Extraction and determination of a-solanine in eggplant fruits

Abstract: A simple and effective high-performance liquid chromatographic (HPLC) method for determination of a-solanine in eggplant fruits is described in our study. A new extraction method is established for extracting a-solanine in eggplant fruits. Single and orthogonal tests were designed to analyze the effect of different extraction methods and ultrasonic wave extraction condition on extraction of a-solanine in eggplant fruits. HPLC separation was achieved on a Waters Nova-pak C18 column with the mobile phase acetonitrile-0.05N potassium dihydrogen phosphate (55:45, V/V). The flow rate was 0.7mL min^-1 and the UV absorbance was monitored at 202 nm. The optimal extraction method was ultrasonic wave extraction in 70% methanol for 60 minutes at 50^oC, and with material to liquid ratio of 1:10. Under the optimal extraction conditions, the average content of a-solanine in skins and flesh of dried eggplant fruits was 0.107?0.006 and 0.626?0.004mg g^-1, respectively. The average recovery efficiency was 97.97%.