Optimizing a recombinant estrogen receptor binding assay for analysis of herbal extracts

Publication date: Available online 10 December 2018Source: Journal of Herbal MedicineAuthor(s): Sandra L. Gray, Brett R. LackeyAbstractPhytoestrogens may directly or indirectly affect the function of estrogen receptors. A method using human recombinant estrogen receptors alpha and beta (ERα and ERβ) was adapted for pure isoflavone compounds: glycitein, glycitin, biochanin A and formononetin; and extracts from chaste tree, Queen-Anne’s lace, Cyperus rhizome, dong quai, flaxseed, black cohosh, Siberian ginseng, saw palmetto, hops, licorice, red clover and alfalfa. Estrogen binding equivalents (EBE) for extracts binding with ERα were: black cohosh < Queen-Anne’s Lace < saw palmetto < hops concentrate < licorice < red clover < alfalfa. Extracts from Cyperus, flaxseed, Siberian ginseng, chaste tree and dong quai had no detectable binding to ERα. For ERβ the estrogen binding equivalents were: chaste tree berry < hops concentrate < Cyperus rhizome < black cohosh < Siberian ginseng < dong quai < Queen-Anne’s Lace seed < flaxseed < saw palmetto berry < licorice < red clover < alfalfa. The relative binding affinity (RBA) of isoflavone standards for ERα and ERβ was compared to that of estradiol. At ERα, the RBA for isoflavone standards were as follows: glycitein > glycitin > biochanin A > formononetin and at ERβ the RBA were: bioc...
Source: Journal of Herbal Medicine - Category: Complementary Medicine Source Type: research