Characterization of cosmetic cream with Mesembryanthemum crystallinum plant extract: influence of formulation composition on physical stability and anti-oxidant activity.

Cosmetic or pharmaceutical composition containing superoxide dismutase (SOD) was usually used in topical administration, particularly, in fighting against skin ageing and in the protection of the skin against radiation exposure. Mesembryanthemum crystallinum is a halophyte plant widely used in the traditional medicine, characterized by the presence of anti-oxidants enzymes in responses to abiotic stresses. In the present study, we prepared a formulation with M. crystallinum extract characterized by naturally occurring SOD and catalase in association with other anti-oxidants molecules. The SOD activity was measured by 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl-tetrazolium bromide/riboflavin method, catalase by colorimetric method and the total anti-radical activity was measured by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) method. Formulations contain a significant SOD activity (8.33 U mg(-1)), a catalase activity (0.5 x 10(7) UC) and an anti-radical activity (30% of DPPH inhibition). The formulation storage (15 days at 4 degrees C) showed a marked loss of total anti-oxidant capacity. The addition of the M. crystallinum extract induced also a reduction in formulation viscosity and pH.