Sometimes it is very difficult, or extremely expensive, to extract essential oils from the plant material by steam distillation or expression, for example, in the case of frangipani. Instead, the aromatic compounds are extracted from the plant material using solvents. The resulting ‘concrete’ is further processed by adding alcohol to extract the aromatic molecules, which is then gently evaporated away under vacuum, leaving the absolute. It is generally considered that an absolute is used for its perfume, rather than for therapeutic purposes, because of the nature of extraction23.
The acid mantle is the term given to describe the acidic nature of the skin. The skin pH (its acidity) influences the skin’s barrier to protection against infection and environmental damage48.
Essential oils are made up of hundreds of chemical constituents, which have specific properties. They can be grouped into chemical families, having broadly similar effects. The chemical family of alcohols have stimulating therapeutic effects, whilst being gentle20.
Essential oils are made up of hundreds of chemical constituents, which have specific properties. They can be grouped into chemical families, having broadly similar effects. The chemical family of aldehydes are anti-inflammatory, antimicrobial and relaxing23.
Amenorrhoea is the absence of menorrhoea.
Antimicrobial is the term used for the effect of a substance against various microbes, for example, bacteria, viruses or fungi.
An antioxidant is a substance that can protect cells from damage by free radicals, which occur as by-products of oxygen during normal cellular metabolism40.
Antispasmodic is the action of relieving muscle spasm or cramp.
Aromatherapy is the study of, and therapeutic use, of essential oils.
An astringent is a substance that tightens cells and tissues of the skin.
A base note is the term used in aromatherapy and perfumery to describe characteristics of an essential oil or component of a perfume. A base note essential oil comprises mainly the largest and least volatile aromatic molecules, which are released last during stream distillation. These oils lose their aroma, and oxidise much more slowly than middle or top note oils.
Bergapten is a naturally-occurring organic chemical compound, part of the family of furocoumarins, and found in essential oils such as Bergamot. It has photosensitising effects, causing the skin to be sensitive to sunlight, but can be removed to produce furocoumarin free (FCF) Bergamot essential oil.
Beta-caryophyllene is a naturally occurring chemical in certain plants and essential oils, such as Piper nigrum (black pepper), with anti-inflammatory and analgesic effects20.
Cerotic acid is a 26-carbon long chain saturated fatty acid, found in beeswax.
Cold expression is a method of extracting essential oils from citrus fruits, whereby the oil is expressed from the zest by squeezing without heat.
Cold maceration refers to the steeping of plant material in a liquid to extract the plant oils. Arnica flowers, for example are steeped in sunflower oil for several weeks to extract the oils.
Cold pressing refers to the pressing of fruit, seeds or nuts with a high oil content, such as jojoba, without the use of heat.
Contraindicated (contraindication) is a term used when something is not recommended, usually in relation to a therapy or treatment.
COSMOS is a certification body for natural and organic ingredients and products.
COSMOS Natural is a certification for natural ingredients and products.
Cyclomethicone is a form of silicone.
Ecocert is a certification body for natural and organic ingredients and products.
An emollient is a substance that is used to soften and smooth the skin, counteracting dryness, whereas a moisturiser adds moisture to the skin40.
Enfleurage is a traditional method of extracting essential oils from petals or leaves. The plant material is laid on trays of animal or vegetable fat for several days, and replaced regularly, until the fat is saturated with the plant extracts. The fat and flower oils, called an enfleurage pomade, is washed with alcohol so that the plant oils separate out from the fat. Once the alcohol has evaporated, the remaining oils are bottles to be used in perfumery and aromatherapy.
Essential oils are the volatile compounds of aromatic plants, so named because they embody the ‘essence’ of the plants, with distinct aromas, chemical composition and properties. They are contained in the glands, sacs, veins and glandular hairs of the plants, and can be obtained by various methods, such as steam distillation, or cold pressing.
Essential oils are made up of hundreds of chemical constituents, which have specific properties. They can be grouped into chemical families, having broadly similar effects. The chemical family of esters are a little different, as they only occur as a combination of an organic acid and an alcohol. They are very gentle and have a balancing, and anti-inflammatory action23.
Ethers are a family of naturally occurring chemicals found in certain plants and their essential oils, with anti-spasmodic and sedative properties23.
Eugenol is a naturally occurring chemical found in some plants, such as the clove bud (Eugenia Caryophyllus, also known as Syzygium aromaticum). It has been shown to have antimicrobial and antioxidant properties45,46.
Free radicals are unstable atoms that cause damage to the body, resulting in aging and degenerative disease. They are produced as a by-product of normal metabolism.
