Research On Characteristics Indices Of Sensitive Skin And Evaluation Methods Of Anti-sensitivity Activity

Sensitive skin(SS)is defined as skin that exhibits high reactivity and low tolerance,allowing the skin to easily become allergic,and concerns regarding SS have gradually increased due to changes of environment and cosmetic industry and increased awareness of skin health.To explore the physiology difference between SS and normal skin(NS)with its causes and test the scientificity of common evaluation methods of anti-sensitive activity,the main works and results are as follows:1)Result of 325 questionnaires shows that the incidence of SS in 18 to 25-year-old youth is about 31%(33% for female,21% for male).2)Comparing the facial sebum secretion,TWEL,moisture content,p H,EI,MI and elasticity of 28 SSs and 38 NSs,results show that sebum secretion of SS is lower,which indicates that the occurence of SS could be related to the chemical composition of sebum.3)Detection of sebum chemical composition of 26 SSs and 35 NSs with UPLC-QTOFMS show that Cer,PE and DG are more in SS sebum;Glc Cer,PS,PC and TG are more in NS sebum.Analysis of the biochemical effects of those components shows that excessive cell apoptosis and moisture deficiency are potential causes of barrier dysfunction of SS,so promoting moderate proliferation of skin keratinocyte and maintaining the stability moisture of skin barrier will be necessary function of anti-sensitive ingredient.4)In vitro hyaluronidase inhibition,free radical scavenging and RBC hemolysis experiments,positive results occur on all 12 commonly-used anti-sensitive ingredients,among which olive leaf extract and brown seaweed extract show better results;5)To verify the reliability of the results of vitro biochemical experiments,detect the influences of 9 water-soluble anti-sensitive ingredients on expression of cytokines like VEGF and protein m RNA like AQP3 of Haca T cell by flow cytometry and Real-time PCR.The results show that 9 ingredients in low concentration range could promote low expression of IL-6,IL-8,VEGF,which contribute to moderate proliferation and differentiation of cells in stratum corneum;at the same time,promote expression of AQP3,Caspase-14,FLG,which is good for the stability of skin moisture and structure.Oats polysaccharide and extract of Stephania tetrandra root show better results among all ingredients.6)Contrast to cells experiments in vitro indicates unreliability of 4 common biochemical experiment in evaluation of kin-barrier-restoring activity,and expressions of IL-6,IL-8,VEGF,AQP3 and Caspase-14 or FLG of Ha Ca T can test the anti-sensitive activity of ingredients more convictively.Results of this research will provide consumers with scientific perception of skin condition to choose the right cosmetics,and provide cosmetic enterprises with theoretical foundation to develop appropriate cosmetic ingredients and evaluation methods of anti-sensitive activity.