Distribution of the plant
The genus Leontopodium (Compositae; Inulae; Gnaphaliinae sensu amplo) consists of between 30 and 40 species () found growing in mountainous areas of Japan (), Asia () and Europe (). A single species, Leontopodium alpinum Cassini, is considered to represent the genus in Europe () and the once separate Leontopodium nivale (Ten) Huet ex Hand.-Mazz. is now regarded as a subspecies, i.e. Leontopodium alpinum subsp. nivale (Ten) Tutin, stat. nov. (). The plant is protected by national legislation in Austria, Germany, Italy and Liechtenstein. Leontopodium alpinum, commonly known as edelweiss, is a perennial plant with a branching rootstock and fibrous roots (). Aerial structures exhibit wide morphological diversity (). Foliage leaves are linear to lanceolate in shape, 3-8 mm wide and pubescent. Inflorescence stalks develop from June to August and grow 2-45 cm high. The characteristically star-shaped “flower” varies in diameter from 1.5-10.5 cm and consists of an inflorescence made up of up to 12 densely aggregated capitula, which are subtended by an involucre of hairly leaves (). Leontopodium alpinum is traditionally found growing on limestone formations at altitudes up to 3140 m but can be easily cultivated on moist, humus-rich soil ().
Conventional Propagation Methods and Commercial Value
Edelweiss plants are grown without difficulty from seed obtained from either wild or cultivated sources. Larger plants are more readily obtained from subdivisions of the senescing root stock made during winter and planting these in a humus-rich soil. When placed in a sunny location, flowering will occur from June of the same year onwards. This vegetative propagation ensures uniformity of the plants grown (). Development of plants from seeds risks the production of hybrids, ready hybridization being a problem considered to be associated with the genus Leontopodium. Although classified as a medicinal plant (), Edelweiss is rarely used as such. The major commercial uses are currently purely decorative, it being offered for sale as a fresh alpine-garden plant or for dried flower arrangements (). Trading is, however, severely restricted in Europe due to the protected status of the plant.
Secondary Metabolites in Species of Leontopodium and Their Medicinal Value
Leontopodium alpinum is listed as a poisonous plant () and several reports refer to it as a herbal folk remedy, for example, in the Ukranian-Carpathian mountains () and in Poland, where it has been used in the treatment of cancer (). More commonly, the aerial parts of Edelweiss plants have been referred to as being useful in the treatment of intestinal disorders such as diarrhea, dysentery and colic (). The active constituents have not been identified; in general, relatively little research has been carried out into the secondary metabolites of Leontopodium species. However, flavonoid glycosides such as cosmosiin and polustrin have been isolated from Leontopodium ochroleucum Beau v. () and luteolin and its glucosides from Leontopodium alpinum Cass. () and Leontopodium ochroleucum (). Various hydroxyacinnamic acid esters have also been found to occur, for example, 3,4-dihydroxycinnamic and vanillic acids in Leontopodium leontopodioides (W) Beauv. () and 3-O-caffeoylquinic (chlorogenic acid) and 3,4-di-O-caffeoyl-quinic acids in L. alpinum (). Organic extracts of aerial structures of L. ochroleucum Beauv. var. campestre (Ledb.) Grub contained various terpenoids (), while L. alpinum and L. espeletia have been found to produce alkanes, predominantly C31 () and the ubiquitous sterols campesterol, stigmasterol and sitosterol ().
Although Leontopodium alpinum cannot be considered as a traditional herbal remedy of major importance, it can now be thought of as a medicinal plant with potential biological activities. The hydroxycinnamic acid esters, i.e. chlorogenic acid and 4,5-di-caffeoylquinic acid, isolated from its aerial structures have also been found to occur in the more important medicinal plants Echinacea species (), Pluchea species () and Artemisia species (). These plants have been traditionally used for the treatment of a variety of conditions, including inflammation, stomach pains, diarrhea, and liver disorders. The caffeoylquinic acids isolated from them have been found to be biologically active, possessing antimicrobial, immunostimulatory, anti-inflammatory, antioxidant and antiviral activities. Phytochemical work on Leontopodium alpinum is ongoing and will examine the intact plant, suspension cultures and “hairy” roots for the presence of other potentially active constituents known to occur in the Inulae, namely, sesquiterpenes (), sesquiterpene lactones (), flavonoid pigments and polyacetylenes. Due to the limited supply of commercially available plant material, micropropagation and other in vitro techniques will enable sufficient material to be produced for research purposes and possible commercial exploitation.
Selections from the book: “Medicinal and Aromatic Plants IV”, 1993.