Release of Propolis Phenolic Acids from Semisolid Formulations and Their Penetration into the Human SkinIn Vitro

Modestas Žilius,Vitalis Briedis,Kristina Ramanauskienė

doi:10.1155/2013/958717

Abstract

Antioxidant and free radical scavenging effects are attributed to phenolic compounds present in propolis, and when delivered to the skin surface and following penetration into epidermis and dermis, they can contribute to skin protection from damaging action of free radicals that are formed under UV and premature skin aging. This study was designed to determine the penetration of phenolic acids and vanillin into the human skin in vitro from experimentally designed vehicles. Results of the study demonstrated the ability of propolis phenolic acids (vanillic, coumaric, caffeic, and ferulic acids) and vanillin to penetrate into skin epidermis and dermis. The rate of penetration and distribution is affected both by physicochemical characteristics of active substances and physical structure and chemical composition of semisolid vehicle. Vanillin and vanillic acid demonstrated relatively high penetration through epidermis into dermis where these compounds were concentrated, coumaric and ferulic acids were uniformly distributed between epidermis and dermis, and caffeic acid slowly penetrated into epidermis and was not determined in dermis. Further studies are deemed relevant for the development of semisolid topically applied systems designed for efficient delivery of propolis antioxidants into the skin.

Highlights

Human skin protects an organism from constant exposure to physical, chemical, biological, and environmental factors [1]
Antioxidant and free radical scavenging effects are attributed to phenolic compounds present in propolis, and when delivered to the skin surface and following penetration into epidermis and dermis, they can contribute to skin protection from damaging action of free radicals that are formed under UV and premature skin aging
Results of the study demonstrated the ability of propolis phenolic acids and vanillin to penetrate into skin epidermis and dermis

Summary

Introduction

Human skin protects an organism from constant exposure to physical, chemical, biological, and environmental factors [1]. Delivery of external antioxidant molecules to the sites of potential UVinduced formation of ROS should be considered when protecting the skin from oxidative damage and retarding aging-related processes. Antioxidant, free radical scavenging, anti-inflammatory, antitumoral, antimicrobial, and wound healing properties have been confirmed for propolis and its products both in vitro and in vivo studies, and these attributes are linked with the presence of phenolic compounds, including flavonoids, phenolic acids, and their esters [4,5,6,7,8]. Published data demonstrate the ability of propolis extract to prevent UV irradiation-induced oxidative stress in the skin [5]. The potential applicability of Brazilian propolis extracts for the prevention of oxidative stress in the skin due to UV irradiation was studied. To cultivate a more complete understanding of the protective capabilities of propolis extracts, topical formulations that diffuse more effectively through the skin could be developed and additional studies be performed

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