Estragole
Estragole is a naturally occurring compound found in various plants, including herbs and spices, and is used as a flavoring agent in foods and beverages. It is a major or minor component of a large number of plants or plant parts used for herbal medicinal products, botanicals, and flavorings[1]. Some of the plants that contain estragole include anise hyssop, garden chervil, tarragon, sweet fennel, bitter fennel, star-anise, lemon balm, sweet chervil, and sweet basil[1].
Estragole is a colorless liquid with an anise odor and is insoluble in water. It has a specific gravity of 0.965 g/L, a boiling point of 215-216°C, and a flash point of 81°C[2]. It is present in volatile oils derived from plants and trees and is used in numerous foods and food products, perfumes, soaps, and detergents[2].
The European Medicines Agency (EMA) has issued a public statement on the use of herbal medicinal products containing estragole, highlighting the potential risks associated with its use. The agency notes that estragole is a naturally occurring genotoxic carcinogen in experimental animals and that 1'-hydroxyestragole, a metabolite of estragole, has been found in the urine of humans dosed with estragole[4].
The EMA recommends that the intake of estragole from herbal medicinal products and food should be minimized, and that the use of herbal medicinal products containing estragole should be subject to certain restrictions[1]. The agency also notes that the background exposure to estragole from foodstuffs and food commodities is a major factor in the risk assessment and actions to be taken[1].
In addition to its use as a flavoring agent, estragole has been reported to occur naturally in the foliar emissions of trees and other vegetation, although its atmospheric persistence is low due to its high reactivity with respect to OH radical attack[3]. It has also been detected in kraft paper mill wastewaters[3].
Overall, estragole is a naturally occurring compound with a wide range of uses, but its potential health risks, particularly its genotoxic and carcinogenic properties, need to be carefully considered and managed.
Citations:
[1] https://www.ema.europa.eu/en/documents/other/public-statement-use-herbal-medicinal-products-containing-estragole-revision-1_en.pdf
[2] https://oehha.ca.gov/media/downloads/crnr/estragf.pdf
[3] https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/chem_background/exsumpdf/estragole_508.pdf
[4] https://food.ec.europa.eu/system/files/2016-10/fs_food-improvement-agents_flavourings-out104.pdf
[5] https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI%3A4867