Phenolic composition and in vitro activity of the Brazilian fruit tree Caryocar coriaceum Wittm.

Introduction: Caryocar coriaceum Wittm. (Caryocaraceae) is a plant found in the region of Araripe (Ceara State, Brazil) and is widely used in folk medicine. The present work aimed to evaluate the chemical composition and synergistic-antibiotic activity of a hydroethanol leaf extract (LECC) and a methanol fraction (LECC-MF) of C. coriaceum. Methodology: Qualitative phytochemical analysis of both extracts was performed and the quantification of phenolic and flavonoid compounds was performed by HPLC-DAD. The antimicrobial activity of a hydroethanol leaf extract of C. coriaceum (LECC) and a methanol fraction (LECC-MF) were analyzed by the microdilution test using standard and clinical multiresistant bacterial and fungal strains (Staphylococus aureus ATCC25923, Escherichia coli ATCC10536, Pseudomonas aeruginosa ATCC15442, Klebsiella pneumonae ATCC4362, E. coli 27, S. aureus 358, Candida albicans ICB12 and Candida krusei ATCC6258). The synergism assay was performed with aminoglycosides (as amikacin, Kanamycin, gentamicin and neomycin) and antifungal drugs (as metronidazole, amphotericin B, nystatin, and benzoylmetronidazole). Results: The phytochemical analysis revealed the presence of pyrogallic and hydrolisable tannins, phenolic compounds, flavonoids and other phytocompounds. HPLC analysis showed a variety of compounds in both of the extracts, including gallic acid, chlorogenic acid, caffeic acid, rutine and quercetine. Both the hydroethanol extract and methanol fraction showed no clinically relevant antimicrobial effect against the tested microorganisms. However, a synergistic activity was demonstrated by both natural products against E. coli 27 and S. aureus 358. Conclusion: These findings suggest that LECC and LECC-MF could be used as an important source of compounds with the potential to reduce the bacterial resistance to aminoglycosides. (C) 2013 Elsevier GmbH. All rights reserved.