Mukherjee S, Yang L, Vincent C, Lei X, Ottaviani M F, Ananthapadmanabhan K P
Unilever HPC-NA, Trumbull, CT, 06611, USA.
Department of Chemistry, Columbia University, New York, NY, 10027, USA.
Int J Cosmet Sci. 2015 Aug;37(4):371-8. doi: 10.1111/ics.12205. Epub 2015 Apr 13.
Skin irritation in personal cleansing has been correlated with surfactant binding with stratum corneum proteins. Polar and non-polar oils are increasingly being used in cleansing formulations which contain high (10-15%) level of anionic and non-ionic surfactants. However, the effects of oils in modulating skin damage from a cleansing product have not been studied in any detail. The objectives of this study are to determine whether low-viscosity polar and non-polar oils differ in their ability to reduce surfactant-induced skin irritation and, if so, how it might be related to their interactions with proteins.
Surfactant-induced skin irritation was measured by a 14-day in vivo cumulative patch irritation test. The methodology was similar to the well-known soap chamber test. Surfactant interactions with the water-soluble protein, bovine serum albumin (BSA), in the presence of oils were measured by conductometric titration. The effects of low-viscosity polar and non-polar oils on stratum corneum protein dynamics in the sulfhydryl group region were studied by electron paramagnetic resonance (EPR) using the covalently bound spin-label 3-maleimido-proxyl (5-MSL). EPR measurements were performed with stratum corneums obtained from discarded skins of 3- to 4-week-old female pigs. Simulation of the complex spectra provided insights on the environment and mobility of the protein-bound spin label.
Addition of 1% polar sunflower seed oil (viscosity 42 centipoise) reduced in vivo irritation of 1% sodium lauryl ether sulphate with two ethoxylate/cocamidopropyl betaine (SLES/CAPB) by 20%, whereas 1% non-polar mineral oil (viscosity 15 centipoise) had no effect. Polar oil glyceryl trioleate (a major component in sunflower seed oil) at 10% level reduced surfactant binding to BSA protein in water by 40%, whereas the non-polar oil dodecane (a major component of mineral oil) at a similar level did not have any effect. The mobility of the spin label in a dry corneum was very low and was increased significantly with the addition of water and glycerol trioleate but less so with mineral oil.
Sunflower seed oil reduces surfactant-induced in vivo skin irritation more than mineral oil. This is possibly due to stronger interaction of polar oil with proteins, thus protecting it from surfactant binding.
个人清洁产品中的皮肤刺激性与表面活性剂与角质层蛋白的结合有关。极性油和非极性油越来越多地用于含有高含量（10 - 15%）阴离子和非离子表面活性剂的清洁配方中。然而，油类对清洁产品引起的皮肤损伤的调节作用尚未得到详细研究。本研究的目的是确定低粘度极性油和非极性油在减少表面活性剂引起的皮肤刺激方面的能力是否存在差异，如果存在差异，其与它们与蛋白质的相互作用有何关系。
通过为期14天的体内累积贴片刺激试验来测量表面活性剂引起的皮肤刺激。该方法类似于著名的肥皂盒试验。在有油存在的情况下，通过电导滴定法测量表面活性剂与水溶性蛋白牛血清白蛋白（BSA）的相互作用。使用共价结合的自旋标记物3 - 马来酰亚胺 - 丙基氧基（5 - MSL），通过电子顺磁共振（EPR）研究低粘度极性油和非极性油对角质层蛋白在巯基区域动力学的影响。EPR测量使用从3至4周龄雌性猪废弃皮肤中获取的角质层进行。对复杂光谱的模拟提供了有关与蛋白结合的自旋标记物的环境和流动性的见解。
添加1%的极性向日葵籽油（粘度42厘泊）可使1%的月桂醇聚醚硫酸酯钠与两种乙氧基化物/椰油酰胺丙基甜菜碱（SLES/CAPB）引起的体内刺激降低20%，而1%的非极性矿物油（粘度15厘泊）则无效果。10%水平的极性油三油酸甘油酯（向日葵籽油中的主要成分）可使水中表面活性剂与BSA蛋白的结合降低40%，而类似水平的非极性油十二烷（矿物油的主要成分）则没有任何作用。自旋标记物在干燥角质层中的流动性非常低，加入水和三油酸甘油酯后显著增加，但加入矿物油后增加较少。
向日葵籽油比矿物油更能减少表面活性剂引起的体内皮肤刺激。这可能是由于极性油与蛋白质的相互作用更强，从而保护其免受表面活性剂结合。
