When we talking about essential oils from medicinal plant then what is the appropriate solvent in plant extraction procedure ?
I completely agree with all the answers above. An aqueous extract is not an essential oil but an infusion or maceration of the plant, and both are different again from the product of pressing plant material. An essential oil is the oil distilled from a plant in some way. Before the discovery of distillation, no essential oils were available but only extracts or infusions made by steeping plant material in water, oil, animal fat, wine or other solvents, or a 'juice' extracted by pressing.
Hi Aloke Purkait,
Essential oils are usually insoluble or sparingly soluble in water. They are usually soluble in organic solvents such as acetone, chloroform etc. An aqueous extract generally do not contain essential oils. Essential oils are also called as volatile oils since they are volatile at room temperature. The extraction of essential oils are carried out in a steam distillation apparatus since steam can liberate and carry them in vapor form from the plant material. The steam and volatile oil vapor mixture is cooled to get water and volatile oil separately. The volatile oil will float on the water surface if it is lighter than water or vice versa. This is the most convenient lab scale method to extract and separate essential or volatile oils. There are other methods also used such as cold press to extract essential oil.
Hi,
Aqueous extract of medicinal plant can not be said as essential oil. the term oil is it self against the principle of water extract.
'Essential Oil' When essences are extracted from plants in natural ways, they become essential oils. They may be distilled with steam and/or water, or mechanically pressed. Oils that are made with chemical processes are not considered true essential oils)(pubmed definition).
Essential oils can be either aromatic in nature and some times odorless.
Solvent extraction is a not appropriate method to isolated essential oil. Steam distillation is most used appropriate method and also used from era.,
Fat infused extraction also considered for some time.
All the best.
Essential oils could not be extracted by water because they were insoluble
They are extracted by organic solvents using soxhlet method or clavenger
Essential oils, also called volatile or ethereal oils, are aromatic oily liquids obtained from plant material (flowers, buds, seeds, leaves, bark, woods, fruits and roots). They can be obtained by expression, fermentation, enfleurage or extraction but the method of steam distillation is the most commonly used method for commercial production of essential oils. solvents used for extraction of essential oils for such as hexane, acetone, di-methylene-chloride. Solvent extraction is a method of extracting essential oils that is dominated by the perfume industry. And technically does not produce therapeutic grade oils.
Aqueous extract of medicinal plant is not called essential oil. Essential oils are fragrant substances produced by plants. They are isolated by hydrodistillation. For more details please read Guenther.
Hexane and Petroleum ether are two best solvents for extraction of essential oils. usually you can't get essential oils from water fraction.
Can separation essential oil by water by using cleavenger apratus, the equeous extract can separate other compound unreleated with essential oil, The compound appeare in aqueous extract different the compound apeare in essential oil
I completely agree with all the answers above. An aqueous extract is not an essential oil but an infusion or maceration of the plant, and both are different again from the product of pressing plant material. An essential oil is the oil distilled from a plant in some way. Before the discovery of distillation, no essential oils were available but only extracts or infusions made by steeping plant material in water, oil, animal fat, wine or other solvents, or a 'juice' extracted by pressing.
Dear Dr. Aloke,
Essential oil is quit different from plants crude extract. However, Is possible that your crude extract contained essential oil but this needs be separated.
Best,
Egbuna, C.
Thank you all of you ..
It's a natural phenomenon that oil doesn't mixed with water, as a consequence using polar solvent like methanol,water etc. we can't extract non polar parts (oils) .
A few researcher, they used aqueous extract of plants parts for their formulation purpose but they are mention their articles headline entitle " Using essential oils..." that's why I asked here..
Again thank you Sir/Madam for your answered.
Just a quick further point. People seem to refer to essential oil as it if is a single compound. Essential oils (extracted by distillation) first are complex mixtures of compounds and second are not oils in the sense of either petroleum based oils or plant oils used for cooking, cosmetics etc. An essential oil from a plant will contain compounds some of which may be soluble in water, others definitely not. This is why some of the same compounds can also be extracted from plants by solvent extraction (using water or organic solvents) and by pressing the plant, but also why an essential oil can only be produced by distillation. Many are also very volatile which is why essential oils are fragrant. The words "essential oil" are frequently misused and I have reviewed many papers in which they are used incorrectly, as in Aloke's example above.
essential oils are insoluble or sparingly soluble in water. organic solvent like ether, alcohol used for polar: Thumb rule like dissoluble like.
Milan Hait how can water be used as solvent in extraction of essential oils? I'm confused! What are essential oils in the 1st place? Thanks.
please find attached file for your kind information you can also web page just open Google page type H.C. Andola Number of paper and presentation will be help for you.
Absolutely, an aqueous extract is not an essential oil. An essential oil is a hydrophobic liquid, an aqueous extract is obtained by steeping it in water. But this doesn't mean that we can't extract essential oil by solvents. Because, they are volatile we use distillation, but we can, also, use solvent extraction to extract less volatile oils with delicate chemical components which can easily be denaturated by the high heat used in steam distillation. Instead, a solvent such as hexane or supercritical carbon dioxide is used to extract the oils. Extracts from hexane and other hydrophobic solvents are called concretes (and not aqeuous extract), which are a mixture of essential oil, waxes, resins, and other lipophilic (oil-soluble) plant material. In general, fresh plant material is extracted with nonpolar solvents (e. g., benzene, toluene, hexane, petroleum ether). On evaporation of the solvent, a semi-solid residue of essential oils, waxes, resins and other lipophilic (oil-soluble) plant chemicals remains. The concrete may be extracted with ethanol to produce an absolute (and not an aqueous extract !).
Hexane and petroleum ether are the best solvents for extracting essential oils.
Hexane and petroleum ether the solvent for extracte fatty acid
Oh dear! We are going round in circles here. Please see my answers above. You cannot extract an essential oil, no matter what solvents you use. Essential oils are only obtainable from plants by distillation. Anything else is an extract. So nothing extracted in water or any other solvent is an essential oil. Nothing extracted by pressing plant material is an essential oil. Only the material extracted by distillation of the plant matter. Any other use of the term essential oil is not correct. Some of the same compounds might be present in extracts and essential oils, but not all, and the extracts and essential oils are not usually the same in composition. For more information look at the previous answers in this stream.
If you extract by water your plant, it is just aqueous extraction. You need to use different method of distillation by water for extraction of essential oils. When the water of distillation cooled down, you can see an oily part in top of aqueous phase. This is essential oils.
However, there is a method of supper critical that by liquid CO2, you can extract essential oils. It is very expensive. Consequently, water is the best.
Simple aq. extracts of medicinal plants does not necessarily men essential oil. You must use different solvent extraction methods and see the desired effect after removing the solvents from each of the extracts. It is because you must define what is "essential" in the extracts.
As already mentioned several times above. In English an essential oil means something very specific. No solvent extract can be an essential oil, regardless of the solvent. An essential oil is extracted from plant material by distillation.
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