Transient increase in cytosolic Ca
2+ concentration evoked by Echinacea extracts is not mediated by CB2 receptor activation. Echinacea extract (100 μg/ml)-evoked cytosolic Ca2+ transients in HEK293 cells (exposure time was 2 mins) cannot be abolished by a 10 min pretreatment with the specific CB2 receptor antagonist SR 144528 (100 μM). The effect of SR 144528 was not significant (p > 0.05) when compared to the control (without treatment of SR 144528). Data are average traces of at least 20 cells in one experiment representative of three independent experiments.