B. verrucosa Ehrh. (= B. pendula); B. alba L. (= B. pubescens) Betulaceae European white birch; moor birch (=B. pubescens) Betulae folium; Betulae cortex Leaves; bark Several classes of pharmacologically active compounds have been isolated from both leaf and bark extracts. The main constituents are polymeric proanthocyanidins; B. pubescens dried leaves contain slightly lower levels of flavonoids (e.g. hyperoside, avacularin, quercetrin) compared with B. pendula. Other phenolic compounds include 3,4′dihydroxypropiophenone 3-glucoside (DHPPG), caffeic acid and chlorogenic acid. The essential oil (0.04–0.05% in leaves) contains methyl salicylate. The bark is rich in pentacyclic triterpenes including betulinic acid, betulin, lupeol and minor components including oleanolic acid, ursolic acid and betulinic aldehyde; fatty acids, e.g. linolenic and linoleic acids; with tannins (4–5%) and smaller amounts of lignans and diarylheptanoids (Cîntă-Pînzaru et al. 2012; Dadáková et al. 2010; Duric et al. 2013; EMA 2008a). Clinical data are lacking for all indications. There is limited evidence to suggest that birch bark topical preparations may be a potential therapeutic option for actinic keratoses (squamous cell carcinomas in situ). In one non-randomised pilot study, 14 patients with actinic keratoses were treated with a standardised birch bark ointment, and 14 patients received a combination therapy with cryotherapy and birch bark ointment. After 2 months of treatment, 79% of the patients receiving the birch bark ointment monotherapy, and 93% of patients receiving the combination therapy had more than 75% clearance of lesions (Huyke et al. 2006). Another uncontrolled clinical study investigated the hepatoprotective effect of birch bark extract in patients with chronic hepatitis C. Patients [n
Birch, Silver and Downy
Betula pendula Roth; B. pubescens Ehrh. and hybrids
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