Everything on géraniol
Definition and origin of géraniol
To understand what géraniol is called rhodinol, you have to immerse yourself in chemistry.
The citral, or lemenal, is the name given to two raw formula isomers C10H16O. both components are stereoisomers: the trans isomer is known as geranial or citral a. the isomer is known as neral or citral b.
Citral is the major constituent of lemon oil and other plants of the genus cymbopogon. It is also present in essential oils of verbena, orange, lemon..
Géraniol is the alcohol corresponding to geranial. it is part of the family of monoterpenic alcohols (alcohols very similar to those of phenols without presenting the disadvantages of these).
It is obtained by fractional distillation from cympobogon winterianus jowitt by extracting all impurities without any chemical means.
Géraniol comes in the form of a colorless liquid and releases a pleasant smell of rose.
Géraniol is naturally present in many essential fruits, vegetables, spices and oils. For example, géraniol can be found in acacia oil, apple juice, beer, bergamote, coriander, ginger, muscade and thyme, ripe, blueberry, rose wood, carrot, grapefruit juice, grapes, jasmine, lavender, lemon juice, even rose juice, etc.
Chemical and physical properties of géraniol
Family: monotonous alcohols
Name uicpa: (2E)-3,7-dimethylocta-2,6-dién-1-ol
Gross formula: C10H18O
Molar mass: 154.2493 ± 0.0096 g/mol
Density: 0.8894 g·cm-3
Boiling temperature: 229 °C
Biological properties of géraniol
- bactericidal activity
- fungicide activity
- virucid activity
- imunomodulante activity
- neurotonic or sedative activity
- spasmolytic activity
Fields of application of géraniol
Thanks to its floral odor (pink) and its particular properties, géraniol is very used by:
- The cosmetic industry (lipsticks, shiny, toothpaste, toilet water, dyed background, hair lacquers, shaving lotions, hair lotions, perfumes, soaps, aerosols,),
- The pharmaceutical industry : numerous specialties for topical use (contact lens cleaners, sucker tablets, apples, suppositories (lemongrass essence, geranium essence, lavender essence, rose essence)
- Food industry : most of the time as a flavour agent (clous of cloves, caramels, chewing gum, ice creams, treats, liqueurs, cinnamon pastries). Géraniol is a product considered by the World Health Organization (oms) as a food additive without special danger.
- The detergent industry (cleaning products, aerosols)
- it is also found in the manufacture of cigarettes (additive to improve the flavor – géraniol can be found in a natural state in certain well-matured tobacco!), in industrial oils and fats, aromatic essences used in bakery and pastry, etc
- Latest application : Géraniol in aqueous solution acts in two ways on insects, regardless of the stage of metamorphosis (egg, larva, adult): by stifling and dehydration acting on chitin (the protective envelope of the insect). Géraniol is one of the best larvaicide and ovicide in the market. It is therefore a product naturally used for the prevention of chips or ticks in domestic animals or to strengthen the insecticide action of a product or even used as a repulsive against hematophageal insects (blood nourishing) in the form of a protective wrist strap.
Géraniol: effective protection against insects
This alcohol concentrates the insect repellent properties of geranium, pelargonium and other geraniaceae and acts as a formidable repulsive insect (acarians, mosquitoes, flies, ants, ticks, mites, etc.)
Although it hunts mosquitoes, flies, cancrelats, ants and ticks, there is this paradox that is the following: bees produce géraniol and use it to help them mark nectar flowers and locate the entrance of their hives.
We saw it above, géraniol acts significantly on insects. This alcohol acts directly on the cuticle of the insect (chitine) by stifling and dehydrating it.
Laboratory studies have found that the application of géraniol on the food substrate of which the insect feeds has resulted in both a very significant reduction in the number of eggs laid on this substrate, but also an ovicide activity. This substance has a strong influence on the adult insect deck. our anti-larve and anti-moustic concentrate based on géraniol has also shown excellent results on insecticide and ovicid properties.
It will be understood, in addition to acting as a repulsive, so this substance also acts as an insecticide (insect destruction). Nevertheless, biocide regulation 528/2012 (which aims to regulate the placing on the European market biocide products whose insecticides and repulsives) classes géraniol in tp19: repulsive; and not in TP18: insecticide.
Its case number (registration number of a chemical, polymer, biological sequence and alloy) is the following case n°106-24-1
In the United States, its toxicological profile allows it to be considered a low-risk pesticide.
Géraniol remains to date an interesting alternative in terms of toxicology for traditional insecticides.
Géraniol, allergenic fragrant substance
The fact that people have allergic reactions to natural materials is well known. There are women and men who do not support hazelnuts and cinnamon or who have hay fever because of pollen. and since a large number of consumers are allergic to fragrant substances, some of them or their components should be declared.
Contact allergies to cosmetic products are very common (2% of the European population would be affected) and may, among other things, cause eczema. in 45% of cases, these allergies are due to the fragrant substances contained in the cosmetic product (since 21% with the preservatives with 21% and 10% with the emulsifiers).
Previously, all fragrant substances were collected under the generic name perfume (fragrance).
Following Directive 2003/15/EC, since 11 March 2005, 26 substances, including fragrant or aromatic properties, identified as potentially allergens, must be clearly listed in the list of ingredients, regardless of their function, as soon as their concentration exceeds 0.001% in non-redged products (creams, etc.). and 0.01% in rinsed products (shampooings, etc.).
Géraniol is listed as a minimum allergen potential.
The inci statement (International name of cosmetic ingredients) does not allow to know whether a cosmetics manufacturer has used a synthetic substance, natural essential oil or an isolated component of the cosmetic ingredients since the first ones have the same inciting denomination as the second. This is why géraniol is found in many cosmetic products on the inci list of ingredients.
Natural géraniol or synthetic géraniol ?
The difference can be decisive for allergic people because there are clear and clear indications that natural oils and synthetic substances cannot be judged in the same way.
The BDIH (German interference) commissioned a study on géraniol. 50 people who reacted positively during a géraniol allergy test were tested, the study focused on the reaction to géraniol contained in essential oils.
-10 of these 50 people (20 per cent) had a reaction to the chemically isolated géraniol odorant substance.
- no one reacted to essential oils containing géraniol.
Allergic reactions due to perfumes is a priority for companies like wala (dr hauschka), which specializes in the manufacture of natural cosmetics. She also commissioned a study on géraniol.
25 people with a contact allergy to the "fragrant mix" were tested (in a university dermatological clinic). the experiment protocol provided in all 500 tests using dr. hauschka oil.
- there were only 17 allergic reactions to the 500 tests. However, it could have been expected that the number of people tested was all "confirmed" allergic.
- no allergic reaction to a concentration of 0.5%.
- 17 reactions in contact allergy only in the case of a concentration of 5%. but it is important to know that in cosmetics, essential oils are generally present at 0.5 to 1%. A 5% dosage is therefore well above normal.
The consumer can not identify at the only reading of the appellations if it is, for one of the odorous substances, a synthetic substance or the component of a natural essential oil. géraniol can be the component of a completely natural product, an essential oil for example. géraniol can also be obtained from mineral oil or completely synthesized (synthetic chemistry).
It may be of essential importance to the consumer to know whether the odorant substance is chemical or the component of a natural oil. In conclusion, prefer natural géraniol (plant extract) to synthesized géraniol.