L’Astralago cretese (Astragalus creticus Lam.) è una specie arbustiva appartenente alla famiglia delle Fabaceae.
Dal punto di vista sistematico appartiene al Dominio Eukaryota, Regno Plantae, Divisione Magnoliophyta, Classe Magnoliopsida, Ordine Fabales, Famiglia Fabaceae, Sottofamiglia Faboideae, Tribù Galegeae e quindi al Genere Astragalus ed alla Specie A. creticus.
Il termine Astragalus proviene da astrágalus, una leguminosa citata da Plinio (forse dal greco ἀστράγαλοϛ astrágalos astragalo, aliosso, tallone, vertebra, un osso utilizzato da greci e romani per ottenere anche dadi da gioco a cui si richiama la forma spigolosa dei semi (secondo A. Gentil e Dave’s Garden) opputre delle radici nodose (secondo D. Gledhill e Flowers in Israel). Secondo A.Neill, il nome deriverebbe invece da ἀστήρ astér astro, stella e da γάλα gála latte, per la forma e colore del fiore e perché si riteneva che incrementasse la produzione di latte delle capre che se ne cibano, come anche il nome comune inglese Milk vetch sembrerebbe confermare).
L’epiteto specifico creticus proviene dall’antico greco Κρήτη Krētē Creta: dell’isola di Creta, cretese.
Distribuzione Geografica ed Habitat –
L’Astralago cretese è una specie endemica dell’isola di Creta dove è confinato ai tre massicci principali, dove è comune mentre è assente nella zona di Lefka Ori o Madàres, la catena montuosa situata nella parte occidentale di Creta.
Il suo habitat è quello dei pendii rocciosi asciutti dai 700 ai 1400-2300 m. s.l.m., generalmente su suoli calcarei, in consociazione con specie xerofile e spinose.
Astragalus creticus is a short stature, thorny deciduous shrub with densely branched stems that forms a wide and thorny cushion 10-30 cm high.
The leaves are paripinnate and the spine ends with a sharp spine.
The flowers are 10-12 mm yellow in color, and arranged in pairs in the axil of the leaves; the conformation is typical of legumes.
The species is hermaphrodite (it has both male and female organs) and is pollinated by bees, lepidoptera (moths and butterflies).
The flowering period is between late June and mid-August.
The fruits are legumes of about 5 mm, ovoid-ellipsoid, covered with long and bristly hairs.
The Cretan astragalus is a shrub that grows in subarid areas with an annual precipitation of no more than 500 mm, with a pronounced dry period of about four months in summer and most of the rainfall in winter. It is possible to grow it outside this habitat, especially in the more continental climates. In humid climates, although it is likely to tolerate low temperatures, it is unlikely to succeed if both summer and winter are excessively rainy unless the soil is very well drained.
This species prefers a gravelly soil with a small percentage of fine soil; the soil must be dry well drained and in a sunny position.
The plant is intolerant to transplanting so it is better to place it directly in its final position.
Like other plants of the same genus, it produces an adragant gum whose color and consistency varies, both within and between species, from white to yellowish brown. The best quality rubber is ribbon and translucent. The color of the rubber, its quantity and its shape depend on the species, the techniques and the conditions of collection.
Plants are generally exploited after their second year of growth and have a profitable life span for rubber production of around 7 years.
This species has a symbiotic relationship with some soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Part of this nitrogen is used by the growing plant, but some can also be used by other plants that grow nearby.
Uses and Traditions –
Astragalus creticus produces, especially from its roots, an adragant gum which is mainly used in the food industry mainly as a thickening agent, mainly in ice cream, candies, syrups, jellies, salad dressings and mayonnaise.
The tragacanth gum has a mucilaginous and emulsifying power.
It is sometimes used as a cough remedy and is commonly used in the pharmaceutical industry in the manufacture of pills, tablets and some medicines. Its main medicinal role is as a mucilage to suspend heavy water insoluble powders such as bismuth or zinc preparations.
The gingival gum gum contains 20-30% of a water-soluble fraction called tragacantina (composed of tragacantic acid and arabinogalactan). It also contains 60 to 70% of a water insoluble fraction called bassorina.
Tragacantic acid is composed of D-galacturonic acid, D-xylose, L-fructose, D-galactose and other sugars.
Tragacantina is composed of uronic acid and arabinose; it dissolves in water to form a viscous colloidal solution.
This rubber is also used by the textile industry where rubber is used as a thickener in the preparation of boiled dyes for the printing of goblets, in the application of textile dyes, for the sizing of yarns and threads and in the dressing of silk fabrics and lace. It is also used in the printing sector; in the production of matches; the preparation of plastic materials; glue and the like; to provide gloss in water and ink colors; in perfumery; manufacture of pencils and in the paper industry as a binding agent.
In the cosmetic industry it is used in bath creams, jellies, lotions, dental creams, etc. It is also used in the production of superior types of soap.
It can be used as an agar substitute in the preparation of nutrients.
The tragacanth gum can sometimes be used as a fuel in areas where wood is scarce.
Like other plants of the same genus, this plant contains toxic glycosides and can accumulate toxic levels of selenium if grown in soils relatively rich in this element.
Preparation method –
The Cretan Astralago is a plant that has long been used in folk medicine for cases of cough also in the form of syrups and has various uses: from pharmaceutical to food.
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– Treben M., 2000. Health from the Lord’s Pharmacy, Tips and experiences with medicinal herbs, Ennsthaler Editore
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Conti F., Abbate G., Alessandrini A., Blasi C. (edited by), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
Warning: Pharmaceutical applications and alimurgical uses are indicated for information purposes only, they do not in any way represent a medical prescription; therefore, no responsibility is accepted for their use for healing, aesthetic or food purposes.