Artemisia dracunculus L., French Tarragon, is a perennial herb, native to Europe, Russia, Siberia, China and western and central North America where it grows wild, especially along river banks. It was introduced to Britain in the mid-fifteenth century. This aromatic plant has an extensive fibrous root system which spreads by runners and stems which reach a maximum heigh of around 1 metre. The generic name is derived from the Greek Goddess Artemis who was believed to have given this group of plants to Chiron the centaur, while the specific name is derived from the Latin dracunculus meaning small dragon or snake, probably in reference to the long tongue-shaped leaves. Its common name of tarragon is thought to be a corruption of the Arabic tarkhun also meaning a little dragon. French tarragon is used mainly as a culinary plant, although its value and popularity in cooking doubtless stems from it medicinal use as an aid to digestion whereby it can be taken as an infusion, or digestif, for poor digestion, intestinal distension, nausea, flatulence and hiccups, not to mention its claimed abilities to improve rheumatism, gout and arthritis as well as acting as a vermifuge and an agent to soothe toothache.
French tarragon, unlike the closely related Artemisia annua and Artemisia absinthium is used solely as a culinary herb. As such, it is widely used in sauces, fines herbes mixtures, marinades, vinegars and preserves, particularly in Chinese and French cuisine. It is best used fresh or with the flavour preserved in oil or vinegar. Where drying is the only option for long-term storage, it should be undertaken as quickly as possible at a temperature of less than 35° C, otherwise the volatile oil is lost and the leaves turn brown. Drying also substantially reduces the microflora associated with fresh plant material. Freezing is another option which allows for French tarragon to be available over the winter months. Although not strictly a medicinal plant, its beneficial properties have long been recorded. The 13th century Spanish physician and botanist Ibn Baithar stated that fresh shoots of French tarragon were cooked with vegetables and the juice of the tarragon used to flavour beverages. He further stated that French tarragon sweetens the breath, dulls the taste of medicines while promoting sleep.
French tarragon is an important culinary herb generally used in mild-flavoured egg and poultry dishes, mayonnaise, salad dressings, light soups, herb butter for vegetables, steak and grilled fish.
A number of studies have been undertaken into the bioactive properties of the volatile oil from Artemisia dracunculus (). In two studies into insect responses to the volatile oil and its constituents, Papilio spp. evoked different reactions to the oil. Using GC coupled electroantennograms, they were able to demonstrate which components from the oil were active in determining oviposition preference and larval performance, areas where plant extracts could be used in insect control. In a further study, the attractiveness or repulsiveness of Artemisia dracunculus volatile oil towards insects infected with tick-borne encephalitis virus allowed not only those infected to be distinguished from those uninfected, but to identify individuals with varying degrees of virus replication.
The antimicrobial properties of various species of Artemisia are well recorded where a number of Gram positive and Gram negative bacteria were inhibited in their growth. The test bacteria are all capable of infection, and include Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus (Enterococcus) faecalis. In a similar study of Artemisia dracunculus oil, Deans and Svoboda included the anaerobic bacterium Clostridium sporogenes as well as Salmonella pullorum and Yersinia enterocolitica, the latter organism having the ability to produce an enterotoxin under conditions of refrigeration. A. larger group of bacteria was tested against a number of Italian species, including Artemisia dracunculus, and found to be very active at preventing the growth of human pathogens, food spoilage/poisoning types as well as animal pathogens.
Mehrotra et al. () reported the marked antifungal activity of Artemisia dracunculus volatile oil against Candida albicans and Sporotrichum schenkii, while Margina and Zheljazkov have highlighted the susceptibility of Artemisia dracunculus to the pathogenic rust fungus Puccinia dracunculina.
Artemisia Dracunculus: Conclusions
French Tarragon has a long history of use as a culinary and medicinal plant. It grows in a wide variety of habitats in various types of soil, preferring light and well aired sites. The composition of the volatile oil varies widely according to geographical location, climate, day length, soil type and cultivar. Its traditional ethnopharmacological applications have been enhanced by more recent studies into the phytochemical nature of the individual oil components. These investigations have revealed the extensive antibacterial, antimycotic and insect-interactive properties of the volatile oil.
Stanley G. Deans and Elisabeth J.M. Simpson
Selections from the book: “Artemisia”. Edited by Colin W. Wright. Series: “Medicinal and Aromatic Plants — Industrial Profiles”. 2002.