Yongkai Sun

Isolation of linoleic acid as an estrogenic compound from the fruits of Vitex agnus-castus L. (chaste-berry)

A methanol extract of chaste-tree berry (Vitex agnus-castus L.) was tested for its ability to displace radiolabeled estradiol from the binding site of estrogen receptors alpha (ERalpha) and beta (ERbeta). The extract at 46 +/- 3 microg/ml displaced 50% of estradiol from ERalpha and 64 +/- 4 microg/ml from ERbeta. Treatment of the ER+ hormone-dependent T47D:A18 breast cancer cell line with the extract induced up-regulation of ERbeta mRNA. Progesterone receptor (PR) mRNA was upregulated in the Ishikawa endometrial cancer cell line. However, chaste-tree berry extract did not induce estrogen-dependent alkaline phosphatase (AP) activity in Ishikawa cells. Bioassay-guided isolation, utilizing ER binding as a monitor, resulted in the isolation of linoleic acid as one possible estrogenic component of the extract. The use of pulsed ultrafiltration liquid chromatography-mass spectrometry, which is an affinity-based screening technique, also identified linoleic acid as an ER ligand based on its selective affinity, molecular weight, and retention time. Linoleic acid also stimulated mRNA ERbeta expression in T47D:A18 cells, PR expression in Ishikawa cells, but not AP activity in Ishikawa cells. These data suggest that linoleic acid from the fruits of Vitex agnus-castus can bind to estrogen receptors and induce certain estrogen inducible genes.

Evaluation of Major Caffeic Acid Derivatives in Echinacea purpurea Dietary Supplements by HPLC with Photodiode Array Detection and Electrospray Mass Spectrometry

Abstract An RP‐HPLC method with photodiode array detection and electrospray ionization mass spectrometry was established for the determination of major caffeic acid derivatives (caftaric acid, chlorogenic acid, cynarin, and cichoric acid) in commercial Echinacea purpurea dietary supplements. The samples were extracted with 60% methanol (3 × 15 mL) by means of sonication at room temperature. The components of interest were separated on a RP‐18 chromatography column using a 20‐min water–methanol–trifluoroacetic acid (TFA) gradient, identified by photodiode array detection, and further confirmed by LC‐ESI‐MS. The quantification was performed using external standards. The sample preparations and stability of the methanolic extracts were extensively explored. Analyses of 16 commercial E. purpurea products revealed that there is a considerable variability in the content of the caffeic acid derivatives among the products tested. The current method may serve as a valuable tool for the Quality assurance (QA)/Quality control (QC) of echinacea dietary supplements.