The antioxidant properties of the polyphenols found in Camellia sinesis, more commonly known as green tea, have been well documented, but researchers at the Institute of Food Engineering, Shanghai Normal University, China, argue that the moisturising qualities the polysaccharides equally make the substance an interesting cosmetic proposition.
According to the study, published in the Journal of Agricultural and Food Chemistry, the moisture absorption and retention of the polysaccharides in green tea is much stronger than the polyphenols.
The team investigated tea polysaccharides of high grade quality, approximately 92 percent of tea polysaccharides, of low grade quality, approximately 20 percent tea polysaccharides and a sample of tea polyphenols, in vitro.
In addition, to looking at moisture absorption, the team also looked at the UV absorption of the substances as well as the effect on mouse fibroblasts.
According to the study, moisturising absorption and retention increased with the percentage of the saccharides in the sample.
The researchers hypothesised that this was due to the presence of hydroxyl, carboxyl and other polar groups in the polysaccharides that can form hydrogen bonds with the water molecules.
However, the polysaccharides had a less impressive effect on the other parameters, when compared with the polyphenols.
The green tea polyphenols absorbed both UVA and UVB rays, and this, along with their antioxidant properties, make them a good candidate for a sunscreen additive, according to the scientists.
In addition, the green tea polyphenols significantly increased fibroblast cell proliferation. As the fibroblasts and their activity decline with age and UV radiation, the scientists argued, the data further supports the use of green tea polyphenols in anti-ageing formulations.
“This indicated that a combination of TPS [green tea polysaccharides] and TPP [green tea polyphenols] would be a favorable possibility for protecting skin, especially for the good moisture retention ability of TPS and fibroblast proliferation effect and strong UV absorbance ability of TPP,” they concluded.
Source: Journal of Agricultural and Food Chemistry
2009, Volume 57, Number 17
Protective Effects of Tea Polysaccharides and Polyphenols on Skin
Xinlin Wei, Ying Liu, Jianbo Xiao, Tuanfeng Wang