Peltogynoids and 2-phenoxychromones from Peltophorum pterocarpum and evaluation of their estrogenic activity.

Phytochemical investigation of the dichloromethane extract of the leaves of Peltophorum pterocarpum, a tropical ornamental tree, led to the isolation of twelve compounds (1-12). One new derivative of peltogynoid ophioglonin (1) and a new 2-phenoxychromone (2) with its 3'-O-ß-D-glucoside derivative (3) are described here for the first time. In addition, nine flavonoid derivatives, including peltogynoid ophioglonin (4), were isolated for the first time from this plant. The structures were determined by spectroscopic and chemical methods. Evaluation of the estrogenic activities of 1, 2, and 4 using different model cell systems revealed that 4 was estrogenic and that 2 was largely inactive. Interestingly, 1 was unable to stimulate the proliferation of breast and endometrial cancer cells but exhibited substantial estrogen receptor α-mediated activation of gene expression. This observation indicates that 1 can be further evaluated for its cancer chemopreventive potential.

On-line identification of phenolic compounds of Trifolium species using HPLC-UV-MS and post-column UV-derivatisation.

In an ongoing search for new active compounds in the field of phytoestrogens, a simple HPLC-UV-MS method has been developed in order to identify phenolic compounds. The study was performed on three different species of Trifolium (Leguminosae), namely Trifolium pratense L., T. pallescens Schreb. and T. alpinum L, collected in Switzerland. The comparison between the dichloromethane extracts revealed that the main aglycones are present in the three species whereas the methanolic extracts show different glycosides and malonate derivatives. The compounds of interest were mainly flavonoids, isoflavonoids and clovamides. Their identities were confirmed from retention times, UV and MS analyses and UV shifts following post-column derivatisation.