Influence of aqueous crude extracts of medicinal plants on the osmotic stability of human erythrocytes.

This work analyzed the effects of the aqueous crude extracts of Artemisia absinthium L., Lippia sp., Bryophyllum sp., Solidago microglossa DC, Cymbopogon citratus DC and Mentha x villosa HUDSON on the osmotic stability of human erythrocytes. Hemolysis was monitored by measurement of absorbance at 540 nm following addition of erythrocytes to NaCl solutions of varying concentration. Absorbance was fitted to sigmoid regression curves given by the Boltzmann equation, and hemolysis was characterized by the NaCl concentration leading to lysis of 50% of cells (H(50)), and by the intensity (H) and the amplitude (dS) of the lysis effect. The parameters were determined in the absence and presence of the crude extracts. The extracts of Artemisia absinthium, Lippia sp., C. citratus and M. villosa protected human erythrocytes against hypotonic shock, as evidenced by a decrease in the values of H and H(50) compared to the control solution (p<0.05). The extracts of Bryophyllum sp. and S. microglossa enhanced hemolysis, since their H(50) values were higher than in the control group (p<0.05), but they also showed protective effects, as evidenced by a decrease in H and an increase in dS.

Malondialdehyde and sulfhydryl groups as biomarkers of oxidative stress in patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown origin associated with oxidative stress. The present study aimed to investigate the presence of oxidative stress in patients with newly diagnosed SLE. SLE patients (n = 36) and control subjects (n = 28) were enrolled in this study. Blood samples were used for malondialdehyde (MDA), sulfhydryl groups (SH) and uric acid determination. MDA levels (µmol/L) were higher in patients (3.9 ± 2.6) than in control subjects (1.6 ± 2.6). SH were significantly lower in SLE patients. The findings suggest that MDA can be a good marker of oxidative stress in SLE.