Extraction, Isolation and Chemical Modification of the Anacardic Acids from Cashew Nut Shell (Anacardium occidentale L.) and Biological Assay

Abstract

1. Abstract <span style=font-size:10.0pt;font-family: times= new= roman,serif;mso-ansi-language:en-us=> The objective of this study was to isolate the Anacardic Acid (AA), present in the Cashew Nutshell Liquid (CNSL) of the species Anacardium occidentale L., to carry out chemical modifications, and to analyze the antioxidant and antibacterial potential of the derivatives. CNSL was obtained using hexane as solvent, in 14% yield. The anacardic acids were purified by the chromatographic process and analyzed by High Performance Liquid Chromatography (HPLC) and 1H and 13C NMR, characterizing the anacardic acids monoene (29.32%), diene (27.06%) and triene (43.62%). Acetylated AA was produced by acetylation reaction. The products, together with the CNSL and the anacardic acid mixture were evaluated for antioxidant potential by DPPH free radical capture method. The results showed that acetylation decrease the antioxidant potential of natural CNSL (597.29 ppm), which are more efficient in inhibiting radicals than the mixture of AAs (> 1000 ppm) and acetylated AA (> 1000 ppm). The antibacterial activity against the standard strains of Escherichia coli and Staphylococcus aureus were also observed, which were sensitive at concentrations equal to and greater than 78,125 ppm for CNSL and for the mixture of anacardic acids. Acetylated AA presented lower antibacterial activity. Free AAs maintain the in vitro antibacterial activity of the CNSL in the strains evaluated and the phenolic hydroxyl is considered important for activity. Thus, the present work made possible a study of the substances presents in the liquid of cashew nuts of the species Anacardium occidentale L. contributing to the expansion of the research arsenal in the area.