Steam-distilled Essential Oil Research Articles

Larvicidal susceptibility of essential oils from Cinnamodendron dinisii, Callistemon viminalis and Myrcia tomentosa against Culex quinquefasciatus (Say) (Diptera: Culicidae)

Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) is a vector of pathogens and parasites, whose form of control is the use of synthetic insecticides. However, the indiscriminate use of these products has led to the emergence of resistant populations. The objective was to evaluate the susceptibility of C. quinquefasciatus larvae to essential oils (EOs) from leaves of Cinnamodendron dinisii Schwacke (CD), Callistemon viminalis (Sol. ex Gaertn.) G.Don (CV) and Myrcia tomentosa (Aubl.) DC. (MT), and the influence on biochemical parameters, in addition to the in silico potential of the most promising EO for the target acetylcholinesterase (AChE) enzyme. The steam distilled EOs were analysed by gas chromatography/mass spectrometry. The EOs lethal concentration of 50 % (LC50) was estimated using different concentrations and probit analysis. Then, the larvae were exposed for 1 h to the LC75 of the most promising EO, and the biochemical parameters were evaluated in vitro: soluble protein concentration, reduced glutathione content, hydrogen peroxide production, lipid peroxidation levels, and AChE enzyme activity. The AChE molecular docking was also performed. The main chemical constituents in CD were pinenes, sabinene and bicyclogermacrene; in CV were α-pinene and 1,8-cineole and in MT were (E)-caryophyllene and germacrene D. The lowest LC50 (1.43 mg. L−1) was estimated for CD EO, although LC75 reduced all biochemical parameters and inhibited AChE activity. The docking results for the major (bicyclogermacrene) and minor compounds (aromadendrene, α-copaene, drymenol, σ- and β-elemene) present in CD EO have high affinity with AChE. In conclusion the effects indicate the promising potential of the CD EO for the development of larvicide against the C. quinquefasciatus.

Exploring the Chemical Constituents, Antioxidant, Xanthine Oxidase and COX Inhibitory Activity of Commiphora gileadensis Commonly Grown Wild in Saudi Arabia.

The use of the synthetic drugs has increased in the last few decades; however, these drugs exhibit various side effects. Scientists are therefore seeking alternatives from natural sources. Commiphora gileadensis has long been used to treat various disorders. It is commonly known as bisham or balm of Makkah. This plant contains various phytochemicals, including polyphenols and flavonoids, with biological potential. We found that steam-distilled essential oil of C. gileadensis exhibited higher antioxidant activity (IC50, 22.2 µg/mL) than ascorbic acid (IC50, 1.25 µg/mL). The major constituents (>2%) in the essential oil were β-myrcene, nonane, verticiol, β-phellandrene, β-cadinene, terpinen-4-ol, β-eudesmol, α-pinene, cis-β-copaene and verticillol, which might be responsible for the antioxidant and antimicrobial activity against Gram-positive bacteria. The extract of C. gileadensis exhibited inhibitory activity against cyclooxygenase (IC50, 450.1 µg/mL), xanthine oxidase (251.2 µg/mL) and protein denaturation (110.5 µg/mL) compared to standard treatments, making it a viable treatment from a natural plant source. LC-MS analysis revealed the presence of phenolic compounds such as caffeic acid phenyl ester, hesperetin, hesperidin, chrysin and transient amounts of catechin, gallic acid, rutin and caffeic acid. The chemical constituents of this plant can be explored further to investigate its wide variety of therapeutic potential.

