Aesculin from Butcher's broom reduces the permeability of endothelial cells in vitro

Herbal medicinal products containing Butcher's broom (Rusci rhizoma, Ruscus aculeatus, Ruscaceae) are used as supportive medications against chronic venous disorders (CVD). Furo- and spirostanol glycosides have been suggested to be responsible for the efficacy of the drug [1]. The aim of this study was to identify phenolic ingredients in Rusci rhizoma which could contribute to the overall effect of Butcher's broom preparations. As a first result, aesculin was isolated from a defatted methanolic extract of Rusci rhizoma by liquid-liquid chromatography between butanol and water and further LC of the butanol fraction by Sephadex-LH20®, silica gel and RP-18. After structure elucidation by modern spectroscopic methods like 1D-, 2D-NMR techniques and ESI-MS, the potential of aesculin to affect endothelial barrier dysfunction in vitro was tested. Therefore, macromolecular permeability of human microvascular endothelial cells (HMECs) was measured in a Transwell® assay (0.4µm pore size) using FITC-dextran (40 kDa, 1mg/ml) as tracer. To induce endothelial barrier breakdown, HMECs were treated with thrombin (3 U/ml) for 60min. The pretreatment (30min) with aesculin concentration-dependently (0.1–10µM) inhibited the thrombin-induced rise of endothelial permeability. In summary, aesculin was for the first time described as an ingredient of Rusci rhizoma. The pharmacological results indicate that phenolic compounds of Butcher's broom, such as aesculin, might also contribute to the efficacy of the whole drug against CVD. Ongoing research focuses on the identification of further compounds from Rusci rhizoma with protective activities on the human endothelium.

Acknowledgements: Thanks are due to Prof. Dr. Heilmann for helpful discussions

References: 1. ESCOP Monographs, 2nd edition (2003).