Preliminary Study On Cosmetic Efficacy Of Bifidobacterium Infantis Strain

As one of the probiotics,Bifidobacteria have been used in food and clinical applications for many years.Since orally applied Bifidobacteria ameliorates signs of aged skin and enhances the skin barrier,there are still few studies on its direct application to the skin.Therefore,we investigated the safety and efficacy of a topically applied cell-free culture supernatant（CFS）from a Bifidobacterium infantis strain.1)Skin irritation of CFS was evaluated by in vitro keratinocyte cytotoxicity test,in vitro skin irritation test（SIT）and human skin patch test.Eye irritation was evaluated by in vitro eye irritation test（EIT）and hen’s egg test-chorioallantoic membrane test（HET-CAM）.The results showed that CFS had no skin irritation and eye irritation,indicating that it was a safe and mild cosmetic raw material.2)The antioxidant capacity of CFS was evaluated by free radical scavenging assay and the H₂O₂-induced oxidative damage model of Ha Ca T cells.The results showed that CFS had strong free radical scavenging activity on DPPH,ABTS,·OH and O₂·-radicals.In addition,CFS treatment fundamentally reduced the intracellular ROS and MDA content and improved the activities of antioxidant enzymes（CAT,SOD and GSH-Px）in H₂O₂-induced Ha Ca T cells.3)The immunomodulatory effect was evaluated by detecting the secretion levels of cytokines in human macrophages and human monocytes after CFS exposure.The results showed that CFS activated the human macrophages and monocytes,and stimulated the secretion of various cytokines,which had a certain immunomodulatory effect.4)Barrier enhancement effect of CFS was evaluated by both Ha Ca T cells and reconstructed human epidermis.The results showed that CFS up-regulated the expression of FLG,LOR,IVL,AQP3 and TGM1 genes in Ha Ca T cells and reconstructed human epidermis to enhance the skin barrier function.5)The effect of CFS on the expression of antimicrobial peptides was evaluated by both Ha Ca T cells and reconstructed human epidermis.The results showed that CFS enhanced skin microecological barrier function by up-regulating skin antimicrobial peptides（CAMP,h BD-2 and h BD-3）expression in Ha Ca T cells and reconstructed human epidermis.6)In order to further verify the efficacy of the CFS-containing cosmetics,a human efficacy evaluation was carried out on a CSF facial mask.The results showed that the CFS mask had good moisturizing,soothing,skin barrier repairing and smoothing skin effects.In conclusion,this study found that Bifidobacterium infantis CFS was a safe and non-irritating cosmetic raw material with strong anti-oxidation,immune regulation and skin barrier function enhancement efficacies.It has a potential application prospect in antioxidant and skin barrier enhancing claimed cosmetics.