Electronic Nose Analysis and Statistical Methods for Investigating Volatile Organic Compounds and Yield of Mint Essential Oils Obtained by Hydrodistillation

A major problem associated with the development of medicinal plant products is the lack of quick, easy, and inexpensive methods to assess and monitor product quality. Essential oils are natural plant-derived volatile substances used worldwide for numerous applications. The important uses of these valuable products often induce producers to create fraudulent or lower quality products. As a result, consumers place a high value on authentic and certified products. Mint is valued for essential oil used in the food, pharmaceutical, cosmetic, and health industries. This study investigated the use of an experimental electronic nose (e-nose) for the detection of steam-distilled essential oils. The e-nose was used to evaluate and analyze VOC emissions from essential oil (EO) and distilled water extracts (DWEs) obtained from mint plants of different ages and for leaves dried in the shade or in the sun prior to hydrodistillation. Principal component analysis (PCA), linear discriminant analysis (LDA), and artificial neural networks (ANN) were performed on electrical signals generated from electronic nose sensors for the classification of VOC emissions. More accurate discriminations were obtained for DWEs sample VOCs than for EO VOCs. The electronic nose proved to be a reliable and fast tool for identifying plant EO. The age of plants had no statistically significant effect on the EO concentration extracted from mint leaves.

Constituents, Enantiomeric Content, and ChE Inhibitory Activity of the Essential Oil from Hypericum laricifolium Juss. Aerial Parts Collected in Ecuador.

The physical properties, chemical composition, enantiomer distribution, and cholinesterase (ChE) inhibitory activity were determined for a steam-distilled essential oil (EO), with a yield of 0.15 ± 0.05 % (w/w), from H. laricifolium aerial parts, collected in southern Ecuador. The oil qualitative and quantitative analyses were performed by GC-EIMS and GC-FID techniques, using two capillary columns containing a non-polar 5%-phenyl-methylpolysiloxane and a polar polyethylene glycol stationary phase, respectively. The main constituents (>10%) detected on the two columns were, respectively, limonene (24.29, 23.16%), (E)-β-ocimene (21.89, 27.15%), and (Z)-β-ocimene (12.88, 16.03%). The EO enantioselective analysis was carried out using a column based on 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin. Two mixtures of chiral monoterpenes were detected containing (1R,5R)-(+)-α-pinene (ee = 83.68%), and (S)-(-)-limonene (ee = 88.30%) as the major enantiomers. This finding led to some hypotheses about the existence in the plant of two enantioselective biosynthetic pathways. Finally, the EO exhibited selective inhibitory effects in vitro against butyrylcholinesterase (BuChE) (IC50 = 36.80 ± 2.40 µg/mL), which were about three times greater than against acetylcholinesterase (IC50 = 106.10 ± 20.20). Thus, the EO from Ecuadorian H. laricifolium is an interesting candidate for investigating the mechanism of the selective inhibition of BuChE and for discovering novel drugs to manage the progression of Alzheimer's disease.

Variations in the Chemical Composition of Essential Oils in Native Populations of Korean Thyme, Thymus quinquecostatus Celak.

The genus Thymus (Lamiaceae) contains numerous medicinally important species. Among them, Thymus quinquecostatus Celak. has been extensively utilized as a traditional medicine and a food flavoring agent in the Korean peninsula, owing to its unique aroma. In particular, T. quinquecostatus has been used for the treatment of gastroenteritis, inflammation, stomach problems, liver disease, arthritis, arteriosclerosis, and menstrual problems. This study aimed to investigate the chemical diversity of essential oils among 103 Korean native populations of T. quinquecostatus. For this purpose, seedlings of T. quinquecostatus populations were purchased from different regions in the Korean Peninsula, and seedlings were grown in the experimental field under the same environmental conditions. The chemical compositions of steam-distilled essential oils were determined using GC-MS. In total, 212 components were identified from 103 populations of T. quinquecostatus. Furthermore, principal component analysis (PCA) was performed in order to understand variations in the essential oil compositions among 103 Korean native populations of T. quinquecostatus. According to the essential oil compositions, 30 components were selected for PCA. Based on the most abundant essential oil components, four chemotypes were identified in T. quinquecostatus populations. PCA and cluster analyses revealed that 103 individuals of T. quinquecostatus could be classified into four clusters, such as thymol, geraniol, geranyl acetate, and linalool. Furthermore, dendrogram construction demonstrated that geraniol and geranyl acetate, as well as linalool and thymol groups, were closely related. This study suggested the significant chemical polymorphism of essential oils in local populations of T. quinquecostatus in Korea. It could be concluded that the intraspecific variations in the essential oil compositions may be associated with genetic diversity among the individuals.

