Performance of Cosmetic Ingredients Evaluated by Their Membrane Protection Efficiency

Abstract

Plant extracts (PEs) are frequently used as ingredients in skin and hair care products to improve protection against the excess of sun exposure. PEs are usually selected based on their antioxidant capacity for reducing the damage in lipids and proteins, which are key molecules in the maintenance of skin homeostasis and hair integrity. Interestingly, biomolecules that do not have any antioxidant capacity can have a protective effect by physically adsorbing and inhibiting leakage of membranes. Our aims are: 1) to develop an experimental protocol that quantifies the level of membrane damage/protection; 2) to recommend an approach to compare the membrane protection efficiency of different PEs; 3) to briefly describe the mechanisms of membrane protection. Evaluation of membrane damage/protection is based on a phospholipid liposome system that signals the membrane rupture caused by photo-induced lipid oxidation. Carboxyfluorescein (CF) emission is monitored as a function of time (120 min) in a controlled experimental setup, in which a certain level of membrane damage is induced by Dimethyl-Methylene Blue (DMMB) photosensitized oxidation during red-light irradiation. Percentage levels of membrane damage/protection are calculated by comparing the CF fluorescence level of DMMB-liposomes in the presence of varying concentrations of membrane-protective ingredients with that of surfactant-dissolved DMMB-liposomes. Membrane protectants reduce the level of CF fluorescence during irradiation of DMMB-liposomes. Gallic acid (GA) and trehalose (Tre) were used as standard compounds to compute the levels of protection by the antioxidant and physical adsorption mechanisms, respectively. The percentage of membrane protection was shown to be linearly proportional to the concentration of the standard protectants. The performance of PEs was measured and compared in terms of GA or Tre membrane protection equivalents. All extracted also had their antioxidant capacities evaluate by the anti-radical DPPH assay. The mem-*Contributed equally to the manuscript.

In Vitro Screening of Ecotoxic and Cytotoxic Activities of Ailanthus altissima Leaf Extract against Target and Non-Target Plant and Animal Cells

“…One reason why the membrane of liposomes deteriorates is the lipid oxidation [97]. However, the presence of large amounts of polyphenols in the natural extract is not sufficient to explain their possible protective effects on liposomal membranes, according to the observations made by Rodrigues et al (2016) [98].…”

“…However, the presence of large amounts of polyphenols in the natural extract is not sufficient to explain their possible protective effects on liposomal membranes, according to the observations made by Rodrigues et al (2016) [98]. Among various phenolic compounds, the leaves of A. altissima contain gallic acid [22,99,100], which has a good capacity to protect membranes from oxidative stress [97].…”