Phytochemical Composition, Antioxidant Activity, and the Effect of the Aqueous Extract of Coffee (Coffea arabica L.) Bean Residual Press Cake on the Skin Wound Healing

Abstract

The world coffee consumption has been growing for its appreciated taste and its beneficial effects on health. The residual biomass of coffee, originated in the food industry after oil extraction from coffee beans, called coffee beans residual press cake, has attracted interest as a source of compounds with antioxidant activity. This study investigated the chemical composition of aqueous extracts of coffee beans residual press cake (AE), their antioxidant activity, and the effect of topical application on the skin wound healing, in animal model, of hydrogels containing the AE, chlorogenic acid (CGA), allantoin (positive control), and carbopol (negative control). The treatments' performance was compared by measuring the reduction of the wound area, with superior result (p < 0.05) for the green coffee AE (78.20%) with respect to roasted coffee AE (53.71%), allantoin (70.83%), and carbopol (23.56%). CGA hydrogels reduced significantly the wound area size on the inflammatory phase, which may be associated with the well known antioxidant and anti-inflammatory actions of that compound. The topic use of the coffee AE studied improved the skin wound healing and points to an interesting biotechnological application of the coffee bean residual press cake.

Figure 1

In vitro cell viability after 24 h exposure to the AE of roasted coffee press cake. Important reductions of cell viability were detected at AE concentration of 3 mg/mL or higher, as determined through the NRU assay. Results are expressed as mean ± standard deviation (sd).

Figure 2

Reduction of the wound area (%) after 14 days of treatment with hydrogels applied daily in mice 9 months old. NC (negative control = 23.56% c), PC (positive control = 70.83% ab), PPGC (postpressing green coffee = 78.20% a), and PPRC (postpressing roasted coffee = 53.71% b). Data are presented as mean ± sem. Distinct letters denote significant differences at p < 0.05 (Tukey's test).