In Vivo Treatment
Subjects applied the colloidal oatmeal skin protectant lotion twice a day for three weeks to the lower leg area. Subjects were instructed to apply an approximate amount of the lotion from the knee to the ankle. Product applications were made at a minimum of 8 hours apart. For the following 2 weeks, no treatment or any moisturizing products were applied to the lower leg area. A mild cleanser was provided for use during all showering or bathing. No product related adverse events were observed during the study.
Dry skin was evaluated by an expert grader and instrumental analysis (trans-epidermal water loss (TEWL): Dermalab (Cortex Technology, Denmark) and Moisture measurements: Skicon 200 EX (IBS Co, Japan)) at baseline and various time points over the 5-week study.
The data used in the statistical analysis were the changes from baseline. For the analysis of visual dryness scores, a Wilcoxon’s Signed Rank Test was conducted at each post treatment time
point. A Student’s t-test was used at each post treatment time point for the analysis of moisturization and transepidermal water loss data, with significance set at P<0.05.
Preparations of Extracts
The hexane extract of colloidal oatmeal (HCO) generated an oily residue (3.8% yield); the aqueous acetone extract of colloidal oatmeal (ACO) generated a sticky amorphous powder (2.6% yield); the aqueous methanol extract of colloidal oatmeal (MCO) generated a dry amorphous powder (2.5% yield); the water extract of colloidal oatmeal (WCO) generated a white powder (0.7% yield). An approximate qualitative composition of each extract based on the nature of extraction processes is presented in Table 1 along with a summary of bioactivities.
Colloidal Oatmeal Extracts Upregulated Barrier Genes
We first analyzed whether colloidal oatmeal extracts can modulate expression of key target genes associated with skin barrier in human primary keratinocytes (KCs). MCO, ACO, and HCO extracts dose-dependently induced mRNA expression