Anti-inflammatory effect of essential oil from Amomum Tsaoko Crevost et Lemarie

Amomum Tsaoko Crevost et Lemarie is a kind of spices and traditional Chinese medicines with great commercial value. Traditional treatment often uses essential oils from Amomum Tsaoko in aromatherapy. In this study, researchers analyzed the composition of steam-distilled essential oil from Amomum tsaoko (ATEO) and evaluated its potential antioxidant and anti-inflammatory activity. GC–MS identified a total of 33 volatile compounds, the majority of which were alcohol (1,8-cineole and nerol) and aldehyde ((2E)-2-decenal) compounds. Additionally, ATEO showed great anti-inflammatory activity in LPS-induced RAW 264.7 macrophages. ATEO markedly inhibited the nitric oxide (NO) release, and decreased the expression level of TNF-α, IL-1β, IL-6 and monocyte chemotactic protein-1 (MCP-1) in a dose-dependent manner. Furthermore, ATEO significantly reduced the expression of iNOS, COX-2, NF-κB p-p65 and p-ERK. These results suggested that ATEO has great anti-inflammatory activity in LPS-induced RAW 264.7 cells, which will facilitate the development of ATEO as a functional food.

Wild-Grown and Cultivated Glechoma hederacea L.: Chemical Composition and Potential for Cultivation in Organic Farming Conditions.

Glechoma hederacea L. is a medicinal plant that is known in traditional medicine for its anti-inflammatory, antibacterial, antiviral, and anticancer properties. This study evaluated the potential for commercial production of G. hederacea and compared the chemical composition and activity of 70% ethanol extracts and steam-distilled essential oils from wild-grown and cultivated G. hederacea collected in different harvesting periods. The main compounds identified in the 70% ethanol extracts were phenolic acids (chlorogenic and rosmarinic acids) and flavonoid O-glycosides. The essential oil varied in the three accessions in the range of 0.32–2.98 mL/kg−1 of dry weight. The extracts possessed potent antioxidant and anti-inflammatory properties in LPS-treated bone-marrow-derived macrophages. The results of flow cytometry show that extracts from different vegetation periods reduced the conversion of macrophages to the proinflammatory phenotype M1. The chemical composition varied the most with the different harvesting periods, and the most suitable periods were the flowering and vegetative phases for the polyphenolic compounds and essential oils, respectively. G. hederacea can be successfully grown under organic farming conditions, and cultivation does not significantly affect the chemical composition and biological activity compared to wild-grown plants.

Yield and Profile of Essential Oil of Kunzea ambigua: Prediction Using Solvent Extraction and Effects of Distillation Time

Essential oil extracted from Kunzea ambigua is new fragrant oil that has been shown to exhibit antimicrobial and anti-fungal properties, however only a few plantations exist to provide for controlled cropping and consistency of product. Extraction technology has been optimised to provide for the rapid assessment of germplasm collected from wild populations of Kunzea ambigua. Small-scale solvent extraction methods were developed to efficiently process large numbers of specimens collected from native stands. The datasets were used to predict the yield and quality of steam distilled essential oils. The effects on volatiles extracted from vegetative material, which had been either frozen or dried prior to extraction, was investigated. Recovery of volatiles was significantly higher from frozen samples, relative to oven-dried, and ethanol was a more efficient solvent compared to petroleum ether. The recovery from solvent extraction of K. ambigua leaf material was similar to, or higher than that from distillation, however, the level of terpinen-4-ol yield increased 15-fold during steam distillation. The compositional profiles and fractional volumes of kunzea essential oil collected at different times during steam distillation were established. The highest oil yield was collected between 30 and 60 mins. α-Pinene and 1,8-cineole dominated the essential oil profile in the early stages of distillation, whilst viridiflorol gradually increased with longer distillation time. This study shows that ethanol extraction of frozen/thawed K. ambigua leaf is useful for predicting the essential oil yield, whilst the time of distillation can be manipulated to maximize the relative concentration of targeted bioactive compounds.

