Bacterially Converted Oat Active Ingredients Enhances Antioxidative and Anti-UVB Photoaging Activities

Abstract

Oat (Avena sativa L.) is one of the most widely consumed cereal grains worldwide and is considered as an important cereal crop with high nutritional value and potential health benefits. With different bacterial strains, fermented oat extracts were examined for the antioxidant and antiaging effects on the skin after optimization of extraction conditions. Fermented oats contained high avenanthramides, and its function was investigated on matrix metalloproteinase-1 and collagen expression with human dermal fibroblast cells. After fractionation, butanol layers showed the highest avenanthramides contents. Therefore, the microbial fermentation of oats enhances the quality and content of functional ingredients of oats, which provide natural dietary supplements, antioxidants, and antiaging agents.

Figure 1

Procedures used for partitioning Avena sativa L.extract with organic solvents. HX, n-hexane; CH₂Cl₂, dichloromethane (MC); EtOAc, ethyl acetate; BuOH, n-butanol; H₂O, residue from fractionation.

Figure 2

MMP-1 (a) and collagen (b) expression levels in groups treated with oats extracted with different ethanol concentrations. Each bar represents the mean ± SD of three replicates. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 versus UV-only group, ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 versus 0% EtOH extracts group. Data were analyzed statistically using one-way ANOVA followed by Tukey's post hoc test. Antiageing effect on dermal skin of fractionated oat extracts.

Figure 3

MMP-1 (a) and collagen (b) expression levels as well as DPPH radical scavenging activity (c) in HDF cells after treatment with oat fractions. Each bar represents the mean ± SD of three replicates. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 versus NTC group, and ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 versus UV group. Data were analyzed statistically using one-way ANOVA followed by Tukey's post hoc test. NTC: negative control; UV: ultraviolet ray irrigated group; HX: n-hexane; MC: dichloromethane; EtOAc: ethyl acetate; BuOH: n-butanol; EtOH: 20% ethanol extract; H₂O: residue from fractionation.

Figure 4

Physiological activity of fermented oat extract. (a) Total polyphenol content, (b) DPPH radical scavenging activity, (c) SOD activity, and (d) hydroxyl radical scavenging activity. Each bar represents the mean ± SD of three replicates. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 versus AOE group, and ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 versus ROE group. Data were analyzed statistically using one-way ANOVA followed by Tukey's post hoc test. ROE: raw oat extracted with 20% ethanol; AOE: autoclaved oat extracted with 20% ethanol; LPE: 20% ethanol extract of oats fermented by Lactobacillus plantarum YS-100; KME: 20% ethanol extract of oats fermented by Kluyveromyces marxianus YS-091.

Figure 5

Structure of avenanthramides (AVA).

Figure 6

Analysis of p-coumaric acid (a), ferulic acid (b), and caffeic acid (c) as N-cinnamoyl anthranilic acid components in fermented oat extracts. Each bar represents the mean ± SD of three replicates. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 versus AOE group, and ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 versus ROE group. Data were analyzed statistically with one-way ANOVA followed by Tukey's post hoc test using GraphPad Prism 8.02. ROE: 20% ethanol extract of raw oat; AOE: 20% ethanol extract of autoclaved oat; LPE: 20% ethanol extract of oats fermented by Lactobacillus plantarum YS-100; KME: 20% ethanol extract of oats fermented by Kluyveromyces marxianus YS-091; BS002E: 20% ethanol extract of oats fermented by Bacillus subtilis NDJ-002; D extract using distilled water as a solvent; M extract using methanol as a solvent.

Figure 7

Contents of AVA-A (a), AVA-B (b), and AVA-C (c) in fermented oats. Each bar represents the mean ± SD of three replicates. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 versus AOE group, and ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 versus ROE group. Data were analyzed statistically with one-way ANOVA followed by Tukey's post hoc test using GraphPad Prism 8.02. ROE: 20% ethanol extract of raw oat; AOE: 20% ethanol extract of autoclaved oat; LPE: 20% ethanol extract of oats fermented by Lactobacillus plantarum YS-100; KME: 20% ethanol extract of oats fermented by Kluyveromyces marxianus YS-091; BS002E: 20% ethanol extract of oats fermented by Bacillus subtilis NDJ-002; D extract using distilled water as a solvent; M extract using methanol as a solvent.