Russian tarragon

Estragole is the dominant aroma compound of many tarragon oils and contributes antimicrobial and flavouring properties. It is also a known rodent hepatocarcinogen and genotoxicant at high doses, which is the basis for restrictions on tarragon essential oil intake; aqueous extracts contain only very low amounts.

Methyleugenol adds to the spicy-anise aroma and, like estragole, is a genotoxic carcinogen of regulatory concern, reinforcing that the essential oil should not be consumed in large amounts.

These volatile monoterpenes shape the odour profile and contribute mild antimicrobial and antioxidant activity; Russian and Central Asian chemotypes are often richer in sabinene and related terpenes than in estragole.

Coumarin derivatives contribute to the plant's antioxidant activity and its characteristic sweet-hay note on drying.

These phenolic bioactives, rather than the volatile oil, are held responsible for the insulin-sensitising and aldose-reductase-inhibiting activity of the standardized ethanolic extract PMI-5011, and for much of the antioxidant activity of the herb.

These lipophilic constituents have reported antifungal and antimicrobial activity in the Artemisia genus.

Tarragon leaf is used fresh or dried as a culinary seasoning and to flavour vinegar. French tarragon is the aromatic, estragole-rich culinary type propagated by cuttings; 'Russian tarragon' is a coarser, seed-grown form with weaker flavour used similarly but less prized.

A teaspoon of dried leaf infused in hot water has traditionally been taken as a digestive, appetite stimulant and mild sedative. Water infusions carry only trace amounts of estragole and are considered low-risk.

Polyphenol-enriched ethanolic extracts have been developed and studied for blood-glucose support. Concentrated essential oil should not be ingested in quantity because of the genotoxic phenylpropanoids estragole and methyleugenol, and tarragon oil is best avoided in pregnancy.

The ethanolic extract PMI-5011 given to diabetic KK-A(y) mice lowered fasting glucose and insulin, enhanced insulin-receptor substrate signalling (IRS-associated PI3-kinase and Akt phosphorylation) and modulated glucose-metabolism gene expression in skeletal muscle, supporting an insulin-sensitising mechanism for tarragon bioactives.

In primary human skeletal-muscle cultures, PMI-5011 and isolated bioactives increased basal and insulin-stimulated glucose uptake and enhanced insulin-receptor signalling, providing human-tissue evidence for the extract's insulin-sensitising activity.

Arab physicians described 'tarkhun' (tarragon), using it to freshen the breath, aid sleep and as a mild anaesthetic for the mouth; Arab writers are credited with introducing the herb to Europe.

The species name dracunculus and folk names reflect a doctrine-of-signatures belief that the serpentine roots made tarragon a remedy for the bites of venomous creatures and mad dogs.

Gerard described tarragon as a salad herb 'not to be eaten alone' and noted its warming, appetite-stimulating qualities, reflecting its established culinary-medicinal use in Renaissance Europe.