Effect of oral intake of winged bean extract on a skin lichenification model: evaluation by microarray analysis

Winged bean (WB), Psophocarpus tetragonolobus, is a tropical legume, the potential of which is not fully understood. We found that 5-week oral administration of a WB seed extract inhibited wrinkle formation induced by repeated tape stripping (TS) as a model of lichenification in human chronic eczematous dermatitis. To elucidate the mechanism of the effect of WB on this model, we applied microarray analysis. Hierarchical clustering revealed that each experimental group formed a distinct cluster, suggesting the presence of a distinct gene expression profile among the three groups of non-TS, TS, and TS with oral administration of WB extract (TS/WB). Gene ontology analysis showed that several gene groups with keratinization and mitosis were significantly upregulated by TS, while other groups with ATP synthesis and glycolysis were significantly downregulated by TS/WB. Moreover, WB extract influenced a number of genes related to epidermal differentiation and inflammation. This suggests that these changes inhibited wrinkle formation by TS.