Inhibitory Activity of Allergic Contact Dermatitis and Atopic Dermatitis-Like Skin in BALB/c Mouse through Oral Administration of Fermented Barks of Alnus sibirica.

Phytochemical isolation of fermented Alnus sibirica (FAS) which was produced by using Lactobacillus plantarum subsp. argentoratensis, exhibited multiple and different composition compared with the original plant. Anti-allergic contact dermatitis (anti-ACD)/anti-atopic dermatitis (anti-AD) activities (visual observation and regulation of Th₁/Th₂ cytokines and IgE in blood) of FAS and the barks of Alnus sibirica extract (AS) and the two diarylheptanoids, hirsutenone (1) and muricarpon B (2), which are major components of FAS, were measured in vitro and in vivo. FAS, AS and the two compounds showed potent anti-oxidative, anti-inflammatory, anti-ACD and anti-AD activity. In particular, FAS showed more potent biological activity than AS. Thus, fermentation might be a prominent way to enhance the biological activity compared with the original plant. In addition, compounds (1) and (2) might be developed as functional materials or herbal medicines for ACD and AD.