Diosmin and Bromelain Stimulate Glutathione and Total Thiols Production in Red Blood Cells

Abstract

Diosmin and bromelain are bioactive compounds of plant origin with proven beneficial effects on the human cardiovascular system. We found that diosmin and bromelain slightly reduced total carbonyls levels and had no effect on TBARS levels, as well as slightly increased the total non-enzymatic antioxidant capacity in the RBCs at concentrations of 30 and 60 µg/mL. Diosmin and bromelain induced a significant increase in total thiols and glutathione in the RBCs. Examining the rheological properties of RBCs, we found that both compounds slightly reduce the internal viscosity of the RBCs. Using the MSL (maleimide spin label), we revealed that higher concentrations of bromelain led to a significant decrease in the mobility of this spin label attached to cytosolic thiols in the RBCs, as well as attached to hemoglobin at a higher concentration of diosmin, and for both concentrations of bromelain. Both compounds tended to decrease the cell membrane fluidity in the subsurface area, but not in the deeper regions. An increase in the glutathione concentration and the total level of thiol compounds promotes the protection of the RBCs against oxidative stress, suggesting that both compounds have a stabilizing effect on the cell membrane and improve the rheological properties of the RBCs.

Keywords: bromelain; diosmin; oxidative stress; red blood cells.

Figure 1

Alterations in carbonyl group and TBARS concentrations in RBCs after 24 h of incubation with diosmin or bromelain. The data were expressed as mean ±standard deviation, n = 16. Statistical significance: * p < 0.05 vs. control.

Figure 2

Alterations in the total non-enzymatic antioxidant capacity in RBCs after 24 h of incubation with diosmin or bromelain. The data were expressed as mean ± standard deviation, n = 16.

Figure 3

Alterations in thiol and amino groups and glutathione concentrations in RBCs after 24 h of incubation with diosmin or bromelain. Data were expressed as mean ±standard deviation, n = 16. Statistical significance: * p < 0.05 vs. control.

Figure 4

Alterations in internal viscosity and maleimide (MSL) spin label mobility in RBCs after 24 h of incubation with diosmin or bromelain. The data were expressed as mean ± standard deviation, n = 12. Statistical significance: * p < 0.05 vs. control.

Figure 5

Alterations in the rotational correlation time of MSL and ISL attached to the crude hemoglobin after 24 h of incubation of RBCs with diosmin or bromelain. The data were expressed as mean ± standard deviation, n = 11. Statistical significance: * p < 0.05 vs. control.

Figure 6

Alterations in the h₊₁/h₀ parameters of 5-, 12-, and 16-doxy-stearic acid incorporated into the erythrocyte’s lipid membranes after 24 h of incubation with diosmin or bromelain. The data were expressed as the median with an interquartile range, n = 11. Statistical significance: * p < 0.05 vs. control.