Active Compounds Of Essential Oils Research Articles

Acaricidal activity and enzyme inhibitory activity of active compounds of essential oils against Psoroptes cuniculi

Plant essential oils and its chemical compositions are commonly applied in medicinal and other industries due to their broad advanced pharmacological activities. In the present study, we systematically evaluated the acaricidal activities of twelve compounds of essential oils against Psoroptes cuniculi in vitro and in vivo. In addition, to support the clinic uses, their toxicities against immortalized human keratinocytes (HaCaT) and human liver cells (HL-7702) and skin irritation were studied for evaluating the liver and skin safety. The possible mechanism of action of certain chemical were investigated by determining the inhibitory activities against cytochrome P450 (P450) acetylcholinesterase (AChE) and glutathione-S-transferase (GST). Among all tested compounds, eugenol exhibited the best acaricidal activity with LC50 value of 56.61 μg/ml in vitro. Meanwhile, after the treatment of eugenol for five times within 10 days, the P. cuniculi were eliminated in the naturally infested rabbits, no skin irritation was found in rabbits treated by eugenol. Moreover, eugenol presented no or weak cytotoxicity against HaCaT cells and HL-7702 cells with IC50 values of greater than 100 μg/ml. Furthermore, the moderate inhibitory activities of eugenol against mites P450 and AChE were demonstrated. Above results indicated that eugenol presented the promising acaricidal activity against P. cuniculi in vitro and in vivo, is safe for both humans and animals at the given doses. This work lays the foundation for the development of eugenol as an environmentally friendly acaricide agent.

Tolerance to exposure to essential oils exposure in patients with allergic asthma

Background: Essential oils are volatile compounds of plant origin increasingly used by allergic and/or asthmatic subjects to purify indoor air. The active compounds of essential oils belong to terpenes, the most widespread biogenic volatile organic compounds (VOC). Although there is substantial literature showing associations between exposure to chemical VOCs and asthmatic symptoms and impaired respiratory function, the impact of essential oils in patients with asthma has never been studied. Objectives: To evaluate the safety of a purifying air spray containing 41 essential oils (PPAS) in patients with mild or moderate allergic asthma. Methods: This was a prospective open study in which 25 mild (19) and moderate (6) asthmatics were exposed to PPAS, one spray twice a day at 8 am and 8 pm in two different corners of a given subjects bedroom for 4 weeks. Before and after 4 weeks of exposure, fractional exhaled nitric oxide (FeNO), lung function and methacholine challenge (PD20) were performed and asthma control was assessed by the 5 questions of the Asthma Control Test (ACT). The spray was weighed after the 4-week exposure to assess compliance. Results: FeNO was the primary endpoint and was thus analyzed in all (N = 25) subjects irrespective of the level of airflow obstruction. The results apply to all (N = 25) subjects in which FeNO could be measured at D1 and D30 (17 subjects). Mean (SD) FeNO amounted to 37.4 (16.6) and to 33.1 (18.7) ppm before and after PPAS exposure, respectively (p = 0.09). No significant change in lung function and methacholine responsiveness was noted after PPAS exposure, the mean PD20 amounting to 1179 (1124.42) μg (range 100–3200) before and to 1226 (1189.8) μg (p = 0.06) after. The mean ACT before and after PPAS exposure amounted to 20.9 (4.2) and 21 (5.15), respectively (p = 0.80). The mean weight of the PPAS bottles was 211.4 g (DS:0) before the first use and 171.41 g (DS: 29.8) at the end of the study. The average amount of PPAS used was 40.0 g (29.8). In the subgroup of subjects who used the highest quantities of essential oils (>40 g), as assessed by the mean weight of the bottle at the end of the study, FeNO after 30 days of exposure decreased more than in the entire group: 7.9 ppm vs 4.2 ppm (p = 0.07). Conclusion: No difference was noted on airway inflammation, lung function or asthma control in mild and moderate allergic asthmatics after exposure twice a day for one month, to a spray containing a mixture of 41 essential oils.

Traceability of Active Compounds of Essential Oils in Antimicrobial Food Packaging Using a Chemometric Method by ATR-FTIR

A simple and rapid Fourier Transform infrared (FTIR) spectroscopy method was developed to determine the main essential oil components (carvacrol, thymol and p-cymene) in the antimicrobial LDPE films incorporated with oregano (Origanum vulgare) and thyme (Thymus vulgaris) essential oils. The ATR-FTIR spectrum of pure active components (carvacrol, thymol and p-cymene) was characterized, and the ranges between 1125 cm-1 - 1095 cm-1, 1170 cm-1 - 1140 cm-1 and 1050 cm-1 - 1017 cm-1 were respectively used for quantitative estimation. Partial least square (PLS) analysis was used for quantitative analysis. FTIR spectroscopy with chemometrics, using the PLS-1st derivative spectra, could predict the content of active compounds accurate to an r2 greater than 0.99 and a standard error of prediction (SEP) less than 0.7. The developed method was successfully applied to predict the concentration of active compounds: carvacrol, thymol and p-cymene in oregano and thyme essential oils with results compared to those of the GC-MS method. The described non-destructive method can be applied in the industry instead of extraction, distillation and blend processes of the mentioned essential oils and can be extended to detect the content of carvacrol, thymol and p-cymene in active packaging and other commercial products.

