A Study on the Skin Whitening Activity of Digesta from Edible Bird's Nest: A Mucin Glycoprotein.

Qunyan Fan,Xin Wang,Maoshen Chen,Fengyang Zou,Xuncai Liu,Jianmei Lian

doi:10.3390/gels8010024

Abstract

Edible bird’s nest (EBN) is an unusual mucin glycoprotein. In China, it is popular among consumers due to its skin whitening activity. However, the relationship between protein, sialic acid, and the whitening activity of EBN after digestion is still unclear. In the present work, the whitening activity (antioxidant activity and tyrosinase inhibitory activity) of digested EBN were studied by HepG2 and B16 cell models. The dissolution rate of protein and sialic acid was 49.59% and 46.45% after the simulated digestion, respectively. The contents of free sialic acid and glycan sialic acid in EBN digesta were 17.82% and 12.24%, respectively. HepG2 cell experiment showed that the digested EBN had significant antioxidant activity, with EC50 of 1.84 mg/mL, and had a protective effect on H2O2-induced oxidative damage cells. The results of H2O2-induced oxidative damage showed that the cell survival rate increased from 40% to 57.37% when the concentration of digested EBN was 1 mg/mL. The results of the B16 cell experiment showed that the digested EBN had a significant inhibitory effect on tyrosinase activity, and the EC50 value of tyrosinase activity was 7.22 mg/mL. Cell experiments showed that free sialic acid had stronger antioxidant activity and tyrosinase inhibitory activity than glycan sialic acid. The contribution rate analysis showed that protein component was the main antioxidant component in digestive products, and the contribution rate was 85.87%; free sialic acid was the main component that inhibited tyrosinase activity, accounting for 63.43%. The products of the complete digestion of EBN are suitable for the development of a new generation of whitening health products.

Highlights

Edible bird’s nest (EBN) is a traditional health food in China, which is a nest formed by mixing saliva and feather of Swiftlets [1]
17.82% of the sialic acid was present in free form, 12.24% was bound to glycans, 15.39% was bound to proteins, and 54.55% was still insoluble in the digestion supernatant
The results showed that free sialic acid (63.43%) was the main bioactive ingredient in the digested products; the contribution rate of protein components was only 27.43%

Summary

Introduction

Edible bird’s nest (EBN) is a traditional health food in China, which is a nest formed by mixing saliva and feather of Swiftlets [1]. Two species of swiftlets (Aerodramus fuciphagus and Aerodramus maximus) build edible bird’s nests that are consumed by humans worldwide, as a delicacy known as the “Caviar of the East” [3]. EBN is well known for its remarkable skin whitening function [7,8]. The content of sialic acid in a bird’s nest is about 10% [9]. Sialic acid could inhibit tyrosinase activity, which was proposed to be a major component for the whitening function of EBN [10]. A rate-limiting enzyme in melanin biosynthesis catalyzes the hydroxylation of L-tyrosine to 3,4-dihydroxy-L-phenylalanine (L-dopa) (monophenolase reaction) and the subsequent oxidation of L-dopa to L-dopaquinone (diphenolase reaction)

Objectives

Methods

Results

Conclusion