Semi-industrial isolation of salicin and amygdalin from plant extracts using slow rotary counter-current chromatography

Salicin in the bark extract of Salix alba and amygdalin in the fruit extract of Semen armeniacae were each separated by slow rotary counter-current chromatography (SRCCC). The apparatus was equipped with a 40-L column made of 17 mm i.d. convoluted Teflon tubing. A 500 g amount of crude extract containing salicin at 13.5% was separated yielding 63.5 g of salicin at 95.3% purity in 20 h using methyl tert-butyl ether–1-butanol (1:3) saturated by methanol–water (1:5) as a stationary phase and methanol–water (1:5) saturated by methyl tert-butyl ether–1-butanol (1:3) as a mobile phase. A 400 g amount of crude extract containing amygdalin at 55.3% was isolated to yield 221.2 g of amygdalin at 94.1% purity in 19 h using ethyl acetate–1-butanol (1:2) saturated by water as a stationary phase and water saturated by ethyl acetate–1-butanol (1:2) as a mobile phase. The flow rate of the mobile phase was 50 ml/min. The results show that industrial SRCCC separation of salicin and amygdalin is feasible using a larger column at a higher flow rate of the mobile phase.