Comparative isoflavone HPLC fingerprints from the extracts of white kwao krua Pueraria mirifica in Thailand

Abstract

The comparative HPLC fingerprint assay for isoflavone content in P. mirifica was established with four different preparation methods including spray dry, methanol, ethanol and water extraction and with the aid of 5 isoflavone reference standards including puerarin, daidzin, genistin, daidzein and genistein. It was found that spray dried powder established highest isoflavone content (109.66 mg/100 g powder). Methanol extract sample established the highest amount of isoflavone, 54.58 mg/100 g powder compared with 26.09, 6.90 mg/100 g powder established by water and ethanol extracted, respectively. The analysis from 29 collected samples represent the provincial distribution revealed a great diversity of both total and individual assayed-isoflavone. The maximum and minimum amount of isoflavone was found in the sample collected from Kanchanaburi (198.29 mg/100 g powder) and Nan province (18.85 mg/100 g powder), respectively. The different collected site in the same province was found influenced to the amount of detectable isoflavone content in the wild plants. Analysis of the cultivated plants revealed that P. mirifica clone Doi Tao and Chaiprakarn grown in different location, harvest in different season have different isoflavone content. P.mirifica, from clonal propagation with different in differentiation stage of the tubers showed difference in isoflavone content of the tubers.