The Plant, its Use and Principal Constituents
Artemisia vulgaris L., mugwort, is a very common species in Europe, Asia and North America. The drug, known as Herba Artemisiae, consists of the leaves and flowering tops of the plant. Mugwort has a faint bitter taste, that almost completely disappears upon drying.
A. vulgaris contains 0.03-0.3% essential oil, in which more than 100 components have been identified. The composition is highly variable. The main constituents depend of the origin of the plant, and are 1,8-cineole, camphor and linalool. Furthermore the sesquiterpenes vulgarin (=tauremisin), psilostachyin and psilo-stachyin C are present. Mugwort contains no sesquiterpene lactones. The plant contains flavonol glycosides, coumarins, polyacetylenes, triterpenes and carotinoids (Wichtl 1989). Thujones are only present in traces or are even absent.
The plant is traditionally used to stimulate the appetite and to relieve "painful periods". Use of extensive doses over long periods may lead to digestive and urinary disorders (Bruneton 1995). Its medicinal usefulness, however, is not documented adequately (De Smet 1993).
It is an aromatic perennial, shrub like plant, 50-150 cm high, pubescent or tormentóse. Stems are branched, red-violet, ribbed, erect and rough. They contain pith. The upper leaves are smaller than the lower. They are 3-lobed or entire, lanceolate. Lower leaves are 5-10 cm long, ovate, pinnately lobed, hairy on both surfaces. The upperside of the leaves bears no hairs and is dark green. The underside of the leaves is silver-grey with a felty-like appearance, due to the presence of hairs. This is an important difference with A. absinthii, which has hairs on both sides of the leaves. The inflorescences of mugwort are racemes of small globulous capitulae of yellow flowers. Flowerheads are small, egg-shaped, reddish, yellow, or whitish, drooping, in branched woolly spikes, heterogamous, minute. It is a very variable plant regarding the leaves and flowerheads (Wichtl 1989, Kapoor 1990, Bruneton 1995).
Because of the presence of many T-shaped hairs, the drug occurs in small "clumps". In the lower epidermis stomata of the anomocytic-type are found (Kartnig and Brantner 1992).
The French Pharmacopoeia requires the verification of the absence of thujone in a hexane extract of the plant (Bruneton 1995). This distinguises it from another European species, A. verlotorum Lamotte, with which it may be confused. A. verlotorum does contain thujone.
According to Bruneton (1995) the official drug should contain >0.1% of essential
The bitter value of A. vulgaris is lower than of A. absithium (Steinegger and Hansel 1972).
Vulgarool (Fig. 8) is a unique constituent of A. vulgaris, and can be used to identify the plant material. Vulgarool can be determined by TLC. The essential oil of mugwort is chromatographed on silica with a mixture of chloroform-methanol 98:2
Figure 8 Vulgarool as the mobile phase. Vulgarool has an Rf value of 0.45. After spraying with vanillin-sulfuric acid, a lilac colour is obtained and with Dragendorff's reagent it turns yellowish white (Nano et al., 1976).
For the identification of A. vulgaris a TLC method has been described by Kartnig and Brantner (1992). This method yields a "fingerprint" which is compared with that of a reference sample. The test solution is obtained by extracting 1.0 g of plant material with 10.0 ml of ethanol for 10 min at 60° C under refux and stirring. After filtration, the solvent is evaporated and the residue taken up in 0.5 ml ethanol. As a reference, a methanolic solution of rutin, isoquercitrin and quercitrin is used. 10 (A of the test solution is applied as a band on silica gel plates. The plates are developed over 10 cm, with ethyl acetate-formic acid-water (88:6:6) as the mobile phase. Detection is obtained by spraying with Neu's reagent and PEG 4000. The chro-matogram is evaluated under UV 366 nm. Rutin has an Rf-value of 0.1, isoquercitrin of 0.34 and quercitrin of 0.54.
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