In vitro Screening of Essential Oil Active Compounds for Manipulation of Rumen Fermentation and Methane Mitigation.

The objective of this study was to investigate the effects of 11 active compounds of essential oils (ACEO) on rumen fermentation characteristics and methane production. Two trials were conducted. In trial 1, ACEO (eugenol, carvacrol, citral, limonene, 1,4-cineole, p-cymene, linalool, bornyl acetate, α-pinene, and β-pinene) at a dose of 1,000 μL/L were incubated for 24 h in diluted rumen fluid with a 70:30 forage:concentrate substrate (16.2% crude protein; 36.6% neutral detergent fiber). Three fistulated Holstein cows were used as donors of rumen fluid. The reduction in methane production was observed with nine ACEO (up to 86% reduction) compared with the control (p<0.05). Among these, only limonene, 1,4-cineole, bornyl acetate, and α-pinene did not inhibit volatile fatty acid (VFA) production, and only bornyl acetate produced less methane per mol of VFA compared with the control (p<0.05). In a subsequent trial, the effects on rumen fermentation and methane production of two concentrations (500 and 2,000 μL/L) of bornyl acetate, the most promising ACEO from the first trial, were evaluated using the same in vitro incubation method that was used in the first trial. In trial 2, monensin was used as a positive control. Both doses of bornyl acetate decreased (p<0.05) methane production and did not inhibit VFA production. Positive effects of bornyl acetate on methane and VFA production were more pronounced than the effects of monensin. These results confirm the ability of bornyl acetate to decrease methane production, which may help to improve the efficiency of energy use in the rumen.

Chemical constituents of essential oils of Tephrosia purpurea and Ipomoea carnea and their repellent activity against Odoiporus longicollis

Chemical constituents of essential oils (EOs) obtained from stem and root of Tephrosia purpurea (Linn.) Pers. and Ipomoea carnea Jacq. were investigated by Gas Chromatography-Mass Spectrometry (GC-MS). Total lipid and oil content was high in the stem than the root of T. purpurea and I. carnea. Essential oils extracted from the stem and root of T. purpurea and I. carnea showed 9 and 8 compounds respectively. Hexadecanoic acid was found to be the principal constituent of stem (69.61%) and root (46.97%) of T. purpurea while 70.61and 88.89% for stem and root, respectively in the case of I. carnea. The findings of the present study suggest that T. purpurea and I. carnea EOs can be used as a source of hexadecanoic acid which could be used for industrial purposes. The essential oils of T. purpurea and I. carnea showed strong repellent activity for males (-0.73 and -0.70 for T. purpurea and I. carnea stem EO respectively) than females (-0.63 and -0.59 for T. purpurea and I. carnea stem EO respectively) against banana pseudostem weevil Odoiporus longicollis. The results indicated that the active compounds of essential oils from stems of T. purpurea and I. carnea can be explored as natural repellents for control of Odoiporus longicollis.

Insecticidal Effects of Monoterpenes on Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Twenty eight monoterpenes including monoterpene hydrocarbons and oxygenated monoterpenes (borneol, borynl acetate, camphene, camphor, 3-carene, carvone, 1,8-cineole, citronellal, β-citronellene, β-citronellol, dihydrocarvone, fenchol, fenchone, geranyl acetate, isomenthol, limonene, limonene oxide, linalool, linalyl acetate, menthol, menthone, myrcene, nerol, neryl acetate, α-pinene, β-pinene, terpinen-4-ol, α-terpineol), the active compounds of essential oils obtained from different plant species were tested against adults of Sitophilus zeamais Motschulsky under laboratory conditions. The monoterpenes were applied at contents of 10, 20 and 30 μl for liquid compounds and 10, 20 and 30 μg for solid compounds. The results show that most of the monoterpenes have significantly insecticidal effect on the tested insects. Insecticidal effects of monoterpene hydrocarbons were found to be lower than those of oxygenated monoterpenes. The ketone and aldehyde and epoxide derivatives of oxygenated monoterpenes were also found to be more toxic as compared with their other derivatives. Mortality percentage of S. zeamais adults, after 96th h of exposure at the maximum dose (30 μl/μg) of oxygenated monoterpenes including borneol, fenchol, linalool, menthol, terpinen-4-ol, α-terpineol (alcohols group); 1,8-cineole, limonene oxide (epoxides group); camphor, carvone, citronellal, dihydrocarvone, fenchone, menthone (ketones and aldehydes group) and neryl acetate (esters group) attained 100%. Concurrently, 3-carene from monoterpene hydrocarbons showed 100% mortality after 96th h of exposure at the maximum dose (30 μl). Carvone, dihydrocarvone, fenchone, limonene oxide, menthone and terpinen-4-ol from these compounds showed 100% insecticidal effect after 48th h of exposure. Among the monoterpenes tested, carvone, dihydrocarvone, menthone and terpinen-4-ol showed the strongest insecticidal activities with 100% of mortality at all doses (96 h after treatment) and then 1,8-cineole, fenchone, linalool and limonene oxide showed stronger insecticidal activities in comparison with other monoterpenes with lethal doses (LD50) values of 1.989, 2.445, 2.445 and 3.235 μl (96 h after treatment) against the test insects, respectively. Mortality rate of S. zeamais adults increased significantly (p < 0.01), as the dosage level and/or exposure time increased. Based on the present results, it can be concluded that the oxygenated monoterpenes may have a potential action for control of S. zeamais adults.

