Determination of Honokiol and Magnolol by semi-micro HPLC with electrochemical detection

Objective:A highly sensitive and selective method was developed for the determination of honokiol and magnolol HPLC-ECD using a microbore column.Method:HPLC conditions were column CAPCELL PAK C18 UG120 S-3μm (1.0 mm×150 ram),methanol-water(64:36 and 60:40,v/v) containing 0.5 % phosphoric acid and polarization potential set at + 0.8 V(vs.Ag/AgCl).Result:Peak heights for honokiol and magnolol were found to be linearly related to the amount of each honokiol and magnolol injected from 2.5 fmol-7.5 pmol.Both of the detection limit(signal-noise ratio,S/N=3)of magnolol and honokiol were 0.5 fmol.The relative standard devia- tions(RSD,n=10)were less than 2.3 % at 50 fmol,1 pmol and 5 pmol for honokiol and magnolol.Conclusion: The proposed method was applied to determine honokiol and magnolol in traditional Chinese herbal medicines and human plasma sample.