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

Abstract

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. Dwarf elder leaf extract was subjected to activity guided fractionation using inhibition of TNFα 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 10μM, VCAM-1 expression (% of control): 5.35±0.38%). Bio-guided isolation resulted in identification of ursolic acid as anti-inflammatory principal. Besides its inhibitory effects against TNFα induced expression of VCAM-1 (IC(50) 6.25 μM), ursolic acid inhibits also TNFα induced expression of ICAM-1 (IC(50) value between 3.13 and 6.25 μM) (positive control: parthenolide 10 μM, 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. Our findings suggest an additional mechanism of the anti-inflammatory activity of ursolic acid by demonstrating its ability to inhibit TNFα-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.