Figure 1.

Variation in monocyte/macrophage stimulatory activity in extracts from bulk Echinacea plant material. Root and aerial (herb) raw material from E. purpurea (E.pur) and E. angustifolia (E.ang) was obtained from six commercial growers (companies “A” – “F”). The indicated plant material was extracted with hot water containing 4% SDS, followed by precipitation and washing of the precipitate with ethanol. Twenty-four hours following transfection with the NF-kappa B luciferase reporter plasmid, THP-1 (a) and RAW 264.7 (b) cells were treated with extracts. Average medium concentrations (µg/ml) for the 12 µg group (gray bars) were 15.9 (E.pur root), 16.8 (E.pur herb), 20.1 (E.ang root), and 20.2 (E.ang herb) and there was no correlation between extract yield and activity (data not shown). Four hours (THP-1) or six hours (RAW 264.7) later cells were harvested for luciferase assay. Extract from E. purpurea root (company E) was also evaluated at a concentration 20 times lower (black bar) since maximal activation was observed at the lower concentration tested for the other extracts (gray bar). Control value for untreated THP-1 cells was 0.76±0.13 and for untreated RAW 264.7 cells was 8.4±3.3. Results represent the average of duplicate samples ± range from a representative experiment that was repeated twice.