Anti-inflammatory effect of green tea petiole extracts in poly(I:C)–stimulated human epidermal keratinocytes and a human 3D skin equivalent

Abstract

Green tea is one of the most popular non-alcoholic beverage crops worldwide. Leaf extracts of the green tea, Camellia sinensis, are known to have natural anti-oxidant and anti-inflammatory effects. However, relatively few studies have focused on the biological activities of green tea petiole (GTP) (the stalk that attaches the leaf blade to the stem, currently considered waste material) compared with other parts of the tree, such as the leaf, root, and flower. Here, we report the first investigation of the anti-inflammatory effect of GTP extract against poly(I:C)–stimulated human keratinocytes (a model of skin inflammatory conditions) and EpiDerm (a three-dimensional skin equivalent). Our results reveal that GTP extract suppresses the induction of the messenger ribonucleic acids (mRNAs) encoding pro-inflammatory cytokines (tumor necrosis factor alpha (TNF-α), Interleukin 1 beta (IL-1β), and Interleukin-8 (IL-8)) and matrix metalloproteinase-1 (MMP-1). These findings indicate that GTP extract could prove useful in protecting skin cells from inflammatory conditions and skin aging.