Ultrasonic extraction of anthraquinone from walnut green husk

Anthraquinone is the main component of walnut green husk. In order to measure the content of anthraquinone from walnut green husk, ethanol extraction with assisted 40 kHz ultrasonic and ultraviolet spectrophotometer method were used in this study. The extracting effect of anthraquinone by ultrasonic wave and its influenced factors were studied. The best extracting scheme and process parameters were discussed. The different extracting conditions for anthraquinone were studied. The results showed that the extracting rate of anthraquinone was related to ethanol concentration, ultrasonic time, extracting temperature and other factors. The effect of different factors on the extraction of anthraquinone was as follows: extracting temperature > ultrasonic time > ethanol concentration. According to experiments, the best extracting parameters were temperature (60 degrees C), ethanol concentration (70%), ultrasonic time (30 minutes). The anthraquinone content could reach 5.7 mg/g.