157 - Skin Antiaging and Detoxifying Properties of Ancient Tea Forest Pu’er Tea

Abstract

Skin aging is mainly linked to degradation of the extracellular matrix, oxidative stress, environmental stress, and weakening of the skin’s natural defenses. Pu’er is a gradually fermented and aged tea (Camellia sinensis) produced in Yunnan, China. Ancient tea forests with tall, old trees are still found growing on acidic soils with rich microfloras at altitudes of 150–1500 m in subtropical southern Yunnan, near the Myanmar border. The leaves of C. sinensis plants in these forests were examined to identify properties having potential skin care applications. Phytochemical analysis of ancient tea forest Pu’er tea reveals a higher polyphenol concentration than in green tea as well as a specific catechin and catechin oligomer composition that may help protect the skin. Elastin is the main protein modified during skin aging, and this explains the loss of biomechanical properties that characterizes this process. We performed a conventional in vitro anti–human leukocyte elastase assay, measuring absorbance at 410 nm. Our polyphenol-rich Pu’er tea extract had an IC50 (µg/ml) of 3.36, while the standard inhibitor, oleanolic acid, had an IC50 of 11.68. Heme oxygenase (HO-1) is a cytoprotective enzyme known to maintain the healthy function of tissues and limit oxidative damage to them. HO-1 expression is directly correlated with pollution—i.e., high concentrations of organic carbon, polycyclic aromatic hydrocarbons, and reactive fine or ultrafine particles. After exposing RAW264.7 macrophages cells to hemin (toxin) at 5 µM/L and Pu’er tea extract at 5 and 50 µg/ml, HO-1 gene expression was measured at 75% and 92% respectively, showing that the extract has strong protective effects. These findings point to potential detoxifying and elastin-protecting properties of value for use in skin care products.