Antioxidant properties of different portions of organic Anoectochilus formosanus hayata with different drying treatments

Abstract

Anoectochilus formosanus HAYATA (Orchidaceae) is a valuable herb used as herbal medicine in Taiwan and other Asian countries. In order to enhance the economic efficiency of organic cultivation and understand how the processing affects plant properties, organic A. formosanus extracts were used as the investigative material in this study. The entire plant, the roots, stems and leaves from organic A. formosanus were freeze-dried or hot air-dried; all samples used methanol to extract. The antioxidant properties and active components were analyzed. The results indicated that antioxidant properties of both the freeze-dried and hot air-dried leaves of organic A. formosanus have better performance, including reducing power and α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity. The contents of phenols and flavonoids showed positive relationships with reducing power, DPPH radical scavenging activity and trolox equivalent antioxidant capacity. The contents of carotenoids positively correlated with trolox equivalent antioxidant capacity and the contents of all active components were negatively correlated with the ferrous ion chelating ability. To summarize the results, freeze-dried leaves of organic A. formosanus have better antioxidant properties at a suitable concentration. This study may raise the economic values of A. formosanus by the organic cultural technique.