Effect of extraction and drying methods on the contents of kava pyrones and phenolic compounds in Alpinia zerumbet leaves

Abstract

Alpinia zerumbet (Pers.) Burtt and Smith (Zingiberaceae) is a perennial ginger growing in tropical and subtropical regions. It has a high valuable economic importance and it is considered as a multi-purpose plant. Previous studies have suggested that the biological activities of A. zerumbet leaves are due to its high contents of dihydro-5, 6-Dehydrokawain (DDK) along with phenolic compounds. In this study, three different extraction procedures (boiling water, autoclaving and ethanol) as well as two different drying methods (air-drying and oven-drying at 70°C) were used to obtain the extracts. The results showed that the significant high DDK content was recovered when A. zerumbet leaves were extracted with boiling water or oven-dried at 70°C. Although, autoclaving or boiling water extraction methods gave significantly higher amounts of phenolic compounds than ethanol, no significant difference was observed between both methods. Furthermore, air-drying and oven-drying at 70°C methods resulted into significant decrease in contents of phenolic compounds than not-dried A. zerumbet leaves. Thus, extraction and drying methods markedly affect the contents of DDK and phenolic compounds of A. zerumbet leaves. © 2011 Asian Network for Scientific Information.