Furocoumarins are a family of naturally occurring chemicals found in certain plants and their essential oils, and have photosensitising effects, causing the skin to be sensitive to sunlight.
Gamma Linolenic Acid
Gamma Linolenic Acid is an omega 6 fatty acid, which is needed for the body to produce essential prostaglandins.
GLA is an abbreviation of Gamma Linolenic Acid.
An Immuno-stimulant is a substance that stimulates the body’s own natural defence system23.
Linoleic acid is a building block fatty acid, the shortest chain omega 6, from which other omega 6 fatty acids and gamma linoleic acid (GLA) are made.
Middle note is a term used in aromatherapy and perfumery to describe characteristics of an essential oil. A middle or ‘heart’ note essential oil comprises midsized and moderately volatile aromatic molecules. These oils lose their aroma and oxidise more quickly than base note oils, but more slowly than top note oils.
Myricyl palmitate is an ester of myricyl alcohol and palmitic acid, both long chain molecules, and is the main component of beeswax.
Myristic acid is a saturated 14-carbon fatty acid occurring in most animal and vegetable fats, such as jojoba and coconut, and has anti-inflammatory properties40.
Oestrogen is a steroidal hormone, present in both males and females, but females have much higher levels. It is present in the form of oestradiol, oestrone and oestriol and has important roles in reproduction.
Oleic acid is a monounsaturated omega-9 fatty acid, which is made naturally by the body, so is called a non-essential fatty acid.
Omega 3 is a family of polyunsaturated fatty acids, such as docosahexaeonoic acid (DHA, found in oily fish), important as anti-inflammatory agents in the body.
Omega 6 is a family of duounsaturated fatty acids, such as linoleic acid, which are needed for the body to produce essential prostaglandins.
Omega 9 is a family of monounsaturated fatty acids, which are made naturally by the body, so are called non-essential fatty acids.
Oxytocin is a peptide hormone and neuropeptide (influencing the brain), produced by the hypothalamus. It has important actions, including contraction of the womb (uterus) during childbirth and lactation, as well as mother/infant and social bonding.
Phlebitis is the term used for inflammation of a vein.
Photosensitivity is an abnormal response or increased sensitivity to UV light. It may occur in response to certain chemicals (such as furocoumarins), or drugs, resulting in skin inflammation and eruptions. Photosensitivity may be phototoxic, or photoallergic (involving an immune response) in nature51.
Phototoxicity is a form of photosensitivity, which occurs quickly after exposure to the phototoxic substance, usually within hours or days51.
Prostaglandin is a hormone-like chemical messenger, found in all cells of the body and responsible for control of many physiological functions, such as inflammation, water loss and cell membrane integrity.
Sebum is produced by sebaceous glands in the skin, forming an oily, protective layer that is very important in maintaining our skin’s acid mantle. It is made up of fatty acids, triglycerides, waxes and cholesterol.
Silicones are artificial substances, often used in cosmetics and skincare products, as they provide a smoothing effect on the skin and hair. However, they are semi-occlusive and may cause skin and hair problems over the long term.
Skin barrier is another term used interchangeably with ‘acid mantle’.
Skin mantle is another term used interchangeably with ‘acid mantle’.
Steam distillation is the most common method of extracting essential oils. The plant material is exposed to steam so that the tiny molecules of essential oil can evaporate. The molecules cool as they travel away from the steam, condensing back into liquid form.
Supercritical CO2 extraction
Compressed carbon dioxide (CO2) is used to extract essential oils in the supercritical CO2 extraction method. The CO2 is under high pressure and low temperatures, resulting in a purer oil, considered to be more like the original essential oil in the plant’s natural state23.
A tisane is a ‘tea’ made from herbs and water, but does not contain any tea leaves from the Camelia Sinensis plant.
Thymol is a naturally occurring substance in essential oils of plants belonging to the Lamiaceae family, such as thyme (Thymus) and oregano (Origanum). It has several important properties, including antioxidant, anti-inflammatory and antimicrobial actions50.
Top note is a term used in aromatherapy and perfumery to describe characteristics of an essential oil. A top note essential oil comprises mainly the smallest and most volatile aromatic molecules. These oils lose their aroma and oxidise more quickly than middle or base note oils.
We can lose water through the epidermal layer of the skin, from the inside of our body to the outside. This is termed trans-epidermal water loss.
“Varroa destructor …….is a parasitic mite of adult bees and brood. In the past hundred years or so it has become the most serious pest of Western honeybees across the globe, particularly for the European honey bee Apis mellifera which lacks natural defences to be able to deal with the mite by themselves. When populations overwhelm a colony, it leads to a disease called Varroosis and if left untreated an infested colony will usually die within 2-3 years”49.