A ginseng-derived oestrogen receptor beta (ERbeta) agonist, Rb1 ginsenoside, attenuates capillary morphogenesis.

Ginseng extracts contain a variety of active ingredients and have been shown to promote or inhibit angiogenesis, depending on the presence of different ginsenosides that exert opposing effects on blood vessel growth. Leung et al. in this issue of the British Journal of Pharmacology report that Rb1, a ginsenoside that constitutes only 0.37-0.5% of ginseng extracts (depending on manufacturing and processing methods), blocks tube-like network formation by endothelial cells in vitro. At the molecular level, Rb1 binds to the oestrogen receptors and stimulates the transcription of pigment epithelium-derived factor that, in turn, inhibits matrix-driven capillary morphogenesis.