. In this study, essential oil (EO) from H. purpurascens was obtained by the hydro-distillation method with a Clevenger-type apparatus. The identification of the chemical composition was carried out by GC-MS and GC-FID in two capillary columns, DB-5ms and HP-INNOWax. A total of 90 compounds were identified, representing more than 98% of the total chemical composition. Germacrene-D, ϒ-terpinene, α-phellandrene, sabinene, O-cymene, 1,8-cineole and α-pinene accounted for more than 59% of the EO composition. The enantioselective analysis of the EO revealed the occurrence of (+)-α-pinene as a pure enantiomer; in addition, four pairs of enantiomers were found (α-phellandrene, o-cymene, limonene and myrcene). The biological activity against microbiological strains and antioxidants and the anticholinesterase properties were also evaluated and the EO showed a moderate anticholinesterase and antioxidant effect, with an IC50 value of 95.62 ± 1.03 µg/mL and a SC50 value of 56.38 ± 1.96. A poor antimicrobial effect was observed for all the strains, with MIC values over 1000 µg/mL. Based on our results, the H. purpurasens EO presented remarkable antioxidant and AChE activities. Despite these promising results, further research seems essential to validate the safety of this medicinal species as a function of dose and time. Experimental studies on the mechanisms of action are essential to validate its pharmacological properties.

Thymol screening, phenolic contents, antioxidant and antibacterial activities of Iranian populations of Trachyspermum ammi (L.) Sprague (Apiaceae).

The seeds of Trachyspermum ammi were gathered at the ripening stage from different regions of Iran and grouped into 14 populations (P1-P14) accordingly. The essential oil (EO) extraction yielded in the 3.16-5% range. EOs were analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) and 11 constituents were identified. Thymol (59.92-96.4%), p-cymene (0.55-21.15%), γ-terpinene (0.23-17.78%), and carvacrol (0.41-2.77%) were the major constituents. The highest contents of thymol and carvacrol were found in the Ghayen population (P2). Also, P2 and P8 (Estahban) had the highest value of total phenol (TPC) 43.2 mg gallic acid equivalent (GAE)/g DW, and total flavonoids (TFC) 8.03 mg quercetin equivalent (QE)/g DW, respectively. P1 (Kalat) had the highest total coumarin (TCC) value (0.26 mg coumarin equivalent CE/g DW). Based on EO constituents, principal component analysis (PCA) and cluster analysis classified populations into two chemotypes of thymol/p-cymene/γ-terpinene and thymol/carvacrol. The highest positive correlation coefficient was between α-terpinene and limonene (0.96), while the highest negative correlation was between thymol and p-cymene (-0.984). The antioxidant activities of extracts and EOs were evaluated by phosphomolybdenum (total antioxidant capacity; TAC), diphenylpicrylhydrazyl (DPPH IC50), and ferric ion reducing antioxidant power (FRAP) assays. Also, the antimicrobial activity of EOs was studied against Escherichia coli and Staphylococcus aureus. P8 with high thymol, EO content (%v/w), TFC, and antibacterial and antioxidant activities is recommended but further studies are needed to confirm the chemotype introduction.

Geraniol and Carvacrol in Essential Oil Bearing Thymus pulegioides: Distribution in Natural Habitats and Phytotoxic Effect.

Phenolic and non-phenolic chemotypes of Thymus pulegioides L. are common in Europe. Essential oils of these chemotypes, as various compositions of allelochemicals, can have different phytotoxic effects on neighboring plants in natural habitats. The aim of this study was to establish the distribution of carvacrol and geraniol in T. pulegioides, growing wild in Lithuania, and compare phytotoxity of essential oils of carvacrol and geraniol chemotypes on selected plant species. In investigating 131 T. pulegioides habitats, essential oils were isolated by hydrodistillation and analyzed by GC-FID and GC-MS. Phytotoxity of essential oils extracted from carvacrol and geraniol chemotypes transmitted through water and air to selected plants was determined under laboratory conditions. Pharmacologically valuable Hypericum perforatum L. and the important forage grass Phleum pratense L. were respectively selected for experimentation from among 35 medicinal plants and 10 feed Poaceae species, growing in T. pulegioides habitats. Field results showed that carvacrol is common throughout Lithuania's territory, whereas the geraniol is predominantly located under the continental climatic conditions of the eastern region of the country. In the laboratory experiment, it was established that there was stronger inhibition of P. pratense seed germination by the essential oil of the geraniol chemotype than the carvacrol chemotype. None of the H. perforatum seeds germinated after exposure to the essential oil of the geraniol chemotype. In general, this study builds on previous studies by providing further evidence that different T. pulegioides chemotypes have contrasting phytotoxic effects on neighboring plants within their natural habitats.

