The birch tree, whose bark of white silver crack over time, has flowers with stamen filaments estamíneos bífidos, unisexual with an ovarian bilocular, ready Monoecius, forming long amentos hanging. The result is an achene surrounded two membranous wings.
Source
This genre-taxonomy is debatable, is typical of the temperate northern hemisphere. B. alba, a species common in the forests of sunny sandy soil of northern and southern Europe, is also in the Asian subarctic and temperate zone.
Chemical composition
It was pretty well known the composition of the road: vitamin C, carotene, acids, phenols, glucoside 3,4 '-dihydroxy propiofenona, Rose and, above all, and flavonoids derived from the metabolism terpénicos: monoterpenes, triterpenes, poliprenoles.
• Flavonoids. The St. John's wort (3 galactosides in quercetol) is the largest compound (2-3%) of total flavonoids, which are concentrated primarily on the upper epidermis [380]. Is accompanied by other heterósidos of flavonols: rutoside, and other quercitrósido Ramnäs, arabinose and galactose of quercetol, kenferol and miricetol, as well as traces of heterósidos of flavones [381,383].
• Glycosides monoterpenes: betulalbósidos, derived from hidroxilinaloles [384].
• triterpenes. Tetracíclicos compounds derived from damarano, have a side chain unsaturated or cyclic and are polihidroxilados: betulafoliendiol, triol-,-tetrol. It has also revealed the presence of derivatives bawdy: betulinol acid, betulin ....
Pharmacological data
The leaves have a recognized property diuretic, but the pharmacological data are generally very old. German researchers have shown that the drug spray, and to a lesser extent, the total flavonoid fraction, causing the dog-in-an increase of diuresis [385]. In 1988, Rau Schilcher and clearly showed the role of this drug in the renal elimination of water and electrolytes [391].
The birch sap (contains mainly sugars), administered per os to the rat, is weakly diuretic and prevents the formation of urinary calculi [387].
Observations on the Man
According Decaux [386], Winternitz found the diuretic properties of the leaves of birch (1897) for the treatment of edema cardiorrenal home. Other observations of the same type were carried out by Decaux. Leclerc said that the drug would be useful in the treatment of rheumatic disorders and gotosas.
Cellulite on their action would lead to a "destruction of the nodules fibro-conjunctive."
Employment
French law recognizing the leaf birch therapeutic indications follows: "traditionally authorized to facilitate the functions of digestive and kidney removal." A review of literature highlights the indications due to its diuretic activity [392]. Tests of acute and subacute toxicity by the oral route have not revealed any toxic effects in animals (2.6 g / kg, 300 and 900 mg / kg / day, dust criomolido of drugs, rat, per os) [393] .
They are also used other parts of the birch:
• buds. Its composition differs little from the flavonoids in the leaves. It contains an essential oil rich in hydrocarbons and alcohols Sesquiterpenes [388]. It is used as a diuretic and rheumatic disorders.
• The bark. This part of the tree is very rich in triterpenes bawdy (betulinol, lupeol, and lupandiol-triol acid, betulin ...) and suberina which is a polymer whose constituent monomers are acids?-Hydroxyl of C16-C24 [389]. It also contains tannins, Betula, allantoin and, like the leaf, is used as a diuretic. It is also hypotensive and healing.
The drug
The leaves are harvested preferably in late spring. The blade (3-7 x 2-4 cm) forms a rounded lozenge (young leaf) or a triangle very rounded at the base (old sheet). The leaves, glabrous, pointy, long petiolated, with finely toothed edges, presented in the lower face a very strong network of nerves anastomosed. The drug powder contains calcium oxalate crystals, polygonal epidermal cells and glands containing a brown as a shield. To identify the main flavonoids, the French Pharmacopoeia advises the analysis of an ethanol extract CFR (thin layer chromatography). In addition, you can make a HPLC (high performance liquid chromatography) [390].
