Development of an enzyme-linked immunosorbent assay to determine puerarin and its aglycone daidzein.

Pueraria candollei (White Kwao Khuer) is a medicinal plant containing puerarin (8-C-glucosyl-4',7-dihydroxyisoflavone) and its aglycone, daidzein, as major isoflavonoids used for its rejuvenating and estrogenic effects. In order to analyze these isoflavonoids, an enzyme-linked immunosorbent assay (ELISA) was developed using polyclonal antibody (PAb) against puerarin. Puerarin was conjugated with bovine serum albumin (BSA) to be used as an immunogen for production of PAb from a rabbit. The PAb has been shown to be specific to puerarin and its aglycone, daidzein. An ELISA was then performed using anti-puerarin PAb in the range of 6.10 ng/ml-1.56 μg/ml of puerarin. Based on validation analysis, this analytical method by ELISA is a precise, accurate, and sensitive method for determining puerarin and daidzein in plant samples.