Determination of iriflophenone 3-C-β-d-glucoside from Aquilaria spp. by an indirect competitive enzyme-linked immunosorbent assay using a specific polyclonal antibody

Polyclonal antibody against iriflophenone 3-C-β-d-glucoside (IP3G), a major compound from the leaves of Aquilaria spp., was produced for the development of an enzyme-linked immunosorbent assay (ELISA). The results showed that the antibodies were specific for IP3G. The produced antibody has low cross reactivity with iriflophenone 3,5-C-β-d-diglucopyranoside (13%), genkwanin 5-O-β-primeveroside (3.55%) and no cross reactivity found in other compounds. The range of ELISA assay extends from 100 to 1560 ng/mL with coefficient of variation (CV) 1.19% to 2.07% for intra-assay and 3.76% to 7.15% for inter-assay precision levels. The recovery rates of IP3G in the leaves of Aquilaria spp. were in the range of 96.0% to 99.0% with CV 4.50% to 5.32%. A correlation between ELISA and high-performance liquid chromatography methods was obtained when analysis of IP3G in the plant samples (R(2) = 0.9321). These results suggest that the developed ELISA method can be applied to determine IP3G content with high specificity, rapidity, and simplicity. The developed immunosorbent assay in this study provides a useful tool for the analysis of IP3G in plant samples and products.