4′,7-Isoflavandiol (Equol) Enhances Human Dermal Fibroblast Renewal and Has Effects Similar to 17β-Estradiol in Stimulating Collagen and Elastin Expression. Cell Cycle and RT-PCR Analysis without Phenol Red

Edwin D Lephart

doi:10.3390/cosmetics8010005

Abstract

Polyphenols have general health benefits including anti-photoaging influences to counter the negative effects of ultra-violet (UV) rays from solar light (via the generation of reactive oxygen species (ROS) and oxidative stress (OS)), which leads to the stimulation of matrix metalloproteinases (MMPs) that break down collagen and elastin. The changes in elastin and collagen represent major factors in dermal aging along with a decrease in skin fibroblast number and function. The purpose of this study was to determine the influence of a polyphenolic molecule, 4′,7-Isoflavandiol (Equol) at 10 nM on: (1) fibroblast number and function via cell cycle testing (including apoptosis) and collagen protein expression (types I and III) using long-term (eight-week) 3D human fibroblast cultures by intracellular fluorescent-activated cell sorting (FACS) analysis, and (2) quantifying elastin gene expression levels in short-term (four day) cultures using human monolayer fibroblasts by RT-PCR. In both in vitro testing methods, the presence of phenol red (tissue culture indicator) interfered with the parameter results. Therefore, all experiments were performed without phenol red. Using FACS analysis in the long-term 3D cultures exposure to 10 nM of equol for four days significantly increased the percentage of cycling fibroblasts (rejuvenation) above vehicle control (dimethyl sulfoxide (DMSO)) or 17β-estradiol levels, while apoptosis was not altered by any treatment. In addition, in the long-term cultures, collagen levels were significantly increased in the equol and 17β-estradiol treatments above vehicle control values. In short-term cultures, 10 nM of equol or 17β-estradiol significantly increased elastin gene expression levels above vehicle control values. In summary: (a) phenol red may interfere with tissue culture parameter results and (b) the polyphenolic equol compound, derived from plants, may provide protection against photoaging in cosmetic formulations by stimulating collagen, elastin, and enhancing fibroblast renewal.

Highlights

Polyphenols found in plants have general health benefits, including use in skin care products [1,2,3]
To examine how equol may influence collagen protein expression, intracellular fluorescentactivated cell sorting (FACS) analysis was employed in long-term eight weeks 3D human fibroblast tissue cultures to quantify the percentage of cells among the 20,000 cells tested along with 17β-estradiol, which served as the natural steroid hormone positive control versus the dimethyl sulfoxide (DMSO) vehicle controls
Equol or 10 nM 17β-estradiol for four days significantly increased the percentage of cells for collagen types I and III above that of the DMSO control values (p < 0.001)

Summary

Introduction

Polyphenols found in plants have general health benefits, including use in skin care products [1,2,3]. This is due to their anti-photoaging influences that counteract the negative effects of ultra-violet (UV) rays from solar light, which generate reactive oxygen species (ROS) and oxidative stress (OS) [1,2,3,4]. The changes in elastin and collagen represent major factors in dermal aging, which are paramount in how skin properties enhance a youthful appearance. UV exposure in photoaging causes a collagen deficit by shifting homeostasis from production/deposition to degradation along with degeneration in the elastin fiber network where disorganized and non-functional deposition of elastin fibers occurs in the upper and middle dermis [6,7,8,9].

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