Silver birch

Betula pendula (Betula verrucosa) – Silver birch, warty birch
Betulaceae – Birch family

The raw material used in medicine is sourced from two species: the silver birch Betula verrucosa and the downy birch Betula pubescens. The pharmaceutical raw material is the leaf (Betulae folium) of both species, harvested by hand in the summer from their natural habitats, dried quickly in the open air in the shade.

Silver birch – appearance and origin:

Betula pendula is commonly found in poor, sandy soil; it also grows in forests where it sometimes forms dense groups, and it is also grown in parks and in roadsides. It is found in the whole of Europe, apart from Iceland and Portugal, in Western Syberia, in Asia Minor and in the Caucasus. It grows up to even 30 m, the tree crown is abundant, the hanging branches are covered in resin glands; the leaves are small, light green. Birch's characteristic trait is a white, shiny bark, peeling around in thin strips.

Betula pubescens is less common in Poland; wetlands, swamps and peatlands are more favorable. The species also has white bark, but it is matte with a grey hue. The downy birch leaves are rounder, and the young branches are densely covered with hairs.

Silver birch – effects and use:

Birch leaf

The birch leaves contain 1-3% of flavonoid compounds. They are flavonols: quercetin glycosides (hyperoside, quercitrin, rutoside, 3-arabinofuranoside, 3-arabinopiranoside and quercetin-3-O-rhamnoside), myricetins (myricetin and kaempferol 3-O-galactoside) and flavones (luteolin glycosides). Apart from flavonoids, the birch leaves contain catechin tannins (9%), organic acids, i.a. ascorbic acid (up to 0.5% in fresh leaves), chlorogenic acids, caffeic acid, p-coumaric acid and dammarane- and lupane-type triterpenes, free and in ester combinations with malonic and acetic acid, polysaccharides, mineral salts – mainly potassium, manganese, zinc and nickel compounds – and essential oil with a significant content of α-betulenol and acetate sesquiterpenes.

The birch leaf increases the production of urine, and of sodium and chloride ions along with it. It is likely conditioned by the flavonoid and potassium content. Infusions, decoctions and juice made from fresh leaves are recommended for increasing diuresis in so-called flush therapy, urinary inflammation caused by bacterial infections, in urolithiasis, rheumatism and gout.

Birch bark

The most interesting compound groups in the birch bark are highly biologically active triterpenes, which have anticancer and antiviral activity, especially towards HIV viruses. Pentacyclic triterpenes are mainly lupane and oleanane derivatives. The most important substances of lupane are betulin, betulinic aicd, betulinaldehyde and lupeol; for oleanane it is oleanolic acid, oleanolic acid 3-acetate and erythrodiol. In 2008 in vitro studies, betulinic acid inhibited the proliferation of Jurkat cancer cells and induced apoptosis in these cells. Other studies also suggested an anticancer effect of birch bark compounds. Moreover, betulin and its derivatives strongly inhibit virus replication, and glutaryl-dihydrobetulin had a stronger effect than zidovudine, a commonly used AIDS medication, therefore it counteracts HIV viruses. The active substances in the birch bark are also hepatoprotective. Betulin and raw material extracts are used to protect liver cells and to prevent and treat acute alcohol poisoning.