Active Ingredients from Euodia ruticarpa Steam Distilled Essential Oil Inhibit PC-3 Prostate Cancer Cell Growth via Direct Action and Indirect Immune Cells Conditioned Media In Vitro.

Active constituents isolated from Euodia ruticarpa (ER) steam distilled essential oil (SDEO) against PC-3 prostate cancer cell growth remain unclear. To clarify the puzzle, ER SDEO was extracted and further resolved into six isolated fractions ERF1–F6 with Sephadex LH-20 gel filtration chromatography to analyze their biological activities. Active ingredients in the isolated fractions were analyzed with GC-MS. Potential isolated fractions were selected to treat PC-3 cells with direct action and indirect treatment by mouse splenocyte- (SCM) and macrophage-conditioned media (MCM). The relationship between PC-3 cell viabilities and corresponding total polyphenols, flavonoid contents as well as Th1/Th2 cytokine profiles in SCM was analyzed using the Pearson product–moment correlation coefficient (r). As a result, ERF1–F3 was abundant in total polyphenols and flavonoids contents with diverse active ingredients. Treatments with ERF1–F3 at appropriate concentrations more or less inhibit PC-3 cell growth in a direct action manner. Only SCM, respectively, cultured with ER SDEO and ERF1–F3 markedly enhanced the effects to inhibit PC-3 cell growth, suggesting that secretions by splenocytes might involve anti-PC-3 effects. There are significantly negative correlations between PC-3 cell viabilities and IL-2, IL-10 as well as IL-10/IL-2 ratios in the corresponding SCM. Total polyphenol and flavonoid contents in the media cultured with ER SDEO isolated fractions positively correlated with IL-10 (Th2) and IL-10/IL-2 (Th2/Th1) cytokine secretion ratios by splenocytes, indicating that polyphenol and flavonoid components in ER SDEO isolated fractions promote Th2-polarized and anti-inflammatory characteristics. These new findings concluded that the inhibitory effects against PC-3 prostate cancer cell growth are attributed to active anti-inflammatory ingredients in ER SDEO and its active ERF1–F3 fractions through direct action and indirect treatment by modulating splenocytes’ cytokine secretion profiles.

The Extended Oxidative and Sensory Stability of Traditional Dairy-Based Oil with Steam-Distilled Essential Oils Extracted from the Bioactive-Rich Leaves of Ziziphora tenuior, Ferulago angulata, and Bunium persicum

The oxidation rate and overall sensory acceptability of Iranian animal oil (IAO) during storage were evaluated after adding the bioactive essential oils extracted from medicinal herbs of Ziziphora tenuior, Ferulago angulata, and Bunium persicum. Results showed that the most dominant chemical constituents in Z. tenuior, F. angulata, and B. persicum essential oils were pulegone (12.77%), ferulagon (14.97%), and (+)-trans-carveol (57.70%), respectively. IAO contained more saturated fatty acids (67.43%, mainly palmitic and myristic acids) than unsaturated (32.27%, mostly oleic acid) ones. B. persicum essential oil compared to the other two oils significantly had more total flavonoid (1.08 mg quercetin equivalent/g), phenolic (123.2 mg GAE/g), carotenoid (591.31 mg/kg), and chlorophyll (24.32 mg/kg) contents. A significant dose-dependent increase in the overall sensory acceptability of IAO was found by increasing the concentration of B. persicum essential oil. Similar to tertiary butyl hydroquinone, the oil blend of IAO+10% B. persicum essential oil obtained the maximum overall sensory acceptability scores during 28 d cold storage due to the remarkable in vitro DPPH inhibition (83.45%) and ferric-reducing power (0.754 at Å700nm). A much slower formation rate in primary and secondary oxidation compounds in IAO rich in B. persicum essential oil during the storage was associated with the overall sensory acceptability data ( p < 0.01 , r = 0.951). Thus, this bioactive additive as a bio-preservative may well stabilize crude oils and emulsions.

