Figure 4.

Inhibition of IL-6 production by H. noldeae constituents. Cells were pre-treated with crude extract (a), EtoAc fraction (b) and partially purified ER 2.4 (d) and ER 2.7 (e) fractions, and caffeic acid (c) for 3 h and stimulated by LPS (1 µg/mL) for 18 h. Dexamethasone (Dex) at 20 µg/mL was used as a control. Cell-free supernatants were harvested and stored at −70 °C until analysis. The concentration of IL-6 in the culture supernatant was measured using IL-6 ELISA kit (BD Biosciences) according to the manufacturer’s instructions. For each experiment, the amount of IL-6 produced was considered as 100% and the remaining treatments was calculated as (Treatment/LPS) × 100. The results are presented as the mean ± SD from a triplicate of the representative experiment. A one-way ANOVA, followed by Benforroni’s multiple comparison test, was used to compare the sample groups. *** stands for a p < 0.0001.