Human Keratinocyte UVB-Protective Effects of a Low Molecular Weight Fucoidan from <i>Sargassum horneri</i> Purified by Step Gradient Ethanol Precipitation

• Main Authors: Ilekuttige Priyan Shanura Fernando, Mawalle Kankanamge Hasitha Madhawa Dias, Dissanayaka Mudiyanselage Dinesh Madusanka, Eui Jeong Han, Min Ju Kim, You-Jin Jeon, Kyounghoon Lee, Sun Hee Cheong, Young Seok Han, Sang Rul Park, Ginnae Ahn
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Antioxidants
• Subjects: oxidative stress; ultraviolet B; gradient ethanol precipitation; fucoidan; HaCaT keratinocyte; heme oxygenase-1
• Online Access: https://www.mdpi.com/2076-3921/9/4/340

Ultraviolet B (UVB) radiation-induced oxidative skin cell damage is a major cause of photoaging. In the present study, a low molecular weight fucoidan fraction (SHC4) was obtained from <i>Sargassum horneri</i> by Celluclast-assisted extraction, followed by step gradient ethanol precipitation. The protective effect of SHC4 was investigated in human keratinocytes against UVB-induced oxidative stress. The purified fucoidan was characterized by Fourier-transform infrared spectroscopy (FTIR), ¹H nuclear magnetic resonance (NMR), agarose gel-based molecular weight analysis and monosaccharide composition analysis. SHC4 had a mean molecular weight of 60 kDa, with 37.43% fucose and 28.01 ± 0.50% sulfate content. The structure was mainly composed of α-L-Fucp-(1→4) linked fucose units. SHC4 treatment dose-dependently reduced intracellular reactive oxygen species (ROS) levels and increased the cell viability of UVB exposed HaCaT keratinocytes. Moreover, SHC4 dose-dependently inhibited UVB-induced apoptotic body formation, sub-G₁ accumulation of cells and DNA damage. Inhibition of apoptosis was mediated via the mitochondria-mediated pathway, re-establishing the loss of mitochondrial membrane potential. The UVB protective effect of SHC4 was facilitated by enhancing intracellular antioxidant defense via nuclear factor erythroid 2–related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling. Further studies may promote the use of SHC4 as an active ingredient in cosmetics and nutricosmetics.