Recently, I came across an advertisement of some essential oils being used for hair growth, and as I actually my wanted to boost my hair volume, my interest was pricked. The page displayed images of these oils and their prices; some them were said to have medicinal benefits. One small bottle of not more than 20mls was being sold for as much as ₦2500 (about 5-6sbds, i guess). Vegetable oil of 3000mls (3litres) and coconut oil of 1000mls (1liter) are being sold for approximately the same amount in the market. ‘What is special about these so called essential oils?’ Are the so called benefits and efficacy myths or facts?

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The current trend is a shift from synthetic or petrol chemical products towards bio organic products (natural sources) in cosmetics, perfumery, health and other human related areas. However, we need to be equipped with adequate knowledge of any product we ingest or apply on our body. Hence, there is the need to know more about these oils. What is really the essence? ## Why ‘essential’? ## Essential oils are concentrated hydrophobic (water repelling) liquid extracts from plant parts. They consist of chemical compounds that can easily vaporize and have specific scent or aroma. They are also known as Scent oils. unlike essential fatty acids and essential amino acids which the body needs but can’t synthesize, essential oils are given the name due to the fact that they contain the main essence of the plant part from which they are extracted. These volatile plant oils are extracted from parts of the plants which include leaves, flower, stems, roots, barks and so on. Unlike carrier oils like coconut oil which stay on the skin surface for a long time, essential oils can penetrate the human skin when applied on the skin surface, into the bloodstreams. ## Method of Extraction ## There are different processes used in the extraction of essential oils from the plant parts depending on the physical properties and concentration level of the volatile oil. The processes include the following: - distillation - Solvent extraction - Cold pressing ### Distillation ### This method is used mainly to extract essential oil from plants like tea tree, lavender, eucalyptus, and so on, especially from the bark, roots, seeds and peels. The plant parts are put in distillation apparatus and heated over water. The stem from the water distills out the volatile compound from the plant parts. This is then collected in containing vessel as distillate. ### Extraction by solvent ### This method of extraction is used to extract essential oil from plant parts with low concentration of the oil, for example from most flowers. Moreover, the chemical components of the oil are easily denatured by high temperature and therefore can’t be distilled. Solvent extraction is therefore more suitable method for extraction of such oil. The organic solvent commonly used for this extraction process is hexane. The extract from hexane (known as concrete) is further extracted using polar solvents like ethylalcohol to extract the scent oil from the concrete. ### Cold pressing ###

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This a mechanical process used to squeeze the oil from the plant parts. It is used to extract essential oils which are known to be of high quantity in the plant parts. For instance, the extraction of citrus peel oils. ## Chemical components of essential oils ## The chemical components of essential oils predetermine their medicinal uses. Generally, the components can be classified into two; hydrocarbons and oxygenated compounds. ### The hydrocarbon group ### This consists of terpenes which are molecules made up of isoprene unit and each isoprene unit has five carbon atoms. Most essential oils consist of large proportion of monoterpenes (ten-carbon compound from two isoprene units). They are reported to be anti-bacterial, anti-inflammatory and because they are readily oxidized they have cleansing effect, hence the use as detoxifier, an examples of essential oil rich in monoterpene are grape fruit and orange oil. Sesquiterpene is another terpene found in essential oil especially in floral oils. They are made up of three isoprene e units (=15 carbon atoms). ### The oxygenated compounds ### Essential oils also contains organic compounds with oxygen atoms they include; - Monoterpene alcohol, sesquiterpene alcohol; they are antiseptic, anti-fungal but skin irritant e.g in rosewood oil - Aldehydes: have calming effect on the nervous system, reduce stress, e.g in lemon grass and cinnamon oils - Ketones: could be toxic but they also have therapeutic effect e.g cell and tissue generation.( rosemary essential oil) - Esters: relaxing and anti-spasmodic, sedative, anti-microbial, anti-fungal, fragrant, and fruity e.g in lavender - Phenols: antiseptic, antibacterial, disinfectant, but is toxic and should be used in very small quantity and for a short period of time .e.g in tea tree oil. Other oxygenated groups that could be found in essential oils are lactones, coumarins and ethers. ## Application ## ### In Aromatherapy ### it is a complimentary therapy that uses essential oil as the main agent of treating diseases. Reports on the healing effect of essential oils have been contradictory, some belief any claim of efficacy could as well be a placebo effect (psychological attribution).

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However, a student of mine shared her experience on therapeutic effect of the scent of a particular plant grown in her neighborhood. She said that anytime someone has boots of migraine or headache, if the leaves are squeezed and the scent inhaled, there is instant relief from the headaches and migraines. I asked her to bring the leaves which were identified by a colleague who is a botanist as *Petivera alliacea*. Studies have confirmed some of these claims Medical aromatherapy is gaining grounds in Europe though it is used mostly as part of beauty treatment in America. - Effect on Sleep^{[source](https://academic.oup.com/chemse/article/31/8/731/363897)} - Reduced anxiety especially in terminal diseased patients^{[source](https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0032645/)} - As antibiotic for Antibiotic resistance bacteria^{[source](https://www.sciencedaily.com/releases/2010/03/100330210942.htm)} - In treatment of Acne ^{[source](http://europepmc.org/abstract/med/2145499)} - In treatment of dandruff ^{[source](https://www.ncbi.nlm.nih.gov/pubmed/12451368)} - in treatment of Stomach disorder using peppermint oil^{[source](https://www.sciencedirect.com/science/article/pii/S1590865807000618)} ### As Pesticides ###

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Some studies have reported that some essential oils have repelling or inhibiting effects on some insects, while they remain non-toxic to man. These natural pesticides derived from plants are known as green pesticides. They include essential oils derived from lemon grass, thyme, eucalyptus, orange peel to mention but few. I’ll be elucidating more on this in my next post on green / biopesticides.

### As flavor/Scent ### Essential oils, especially those with ester groups are used in beverage industries and confectioneries. They are also used in perfumery and cosmetics for their natural fragrance.

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## Hazards ## The potential hazard of using essential oil is in the level of purity and toxicity of the chemical components. Also, most essential oils are aroma therapeutic in nature (usually inhaled or sniffed) and should not be applied directly on the skin. ## Conclusion ## My advice therefore is that though essential oils have benefits in diverse applications, precautionary measures should be taken before using them. Some could be missed with normal body oils (like coconut oil), shampoo and so on rather than directly applying them directly on the body. Also, professional advice should be sought where necessary, like in the case of pregnant women, those having epileptic conditions and so on. Moreover, the oils should be used in minuscule quantity. Thanks for the time taken to read my post. Hope you were enlightened. ## References ## 1. https://en.wikipedia.org/wiki/Essential_oil 2. https://www.naturalfoodseries.com/30-essential-oil-benefits-uses/ 3. https://www.livescience.com/52080-essential-oils-science-health-effects.html 4. https://paleoleap.com/essential-oils/ 5. http://essentialoils.co.za/components.htm 6. http://www.experience-essential-oils.com/chemistry-of-essential-oil.html