Persistence of active compounds of essential oils of clausena anisata (rutaceae) and plectranthus glandulosus (labiateae) used as insecticides on maize grains and flour

Maize occupies an important place in the resolution of food insecurity problems in the sub-Saharan region of Africa. However due to poor post-harvest technologies, more than 35% of annual crop yield is often lost during storage as a consequence of insect attack. While chemical pesticides constitute an efficient tool for reducing these losses, current excessive usage runs the risk of modifying the quality and safety of foods produced from these grains. The use of essential oils of plant origin for grain storage has been advocated as a non invasive method with limited or no effect on the quality and safety of the grains or their products. This study was carried out as an evidence of bioactivity of two essential oils of Clausena anisata (Willd.) Hook and Plectranthus glandulosus Hook F. against adults of Tribolium castaneum Herbst and Sitophilus zeamais Motschulsky, which are two important stored product insect pests in Northern Cameroon. Because of the low persistence of the insecticidal activities of these plants, their essential oils to achieve a complete protection of the stored products must be applied at frequent delays. The present investigation focuses on the occurrence of residues of these oils on treated maize grain and flour. The doses of crude essential oils used to treat adults of S. zeamais and T. castaneum in a contact and inhalation process were their LD99s. After the evaluation of their insecticidal activity the persistence of each essential oil was observed every 2 days till 14 days. After the disappearance of their insecticidal activities, essential oil was re-extracted and their residual compounds were identified from treated grain and flour. The major compounds of C. anisata are, estragole, a-humulene, germacrene D and (E)-nerolidol. In P. glandulosus they are: fenchone, a-terpinolene and piperitenone oxide. After 14 days, only 64.24% of compounds of C. anisata were recovered on treated flour and 55.16% on grains. Concerning P. glandulosus, 48.94% was recovered on grains and 61.23% on flour. Key woods : Essential oils, persistence, stored products insects

Effect of Mixed Antimicrobial Agents and Flavors in Active Packaging Films

Active packaging is an emerging food technology to improve the quality and safety of food products. Many works have been developed to study the antimicrobial activity of essential oils. Essential oils have been traditionally used as flavorings in food, so they have an important odor impact but they have as well antimicrobial properties that could be used to protect the food. Recent developments in antimicrobial active packaging showed the efficiency of essential oils versus bread and bakery products among other applications. However, one of the main problems to face is the odor and taste they could provide to the packaged food. Using some aromas to mask the odor could be a good approach. That is why the main objective of this paper is to develop an antimicrobial packaging material based on the combination of the most active compounds of essential oils (hydrocinnamaldehyde, oregano essential oil, cinnamaldehyde, thymol, and carvacrol) together with some aromas commonly used in the food industry. A study of the concentration required to get the antimicrobial properties, the organoleptic compatibility with typical aroma present in many food systems (vanilla, banana, and strawberry), and the right combination of both systems has been carried out. Antimicrobial tests of both the mentioned aromas, the main components of some essential oils, and the combination of both groups were carried out against bacteria (Enterococcus faecalis, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella choleraesuis, Yersinia enterocolitica, Escherichia coli), yeasts (Candida albicans, Debaryomyces hansenii, Zygosaccharomyces rouxii), and molds (Botrytis cinerae, Aspergillus flavus, Penicillium roqueforti, Eurotium repens, Penicillium islandicum, Penicillium commune, Penicillium nalgiovensis). The sensory properties of the combinations were evaluated with a triangular test and classification was by an order test; the odor threshold of the aroma compounds was also studied. The results reveal that none of the aromas had antimicrobial properties. The most antimicrobial compounds are thymol, carvacrol, and cinnamaldehyde, but none of them could be combined with banana aroma, whereas only thymol with strawberry aroma gave the right combined organoleptic profile. All of the antimicrobials under study could be combined with vanilla aroma, providing both antimicrobial property and the odor expected.