Biotransformação do café verde por Aspergillus oryzae: avaliação das alterações do perfil químico e da penetração cutânea

Abstract

Topical antioxidants have been recognized as a promising strategy of photoprotection and prevention of photoaging and skin cancer. Green coffee beans (Coffea arabica L.) contain a complex blend of phenolic compounds with proven antioxidant activity. However, most of these coffee compounds have high molecular mass, low lipophilicity, and are often chemically bound to sugar molecules, which difficult the cutaneous penetration. In the present study, the green coffee fermentation was carried out by Aspergillus oryzae to biotransform phenolic compounds into molecules more lipophilic and with lower molecular mass targeting a greater penetration of them into epidermis. Antioxidant activity of the hydroethanolic extracts of non- biotransformed and biotransformed coffee for 24, 36 and 48 hours was evaluated by the 2, 2- diphenyl-2-picryl-hydrazyl (DPPH·) spectrophotometric and thin layer chromatography (TLC) methods. The quantification of chlorogenic acid (5-CQA), caffeine and caffeic acid in the extracts was carried out using high-performance liquid chromatography (HPLC). The chemical characterization of the different extracts was performed using the ultra-high performance liquid chromatography coupled to mass spectrometry with time-of-flight analyzer (UPLC-MS-Q- TOF). The results of the analyzes by HPLC, TLC and UPLC-MS-Q-TOF showed quantitative and qualitative changes in the chemical composition of green coffee. It was evidenced the breakage of the esters of chlorogenic acids with consequent formation of quinic and caffeic acids in the interval of 36 hours of solid state fermentation without loss of antioxidant activity. Biotransformation of green coffee by A. oryzae has shown to be an effective strategy to promote changes in the profile of secondary metabolites of green coffee. The in vitro permeation and retention results showed that caffeine was the only compound able to permeate and be retained in dermis and epidermis. Caffeine penetration was higher when the added formulation of the biotransformed extract was used than to to the non-biotransformed extract. The results reinforce the importance of conducting skin penetration studies in order to guarantee the efficacy of pharmaceutical and cosmetic formulations