Identification and pharmacological characterization of the anti-inflammatory principal of the leaves of dwarf elder (Sambucus ebulus L.)

Aim of the study: The performed investigations aimed on the identification of the anti-inflammatory principal of extracts of leaves of Sambucus ebulus L (dwarf elder) in order to rationalize the traditional use of this plant for the treatment of chronically inflammatory diseases. Materials and methods: Dwarf elder leaf extract was subjected to activity guided fractionation using inhibition of TNF alpha induced expression of vascular cell adhesion molecule 1 (VCAM-1) on the surface of human umbilical vein endothelial cells (HUVECs) as monitoring tool (positive control: parthenolide 10 mu M, VCAM-1 expression (% of control): 5.35 +/- 0.38%). Results: Bio-guided isolation resulted in identification of ursolic acid as anti-inflammatory principal. Besides its inhibitory effects against TNF alpha induced expression of VCAM-1 (IC50 6.25 mu M), ursolic acid inhibits also TNF alpha induced expression of ICAM-1 (IC50 value between 3.13 and 6.25 mu M) (positive control: parthenolide 10 mu M, ICAM-1 expression (% of control): 38.89 +/- 16.6%). Toxic effects of ursolic acid on HUVECs can be drastically reduced using an enriched extract instead of the pure compound. Conclusions: Our findings suggest an additional mechanism of the anti-inflammatory activity of ursolic acid by demonstrating its ability to inhibit TNF alpha-stimulated expression of VCAM-1 and ICAM-1 and support the traditional use of extracts and preparations of Sambucus ebulus L, rich in ursolic acid, for the treatment of chronically inflammatory processes. (C) 2010 Elsevier Ireland Ltd. All rights reserved.