title: Reverse-phase HPLC separation of D-amygdalin and neoamygdalin and optimum conditions for inhibition of racemization of amygdalin.
abstract: In boiling aqueous solution, D-amygdalin usually begins to convert into neoamygdalin in 3 min and more than 30% of the initial D-amygdalin is found as neoamygdalin after 30 min. In this report, we establish methods for simple HPLC analysis and the inhibition of D-amygdalin conversion. D-Amygdalin and its conversion product, neoamygdalin, were clearly separated on reverse-phase column chromatography by an optimized eluent of 10 mM sodium phosphate buffer (pH 3.8) containing 6% acetonitrile. Linearity for analyzing D-amygdalin and neoamygdalin was observed in the range from 0.05 to 0.5 mM. The detection limits for D-amygdalin and neoamygdalin were ca. 5 microM per injected amount. We found that D-amygdalin conversion was completely inhibited by adding 0.05% citric acid to the aqueous solution before boiling. To prevent the loss of pharmaceutical potency of Tonin, we applied this method to measure the conversion rate of D-amygdalin. We confirmed that D-amygdalin conversion in Tonin is effectively inhibited by acidic boiling solution with 0.1% citric acid.
authors.affiliation: Department of Oriental Pharmaceutical Sciences, Kyung Hee University, Seoul, Korea.
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Hwang
authors.forename: Je-Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Yong-Moon
authors.initials: YM
authors.lastname: Lee
authors.forename: Seon-Pyo
authors.initials: SP
authors.lastname: Hong
mesh_terms: D000678:Amygdalin / Q000032:analysis* / Q000037:antagonists & inhibitors* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods
chemical_list: D000678:Amygdalin