Origanum vulgare ssp. hirtum (Lamiaceae) Essential Oil Prevents Behavioral and Oxidative Stress Changes in the Scopolamine Zebrafish Model.

Origanum vulgare ssp. hirtum has been used as medicinal herbs promoting antioxidant, anti-inflammatory, antimicrobial, and neuroprotective activities. We investigated the protective effects and the mechanism of O. vulgare ssp. hirtum essential oil (OEO) on cognitive impairment and brain oxidative stress in a scopolamine (Sco)-induced zebrafish (Danio rerio) model of cognitive impairment. Our results show that exposure to Sco (100 µM) leads to anxiety, spatial memory, and response to novelty dysfunctions, whereas the administration of OEO (25, 150, and 300 µL/L, once daily for 13 days) reduced anxiety-like behavior and improved cognitive ability, which was confirmed by behavioral tests, such as the novel tank-diving test (NTT), Y-maze test, and novel object recognition test (NOR) in zebrafish. Additionally, Sco-induced brain oxidative stress and increasing of acetylcholinesterase (AChE) activity were attenuated by the administration of OEO. The gas chromatography-mass spectrometry (GC-MS) analyses were used to elucidate the OEO composition, comprising thymol (38.82%), p-cymene (20.28%), and γ-terpinene (19.58%) as the main identified components. These findings suggest the ability of OEO to revert the Sco-induced cognitive deficits by restoring the cholinergic system activity and brain antioxidant status. Thus, OEO could be used as perspective sources of bioactive compounds, displaying valuable biological activities, with potential pharmaceutical applications.

Highly effective pre-concentration of thymol and carvacrol using nano-sized magnetic molecularly imprinted polymer based on experimental design optimization and their trace determination in summer savoury, Origanum majorana and Origanum vulgare extracts.

To ascertain thymol and carvacrol in pharmaceutical syrups, a valid and effective magnetic molecular imprinted polymer dispersive solid phase microextraction (MMIP-DSPME) process was developed in this study, which was in combination with a high performance liquid chromatography-ultra violet (HPLC-UV) technique for the assessment of thymol and carvacrol separation and pre-concentration. Contact time, eluent kind and volume, pH, the mass of the MMIP were all taken into consideration as key factors. Design expert and multi-objective response surface methodology (RSM) were used to optimize these variables. The mass of the MMIP, sample pH, eluent kind, time of sorption, the volume of eluent, and time of elution were 10 mg, 6, acetonitrile, 28 min, 200 µL, and 5.5 min, respectively, for the maximum extraction recovery of the analytes. The limit of detection (LOD) was 0.042 ng mL-1 at the optimal conditions, while the value for the limit of quantification (LOQ) was 0.140 ng mL-1. At the optimized conditions for thymol and carvacrol, the suggested MMIP sorbent had sorption capacities of 64.1 and 72.6 mg g-1, respectively. Furthermore, for triplicate measurements, the linear dynamic range (LDR) was 0.40-5000 ng mL-1, and the method's accuracy (RSD %) was 6.26%. The saturation magnetization for the MMIP was 19.0 emu g-1 obtained by VSM, allowing the sorbent to be separated quickly. The sorption experiments confirmed the large sorption capacity of the MMIP for thymol and carvacrol, as well as its homogeneous binding sites. The extraction recovery for thymol and carvacrol was 96.9-103.8% and 96.6-105.4%, respectively, at all spiked amounts (20, 100, 200, and 500 ng mL-1). The findings of seven desorption-regeneration cycles using MMIP demonstrated the high stability of the sorbent. The MMIP revealed a particular behavior of sorption for thymol and carvacrol, implying a selective, simple, effective, and flexible analytical method.

Separation performance of the copolymer and homopolymer of aliphatic polycarbonate diols as the stationary phases for capillary gas chromatography.

