Extraction optimization of coumarins from radix angelicae pubescentis by HPLC-DAD coupled with uniform design

Uniform design was used to optimize extraction condition of direct refluence extraction of coumarins from the Chinese traditional medicine of radix angelicae pubescentis(Duhuo); the sum peak area of coumarins separated with high performance liquid chromatography (HPLC) at detection wavelength of 320 nm was considered as detection index, two factors of solvent concentration and extraction time were mainly studied at extraction temperature of 85°C and a volume ratio of solvent to sample of 10 : 1. Optimal subclass, quadric polynomial step by step aggression and neural network method were applied to process the experimental results. The results show that the first and second methods give the same factors combination (concentration of ethanol: 95%, extraction time: 3.6 h) and the second method is much better than the first one. The extraction model is consequently developed.