In vitro skin permeation and cellular protective effects of flavonoids isolated from Suaeda asparagoides extracts

The objective of this study was to compare astragalin (kaempferol-3-O-glucoside) isolated from Suaeda asparagoides extract with kaempferol, an aglycone of astragalin showing the anti-oxidative activity, the cellular protective effect, and skin permeability. Kaempferol was superior to (+)-α-tocopherol and l-ascorbic acid known as strong antioxidants in the antioxidative activity by DPPH method and chemiluminescence assay. Astragalin and kaempferol exhibited more prominent cellular protective effect than the lipid peroxidation chain blocker, (+)-α-tocopherol. In this in vitro permeation experiment of astragalin and kaempferol through the ICR mouse skin, kaempferol permeated deeper into the skin than astragalin. These results indicate that kaempferol and astragalin can function as antioxidants in biological systems, particularly skin exposed to solar radiation, and protect cellular membranes against reactive oxygen species.