Reflections concerning the safety and the activity of herbal remedies containing salicin

Author(s): Liebi, M.

Abstract: Salicin is probably the most active compound in herbal remedies of willow and poplar. It is the glucoside of salicyl alcohol and a prodrug, which is metabolized to salicylic acid. The metabolism of salicin is practically identical with the metabolism of acetylsalicylic acid.Salicylic acid was found in plasma a short time after the dosage of 55 mg salicin incorporated in a standardized extract, which was pressed to solid dosage forms.Salicortin is normally the main salicylate in willow species. In vitro (artificial intestinal fluid, Ph. Helv. VI, pH=7,4-7,6, 37 oC) the hydrolysis was not very fast (Fig.3). After six hours 60 % of salicortin have been decomposed, 2/3 of the theoretical yield could be detected as salicin (t1/2=4 h). To guarantee a high bioavailability of salicin, the hydrolysis of salicylates in salicaceae can be raised up by pH-controlled extraction procedure. The plant material has to be selected carefully, because a lot of Salix and Populus species are quite poor in salicylates. Preparations standardized to a salicin content are of advantage in phytotherapy. All other preparations cannot guarantee the daily intake of salicin proposed by the German monograph.In opposite to the acetylsalicylic acid, salicin is no direct inhibitor of cyclooxygenase in thrombocytes. Therefore, main side effects of acetylsalicylic acid are not expected for salicin in phytotherapeutic dosages (60-120 mg daily intake up to the monograph of German Kommission E).

Keyword(s): Salicylates

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