Figure 2.

The majority of the in vitro monocyte/macrophage stimulatory activity of extracts from bulk Echinacea plant material is abrogated by treatment with lipoprotein lipase and polymyxin B. 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”). Preparation of extracts and assay protocols are the same as described in Fig. 1. In the lipoprotein-sensitive THP-1 cells (a), black bars represent extracts added to cell culture after they were incubated at 37°C for 16 hours with lipoprotein lipase (1 mg/ml), 10 μM AEBSF protease inhibitor cocktail solution (Sigma), 1% octylglucoside and 0.2% BSA. Control extracts (without lipoprotein lipase, white bars) were run under identical conditions prior to adding to culture wells. In the LPS-sensitive RAW 264.7 cells (b), extracts were added to cell culture in the presence (black bars) or absence (white bars) of polymyxin B (100µg/ml). Polymyxin B was added 30 minutes prior to sample addition. Ultra pure E. coli LPS (UL) was run at 100ng/ml and synthetic lipoprotein Pam3CSK4 (P) at 0.5ng/ml. (CT) refers to untreated cells. Numbers below bars indicate extract medium concentrations in µg/ml. Values are the average of duplicate determinations ± range from a representative experiment that was repeated twice.