Avaliação das atividades antioxidante e anti-inflamatória tópica das folhas de café (Coffea arabica L.)

Abstract

Coffee beans have constituents of great pharmacological importance capable of triggering protective mechanisms in the body against various pathologies, such as cardiovascular, cancer, neurodegenerative diseases and diabetes mellitus. The coffee leaves are considered as residues of the coffee processing, its technological and industrial use is extremely important. Whereas that few researches are directed to application in medicinal purposes or bioprospection for employment in the pharmaceutical industry, the objective of the present study was to identify and quantify bioactive constituents present in the Coffea arabica L. leaves, as well as to evaluate the antioxidant and topical anti-inflammatory activities. The leaves were pulverized and subjected to static maceration in methanol, followed by liquid / liquid partition to obtain hexane, dichloromethane, ethyl acetate and butanolic fractions. The 5-caffeoylquinic acid (5-CQA) and mangiferin were identified and quantified by high performance liquid chromatography coupled to ultraviolet detector (HPLC-UV). The total phenolics and flavonoids contents were determined by spectrophotometric methods and the antioxidant activity evaluated by the 2,2-diphenyl-1-picrylhicrazil (DPPH •) free radical scavenging, ferric reducing power (FRAP) and the β-carotene bleaching assays. The topical anti-inflammatory activity was investigated using ear edema models induced by croton oil, phenol and histamine. The total phenolic and flavonoid contents ranged from 1.65 ± 0.01 to 20.60 ± 0.39 g gallic acid equivalents/100g and from 0.26 ± 0.17 to 14.96 ± 0.05 g rutin equivalents/100g, respectively. The 5-CQA content ranged from 2.29 to 5.50g/100g, and mangiferin was 1.46 to 4.00 g/100g. The effective concentrations 50% values in the DPPH and FRAP assays were 7.47 ± 0.12 and 122.76 ± 1.38 μg/mL and 4.67 ± 0.02 and 71.90 ± 0,22 μg/mL, respectively. The percentage inhibition of lipid peroxidation determined by the β-carotene / linoleic acid assay ranged from 32.87 ± 0.50 to 52.49 ± 0.52. The application of the methanolic extract (ME) was able to significantly decrease the edema induced by croton oil, phenol and histamine. The histopathological analysis results and the evaluation of activity of the enzymes myeloperoxidase and n-acetyl-β- d-glucosaminidase attest the effect of ME on the inhibition of the inflammatory process induced by croton oil. The results evidence that the Coffea arabica L. leaves present high concentrations phenolic substances and important pharmacological effects for technological application to development of new products in the pharmaceutical area.