Antioxidant and in vitro cosmeceutical activities of germinated oats

Background and Objectives

Oat (Avena sativa L.) is well known for its biofunctional properties, primarily attributed to cereal phytochemicals. Germination may amplify the formation of secondary metabolites in oat, enhancing its nutritional and bioactive quality. Despite this, the impact of germination of oat on skin health remains unknown. This study investigated how germination influences the in vitro antioxidant activity and enzyme inhibitory activity related to skin health (tyrosinase and elastase).

Findings

Oat was germinated at 25°C for 6 days, and the germinated samples were collected every 2 days. The samples were then divided into kernel and radicle (including germ) fractions for analysis. The radicle fraction exhibited significantly higher antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH] radical scavenging) and in vitro cosmeceutical activity compared to the whole kernel. Phenolic acids were identified to be responsible for the antioxidant activity and tyrosinase inhibition at all germination times, whereas phytosterols including β-sitosterol played the key role in elastase inhibition. Avenanthramides, synthesized during oat germination, were proved to be crucial in inhibiting the enzymes deteriorating skin health.

Conclusions

This study revealed that germination, as a bioconversion process, enhanced antioxidant activity and cosmeceutical activity of oat by inhibiting the key enzymes responsible for skin aging. However, further research is imperative to fully comprehend the roles and mechanisms of these substances produced during germination.

Significance and Novelty

This study revealed the impacts of germination with cereals, offering valuable insights into the strategies for future investigations in the field of skin health and bioactive cereal compounds.