Investigation of the phytoestrogenic activity of Cyclopia genistoides by pER8:GUS reporter system

The popular South African herbal tea, honeybush, comprises several Cyclopia species (family: Fabaceae), amongst them Cyclopia genistoides, which is traditionally used as a restorative or expectorant, but it also consumed to stimulate milk production in breast feeding women. Recently, the phytoestrogenic potential of extracts from different Cyclopia species were reported, as well as some compounds, present in Cyclopia were also tested, however bioactivity-guided isolation have not yet been performed. A transgenic plant system, Arabidopsis thaliana pER8:GUS, was used to assay the estrogen-like activity of Cyclopia genistoides. The ethyl acetate and dichlormethane fractions of both the fermented and non-fermented leaves, derived from the methanolic crude extracts, exhibited significant bioactivity in this assay. Subsequent bioactivity guided fractionation, by the means of HPLC, RPC, CC and preparative TLC, led to the isolation of genistein, naringenin and a naringenin glycoside, which were also quantified in the fermented and non-fermented drugs to evaluate the effect of fermentation on the reported phytoestrogens. Estradiol was used as positive control and minimal active concentration was used to express the estrogenic activity.

Acknowledgements: This research was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP-4.2.4.A/2 – 11/1 – 2012 – 0001 'National Excellence Program'.

Keywords: phytoestrogen, Cyclopia, pER8:GUS

References:

Joubert E, Gelderblom WC, Louw A, de Beer DE. South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides–a review. J Ethnopharmacol. 2008; 119: 376 – 412