determination of juglone (5-hydroxy 1,4-naphthoquinone) in pterocarya fraxinifolia by rp-hplc

a method for determination of juglone in leaves and hulls of pterocarya fraxinifolia was developed, based on rp-hplc. this compound was extracted from leaves and hulls by chloroform refluxing about 2 hours. the chloroform was evaporated under low pressure at   50 ºc to produce a dry residue. the remained materials were dissolved in acetonitrile to be used for determination of this compound. appropriate conditions for rp-hplc were determined using standard of juglone. these conditions include, acetonitrile percentage in mobile phase, ph of mobile phase (phosphate buffer) and temperature of column, which were 50%, 4 and 30ºc, respectively. juglone concentration was determined using standard addition method. the concentrations of juglone were 2.15, 2.74,1.77,1.12and 0.34 g in 100 g of dry leaves in may, june, july, august and september 2001, respectively. the content of juglone in hulls was 0.44 g in 100 g of dry hulls in may.