Determination of contents of eight alkaloids in fruits of Macleaya cordata (Willd) R. Br. from different habitats and antioxidant activities of extracts

A reliable ultrasound-assisted extraction (UAE) method combined with HPLC-UV for quantification of eight active alkaloids in fruits of Macleaya cordata (Willd) R. Br. was developed. The optimization conditions of UAE were obtained by using Box-Behnken design of response surface methodology. Chromatography was carried out using a Kromasil C-18 column by gradient elution with 0.1% phosphoric acid aqueous solution for HPLC-UV. All calibration curves showed good linear correlation coefficients (R-2>0.999 6) and recoveries (from 97.3% to 104.9%) were acceptable. 1,1-diphenyl-2-picrylhydrazyl (DPPH) method was employed to test the antioxidant activity of the extract from the samples. The proposed method was successfully applied to quantifying eight components in nine samples of M. cordata, and significant variations of alkaloid contents and antioxidant activity of the samples from different habitats were demonstrated. It presents a powerful proof for the selection of the best sources to extract eight kinds of alkaloids.