摘要
This paper reports the extraction of aloe-emodin from aloe by microwave-assisted extraction. The effects of various factors, including the solvent, the ratio （mL/g） of the solvent to the sample, microwave irradiation time and microwave power, were discussed in the experiments. The yield of aloe-emodin was determined by HPLC. The optimized conditions for micro- wave-assisted extraction of aloe-emodin were concluded as follows： the solvent is 80% ethanol （V/V） solution, microwave ir- radiation time is 3 rain and microwave power is 340 W. Additionally, HPLC fingerprint was developed for consistency evalua- tion of aloe. The similarities of 3 aloe samples obtained by microwave-assisted extraction, ultrasound-assisted extraction and Soxhlet extraction were more than 0.9, indicating that 3 aloe samples were consistent. Compared with Soxhlet extraction and ultrasound-assisted extraction, microwave extraction is a rapid method with higher yield and less solvent consumption. Aloe samples treated by microwave-assisted extraction, ultrasound-assisted extraction and Soxhlet extraction were observed using transmission electronic microscopy. The micrographs provide evidence of more breakage of chloroplasts treated by micro- wave-assisted extraction as compared to Soxhlet extraction and ultrasound-assisted extraction.
This paper reports the extraction of aloe-emodin from aloe by microwave-assisted extraction.The effects of various factors,including the solvent,the ratio (mL/g) of the solvent to the sample,microwave irradiation time and microwave power,were discussed in the experiments.The yield of aloe-emodin was determined by HPLC.The optimized conditions for microwave-assisted extraction of aloe-emodin were concluded as follows: the solvent is 80% ethanol (V/V) solution,microwave irradiation time is 3 min and microwave power is 340 W.Additionally,HPLC fingerprint was developed for consistency evaluation of aloe.The similarities of 3 aloe samples obtained by microwave-assisted extraction,ultrasound-assisted extraction and Soxhlet extraction were more than 0.9,indicating that 3 aloe samples were consistent.Compared with Soxhlet extraction and ultrasound-assisted extraction,microwave extraction is a rapid method with higher yield and less solvent consumption.Aloe samples treated by microwave-assisted extraction,ultrasound-assisted extraction and Soxhlet extraction were observed using transmission electronic microscopy.The micrographs provide evidence of more breakage of chloroplasts treated by microwave-assisted extraction as compared to Soxhlet extraction and ultrasound-assisted extraction.
基金
supported by the National Key Technology R&D Program (2006BAI09B07-02)
