Radical scavenging effect of skin delivery systems using Korean red ginseng extract and assessment of their biocompatibility with human primary dermal fibroblasts and HaCaT keratinocytes

Korean red ginseng (KRG) extract is proposed for cosmetic use, but no data on biological effects of KRG-loaded vehicles exist. The study aimed to optimize new multi- and monophase vehicles for KRG extract delivery, assess their biocompatibility and evaluate their radical scavenging effect in vitro. Storage stability of oil-in-water nanoemulsions (NEs) and hydroalcoholic gels (2 % w/w KRG) was assessed over twelve weeks using dynamic light scattering, rheology and pH measurements. Release profiles of ginsenosides Rb1 (more hydrophilic) and Rg1 (moderately lipophilic) through a cellulose membrane were also investigated employing Franz diffusion cells. Antioxidant potential and biocompatibility were assessed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and cell viability assays. Vehicles remained stable over twelve weeks at 8 °C (NEs D_h stable, gel viscosity + 3.5 %). Diffusion studies showed higher release of Rg1 vs. Rb1 (7.10 vs. 1.39 µg/cm^-2 after 28 h). KRG-formulations demonstrated good biocompatibility with primary human dermal fibroblasts and HaCaT keratinocytes (72-94 % viability). Radical scavenging capacity of KRG extract did not differ between pure and incorporated form and was lower than that of a Hypericum extract or ascorbic acid. Results render KRG-formulations a potentially promising alternative to conventional antioxidants used in daily products.