This work presents the investigation of two aliphatic polycarbonate diols (CAPC and HAPC) as the stationary phases for capillary gas chromatography (GC). The CAPC and HAPC capillary columns showed moderate polarity and high column efficiency of 3704 - 4545 plates/m measured by n-octanol and naphthalene at 120 °C. It was found that despite their similar chemical compositions, CAPC and HAPC differ largely in their selectivity towards the isomers of alkanes, methylpyridines and xylenes. As demonstrated, the CAPC column exhibits advantageous comprehensive performance over the HAPC column and the commercial PEG column. Particularly, the CAPC column exhibits higher resolving performance towards the isomers indicated above and the Grob mixture than the HAPC column. Also, it shows distinct advantages over the PEG column in separating the Grob mixture, the isomers of diethylbenzenes and cymenes, and practical analysis of chemical products and the essential oil from the leaves of Rhododendron dauricum L. Additionally, the CAPC column has excellent repeatability and reproducibility on analyte retention times with the relative standard deviation (RSD) values in the range of 0.05% - 0.08% for run-to-run, 0.12% - 0.19% for day-to-day and 2.6% - 4.9% for column-to-column, respectively. Its applications to purity test of chemical products and GC-MS analysis of the essential oil demonstrate its promising future for practical GC analyses.

Improving carvacrol bioaccessibility using core-shell carrier-systems under simulated gastrointestinal digestion.

The impact of encapsulating carvacrol in chitosan-albumin based core-shell nano-carriers (NCs) on its stability and bioaccessibility was determined under simulated digestion conditions. These NCs consisted of chitosan (C) core enclosed by bovine serum albumin (BSA) shell. The mean particle size ranged from 52.4 ± 10 nm to 203 ± 6 nm and zeta-potential from + 21 ± 3.6 to -18 ± 2.7 mV. The size and charge were significantly modified after the protein-shell formation around the polysaccharide-core. Core-shell NCs were more stable, with less aggregation under simulated gastrointestinal conditions than C-NCs, presumably due to greater steric repulsion. Likewise, core-shell NCs were observed relatively more stabilized in the intestinal phase than gastric phase. The bioaccessibility of carvacrol was enhanced significantly when it was encapsulated in the core-shell NCs. These findings imply that C-BSA based core-shell NCs might be an efficient means of encapsulating, protecting and delivering hydrophobic bioactive compounds for applications in functional foods.

Antifungal and antibiofilm activities of the essential oil of leaves from Lippia gracilis Schauer against phytopathogenic fungi.

AIMS: This study aimed to evaluate the antifungal and antibiofilm effects of essential oil (EO) from leaves of Lippia gracilis and its major constituents, thymol and carvacrol, against phytopathogenic fungi. METHODS AND RESULTS: The leaves of L. gracilis were hydrodistilled to obtain the EO and the chemical composition was determined by GC/MS analysis. The antifungal activity of EO of L. gracilis was evaluated on the vegetative and mycelial growth of Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum and Fusarium solani. In addition, the ability of the oil to inhibit fungal biofilm formation was assessed by total biomass quantification using crystal violet staining, analysis of metabolic activity, and scanning electron microscopy (SEM). Moreover the antifungal and antibiofilm activities of the monoterpenes, thymol and carvacrol, present in EO of L. gracilis were evaluated against F. oxysporum. The analysis of the chemical composition of EO extracted from L. gracilis, revealed the presence of monoterpenes (94·13%), which included carvacrol (48·57%) and thymol (7·78%), and 4 sesquiterpenes (3·74%). In general, EO showed significant antifungal activity and inhibited the formation of fungal biofilms. Furthermore, thymol and carvacrol showed significant antifungal and antibiofilm activities against F. oxysporum. SEM images showed structural changes in fungal morphology upon treatment with EO of L. gracilis. CONCLUSION: The results presented in this study showed promising antifungal and antibiofilm effects of EO of L. gracilis and its major components, carvacrol and thymol. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings indicate that the EO extracted from L. gracilis, and the monoterpenes, carvacrol and thymol have a great potential as antifungal and antibiofilm agents. Furthermore, this is the first report of the antibiofilm activity of the EO of L. gracilis and its major components against phytopathogenic fungi.

Variation in essential oil composition of Rydingia michauxii at the three developmental stages.

