Study on the properties of Dendrobium officinale fermentation broth as functional raw material of cosmetics

Background With the trend that cosmetics containing natural extracts are favored by consumers, many natural herbs are used in cosmetics to enhance the moisturizing and whitening properties of cosmetics. Dendrobium officinale is the stem of the orchid Dendrobium officinale. In China, it is considered as a tonic beneficial to human health. Its main components are Dendrobium polysaccharides, alkaloids, phenanthrene, etc. Its extract has good skin coating comfort and has the potential to be developed as cosmetic raw materials. Objective To investigate the antioxidant activity, tyrosinase inhibitory activity, and ultraviolet absorption capacity of the fermentation extract of Dendrobium officinale fermented by different microorganisms, so as to provide the basis for Dendrobium officinale as functional cosmetic raw materials. Methods The fermentation of Dendrobium officinale was carried out by yeast, Lactobacillus, Bacillus subtilis, and the mixed bacteria (prepared according to the mass ratio of 1:1:1). Compared with the non-fermentation group, the contents of polysaccharides, flavonoids, and polyphenols in the fermentation broth of Dendrobium officinale were determined by spectrophotometry, and the antioxidant activity to common free radicals, inhibition to tyrosinase, and absorption to ultraviolet B were determined. Results The fermentation effect of mixed strains on Dendrobium officinale was better than that of a single strain. The content of polysaccharide decreased, while the content of flavonoids and polyphenols increased in the fermentation broth of Dendrobium officinale. With the extension of fermentation time, the scavenging rate of ·OH, DPPH, ABTS free radical, the inhibition rate of tyrosinase, and the absorption of ultraviolet B of Dendrobium officinale fermentation broth first increased (0-3 days), and then decreased (4 days). On the third day of mixed fermentation, the contents of polysaccharides, flavonoids, and polyphenols in the fermentation broth of Dendrobium officinale were - 22.15%, + 118.20%, and +128.17%, respectively. The scavenging rate of ·OH, DPPH, ABTS free radical, tyrosinase inhibition rate and SPF value were increased by 43.03%, 60.05%, 94.87%, 340.85%, and 31.73%, respectively. Conclusions The fermentation broth of Dendrobium officinale is superior to the non-fermentation group in active ingredients, antioxidant activity, tyrosinase inhibition, and ultraviolet B absorption. It has the potential as a functional cosmetic raw material.