Anti-glycation activities of phenolic constituents from Silybum marianum (Milk Thistle) flower in vitro and on human explants.

Seoungwoo Shin,Hyunwoo Kum,Minkyung Kim,Jung-A Lee,Deokhoon Park,Eunsun Jung

doi:10.3390/molecules20033549

Abstract

Glycation is an ageing reaction of naturally occurring sugars with dermal proteins, with clinical signs appearing in vivo around age 30, and increasing steadily/regularly with age. The suppleness of the dermis is affected by the formation of bridges between proteins and sugars (Maillard’s reaction). The accumulation of advanced glycation end products (AGEs) in skin plays a very important role in skin ageing. Therefore, natural compounds or extracts that possess antiglycation activities may have great anti-ageing potential. In the present study, Silybum marianum flower extract (SMFE) was demonstrated to possess antiglycation activity. We found that SMFE inhibits glycation reaction between BSA and glucose. In addition, antiglycation activity of SMFE was confirmed in a human skin explants model. SMFE reduced Nε-(carboxymethyl) lysine (CML) expression, whereas SMFE stimulated fibrillin-1 expression compared to treatment with methyglyoxal. An active ingredient contributing to the observed activities was identified as silibinin. The antiglycation activity of silibinin was dose-dependent. The beneficial effects of silibinin may be applied to prevention or management of AGE-mediated pathologies, targeting in a pleiotropic and complementary way the biochemical and cellular bases of skin aging.

Highlights

Chronological ageing induces bridging reactions between the amino groups of dermal proteins and the hydroxyl groups of sugars in the skin, i.e., Maillard reactions [1]
After Silybum marianum flower extract (SMFE) was added to the reaction media containing Bovine Serum Albumin (BSA)/glucose, the fluorescence intensity significantly decreased in a concentration-dependent manner throughout the study period
When BSA was incubated with glucose, a significant increase in fluorescence intensity was observed at week 3 of the experiment

Summary

Introduction

Chronological ageing induces bridging reactions between the amino groups of dermal proteins and the hydroxyl groups of sugars in the skin, i.e., Maillard reactions [1]. This translates into a stiffening of linkages between components of the extracellular matrix, which induces, in vivo, a decrease in the suppleness of the dermis. Glycation reactions start as soon as reducing sugars come into contact with available free amino groups. The clinical signs of glycation appear when the slowdown of protein expression can no longer counterbalance their degradation rate. Glycation is a reaction of dermal ageing, slow to appear, but producing permanent damages [2,3]

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