Photoprotective effect of Astragalus membranaceus polysaccharide on UVA-induced damage in HaCaT cells.

Background: The skin provides a predominant barrier against chemical, physical and microbial incursion. The intemperate exposure to ultraviolet A (UVA) radiation can cause excessive cellular oxidative stress, leading to skin damage, proteins damage and mitochondrial dysfunction. There is sufficient evidences supporting the proposal that mitochondria is highly implicated in skin photo-damage.

Protective effect of d-tetramannuronic acid tetrasodium salt on UVA-induced photo-aging in HaCaT cells.

UVA radiation from the sun is the main external stimulus in the pathogenesis of skin photo-aging. This process is associated with cellular oxidative stress. Here we aim at showing the protective effect of d-Tetramannuronic Acid Tetrasodium Salt (M4), a natural product, against UVA (30J/cm) irradiation-induced oxidative stress and photo-aging in HaCaT cells, and to reveal the molecular mechanism underlying the protective efficacy.

Protective Effect of L-Hexaguluroic Acid Hexasodium Salt on UVA-Induced Photo-Aging in HaCaT Cells.

This study aimed to show the α-L-Hexaguluroic acid hexasodium salt (G6) protective effect against UVA-induced photoaging of human keratinocyte cells. We found that G6 localized to the mitochondria and improved mitochondrial functions. G6 increased respiratory chain complex activities, which led to increased cellular ATP content and NAD/NADH ratio.