Safety and uses of Artemisia Absinthium (Tethwein): The Wormwood in Man and Animals

Safety and uses of Artemisia Absinthium (Tethwein): The Wormwood in Man and Animals
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KHURSHID AHMAD TARIQ

Kashmir valley harbours a rich and economically valued floral diversity characterized by  multiple medicinal uses in human as well as in domestic animals. In view of the resurgence in the use of medicinal plants or natural medicine worldwide, this treasure of plants has achieved much of the importance due to their easy to use, safe, cheap, effective, easily available, cultivable and sustainable features. As source of medicines, plants have formed the basis for traditional systems times immemorial and continuously provide mankind with new remedies. In ethno-medicine, at least 75 – 80% of the world’s population in developing countries uses plant materials as their source of primary health care. Therefore, traditional knowledge is a cultural asset for recognition and preservation of these medicinal plants in Kashmir valley.

Many chemical anthelmintics are used to treat  animals suffering from worm infections. These worm infections are characterized by anemia, abortion, anorexia, reduced feed intake, impaired digestive tract function, dull hair coat, loss of blood and plasma proteins, alterations in metabolism, changes in water balance, enteritis, diarrhea, reduced body weight, wool growth, reproduction and even death due to secondary infections. The indiscriminate, untimely and excessive use of these anthelmintics has enabled the worms to develop resistance against them, which has resulted into their diminished efficacy. This has subsequently created an interest to study alternative measures based on plants for worm control in animals. Out of the many known medicinal plants, Artemisia absinthium is the most potent and shows significant anthelmintic action in terms of its high efficacy against parasitic worms.

Description of Artemisia absinthium: It belongs to the Compositae/Asteraceae family (daisies), which is characterized by medicinal features since times immemorial. It is commonly called wormwood and is locally known as ‘tethwein’ in Kashmir valley. Besides, this plant species is native to other temperate regions of the world including Eastern Europe, Western Asia, Northern Africa, parts of the USA and South America. It is found throughout the Kashmir valley usually on open mountainous slopes and on uncultivated fields with non-acidic and sandy loam soil condition. Tethwein is an erect, herbaceous, perennial plant, 0.9 to 1.9 meter tall with many branching stems that arise from a woody base with strong characteristic odour.

Its leaves are small, pinnately compound and silvery in colour with deeply dissected leaflets. Numerous small, pale yellow flower heads are borne along the branch ends and are arranged in an erect, leafy panicle. The flowering period continues from July to September and this is the right time to collect the aerial parts of the plant because at the end of growing season, the above ground parts die. The plant can be easily propagated by division or root cuttings besides the seeds.

Medicinal uses and Toxicity: The easiest way of using the A. absinthium is by preparing a water infusion of its leaves directly (tea or tincture). Its aerial parts are rich in bitter molecules (absinthin, anabsinthin) besides various organic acids and resins. Chemical analysis of A. absinthium has shown that its volatile oil is rich in monoterpenes (thujone α & β), which has a good anthelmintic (wormicidal) action, but with also adverse toxic effects. Interestingly, during the course of my PhD, I was also able to prove its anthelmintic activity against worm parasites of sheep in Kashmir valley.

Research has shown that thujone is a neuro-stimulant and acts by modulating gamma-aminobutyric acid (GABA), which is a chief inhibitory neurotransmitter in mammalian brain. The easier and rapid transcuticular absorption of its alcoholic extracts and infusions into the body of the worms is responsible for its anthelmintic activity. Besides its anthelmintic usage, the plant’s water infusion (with bitter taste) is used in indigenous systems of medicine as insecticide, as antispasmodic, anti-inflammatory, against renal disorders (as diuretic), as a  sedative, in the treatment of chronic fevers, for digestive disorders, as appetite enhancer, as an antispasmodic and antiseptic (external use for wounds, ulcers, skin blotches, insect bites and so on.  Its essential oil has antimicrobial and antifungal activity besides its usage in beverage preparation.

The crude extracts of tethwen exhibits hepato-protective action thereby preventing hepatic damage. However, its consumption is not advisable during pregnancy and lactation in human and domestic animals. In traditional folk medicine, application of its paste on head scalp is quite effective in controlling convulsions/epilepsy. The plant is commercially available as an essential oil, capsule, tablet, tincture and aqueous extract forms. However, no documented or effective pharmaceutical dosage is available despite its usage either orally or topically.

Recently, tethwein has also been claimed to have anti-cancer properties. This has been shown through in-vitro studies in mammalian breast cancer and leukemia cell lines as apoptosis (programmed cell death) activator/promoter. However, as of now no data is available about its clinical use or in case studies against cancer.

There is an urgent need to protect this species as it is susceptible to damage due to overgrazing, overharvesting, indiscriminate usage, illegal trade and invasion by exotic species. The extra and indiscriminate usage of tethwen is responsible for the development of convulsions in human because of its property of exciting the central nervous system (neurotoxic). Interestingly, the US FDA has classified wormwood as an unsafe herb due to its neurotoxicity. There is lack of awareness and knowledge among the masses about its toxic and lethal effects. Therefore, utmost care must be taken while consuming the leaves of this plant for various ailments in man and his domestic animals by the rural people.  The plant’s consumption has been reported to cause a syndrome called as absinthism characterized by addiction, gastrointestinal problems, hallucinations (auditory, visual), epilepsy, brain damage, psychiatric illness and suicide attempts. Absinth, which is an alcoholic drink prepared from the macerated leaves of A. absinthium and consumed on a large scale in various parts of the world is already banned due to its toxic cerebral effect. To conclude, people must consider tethwein’s toxic effects while using the A. absinthium (tethwen) as a medicine and its awareness must find  priority place in various forms of media for the benefit of the masses.

 

The writer has a Ph. D. in Parasitology and works as Assistant Pprofessor of Zoology at the Islamia College of Science and Commerce, Srinagar. He can be reached at: drkatariq@gmail.com