Orthogonal test design for optimizing the extraction of total flavonoids from Inula helenium.
BACKGROUND
Inula helenium, which belongs to thecomposite family, is an important crude drug in traditional Chinese medicine.


METHODS
The effects of ethanol concentration, liquid to solid ratio, extraction temperature, and duration of microwave irradiation on the flavonoid extraction yield were studied through a single-factor experiment. An orthogonal array (L9(3(4))) was then constructed to achieve the best extraction conditions.


RESULTS
Variance analysis revealed that ethanol concentration significantly affected the extraction yield. The optimal conditions were as follows: ethanol concentration, 50% (v/v); liquid to solid ratio, 15:1; duration of microwave irradiation, 240 s; and extraction temperature, 60°C.


CONCLUSIONS
Under these optimal conditions, the total flavonoid yield was 18.34 ± 0.64 mg/g. The use of a microwave-assisted process dramatically reduced the time needed for extraction of flavonoids from I. helenium.
Department of Graduate, HeBei Medical University, Shijiazhuang 050017, Hebei, China.
Chun-Yan
CY
Guo
Jin
J
Wang
Yong
Y
Hou
Yong-Ming
YM
Zhao
Li-Xia
LX
Shen
Dan-Shen
DS
Zhang
Inula helenium; microwave–assisted extraction; orthogonal design; total flavonoids