Antioxidant and antifungal activity of carnauba wax powder extracts

Abstract

Carnauba wax is a commercially valuable product derived from epicuticular wax powder (CWP) from the leaves of Copernicia prunifera (Arecaceae), a palm tree native to northeastern Brazil. CWP exists as a fine powder on both young, upright, closed leaves (type A wax), and mature, pendant, open leaves (type B wax). The aim of this study was to evaluate the effect of extraction time on aqueous and ethanolic extracts of carnauba wax powder and quantify their antioxidant potential. Furthermore, we determined the total phenols, flavonoids, and flavonols in the extracts, and tested the effects of the extracts on the dermatophyte fungi Trichophyton rubrum and Microsporum canis. Antioxidant capacity was evaluated by measuring the scavenging effect of the extracts on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radicals. Overall, higher extract yields were obtained using ethanol as a solvent, rather than water. All extracts showed antioxidant activity and the extraction time did not influence the antioxidant activity of the extracts; the strongest activity was observed for the ethanolic extract of type B wax powder (EtB) with an EC50 values of 365 ± 7 μg/mL (by DPPH assay) and 317 ± 6 μg/mL (by ABTS). Total phenolic, flavonoid, and flavanol contents varied from 280.73 ± 4.85 to 114.06 ± 4.45 gallic acid equivalents (GAE), 24.59 ± 0.45 to 5.34 ± 0.12 quercetin equivalents (QE), and 32.36 ± 0.93 to 9.41 ± 0.37 catechin equivalents (CTE), respectively. Qualitative high-performance liquid chromatography (HPLC) analysis revealed the presence of gallic acid, catechin, and chlorogenic acid in type A and type B wax aqueous extracts. The aqueous extracts showed antifungal activity against dermatophytes M. canis and T. rubrum. These results provide evidence that carnauba wax powder extracts might be potential sources of natural antioxidant and antifungal agents.