Artemisia Herba-Alba

2015

The genus Artemisia is a member of the large and evolutionary advanced plant family Asteraceae (Compositae). More than 300 different species comprise this diverse genus which is mainly found in arid and semi-arid areas of Europe, America, North Africa as well as in Asia. Artemisia species are widely used as medicinal plants in folk medicine. Some species such as Artemisia absinthium, Artemisia annua or Artemisia vulgaris have even been incorporated into the pharmacopoeias of several European and Asian countries.

Sesquiterpene lactones are among the most prominent natural products found in Artemisia species and are largely responsible for the importance of these plants in medicine and pharmacy. For example, the antimalarial effect of the long known Chinese medicinal plant Qing Hao (Artemisia annua) is due to the sesquiterpene lactone artemisinin which is active against Plasmodium falciparum (). Another sesquiterpene lactone, absinthin, is the bitter tasting principle found in Artemisia absinthium formerly used to produce an alcolohic beverage called “absinth”. In addition to sesquiterpene lactones volatile terpenoids that constitute the so called essential oils are also characteristic metabolites of Artemisia species. Essential oils are primarily responsible for the use of Artemisia species as spices.

In common with many other members of this genus, Artemisia herba-alba which is characteristic of the steppes of the Middle East and North Africa is used in folk medicine in order to treat various ailments that include toothache, respiratory diseases, enteritis, intestinal disturbances and diabetes mellitus.

Brief Botanical Description

Artemisia herba-alba is a perenial herb grows 20-40 cm in height; it is a chamaeophyte (i.e. the buds giving rise to new growth each year are borne close to the ground). The stems are rigid and erect. The grey leaves of sterile shoots are petiolate, ovate to orbicular in outline whereas leaves of flowering stems are much smaller. The flowering heads are sessile, oblong and tapering at base. The plants flower from September to December. Plants are oblong and tapering at base. Plants are found on the steppes of the Middle East and of North Africa where they are common and sometimes stand-forming. It has been suggested that North African Artemisia herba-alba is the same as A. inculta but a study of the sesquiterpenes from A. inculta does not support this.

Reported Uses of Artemisia Herba-Alba in Folk Medicine

Artemisia herba-alba is used in the Middle East against a variety of ailments including enteritis and intestinal disturbance. In a study aimed at revealing the rationale for the described use of these plants the essential oil of Artemisia herba-alba was tested against various bacteria that reportedly cause intestinal problems as well as for antispasmodic activity on the rabbit jejunum. The essential oil of Artemisia herba-alba collected in Israel showed antibacterial activity for example towards Escherichia coli, Shigella sonnei or Salmonella typhosa at concentrations of 1-2 mg/ml. The highest activity was found for linalool, pinocarveol and especially terpinen-4-ol. The antispasmodic effects of the essential oil of Artemisia herba-alba were approximately 100-1000 times higher than the observed antibacterial effects. The authors concluded that the extensive use of A. berba-alba in folk medicine especially against intestinal disturbances may be attributed to the combination of an antibacterial and antispasmodic effect.

By far the most frequently cited use of A. herba-elba is its employment in the therapy of diabetes mellitus. Several authors report on the hypoglycaemic effects of aqueous extracts of A. berba-alba on rabbits and mice that had been made diabetic by injection of alloxan monohydrate. Alloxan is widely used in animal experiments focussing on diabetes mellitus since it destroys the beta-cells of the islets of Langerhans. Oral administration of an aqueous extract (0.39 g plant material/kg body weight) of A. berba-alba as used in folk medicine for 2-4 weeks given to treated rabbits produced significant hypoglycaemic activity. The extract caused a pronounced fall in plasma glucose level. Maximum effect on plasma glucose concentration (22% decrease compared to untreated diabetic animals) was observed 6 h after treatment. Oral administration of the aqueous A. berba-alba extract to rabbits also protected the animals from body weight loss compared with control diabetic animals that had received no treatment. Administration of the Artemisia herba-alba extract also caused a reduction of serum lipids (); an increase in serum lipids accompanies diabetes mellitus and is a major risk factor for coronary heart disease. The frequently reported uses of Artemisia herba-alba for the treatment of diabetes mellitus and also for hypertension (the latter may be a consequence of diabetes) may thus have a rationale. The compounds responsible for the effects observed in the animal experiments, however, remain to be elucidated.

Artemisia herba-alba is one of a number of plants used traditionally in Jordan as an antidote to snake and scorpion venoms. An aqueous extract of Artemisia herba-alba was found to inhibit the haemolytic activities of the desert viper (Cerastes cerastes) and the scorpion (Leiurus quinquesteiartus). Recently, aqueous extracts of Artemisia herba-alba have been reported to protect against ethanol-induced gastric lesions in rats. Protection was found to be greatest when the extract was given at the same time as the ethanol; however, the acid content of the stomach was significantly increased by the extract. Artemisia herba-alba extract did not precipitate protein (ovine haemoglobin) and it is suggested that phenolic compounds present in the extract may strengthen the gastric mucosal barrier.

Peter Proksch

Selections from the book: “Artemisia”. Edited by Colin W. Wright. Series: “Medicinal and Aromatic Plants — Industrial Profiles”. 2002.