Changes in Icariin contents and antioxidant activities of Epimedium koreanum Nakai leaf by far infrared irradiation

초록

The objective of this research was to explore the suitable temperature to obtain a maximum total polyphenol content and optimum conversion of icariin using far infrared irradiation (FIR) as a thermal source of Epimedium koreanum Nakai leaf. The changes were monitored and quantified by HPLC and UV-spectrophotometry. Further, the alteration in antioxidant activity due to FIR at different temperatures was also evaluated. The increase in the temperature in FIR caused a gradual increase in icariin production. The maximum increase in icariin was achieved with 5.49 mg g(-1) DW at 100 degrees C. However, an over-exposure (120 degrees C) decreased the content. The total polyphenol content was also altered with the increase in the temperature and reached a plateau (147.10 mg GAE g(-1) DW extract) at 100 degrees C which was 1.28 fold higher than that of the control. In an antioxidant assay, the DPPH free radical inhibition activity, reducing power and total antioxidant capacity were also increased with the temperature in a dose-dependent manner in the same trend of the total polyphenol content. Overall, the FIR thermal treatment could enhance the bioactivity (antioxidant) in Epidemidium koreanum leaf by increasing total polyphenol and icariin content.

키워드