Raw Essential Oil Research Articles

Feasibility of fractional distillation of Eucalyptus hybrida essential oil for the separation of valuable compounds

Raw essential oil (EO) of Eucalyptus hybrida extracted from the leaves of trees found in Uttarakhand state and nearby areas consists of a mixture of monoterpenoids, sesquiterpenoids and several different volatile compounds of which 1,8-cineole i.e., eucalyptol, a monoterpenoid cyclic ether is a major component. The eucalyptol rich EO also holds antimicrobial, anti-inflammatory, broncholytic and mucolytic potential. In this work experimental tests were done to evaluate the feasibility of batch fractionation or fractional distillation (FD) technique in performing value addition of eucalyptus essential oil. The proximity of boiling points of eucalyptol, limonene and p-cymene act as a barrier in separating these compounds. A two-stage FD procedure was devised, which recovers relatively light terpene fractions in first stage and provides eucalyptol rich fractions in second stage. The GC-MS analysis of the fractionated samples revealed good separation results with three stage-B fractions (B8, B9 and B10) containing >90% purity of eucalyptol, while two stage-A fractions (A1 and A2) containing >90% purity of pinene mixture (α-pinene and β-pinene). FD thus proved to be an effective method for adding value to the eucalyptus EO.

Vacuum fractional distillation of Cunila galioides Benth. essential oil: chemical composition and biological activities of raw oil and its fractions

This work aimed to rectify Cunila galioides essential oil and evaluate the raw oil and the fractions’ antifungal, allelopathic, and antioxidant activities. The results showed that the raw essential oil and the bottom fraction were primarily composed of linalyl propionate (42.9 wt.% and 60.2 wt.%). The top fraction was composed mainly of limonene (45.7 wt.%). The antioxidant activity changed with the radical and the fraction. The bottom had a weaker antifungal effect than the raw oil and the top. Nevertheless, the essential oil and the fractions had a similar antifungal activity at 0.50 % v/v and higher. Similar behavior was observed for the allelopathic tests. No difference occurred between the raw oil and the fractions, with reduced germination percentages and speed at 0.25 % v/v and complete inhibition at 0.50 % v/v. The oil can be rectified, and the fractions may be used without harming their biological activity.

Chemical composition, antibacterial and antioxidant activities of lemongrass (Cymbopogon citratus) essential oil and its fractions obtained by vacuum distillation

Lemongrass (Cymbopogon citratus) essential oil (raw oil) is a natural product with many biological activities and is commonly used in the food and cosmetic industries. In this study, fractions of lemongrass essential oil were segregated from raw oil by vacuum fractionation. These fractions were then examined for their constitution, antioxidant and antimicrobial activities. Gas chromatography-mass spectrometry results indicated a difference in constitution and content of compounds among the fractions and raw oil. β -myrcene was the main ingredient in two fractions, F1and F2, with content 2-4 times higher than the original content in raw oil. At the same time, F4 was the primary fraction for citral recovery, with the highest citral content of 83.53%. Fractions F3, F4, and undistilled oil (Unoil) showed better antioxidation than raw essential oil. On the other hand, the antimicrobial experiments indicated that F1, F2, and F4 had the highest activity in both cases against Staphylococcus aureus and Escherichia coli bacteria. These outcomes could increase the applicability of lemongrass essential oil in many fields, especially in medical and food applications.

Lipidic Matrixes Containing Lemon Essential Oil Increases Storage Stability: Rheological, Thermal, and Microstructural Studies

Lemon essential oil (LEO) is known for having excellent antioxidant properties with applications in the pharmaceutical, food and cosmetic sectors. However, its deficient stability to light and temperature compromise this activity. In this study, waxy emulsifiers, such as beewax, candelilla wax, carnauba wax, and ozokerite wax, were employed in order to create lipidic matrixes with LEO as a continuous phase by heating to 80 °C under homogenization, followed by rapid cooling to 25 °C. The thermal, microstructural, rheological, and antioxidant tests were then conducted on such matrixes. The difference in melting, crystallization, and gelling temperatures was explained by the diverse chemical composition (long-chain wax esters in carnauba wax having a high melting point, and short-chain fatty acids and hydrocarbons in beewax and ozokerite wax, respectively). Crystal habits of these matrix systems varied from grainy, oval, to fiber-like shape, whereas there was a prevalent orthorhombic allomorph. The alignment and reorganization of carnauba and candelilla wax crystals led to an increase in the matrix strength as compared to those of beeswax and ozokerite matrixes, which showed a weak texture and poor crystallization behavior. The last two matrix systems showed the best flow and extensibility. These lipidic matrixes showed potential use for topical applications having good oil retention capacity and better antioxidant properties as compared to the raw essential oil.

Direct Identification of α-Bisabolol Enantiomers in an Essential Oil Using a Combined Ion Mobility-Mass Spectrometry/Quantum Chemistry Approach.