Acorus gramineusand and Euodia ruticarpa Steam Distilled Essential Oils Exert Anti-Inflammatory Effects Through Decreasing Th1/Th2 and Pro-/Anti-Inflammatory Cytokine Secretion Ratios In Vitro.

To clarify the effects of steam distilled essential oils (SDEO) from herbs used in traditional Chinese medicine on immune functions, two potential herbs, Acorus gramineusand (AG) and Euodia ruticarpa (ER) cultivated in Taiwan, were selected to assess their immunomodulatory effects using mouse primary splenocytes and peritoneal macrophages. T helper type 1 lymphocytes (Th1) (IL-2), Th2 (IL-5), pro-inflammatory (TNF-α) and anti-inflammatory (IL-10) cytokines secreted by correspondent immune cells treated with SDEO samples were determined using enzyme-linked immunosorbent assay. The total amounts of potential phytochemicals, including total flavonoids, polyphenols and saponins, in these two selected SDEOs were measured and correlated with cytokine levels secreted by immune cells. Our results evidenced that ER SDEO is rich in total flavonoids, polyphenols and saponins. Treatments with AG and ER SDEO significantly (p < 0.05) increased IL-5/IL-2 (Th2/Th1) cytokine secretion ratios by splenocytes, suggesting that both AG and ER SDEO have the Th2-polarization property and anti-inflammatory potential. In addition, AG and ER SDEO, particularly ER SDEO, markedly decreased TNF-α/IL-10 secretion ratios by macrophages in the absence or presence of lipopolysaccharide (LPS), exhibiting substantial effects on spontaneous and LPS-induced inflammation. Significant correlations were found between the total polyphenols, flavonoids or saponins content in the two selected SDEOs and Th1/Th2 immune balance or anti-inflammatory ability in linear, non-linear or biphasic manners, respectively. In conclusion, our results suggest that AG and ER, particularly ER, SDEO have immunomodulatory potential in shifting the Th1/Th2 balance toward Th2 polarization in splenocytes and inhibiting inflammation in macrophages in the absence or presence of LPS.

Comparison between Citral and Pompia Essential Oil Loaded in Phospholipid Vesicles for the Treatment of Skin and Mucosal Infections.

Citrus species extracts are well known sources of bio-functional compounds with health-promoting effects. In particular, essential oils are known for their antibacterial activity due to the high content of terpenes. In this work, the steam-distilled essential oil from the leaves of Citrus limon var. pompia was loaded in phospholipid vesicles. The physico-chemical characteristics of the essential oil loaded vesicles were compared with those of vesicles that were loaded with citral, which is one of the most abundant terpenes of Citrus essential oils. The biocompatibility of the vesicles was assessed in vitro in human keratinocytes. Furthermore, the antimicrobial activity of the vesicles was tested while using different bacterial strains and a yeast: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans, respectively. The vesicles were small in size (~140 nm), slightly polydispersed (PI ~ 0.31), highly negatively charged (~ −73 mV), and able to incorporate high amounts of essential oil or citral (E% ~ 86%). Pompia essential oil and citral exhibited antimicrobial activity against all of the assayed microorganisms, with P. aeruginosa being the least sensitive. Citral was slightly more effective than pompia essential oil against E. coli, S. aureus, and C. albicans. The incorporation of citral in vesicles improved its antifungal activity against C. albicans.

Chemical Composition and Antioxidant Activity of Steam-Distilled Essential Oil and Glycosidically Bound Volatiles from Maclura Tricuspidata Fruit.