In this study, the essential oil composition of Rydingia michauxii was evaluated during the dormant, vegetative and flowering stages. The major chemical constituents of R. michauxii at the dormant stage were eugenol (36.81%), eugenol acetate (21.02%), and carvacrol (9.35%). While the main chemical constituents for the vegetative stage were carvacrol (16.08%), eugenol (13.23%), cumin aldehyde (9.63%), and linalool (8.28%). In addition, carvacrol (14.20%), eugenol (8.98%), δ-cadinene (8.90%), caryophyllene oxide (8.43%) and n-hexadecanoic acid (7.07%) were the major volatile components during the flowering stage. Variation in chemical compositions of R. michauxii during the various developmental stages might be affected by environmental and climatic factors.

Composition of the essential oil of Satureja metastasiantha: a new species for the flora of Turkey.

The aerial parts of Satureja metastasiantha were hydrodistilled for 3 h using a Clevenger-type apparatus. The essential oils were analyzed by gas chromatography/flame ionization detector and gas chromatography/mass spectrometry, simultaneously, the main compounds of which were characterized as p-cymene (22.3%), thymol (21.0%), carvacrol (18.4%), and γ-terpinene (12.1%). Antioxidant capacity, acetylcholinesterase and butyrylcholinesterase inhibition effects, and antimicrobial and antifungal properties of the species were evaluated. The anticholinesterase activity of the essential oil of S. metastasiantha was observed with 30% inhibition at 200 µg/mL. The essential oil of the species showed activity against Staphylococcus aureus with 128 µg/mL minimum inhibitory concentration value.

Oregano Essential Oil Interactions with Photogenerated Singlet Molecular Oxygen.

Essential oils are a mixture of volatile compounds, products of the secondary metabolism of plants. Once extracted, they can be deteriorated losing their organoleptic and therapeutic properties due to various environmental factors, being light exposure in aerobic conditions the main cause. In this work, the oregano essential oil extraction and characterization from Origanum vulgare plants grown in the experimental field of the FTU-UNSL and its photodegradation in MeOH:H2 O 60:40 v/v solvent were studied. Characterization by EIMS and NIST Mass Spectrometry indicates the main compounds of oregano essential oil, quantified in the extracted oil by GC-MS, are carvacrol (7.14%) and thymol (47.37%). Degradation of essential oil and its two major components can be caused by reactive oxygen species photogenerated from endogenous sensitizers as riboflavin. Our results suggest degradation occurs involving singlet molecular oxygen. Interaction of carvacrol and thymol with singlet oxygen is mainly a physical process, while essential oil has an important reactive component, which indicates there might be other constituents which could contribute to reactive photoprotection. The effect of simultaneous presence of oregano essential oil and tryptophan amino acid-used as a photooxidizable model under riboflavin-photosensitizing conditions-was studied in order to evaluate the possible photoprotection exerted by the essential oil.

Stability study of thymoquinone, carvacrol and thymol using HPLC-UV and LC-ESI-MS.

The aim of this study was to investigate the stability of three major antioxidants of Nigella sativa: thymoquinone (TQ), carvacrol (CR) and thymol (THY), under different stress conditions using HPLC and LC-MS/MS. Forced degradation for each compound was performed under different conditions, including oxidation, hydrolysis, photolysis and thermal decomposition. The results showed that both CR and THY were stable under the studied conditions, whereas TQ was not affected by acidic, basic and oxidative forced conditions but the effect of light and heat was significant. The degradation products of TQ were further investigated and characterized by LC-MS/MS. HPLC-UV method has been fully validated in terms of linearity and range, the limit of detection and quantitation, precision, selectivity, accuracy and robustness. The method was successfully applied to quantitative analysis of the principal antioxidants of Nigella sativa TQ, CR and THY in different phytopharmaceuticals.

Ascaridole-rich essential oil from marsh rosemary (Ledum palustre) growing in Poland exerts insecticidal activity on mosquitoes, moths and flies without serious effects on non-target organisms and human cells.