Enantiomer-specific identification of chiral molecules in natural extracts is a challenging task, as many routine analytical techniques fail to provide selectivity in multicomponent mixtures. Here we describe an alternative approach, based on the combination of ion mobility-mass spectrometry (IM-MS) and quantum chemistry (QM), for the direct enantiomers differentiation in crude essential oils. The identification of α-bisabolol enantiomers contained in the raw essential oil (EO) from the Corsican Xanthium italicum fruits is reported as a proof-of-concept. Accordingly, IM-MS experiments performed in Ag+-doped methanol revealed the presence of both (+)- and (-)-α-bisabolol in the EO, while molecular simulations provided the structures of the two α-bisabolol enantiomer silver(I) adducts.

Composition and insecticide potential against Tribolium castaneum of the fractionated essential oil from the flowers of the Tunisian endemic plant Ferula tunetana Pomel ex Batt

For several years, plant derived substances, in particular essential oils, have been the subject of increasing attention in their safe and ecofriendly application to crops, as a powerful alternative to chemical insecticides. For this reason, the essential oil isolated from flowers of Ferula tunetana, a Tunisian endemic plant, was investigated for the first time for its chemical profile, and its toxicity and repellency effects against Tribolium castaneum (Herbst) adults. The analysis by gas chromatography coupled with mass spectrometry (GC/MS) led to determine 92.8–99.1% of the total oil (FEO) and its fractions (F1-F12) obtained every 15 min during the hydrodistillation process. The chemical analysis allowedto identify 77 compounds. α-Pinene (14.3%), a monoterpene hydrocarbon, was the major compound of the raw essential oil. Relatively high amounts of oxygenated sesquiterpenes (44.9–76.8%) were detected, consisting mainly of epi-α-muurolol (3.6–9.5%), himachalol (6.8%) and β-chenopodiol (5.1–7.1%). Regarding the repellency assay, results demonstrated that flowers essential oil of F. tunetana and its fractions displayed interesting repellent property (93%). The median lethal dose (LD50) of the topical application of the oil was 10.44%. Fumigation with the raw essential oil gave a LD50 of 161.89 μL/L air. The overall data suggest that the F. tunetana essential oil might be used to protect stored products from pest attacks, but further studies are needed in order to better understand the synergistic relationship between the phytochemicals contained in the essential oil.

Effect of the Chemical Composition of Free-Terpene Hydrocarbons Essential Oils on Antifungal Activity.

In this study, Carum carvi L. essential oil (CEO) and Origanum majorana L. essential oil (MEO) was steam-distillated under reduced pressure. We henceforth obtained three fractions for each essential oil: CF1, CF2, CF3, MF1, MF2, and MF3. Then, these fractions were characterized using the gas chromatography–mass spectrometry (GC-MS) technique. The results indicated that some fractions were rich in oxygenated compounds (i.e., CF2, CF3, MF2, and MF3) with concentrations ranging from 79.21% to 98.56%. Therefore, the influence of the chemical composition of the essential oils on their antifungal activity was studied. For this purpose, three food spoilage fungi were isolated, identified, and inoculated in vitro, in order to measure the antifungal activity of CEO, MEO, and their fractions. The results showed that stronger fungi growth inhibitions (FGI) (above 95%) were found in fractions with higher percentages of oxygenated compounds, especially with (−)-carvone and terpin-4-ol as the major components. Firstly, this work reveals that the free-terpenes hydrocarbons fractions obtained from MEO present higher antifungal activity than the raw essential oil against two families of fungi. Then, it suggests that the isolation of (−)-carvone (97.15 ± 5.97%) from CEO via vacuum distillation can be employed successfully to improve antifungal activity by killing fungi (FGI = 100%). This study highlights that separation under reduced pressure is a simple green method to obtain fractions or to isolate compounds with higher biological activity useful for pharmaceutical products or natural additives in formulations.

Lippia origanoides essential oil: An efficient alternative to control Aedes aegypti, Tetranychus urticae and Cerataphis lataniae

