We examined the effect of the daily ingestion of herb extract from Eucommia ulmoides leaves and Korean ginseng on skin damage induced by repeated UV irradiation of hairless mice. The herb extract was orally administered to mice at a dose of 1000 mg/kg/day. The hydration of mice dorsal skin decreased significantly with repeated UV irradiation, but did not decrease when the herb extract was administered for seven weeks. Transepidermal water loss (TEWL) increased with UV irradiation, but decreased with the administration of dietary herb extract. These effects were more pronounced when combined with the administration of collagen hydrolysate. Geniposidic acid from E. ulmoides leaves and ginsenoside Rg1 from Korean ginseng reduced TEWL and increased the skin moisture content of UV-damaged skin on hairless mice, respectively. We concluded that this dietary herb extract reduced the skin damage caused by UV-induced aging, with geniposidic acid and ginsenoside Rg1 detected in the blood.
Keywords: Eucommia ulmoides leaves; Korean ginseng; TEWL (transepidermal water loss); photoaging; skin hydration.