Marsh rosemary (Ledum palustre, Ericaceae) has been widely used in the traditional medicine of various regions worldwide, and as insect repellent. Little is known on its essential oil insecticidal potential. This study explored the insecticidal effects of the essential oil obtained from L. palustre growing in Poland on selected insect pests and vectors. GC-MS analysis evidenced an uncommon chemotype characterized by ascaridole (35.3% as sum of cis-ascaridole and isoascaridole) and p-cymene (25.5%). The essential oil was effective against Culex quinquefasciatus, Spodoptera littoralis and Musca domestica, showing LC50/LD50 of 66.6 mg L-1, 117.2 µg larva-1 and 61.4 µg adult-1, respectively. It was not toxic to non-target Eisenia fetida earthworms and moderately toxic to Daphnia magna microcrustaceans, over the positive control α-cypermethrin. The essential oil cytotoxicity on human keratinocytes and fibroblasts showed high IC50 values (71.3 and 84.4 µg mL-1, respectively). Comet assay data highlighted no DNA damages. Based on our findings, this essential oil, characterized by the ascaridole/p-cymene chemotype, could be a candidate for the formulation of botanical insecticides; large-scale production of green insecticides by this rare species may be assured by ex situ cultivation and biotechnological techniques.

Components of Volatile Fractions from Eucalyptus camaldulensis Leaves from Iraqi-Kurdistan and Their Potent Spasmolytic Effects.

Inhalation of vapors from a hot tea of Eucalyptus camaldulensis Dehnh. leaves is considered by Iraqi-Kurdistan people an effective spasmolytic and antipyretic remedy for the treatment of respiratory diseases. The constituents of volatile fractions isolated by hydrodistillation from dried leaves of the plant collected in Kurdistan were determined by GC-FID and GC-MS analyses. More than 90% components were identified. The most abundant constituents were 1,8-cineole, p-cymene, α-pinene, terpinen-4-ol, aromadendrene, and α-terpineol. The different volatile fractions induced relaxation on rat isolated aortic and tracheal rings in concentration-dependent manner. These effects appeared to be due to a complex interaction between various terpenoid components rather than being only due to the main oil constituent, 1,8-cineole. The KCa channel and the NO pathway were not significantly involved in the relaxation mechanism, while Ca2+ channels played a major role in the spasmolytic effects.

Simultaneous determination of carvacrol and thymol in bee pollen by using a simple and efficient solvent extraction method and gas chromatography-mass spectrometry.

A novel method is proposed to determine residues of carvacrol and thymol in bee pollen by means of gas chromatography coupled to mass spectrometry. This is an efficient and simple sample treatment (with average analyte recoveries between 90% and 104%) involving solvent extraction with hexane followed by evaporation. There is no need for any additional clean-up step, as the matrix did not affect determination of mass spectrometry for either compound. The chromatographic conditions are also optimized: a ZB-WAX column is employed, helium is the carrier gas at a flow rate of 1.1 mL/min, and a temperature program is included, allowing baseline separation of both compounds in less than 21 min. The method is fully validated in terms of selectivity, limits of detection and quantification, matrix effect, linearity, precision and trueness. Results show that not only is it selective, but that it also displays a wide linearity range (limit of quantification-1000 µg/kg), good precision (relative standard deviation values lower than 8%) and sensitivity (limits of detection and quantification lower than 15 µg/kg). Finally, several bee pollen samples are analysed, and thymol and carvacrol residues are found at low concentrations (limit of quantification-57 µg/kg) in some cases.

A New Method for Determination of Thymol and Carvacrol in Thymi herba by Ultraperformance Convergence Chromatography (UPC2).

Ultraperformance convergence chromatography is an environmentally friendly analytical technique for dramatically reducing the use of organic solvents compared to conventional chromatographic methods. In this study, a rapid and sensitive ultraperformance convergence chromatography method was firstly established for quantification of thymol and carvacrol, two positional isomers of a major bioactive in the volatile oil of Thymi herba, the dried leaves and flowers of Thymus mongolicus or Thymus przewalskii, known in China as "Dijiao." Using a TrefoilTM CEL1 column, thymol and carvacrol were separated in less than 2.5 min and resolution was enhanced. The method was validated with respect to precision, accuracy, and linearity according to the National Medical Products Administration guidelines. The optimized method exhibited good linear correlation (r = 0.9998-0.9999), excellent precision (relative standard deviations (RSDs) < 1.50%), and acceptable recoveries (87.29-102.89%). The limits of detection for thymol and carvacrol were 1.31 and 1.57 ng/L, respectively, while their corresponding limits of quantification were 2.63 and 3.14 ng/L. Finally, the quantities of the two compounds present in 16 T. mongolicus and four T. przewalskii samples were successfully evaluated by employing the developed method. It is hoped that the results of this study will serve as a guideline for the quality control of Thymi herba.

