Korean J Nutr.  2006 Sep;39(6):520-528.

Dietary Effect of Silk Protein Sericin or Fibroin on Plasma and Epidermal Amino Acid Concentration of NC/Nga Mice

Affiliations
  • 1Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Seoul 130-701, Korea. choyunhi@khu.ac.kr
  • 2Department of Agricultural Biology, National Institute of Agricultural Science and Technology, Suwon 441-100, Korea.
  • 3Nutrex Co., Ltd., Seoul, 137-919 Korea.

Abstract

Free amino acids in epidermis function as a major component of Natural Moisturizing Factor (NMF), which maintains the optimal level of water in skin even at the low humidity. In fact, the depletion of free amino acids is reported in the epidermis of atopic dermatitis, the skin condition involving dryness. As an effort searching the dietary source for improving the level of water and free amino acid in epidermis, the dietary effects of silk protein, sericin (S) and fibroin (F) on trans epidermal water loss (TEWL), and plasma and epidermal levels of free amino acids were compared in this study. Thirty of male NC/Nga mice, an animal model of atopic dermatitis, were divided into three groups: group CA as an atopic control with control diet, group S: 1% sericin diet and group F: 1% fibroin diet. Ten of male BALB/c mice were served as group C (control group) with control diet. All mice were fed on diet and water ad libitum for 10weeks. Dry skin condition was established in group CA as TEWL was increased (148.7% of group C). In parallel, epidermal level of glutamate, one of major amino acids functioning as NMF, was dramatically decreased and epidermal levels of methionine and alanine were inversely elevated. Dietary supplementation of sericin (group S) reduced TEWL at the similar level with group C and increased epidermal levels of glutamate as well as serine and glycine, the other major amino acids as NMF. Despite a marked decrease of methionine and alanine, the reduction of TEWL and epidermal levels of glutamate, serine and glycine of group F were less than of group S. Furthermore, in contrast to similar levels of other free amino acids in plasma and epidermis of group S and group C, plasma and epidermal levels of other free amino acids, specifically phenylalanine, isoleucine, cysteine and tyrosine in epidermis of group F, were significantly higher than of group C. Together, our data demonstrate that dietary supplementation of sericin is more effective at improving dry skin condition that paralleled with the normalization of free amino acids in plasma and epidermis of NC/Nga mice.

Keyword

sericin; fibroin; amino acid; Natural Moisturizing Factor; NC/Nga mice

MeSH Terms

Alanine
Amino Acids
Animals
Cysteine
Dermatitis, Atopic
Diet
Dietary Supplements
Epidermis
Fibroins*
Glutamic Acid
Glycine
Humans
Humidity
Isoleucine
Male
Methionine
Mice*
Models, Animal
Phenylalanine
Plasma*
Sericins*
Serine
Silk*
Skin
Tyrosine
Alanine
Amino Acids
Cysteine
Fibroins
Glutamic Acid
Glycine
Isoleucine
Methionine
Phenylalanine
Sericins
Serine
Silk
Tyrosine
Full Text Links
  • KJN
Actions
Cited
CITED
export Copy
Close
Share
  • Twitter
  • Facebook
Similar articles
Copyright © 2024 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: koreamed@kamje.or.kr