Extraction and antioxidant activities of flavonoids from Kalimeris indica

The subcritical water extraction technique for flavonoids from Kalimeris indica was studied, and the optimization of technological parameters were obtained by orthogonal experiments with flavonoids yield as index, and the antioxidant activities of flavonoids in the extracts were determined. The results were as follows: the flavonoids yield was 9.01% under the conditions of pressure 5.0 MPa, temperature 200℃, extraction time 25 min and the liquid-solid ratio 20 mL/g, while it was 5.12% and 7.13%, respectively by reflux extraction with water and ethanol. Compared with traditional method, subcritical water extraction method has obvious advantage in saving time and extraction rate. In addition, the flavonoids extracted from Kalimeris indica was found to be possessed power scavenging free radicals and antioxidant activities in the experiment concentration range. These results can provide references for the development of flavonoids extraction from Kalimeris indica.