Pueraria candollei is a traditional herb widely used in Thailand as a source of phytoestrogen and was
considered to be the standard herbal estrogen replacement therapy because of its highly
estrogenic activity [1]. Isomiroestrol was a compound found in P. candollei. It has estrogenic activity the same as another miroestrol, deoxymiroestrol, and
isoflavonoids thus isomiroestrol was used as an identical marker for P. candollei [2]. To date, LC-MS-MS, LC-Q-Orbitrap/MS and enzyme-link immunoassay (ELISA) have
been used to quantify isomiroestrol levels in plant samples which has several limitation
such as long time-consuming and needed for expensive equipment [2 – 3]. Therefore,
lateral-flow immunoassay using a colloidal gold-antibody probe was developed for the
analysis of isomiroestrol in plant and product obtained from P. candollei. The competitive immunoassay was based on anti-isomiroestrol monoclonal antibody
conjugated with colloidal gold-antibody (detection reagent). Secondary antibody was
immobilized on one end of a nitrocellulose membrane (control line) and isomiroestrol-bovine
serum albumin conjugate was immobilized on the other end (test line). Then eighteen
different plant and products were tested using developed and validated method. The
detection limit of isomiroestrol was 7 µg/mL. Detection time was 15 min. Our results
demonstrated that the applied method was effective to detect isomiroestrol in P. candollei and its product.
[1] Chansakaow S, Ishikawa T, Seki H, Sekine K, Okada M, Chaichantipyuth C. J Nat
Prod 2000; 63: 173 – 175.
[2] Kitisripanya T, Jutathis K, Inyai C, Komaikul J, Udomsin O, Tanaka H, Putalun
W. J Pharm Biomed Anal 2017; 137:229 – 234.
[3] Lee JH, Kim JY, Cho SH, Jeong JH, Cho S, Park HJ, Baek SY. J Chromatogr Sci 2017;
55: 214 – 221.
