title: Anacardic Acid Constituents from Cashew Nut Shell Liquid: NMR Characterization and the Effect of Unsaturation on Its Biological Activities.
abstract: Anacardic acids are the main constituents of natural cashew nut shell liquid (CNSL), obtained via the extraction of cashew shells with hexane at room temperature. This raw material presents high technological potential due to its various biological properties. The main components of CNSL are the anacardic acids, salicylic acid derivatives presenting a side chain of fifteen carbon atoms with different degrees of unsaturation (monoene-15:1, diene-15:2, and triene-15:3). Each constituent was isolated by column chromatography using silica gel impregnated with silver nitrate. The structures of the compounds were characterized by nuclear magnetic resonance through complete and unequivocal proton and carbon assignments. The effect of the side chain unsaturation was also evaluated in relation to antioxidant, antifungal and anticholinesterase activities, and toxicity against Artemia salina. The triene anacardic acid provided better results in antioxidant activity assessed by the inhibition of the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), higher cytotoxicity against A. salina, and acetylcholinesterase (AChE) inhibition. Thus, increasing the unsaturation of the side chain of anacardic acid increases its action against free radicals, AChE enzyme, and A. salina nauplii. In relation to antifungal activity, an inverse result was obtained, and the linearity of the molecule plays an important role, with monoene being the most active. In conclusion, the changes in structure of anacardic acids, which cause differences in polarity, contribute to the increase or decrease in the biological activity assessed.
authors.affiliation: Chemistry Course, Master Course in Natural Resources, University of Ceará State, Fortaleza, CE, Brazil. selenemaiademorais@gmail.com.|Post-Graduation Course in Biotechnology, University of Ceará State, Fortaleza, CE, Brazil. selenemaiademorais@gmail.com.|Post-Graduation Course of Veterinary Sciences, University of Ceará State, Fortaleza, CE, Brazil. selenemaiademorais@gmail.com.
authors.forename: Selene M
authors.initials: SM
authors.lastname: Morais
authors.affiliation: Chemistry Course, Master Course in Natural Resources, University of Ceará State, Fortaleza, CE, Brazil. katheasilva@hotmail.com.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Silva
authors.affiliation: Chemistry Course, Master Course in Natural Resources, University of Ceará State, Fortaleza, CE, Brazil. halisson.araujo@gmail.com.
authors.forename: Halisson
authors.initials: H
authors.lastname: Araujo
authors.affiliation: Post-Graduation Course in Biotechnology, University of Ceará State, Fortaleza, CE, Brazil. icarogpv@uol.com.br.
authors.forename: Icaro G P
authors.initials: IG
authors.lastname: Vieira
authors.affiliation: Post-Graduation Course of Veterinary Sciences, University of Ceará State, Fortaleza, CE, Brazil. alves.danielaribeiro@gmail.com.
authors.forename: Daniela R
authors.initials: DR
authors.lastname: Alves
authors.affiliation: Curso de Ciências Biológicas, Universidade Estadual Vale do Acaraú, Sobral, CE, Brazil. raquelbios@yahoo.com.br.
authors.forename: Raquel O S
authors.initials: RO
authors.lastname: Fontenelle
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal. artur.silva@ua.pt.
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
keywords: Anacardium occidentale; anacardic acids; cashew nut shell liquid