Two new eudesman-4α-ol epoxides from the stem essential oil of Laggera pterodonta from Côte d'Ivoire.

The investigation of the stem essential oil of Laggera pterodonta (DC.) Sch. Bip. ex Oliv. (Asteraceae) from Côte d'Ivoire was carried out, using a combination of chromatographic (GC-RI, CC, pc-GC) and spectroscopic (GC-MS, 13C NMR) techniques. This study led to the identification of fifty constituents of which two new natural compounds 7ß,11ß-epoxy-eudesman-4α-ol and 7α,11α-epoxy-eudesman-4α-ol. Their structures were elucidated by 1 D and 2 D NMR spectroscopy after pc-GC purifying. Finally, 98.9% of the whole composition of the oil was identified with a high amount of 2,5-dimethoxy-p-cymene (78.9%). The other significant components were α-humulene (6.2%), (E)-ß-caryophyllene (1.7%), thymyl methyl oxide (1.7%), α-phellandrene (1.5%), p-cymene (1.2%), (3αH,4ßH,6αH,1αMe)-1,6-epoxy-3-hydroxycarvotanacetone angelic acid ester (1.1%) and 10-epi-γ-eudesmol (1.0%).

Comparative analysis of oil composition and antibacterial activity of aerial parts of Terminalia arjuna (Roxb.).

Volatile oil composition of leaves and fruits of Terminalia arjuna (Roxb.) was reported for the first time. Oils were extracted by microwave assisted hydrodistillation where yield of both oils were found to be 0.20% and their GC-MS analyses led to the identification of 65 and 48 constituents, respectively. Major constituents of leaves were carvacrol (11.17%), thymol (6.52%), α-terpinyl acetate (5.92%) and anethole (5.13%) while that of fruits were (E)-isoeugenol (11.48%), furfural (8.25%), p-vinylguaiacol (6.8%) and p-ethylguaiacol (5.72%) that demonstrated a significant difference between composition of its aerial parts, however, 33 constituents were identical that showed similarity characteristics in quality of these oils. Both leaf and fruit oils were found active against pathogenic and drug-resistant microbes: E. coli, Methicillin-resistant S. aureus, P. aeruginosa, Total-drug-resistant P. aeruginosa and K. pneumoniae with MIC values of 0.32, 0.32, 0.64, 0.64, 2.56 mg/mL and 0.16, 0.16, 0.32, 0.64, 1.28 mg/mL, respectively.

Ammoides verticillata Essential Oil as Biocontrol Agent of Selected Fungi and Pest of Olive Tree.

BACKGROUND: Ammoides verticillata Briq is an aromatic and medicinal herb that has been widely used in folk medicine for treatment of several types of pathologies such as respiratory problems, colds, fever, headache, gastric disorders and renal infections. OBJECTIVE: Essential oils have been subjected of numerous works for their antimicrobial and insecticidal properties which have been valued by hundreds of publications and patents. The main objective of this work was to evaluate the chemical composition, and the in vitro and in vivo antifungal, and insecticidal properties of essential oil of Ammoides verticillata. METHODS: In this work, the air-dried aerial parts of Ammoides verticillata were hydrodistilled in a Clevenger-type apparatus. The essential oil isolated was analyzed using gas chromatography (GC) and mass spectrometry (GC/MS). The in vitro antifungal activity of the essential oil was investigated against four plant fungi using radial growth technique. The effect of the essential oil on disease development of olive caused by Penicillium crustosum and Aspergillus niger in the in vivo conditions. The fumigation test of the essential oil was evaluated against L3 stages, pupas and adults of Bactrocera oleae known as the olive fly. RESULTS: The essential oil of A. verticillata was characterized mainly by carvacrol (44.3%), limonene (19.3%) and p-cymene (19.2%). The result of in vitro antifungal activity of essential oil showed an interesting antifungal inhibition against Alternaria alternata and Fusarium solani strains with percentage inhibition of 89%. Furthermore, oil of A. verticillata has demonstrated promising in vivo antifungal activity to control infections of olives caused by Aspergillus niger and Penicillium crustosum. In addition, the essential oil exhibited fumigation toxicity against Bactrocera oleae with mortality percentage of 100% at 2 µL/L air. CONCLUSION: The results showed that essential oil of A. verticillata has interesting biological activities, which suggests that oil have the potential to be used as biocide to protect olives of pathogenic fungi and pests.