Antioxidant Effects of Caesalpinia paraensis Extract on Human Skin Lipid Peroxidation

To confirm the antioxidant effects of the extract taken from Caesalpinia paraensis (ECP), we conducted various oxidation tests where the efficacy of this extract was compared to tocopherol (Toc) and ascorbic acid (AsA). We also evaluated the antioxidant effects of ECP on human-skin-lipid peroxidation using a chemiluminescence-HPLC (CL-HPLC) method. The ECP exhibited moderate antioxidant effectiveness in the conductometric determination method (CDM) test and oven test, which we carried out in homogeneous solution systems. In the β-carotene decoloring tests, which were heterogeneous systems, ECP had a strong antioxidant effect in both lipophilic and hydrophilic radical generation systems. In the singlet oxygen generating test, the ECP demonstrated very weak antioxidant properties. Furthermore, the topical application of ECP (at a concentration of 0.1 %) significantly suppressed the increase in the squalene monohydroperoxide (SqOOH)/squalene (Sq) ratios in human skin after UV irradiation. The ECP demonstrated various antioxidant effects, especially superior efficacy in the heterogeneous systems. Human skin consists of polyphasic systems. Therefore, we consider that the ECP could effectively prevent the skin lipid peroxidation caused by UV irradiation.