Figure 1.

Blue cohosh extract and purified saponins exert biphasic effects on cellular oxygen consumption. (A) Blue cohosh extract disrupted cellular oxygen consumption in a concentration- and time-dependent manner (left panel: Hep3B cells; right panel: T47D cells). Extract sample was tested at the concentrations of 10, 30, 50, and 100 μg mL⁻¹. Oxygen consumption rates were recorded 30, 115, and 295 s (◢) after the addition of samples to intact cells and presented as “% Inhibition” of the untreated control. Negative values indicate stimulation of oxygen consumption. Data shown are average + SD from two independent experiments for Hep3B cells (n = 3), and average + SD of three independent experiments for T47D cell. (B) Effect of 1 on cellular respiration. Compound 1 was tested at 5.6, 10.0, 17.8 and 30.0 μM. Data presentation is the same as that described in (A) except that data shown are average + SD of three independent experiments. (C) Effect of 2 on cellular oxygen consumption. Experimental conditions, data collection, and presentation are the same as described in (B) except that n = 1 for Hep3B cells and n = 3 for T47D cells. (D) Effect of 3 on cellular respiration. Experimental conditions, data collection, and presentation are the same as described in (B). The uncoupler, FCCP (0.3 μM), was used as a positive control in the initial experiments. FCCP increased respiration at all time points [T47D cells: 30 s (108%, ± 9% SD); 115 s (114%, ± 9% SD); 295 s (103%, ± 14% SD); Hep3B cells: 30 s (149%, ± 13% SD); 115 s (157%, ± 24% SD); 295 s (148%, ± 30% SD)]; representative results from one independent experiment (n = 3), controls produced similar results in multiple independent experiments. Additionally, a separate digitonin (mechanistically similar) positive control experiment was performed, Figure 2).