Essential oil obtained from Maclura triscuspidata fruit has been reported to have functional properties. This study aimed at determining chemical compositions and antioxidant activities of steam-distilled essential oil (SDEO) and glycosidically bound aglycone fraction (GBAF) isolated from fully ripe M. triscuspidata fruit. SDEO was isolated by simultaneous steam distillation and extraction (SDE). GBAF was prepared by Amberlite XAD-2 adsorption of methanol extract, followed by methanol elution and enzymatic hydrolysis. Both fractions were analyzed by gas chromatography–mass spectrometry (GC–MS). A total of 76 constituents were identified from both oils. Apart from fatty acids and their esters, the SDEO contained p-cresol in the highest concentration (383.5 ± 17.7), followed by δ-cadinene (147.7 ± 7.7), β-caryophyllene (145.7 ± 10.5), β-ionone (141.0 ± 4.5), n-nonanal (140.3 ± 20.5), theaspirane A (121.3 ± 4.5) and theaspirane B (99.67 ± 9.05 µg/g). Thirteen carotenoid-derived compounds identified in the SDEO are being isolated from M. triscuspidata fruit for the first time. Out of the 22 components identified in GBAF, 14 were present only in the glycosidically bound volatiles. Antioxidant activity of the GBAF was higher than that of SDEO. These results suggest that glycosidically bound volatiles of M. triscuspidata fruit have a good potential as natural antioxidants.

Phenolic Profile, Essential Oil Composition and Bioactivity of Lasia spinosa (L.) Thwaites

Abstract Lasia spinosa (L.) Thwaites is a widely used ethnomedicinal plant in Bangladesh. In this study, we investigated phenolic contents, volatile compounds and fatty acids, and essential oil components of extracts prepared from aerial parts of the plant. The main volatile compounds were methyl ester of oleic acid, palmitic acid and stearic acid as determined by GC/MS. Phenolic contents of the extracts were determined qualitatively and quantitatively by HPLC/TOF-MS. Six phenolic compounds (syringic acid, morin, gentistic acid, 4-hydroxybenzoic acid, cinnamic acid, and apigenin) were found in the extracts. GC/MS analysis of steam distilled essential oil showed camphor, α-pinene and δ-3-carene as the main constituents. In DPPH radical scavenging assay, the highest free radical scavenging activity was observed for the methanol extract with an IC50 value of 0.48 ± 0.04 mg/mL, whereas, in metal chelating activity on ferrous ions (Fe2+) assay, the highest chelating activity was observed for hexane extract (IC50 = 0.55 ± 0.08 mg/mL). The extracts and essential oil were tested against five severe human pathogenic bacteria using disc diffusion assay and subsequent MIC values were also determined. All the extracts (except methanol extract) and the essential oil were found to possess potential antimicrobial activity with corresponding inhibition zone and minimum inhibitory concentration (MIC) ranging from 9-23 mm and 62.5-500 µg/mL. This study has been explored the plant Lasia spinosa can be seen as a potential source of biologically active compounds.

GAS CHROMATOGRAPHY–MASS SPECTROMETRY ANALYSIS, IN VITRO ACTIVITIES, AND IN SILICO MOLECULAR DOCKING OF MAJOR COMPONENTS OF MICHELIA ALBA DC ESSENTIAL OIL AND SCENTED EXTRACTS

Objective: The essential oil and scented extracts of Michelia alba DC. were analyzed by gas chromatography–mass spectrometry (GC–MS) and investigated for antidiabetic activities in vitro and in silico.Methods: The identification of steam distilled essential oil and scented extracts of M. alba was performed by GC–MS on the Agilent 7890A chromatograph couple with GC-7000 Mass Triple Quadrupole. The extractions have been evaluated the antidiabetic activities by alpha-amylase (α-amylase) assay using starch as substrates. In addition, computational molecular docking analysis of significant components was studied to understanding how selected compounds interacted with α-amylase using AutoDock 4.2.Results: The yields of M. alba of steam distilled essential oil and solvent extractions including hexane, diethyl ether, and dichloromethane were 0.16%, 0.02%, 0.47%, and 0.92%, respectively. GC–MS analysis of essential oil revealed that the main component was monoterpenoids β-linalool (65.03%). Meanwhile, 2-methylbutanoic acid was a primary in hexane extract (36.54%) and dichloromethane extract (33.07%). In the case of ether extract, the primary compound was β-linalool (37.32%) same as in essential oil. The antidiabetic activities evaluation demonstrates that essential oil and scented extracts have shown promising α-amylase inhibition activity. Essential oil from steam distillation revealed the best inhibition potential with a half maximal inhibitory concentration value of 0.67±4.7 mg/ml and their significant components demonstrated negative binding energies, indicating a high affinity to the α-amylase-binding site using molecular docking simulation.Conclusion: Data from this study suggest that essential oil and scented extracts of M. alba DC possess in vitro α-amylase activities and can be used for therapy of diabetes.

