Tarragon / Artemisia dracunculus – L

General features: The botanical name of Tarragon is Artemisia dracunculus -L and the plant belongs to the sunflower family. Usually, fresh or dried leaves and stems are used for the cooking. It is a perennial aromatic herb often used in culinary and medicinal practices. The herb actually originates in the Eurasian region afterward transported to the mainland Europe and North America. It has polymorphic origin. The origin is indicated by its naming like, French tarragon, Russian tarragon, Spanish tarragon, Mexican tarragon, Texas tarragon or Wild tarragon etc. They all possess the aroma with variable intensity including the other chemical contents. Concerning the aroma, French Tarragon holds the major virtues for culinary uses whereas the Russian and others varieties appear being the next. The plant is about 50 to 60 inches tall with slender and branched stems having lanceolate leaves, 1 to 4 inches long and 1/ 3 inch broad with glossy green appearance. The small yellowish flowers are grown in clusters. The plant has rhizomatous roots that helps its spreading or reproduction. French tarragon is often used for making the dishes of chicken, egg or any fish preparations. It is included in the family of four fines herbes of French culinary practices. It earns reputation, being called as the father of all French spices and often revered to be master spice by the most culinary experts. Many legendary cooks and syndicated food columnists in Europe and the US often shower high appreciation for its sensational spicy role. In other regions of the world like in Persia, Armenia, Russia, Eurasian nations and Slovenia or Hungary, the chopped and dried roots are used for spicing vinegar to make various pickles or soft drinks. Historically, the herb was introduced to the Europeans during invasion of Italy by the Mongols in 10^th century. The Mongolians used this herb as sleep aid, breath freshener and also for seasoning the meat. According to the Christian history, St Catherine brought this herb to France from Italy after visiting the Pope Clement VI. The soft pungent aroma of this herb which is often appreciated is due to the presence of cis – pellitorine, an isobutyramide.

The compound has immense pharmacological role while acting as an antagonist toward the TRPV-1 receptor thereby enabling to induce analgesia. It also has larvacidal, anti-mycobacterial and anti-tuberculosis effects. It is α – glucosidase inhibitor thus often used as anti-diabetic medication. As per its further actions, it also acts as anti-cancer, anti-inflammatory and anti-infection compound. The inhibiting action toward Acyl-CoA cholesteryl acyl transferase leads to the potential anticancer effect.

Health benefits of Tarragon: Being a spice / herb, Tarragon of any varieties provide significant number of health benefits. It is an excellent source of several minerals like Mg, Fe, Zn and Ca. In addition, it is highly enriched with vitamin – A, vitamin – C and vitamin – B6. It shows strong antioxidant effect enabling to scavenge any endogenous free radicals, harmful to the health. Consuming Tarragon leaves would help relieve pain caused by the teeth or mouth. Tarragon tea provides similar effect along with the induction of sleep at night with simultaneous calming effect. Experience further indicates that it also induces appetite and promote reproductive health for the adult female. The herb displays vermifuge ability enabling to expel parasites from the intestinal canal thereby preventing malabsorption as well as protecting from other ailments inside the intestine. Because of its anti-aggregating effect on platelets, tarragon is seen to be beneficial for the cardiovascular health particularly reducing the possibility of stroke. Other than culinary uses, the extracted oil of Tarragon finds numerous utilizations. One of them is for the aromatherapy due to its unique pleasure inducing smell. Additionally, the oil has large antimicrobial role. It also helps blood circulation enabling to remove uric acid from the blood by exerting diuretic effect. It is the reason, it is often recommended to the rheumatic and arthritic patients. The herb possesses several components which can reduce blood sugars, especially in the case of type -2 diabetic patients. Some of the compounds produce stimulating action on the CNS and also other beneficial effects on endocrine and immune system.