The main objective of the present study is to find an alternative controlling agent for some devastating greenhouse pests, and the yellow fever mosquito larvae. More specifically, the potential bioactivity of Lippia origanoides Kunth. (“erva-de-Marajó”) has been evaluated here against three most common pests found in tropical and subtropical countries: Tetranychus urticae Koch. mites, Cerataphis lataniae Boisd. aphids and Aedes aegypti Linn. larvae. The essential oil extracted from leaves of Lippia origanoides Kunth. has been analyzed by GC-FID and GC–MS and 32 compounds have been identified, representing 97.63% of the raw essential oil. The major compounds are carvacrol (48.31%), p-cymene (9.11%) and thymol (8.78%). The essential oil has been tested for AChE inhibition, obtaining IC50=16.93μg/mL, as well as for its potential antioxidant activities by different methods [DPPH: IC50=8.4±0.1μg/mL, ABTS: 691.8±44.3μM TEs/g (Trolox Equivalents) and FRAP: 933.1±8.1μM Eq Fe(II)/g]. Our results have shown acaricidal and insecticidal activities of this oil against T. urticae Koch. and C. lataniae Boisd. Volatile phase effects have been evaluated for T. urticae (LD50=25.1±1.1μg/mL for 24h) and for C. lataniae (LD50=6.6±0.5μg/mL for 24h, and LD50=2.7±0.6μg/mL for 48h), whose values are in the same order of magnitude as the enzymatic activity. These results show the susceptibility of T. urticae and C. lataniae species to the AChE inhibitory activity. Thus, the mortality of these species may be due to the neurotoxic mode of action, which affect the transport of ions and AChE. Furthermore, L. origanoides essential oil has shown a moderate larvicidal potential with LD50=187.3±0.9μg/mL after 24h. The occurrence of the larvicidal activity at very large concentration indicates that the larval mortality may occurs by ingestion or contact. The present study clearly illustrates the efficacy of the investigated essential oil as a natural pest controlling agent.

Potential Development Essential Oil Production of Central Java, Indonesia

Indonesia is the source of raw essential oil in the world. Essential oils are used in various types of industries such as food and beverage, flavour, fragrance, perfumery, pharmaceuticals, and cosmetics. However, the development of Indonesian essential oil industry has not been encouraging for the production of essential oils, further it is unable to meet global demand. Besides that, the quality of volatile oil resulted cannot meet the international market standards. Based on the facts, the potential of Indonesian essential oils needs to be developed to provide added value, through increased production, improved quality and product diversification. One part of Indonesia having abundant of raw essential oil source is Central Java. Central Java has the quite large potential production of essential oils. Some essential oils produced from refining industry owned by the government, private and community sectors include cananga oils (Boyolali district), clove oils (Semarang district), patchouli oils (Brebes district, Pemalang district, and Klaten district). The main problem in the development of plants industries that producing essential oil in Central Java is low crops production, farming properties, quality of essential oils are diverse, providing poor-quality products and volatile oil price fluctuations. Marketing constraints of Central Java essential oils are quite complex supply chain. In general, marketing constraints of essential oils due to three factors, namely the low quality due to type of essential oil business that generally shaped small businesses with different capital and technology, domestic marketing is still a buyer-market (price determined by the buyer) because of weak bargaining position processors businessman, and prices fluctuate (domestic and foreign) due to uncontrolled domestic production and inter-country competition among manufacturers.

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD) complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed–uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC–MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole) was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

EFECTO ACARICIDA DEL ACEITE ESENCIAL DE AGUARIBAY (SCHINUS MOLLE L.) Y SUS FRACCIONES EN COLMENARES DE ABEJAS (APIS MELLIFERA) EN RELACIÓN CON LA COMPOSICIÓN QUÍMICA

The acaricides power of aguaribay (Schinus molle L.) raw essential oil and its fractions were determined. For the sanitary control of varroa (Varroa destructor), considering their chemical composition. Test in different hives of bees (Apis mellifera) were carry and the total amount of acarus and those eliminated in the product were determined. Efficiency values were 30± 6 for the fraction 2 having more pinene concentration and 38+6 for fraction 5 with highest concentration in terpine-4-ol, compared with the raw essential oil whose effectiveness is 9.2. The use of this natural product, when the synthetic ones cannot be applied, maintain lower amounts of varroa. The enhancement in the acarus death can be attributed to the increased concentration of pinene and to the high concentration of terpinen-4-ol in the fractions tested.

Characterization of the raw essential oil eugenol extracted from Syzygium aromaticum L.

Eugenol is the main volatile compound extracted oil from clove bud, Syzygium aromaticum L., and used in traditional medicine, as a bactericide, fungicide, anesthetic, and others. Its extraction was performed using hydrodistillation which is the most common extraction technique. Its components and thermal behavior were evaluated using gas chromatography (GC) and differential scanning calorimetry (DSC), which provide a better characterization of these natural compounds. This extracted product was compared to the standard eugenol results. The GC results suggested ~90% eugenol was found in the total extracted oil, and some of its boiling characteristics were 270.1 °C for peak temperature and 244.1 J g−1 for the enthalpy variation.

Evaluación del Poder Antioxidante de Fracciones de Aceite Esencial Crudo de Schinus molle L. obtenidas por Destilación al Vacío

The antioxidant characteristics of the Schinus molle L (molle, aguaribay) raw essential oil were evaluated and compared with different cuts from the same oil obtained by vacuum distillation. The samples were analysed using GS/MS chromatography and the antioxidant efficiency was determined using the DPPH method, 2.2 Diphenyl 1 picrylhydrazyl. An analysis of the results we may conclude that the fraction is the heaviest it has greater power antiradical. The results show that the heaviest fraction contains higher concentration of Terpinen-4-ol and Germacreno D, compounds that are collectors of free radicals. Therefore, the heaviest fraction has greater antiradical power.