Essential oil is a volatile oil obtained from plants. They have a strong odor and undergoe evaporation on exposure to normal temperature.
They are very volatile; hence on exposure, they evaporate fast, leaving empty residues behind.
Therefore they are the essence of the flowers or fruits containing them.
They are the key components responsible for the fragrance and odor of aromatic plants.
On exposure to normal temperature, these essential oils evaporate, but some exist as liquids (anise oil, rose oil), while some are even solid crystals like mentha.
Chemically, though they are termed as oils, they are entirely different from natural oils obtained from plants. They are less complex and less dense than regular oils obtained from plants.
Essential oils are needed for healthy living, and so they are in quite demand in the market. Some of the important essential oils are
1. Essential oils use in Medicine
Many essential oils are quite important in medicine. Some of them have a direct medical application due to their inherent medicinal properties.
In contrast, others are used as flavoring agents, adjuvants, and additives to prepare medicinal formations like syrups, ointments, lotions, etc.
a) Essential oils with medicinal applications
It is used for its properties like antiseptic (to kill microbes), carminative (to expel gas in the stomach, stimulant (to improve mood), stomachic (increases hunger or appetite), and a diuretic (enhance urination, i.e., to minimize blood pressure and also prevent fluid accumulation)
It is an essential oil obtained from clove. It is used as an antiseptic, dental analgesic, tooth decay.
It is used as a nasal decongestant to relieve stuffy nose, counter-irritant, antiseptic, and expectorant (to expel phlegm from the respiratory tract).
Primarily it is used during cough and colds and hence incorporated in cold creams and balms.
As an expectorant in bronchitis, tuberculosis, and antiseptic, anesthetic (minimize or nullify pain) in inflammation.
As an Anthelmintics to remove nematode worms from the intestine of infected patients.
Myrtenal leaves are frequently used as a mild diuretic and also in liver disorders like jaundice. In Latin America, it is also recommended for gonorrhea like urogenital inflammations.
It is used as a rubefacient to enhances blood circulation when applied to the skin.
This helps the drug to be absorbed easily from the skin surface.
Hence we see many analgesics ointments comprising of diclofenac having menthol as one of the constituents.
b) Essential oils used for medicinal formulation:
Some of the medicine ingredients possess a pungent odor that might be disagreeable to consume.
Hence during the formulation of syrups, ointment, etc., an essential oil is included to mask the bad odor.
Some of the essential oils are also used as preservatives. Examples are eugenol, menthol, vanilla, etc.
2. Essential Oils Uses for food
- Essential oils impart a good and pleasant flavor when added to foodstuff.
- Some of them are also added as preservatives and sometimes as to impart health benefits like to expel gas from the stomach (carminative) to increase appetite etc.
- Some of them include fennel (due to essential oil fenchone), cardamom, etc.
- Vanilla is another one which is used in making ice creams, chocolates, etc. Safranal is used in confectionery.
- Perillaldehyde is another essential oil that forms oxime used as a sweetening agent. It is found to be about 2000 times sweeter than sugar itself.
- Citronellal is used to impart citrus flavor artificially.
To get an idea of the source of the plant producing these essential oils, refer to the list of medicinal plants.
3. Essential oils use in cosmetics
Most essential oils are used in cosmetics like perfumes, toothpaste, soaps, facial creams, etc. They impart a pleasant odor and even antiseptic properties.
It imparts citrus flavor; hence it is used in many soaps and perfumes.
Examples are Carvone used in toothpaste, mouthwashes, soaps, and perfumes. It is also used in perfumes.
It is majorly used in toothpaste and mouthwashes due to its antimicrobial, analgesic, and flavoring properties.
It is used in perfumes as it imparts the smell of French lavender oil. Geraniol and Geranyl Acetate are also used to scent the soaps and perfumes.
These essential oils are used in cosmetics and medicinal preparation because of their ability to mask the odors even at low concentrations without disturbing the actual active ingredient in the formulation.
Ex: Myrcene, Ocimene from basil
4. Essential oils to control pests/ insects
- Citronellal is an insect repellent.
- Turpentine oil is used in paints as an insect repellent.
- Carvacrol is used as a disinfectant to clean the floors, walls, and other surfaces.
- Furfural is used as insecticide, germicide, and fungicide.
- Cineole is used in room sprays. Thymol is anti-bacterial and antifungal.
5. In cold & alcoholic beverages:
Essential oils like carvone, vanilla are used in making beverages to impart a pleasant odor to preparation.