Reporting effective extraction methodology and chemical characterization of bioactive components of under explored Platycladus orientalis (L.) Franco from semi-arid climate

The bioactive ingredients of many essential oils are complex and difficult to reproduce synthetically. In the present study, the influence of extraction method on relative extraction of bioactive compounds of essential oil of Platycladus orientalis (L.) Franco (Thuja orientalis L. is a synonym of it) leaves gathered from semi-arid climate was studied. A higher yield of essential oil was obtained by hydrodistillation (0.1%) as compared to steam distillation (0.07%) under newly optimized conditions. Initial analysis of these oils by TLC showed the presence of different polarity groups ranging from non-polar terpene hydrocarbons to polar terpenoid alcohols. GC-MS analysis revealed that major component of hydrodistilled essential oil of Platycladus orientalis (L.) Franco leaves was α-pinene (17.83%) and steam distilled essential oil contained α-cedrol (12.44%). The results obtained in the present study emphasize that suitable extraction technique should be used to obtain particular component of interest.

Biorefining of Cymbopogon nardus from Reunion Island into essential oil and antioxidant fractions by conventional and high pressure extraction methods

Steam distilled essential oil of Cymbopogon nardus has been widely studied and commercialized; however, comprehensive valorisation of plant material requires more systematic characterization of other, non-volatile extracts and their potential activities. For this purpose C. nardus herb was fractionated into essential oil (EO) and non-volatile fractions by hydrodistillation (HD), Soxhlet (S), supercritical CO2 (SFE-CO2) and pressurized liquid (PLE) extractions. Antioxidant potential was evaluated by total phenolics (TPC), DPPH•/ABTS•+ scavenging and oxygen radical absorbance (ORAC) capacity. The yields were from 1.37/1.39% for SFE-CO2 (50 °C)/HD to 12.2/12.6% (w/w) for PLE-water/freeze dried after EO-HD water (PLE-WE/FD-WE). TPC was higher in S-acetone (S-AE) and PLE-WE, 70 and 60 mg of gallic acid equivalents (GAE)/g dew (dry extract weight), respectively. S-AE and S-ethanol extracts were strongest antioxidants, on average equivalent to 770 μmol of trolox equivalents (TE)/g dew in ABTS assay. Antibacterial activity was tested by well agar diffusion and minimal inhibitory concentration (MIC) methods with various microorganisms; EO at 3% inhibited all bacteria, except for S. aureus and S. typhimurium; MICs were in the range of 0.39–12.5 mg/mL. C. nardus extracts may be considered as potential natural antioxidants and antibacterial agents and a good source of phenolics.

Attenuation of Listeria monocytogenes Virulence by Cannabis sativa L. Essential Oil.