Chemical components: The major bioactive compounds exist in this herb are categorized as coumarins, flavonoids and phenolic acids. In addition, various terpenes, vitamins and tannins are also identified. The major terpenes are elemicin, sabinene, terpinene -4 – ol, limonene, α – pinene, Estragole, methyl eugenol and capillin. The coumarins that are found in significant amount are, 7 – methoxy coumarin, dracumerin and scopoletin. The presence of Estragole raises a question regarding the use of Tarragon since it is considered to be a suspected carcinogen and teratogen in mice. But so far no data on human is available yet. The European Union drug safety investigation indicates that the risk is minimal considering the level and amount of consumption as a spice.

Among the flavonoids and chalcones the major ones are Sukranetin, 2’,4’-dihydroxy-4 methoxy dihydro chalcone, davidagenin and 6-methoxy capillarisin. The phenyl propanoids like chicoric acid or 5 – o-caffeoyl quinic acid also exist in appreciable amount. The average essential oil content varies from 0.15 to 3.1 %. The total content and also the nature of composition vary according to the species whether Russian or French or any other kinds.

Major flavonoids and chalcones

Phenyl propenoids

Terpenes

Pharmacological effects: The herb or its extract exerts manifold physiologic effects when administered both orally or externally. Here are some of the effects described below:

Antimicrobial and antifungal action – It inhibits the growth of number of bacteria like Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes, Staphylococcus epidermidis, Bacillus subtilis and several others. It is seen effective also against Helicobacter pylori preventing the occurrence of gastric-duodenal ulcers. The herb possesses strong antifungal action which makes its application against pathogenic fungi in the field of agriculture like, Phythium ultimum, Sclerotinia fragariae, Colletrotichum gloeosporioides and many others.

Antiplatelet effect – The extract prevents platelet adhesion, aggregation and expression of several proteins induced by the thrombin. Further the extract shows inhibitory action in producing Thromboxane A₂, a potent aggregating agent. In that way, it prevents the incidence of thrombosis. The effect could be due to large presence of coumarin derivatives.

Anti-inflammatory action – The extract or oil shows potent anti-inflammatory action due to the inhibition of PGE2 formation and arresting the NO production.

Effects on stomach and liver – The herb has the ability to prevent gastric ulcer formation. Uniquely, it has been reported that it also enhances the secretion of gastric juice inside stomach. The protective action against ulceration could be due to the suppression of Helicobacter pylori. The extract can significantly lower the level of elevated liver transaminases observed during hepatitis and help further healing the necrotic zones of the organ. In that way it is helpful against the hepatitis.

Antidiabetic effect – Many of varieties of tarragon have considerable effect on diabetes. The presence of Davidagenin, Sukranetin, 6 – Methoxy capillarisin, 2’,4’ Dihydroxy – 4- methoxy dihydro chalcone, 5 – O – Caffeoyl quinic acid and 4, 5-di-O- caffeoyl quinic acid are identified to be the responsible for the anti-diabetic actions.

Effects on neurological problems – The presence of Cineole, α – pinene, Eugenol, Terpenen – 4 –ol have choline-esterase inhibitor property. Among them eugenol is seen to be highest (IC₅₀ ~ 1.0 µg / ml). In that regard the herb which is loaded with these terpenes could be preventive in the progression of Alzheimer’s, Parkinson’s or any cognitive impairments including schizophrenia. Tarragon is effective in treating autism because of its enhancing role on Rapid eye movement sleep.

Pharmacological effects

Safety:  The real issue in this concern might be the same for many spices that is due to the presence of estragole and methyl-eugenol. Estragole by itself does not exert direct carcinogenic effect. But several of its unstable metabolites have the possibility to form adducts with the nucleic acids that induces genotoxicity in the experimental rodents. The metabolism is dose-dependent but the metabolites are extremely unstable. Since the biotransformation differs in animals and humans so, it raises a doubt whether those mutagenic metabolites are produced at all within the humans or they could exert any effects. Experiments in humans actually showed no traceable DNA adduct but still no one could exclude that possibility totally. The major metabolites of estragole are depicted below. Methyl eugenol is the another component that also shows genotoxicity in rodent and mice but not in the case of human although EU food safety commission shows some concern but offers no guide line about the level or exposure for its use. In US, FDA offers no particular guidance except to be cautious about the use.

Major metabolites of estragole