Effects of ozone in normal human epidermal keratinocytes.

Ozone is a tropospheric pollutant that can form at ground level as a result of an interaction between sunlight and hydrocarbon engine emissions. As ozone is an extremely oxidative reaction product, epidermal cells are in the outer layer of defense against ozone. We exposed normal human epidermal keratinocytes (NHEK) to concentrations of ozone that have been measured in cities and assayed for its effects.

Modification of skin discoloration by a topical treatment containing an extract of Dianella ensifolia: a potent antioxidant.

Skin hyperpigmentation, and the reactions that precipitate it, have been linked to free radicals by the fact that free radical scavengers or antioxidants can slow that hyperpigmentation. We have screened several hundred plant extracts for antioxidants and discovered one that is both a strong antioxidant and can reduce skin hyperpigmentation. Extracts of Dianella ensifolia contain 1-(2,4-dihydrophenyl)-3-(2,4-dimethoxy-3-methylphenyl) propane (DP), which was found to inhibit the free radical 1-1-diphenyl-2-picryl-hydrazyl (DPPH) with an EC(50) value of 78 mum.