Anti-virulence strategies are being explored as a novel approach to combat pathogens. Such strategies include inhibition of surface adhesion, tissue invasion, toxin production, and/or interference with the gene regulation of other virulence traits. Listeria monocytogenes, the causative agent of listeriosis, is a facultative intracellular food pathogen characterized by a wide distribution in the environment. Its ability to persist within biofilms and to develop resistance to sanitizers is the cause of significant problems in food processing plants and of steep costs for the food industry. In humans, the treatment of listeriosis is hampered by the intracellular location of listeriae and the poor intracellular penetration of some antibiotics. Eleven L. monocytogenes isolates from patients who were diagnosed with invasive listeriosis in Italy in 2014–2016 were studied. This in vitro and in vivo study explored the antibacterial and anti-virulence properties of a steam-distilled essential oil of Cannabis sativa L., which is being intensively investigated for its high content in powerful bioactive phytochemicals. Susceptibility experiments demonstrated a moderate bactericidal activity of the essential oil (Minimum Bactericidal Concentration > 2048 μg/mL). Assessment of the effects of sublethal concentrations of the essential oil on L. monocytogenes virulence traits demonstrated a significant action on motility. Listeriae were non-motile after exposure to the essential oil. Light and scanning electron microscopy documented aggregates of listeriae with the flagella trapped inside the cluster. Real-time RT-PCR experiments showed downregulation of flagellar motility genes and of the regulatory gene prfA. The ability to form biofilm and to invade Caco-2 cells was also significantly reduced. Galleria mellonella larvae infected with L. monocytogenes grown in presence of sublethal concentrations of the essential oil showed much higher survival rates compared with controls, suggesting that the extract inhibited tissue invasion. Food contamination with L. monocytogenes is a major concern for the food industry, particularly for plants making ready-to-eat and processed food. The present work provides a baseline in the study of the anti-virulence properties of the C. sativa essential oil against L. monocytogenes. Further studies are needed to understand if it could be used as an alternative agent for the control of L. monocytogenes in food processing plants.

Thymus essential oil extraction, characterization and incorporation in phospholipid vesicles for the antioxidant/antibacterial treatment of oral cavity diseases.

The aim of the work was to extract, characterize, and formulate Thymus capitatus (Tymbra capitata) essential oil in phospholipid vesicles: liposomes, glycerosomes and Penetration Enhancer-containing Vesicles (PEVs). The steam-distilled essential oil was mainly composed of carvacrol. The oil was mixed with lecithin and water to produce liposomes, or different ratios of water/glycerol or water/propylene glycol (PG) to produce glycerosomes and PG-PEVs, respectively. Cryo-TEM showed the formation of unilamellar, spherical vesicles, and light scattering disclosed that their size increased in the presence of glycerol or PG, which improved long-term stability. The formulations were highly biocompatible, and capable of counteracting oxidative stress and favouring wound repair in keratinocytes, thanks to enhanced uptake. The antibacterial activity of the oil was demonstrated against cariogenic Streptococcus mutans, Lactobacillus acidophilus, and commensal Streptococcus sanguinis. The combination of antioxidant and antibacterial activities of Thymus essential oil formulations may be useful for the treatment of oral cavity diseases.

Chemical composition and cytotoxic activity of the essential oils of Cymbopogon citratus L. Grown in phu tho province

Culms and leaves of Cymbopogon citratus L. were collected from two regions of Phu Tho province (Thanh Son and Phu Ninh) and used as materials for essential oil extraction. Oils obtained were steam-distilled, analyzed for chemical composition and evaluated for cytotoxic activity against three different cancer cell lines. The GC/MS analysis showed that citral is the major content of the steam-distilled essential oils which was found in the range of 64.15-76.22%. Camphene was found only in culm oils of both regions but it was not detected in the leaf oils. Interestingly, the isomer forms of ocimene present at higher content in the culm oils than in the leaf oils whereas myrcene content in the leaf oils is higher than that in the culm oils. In a cytotoxicity test, four essential oils of culms and leaves of C. citratus from Thanh Son and Phu Ninh showed potent activity against A549 (human lung carcinoma) cell line with the IC50 values ranging from 4.01±0.39 to 6.3±0.54 µg/ml. The essential oils (culms and leaves) from Phu Ninh exhibited moderate effects on the Hela (human cervical adenocarcinoma) cells with the IC50 values of 19.43±1.16 and 42±2.41 µg/ml, respectively. However, they were inactive against the human hepatocellular carcinoma Hep3B cell line. The essential oils from Thanh Son exhibited potent cytotoxic activity against Hela and Hep3B cell lines with the IC50 values ranging from 1.18±0.26 to 8.91±0.32 µg/ml. The results indicated that the essential oils of C. citratus from Thanh Son, Phu Tho could be considered as a promising candidate for the natural sources of anticancer agents.