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.

Metagenomic Shotgun Sequencing and Unbiased Metabolomic Profiling Identify Specific Human Gut Microbiota and Metabolites Associated with Immune Checkpoint Therapy Efficacy in Melanoma Patients

“…Strikingly, 15:2 anacardic acid levels were markedly increased in all ICT (62-fold, P = .0077, Welch's two-sample t test) and IN (94-fold, P = .0288) responders. Anacardic acid is an alkyl derivative of salicylic acid and produced in the nutshell of cashews [31] and also in mangos. Interestingly, anacardic acids stimulate phagocytes and can augment bactericidal activity [32] , [33] .…”

Cardanols detected in non-polar propolis extracts from Scaptotrigona aff. postica (Hymenoptera, Apidae, Meliponini)

“…Cardanol and cardol are non-polar compounds typical of plants of the genus of the family Anacardiaceae, both in native and cultivated cultures. Anacardic acid, cardanol, cardol and methyl cardol, with different degrees of unsaturation (monoene-15:1, diene-15:2, and triene-15:3), were isolated from cashew (Anacardium occidentale), family Anacardiaceae (Morais et al, 2017;Fadeyi et al, 2015;Gómez-Caravaca et al, 2010). Thus, possibly a plant of the Anacardiaceae family, probably Anacardium occidentale and/or Mangifera indica, could be the resin source for this propolis.…”

Current Concepts in Pharmacometabolomics, Biomarker Discovery, and Precision Medicine

“…In a landmark PMx and metagenomics study of patient's response to an immune checkpoint inhibitor (ICT), the metagenomic analysis of fecal samples showed the gut microbiome was enriched with Bacteroides caccae, while PMx analysis of fecal samples revealed that anacardic acid levels were increased in all ICT responders (62-fold, p = 0.0077). Anacardic acid is a derivative of salicylic acid and is found in cashews and mangos [94]. Anacardic acid has been shown to supplement bactericidal activity [95].…”