Study on Moisturizing Effect of Dendrobium officinale, Sparassis crispa, and Their Compound Extracts.

Background: Recently, natural plants have been widely developed and applied in moisturizing cosmetics. Dendrobium officinale Kimura et Migo (D. officinale) is known as one of the "Nine Immortals" of Chinese herbal medicine, whereas Sparassis crispa (Wulf.) Fr. (S. crispa) is known as the "king of mushrooms"; both of which have excellent biological activity.

Aims: To explore the effects of D. officinale polysaccharide (DOP) with different molecular weights and S. crispa on the expression of moisturizing-related genes and verify the moisturizing performance of their complex.

Methods: PCR was carried out to explore the aquaporin 3 (AQP3), hyaluronic acid synthetase1 (HAS1), HAS2, and HAS3 genes expression. Immunofluorescence (IF) analysis was used to test the protein level expression of hyaluronic acid (HA), AQP3, claudin-1, and filaggrin (FLG) influenced by moisturizing composition in a reconstructed epidermis skin model. The ability of samples to resist cell drying damage was evaluated by a cell drying damage model. Furthermore, this study validated the effect of the compositions during their application in cosmetics through tests of skin moisture content, crow's feet, and skin elasticity.

Results: The results showed that DOP with molecular weights of 100 k-500 kDa (Dalton) had higher effects on AQP3 gene expression compared to that with molecular weights of 10 k-100 kDa and 1 k-10 kDa. Additionally, the extract of S. crispa significantly promoted the expression of HAS1, HAS2, and HAS3 genes, which are genes encoding hyaluronic acid synthesis. In addition, the mRNA and protein expression levels of HA, AQP3, claudin-1, and FLG were significantly increased as a result of the moisturizing composition consisting of DOP (100 k-500 kDa) and S. crispa. The application of the moisturizing composition markedly increased the skin moisture content, improved eye wrinkles, and enhanced skin elasticity.

Conclusions: In summary, our study proved that D. officinale and S. crispa had good moisturizing effects, and as natural plant humectants, they may have broad applications in future moisturizing cosmetics.