Anacardic Acids Research Articles

Front Cover: Productivity of a preparative high‐performance liquid chromatography isolation of anacardic acids from cashew nut shell liquid

Front Cover: Productivity of a preparative high‐performance liquid chromatography isolation of anacardic acids from cashew nut shell liquid

Productivity of a preparative high‐performance liquid chromatography isolation of anacardic acids from cashew nut shell liquid

AbstractThe anacardic acids are alkyl phenols, with biological activities, obtained as a byproduct from cashew nut processing. The anacardic acids isolation by preparative reversed phase high‐performance liquid chromatography was developed injecting large pulse from 50 to 200 mg of cashew nut shell liquid through a C18 column eluted with methanol, water and acetic acid (80:20:1). The separations were carried out at 25°C and monitored at 280 nm. Yield, recovery, purity, solvent consumption and productivity were analyzed. The results of anacardic acids isolation pointed the concentration loading of 100 mg as a process threshold leading to a productivity of 0.681 Kg.day−1.Kg−1 of anacardic acids with purity of 96.41, 95.32 and 90.77% for anacardic acid triene, diene and monoene, respectively.

Chemical Constituents of Anacardium occidentale as Inhibitors of Trypanosoma cruzi Sirtuins.

Benznidazole and nifurtimox, the only drugs available for the treatment of Chagas disease, have limited efficacy and have been associated with severe adverse side effects. Thus, there is an urgent need to find new biotargets for the identification of novel bioactive compounds against the parasite and with low toxicity. Silent information regulator 2 (Sir2) enzymes, or sirtuins, have emerged as attractive targets for the development of novel antitrypanosomatid agents. In the present work, we evaluated the inhibitory effect of natural compounds isolated from cashew nut (Anacardium occidentale, L. Anacardiaceae) against the target enzymes TcSir2rp1 and TcSir2rp3 as well as the parasite. Two derivates of cardol (1, 2), cardanol (3, 4), and anacardic acid (5, 6) were investigated. The two anacardic acids (5, 6) inhibited both TcSir2rp1 and TcSir2rp3, while the cardol compound (2) inhibited only TcSir2rp1. The most potent sirtuin inhibitor active against the parasite was the cardol compound (2), with an EC50 value of 12.25 µM, similar to that of benznidazole. Additionally, compounds (1, 4), which were inactive against the sirtuin targets, presented anti-T. cruzi effects. In conclusion, our results showed the potential of Anacardium occidentale compounds for the development of potential sirtuin inhibitors and anti-Trypanosoma cruzi agents.

Gems from past: Neuroprotective effects of Bhilawinol and Anacardic acid against Glutamate-induced excitotoxicity in PC-12 cells.

Gems from past: Neuroprotective effects of Bhilawinol and Anacardic acid against Glutamate-induced excitotoxicity in PC-12 cells.

Antiplasmodial evaluation of Anacardium occidentale and alkyl-phenols

The ethanol crude extract from cashew (Anacardium occidentale L. Anacardiaceae) displayed significant antiplasmodial activity (IC50 0.577μg/ml). Liquid chromatography-high resolution Mass spectrometry analysis was performed to identify the main compounds existing in the ethanol extract. The occurrence of anacardic acids, cardols, and 2-methylcardols derivatives was confirmed in the extract. The IC50 obtained, when the main isolated compounds were evaluated in Plasmodium falciparum D6 strain, ranged from 5.39μM to >100μM. Tested here for the first time, the data showed that cardol triene 1 (IC50=5.69μM) and 2-methylcardol triene 4 (IC50=5.39μM) demonstrated good antimalarial activity. In conclusion, Anacardium occidentale nuts presented relevant biological potential, and further studies should be considered.

Recovery of Anacardic Acids from Cashew Nut Shell Liquid with Ion-Exchange Resins

Anacardic acids might have the potential for industrial and pharmaceutical applications, which could represent an important diversification option for the cashew industry. However, industrial separation processes for high-purity anacardic acids are challenging because of the presence of phenolic components (cardols and cardanols) with similar chemical behavior but lower market price. In this work, the feasibility and operating conditions for a method to separate anacardic acid by resin adsorption is proposed. An anion-exchange resin is employed to purify anacardic acids from cashew nut shell liquid (CNSL) alcoholic solutions. Anacardic acid quantification was performed by spectrophotometry, and the optimum operation conditions were determined by varying pH, temperature, and CNSL/resin ratios. Using the optimal conditions, a high-purity mixture of anacardic acids (>95%) was obtained.

A Heck-Based Strategy To Generate Anacardic Acids and Related Phenolic Lipids for Isoform-Specific Bioactivity Profiling.

A synthetic strategy for phenolic lipids such as anacardic acid and ginkgolic acid derivatives using an efficient and selective redox-relay Heck reaction followed by a stereoselective olefination is reported. This approach controls both the alkene position and stereochemistry, allowing the synthesis of natural and unnatural unsaturated lipids as single isomers. By this strategy, the activities of different anacardic acid and ginkgolic acid derivatives have been examined in a matrix metalloproteinase inhibition assay.

Impregnation of catheters with anacardic acid from cashew nut shell prevents Staphylococcus aureus biofilm development.

The effect of anacardic acid impregnation on catheter surfaces for the prevention of Staphylococcus aureus attachments and biofilm formations were evaluated. Silicon catheter tubes were impregnated using different concentrations of anacardic acids (0·002-0·25%). Anacardic acids are antibacterial phenolic lipids from cashew nut (Anacardium occidentale) shell oil. Anacardic acid-impregnated silicon catheters revealed no significant haemolytic activity and were cytocompatible against fibroblast cell line (L929). Sustained release of anacardic acids was observed for 4days. Anacardic acid-impregnated silicon catheters efficiently inhibited S. aureus colonization and the biofilm formation on its surface. The invivo antibiofilm activity of anacardic acid-impregnated catheters was tested in an intraperitoneal catheter-associated medaka fish infection model. Significant reduction in S. aureus colonization on anacardic acid-impregnated catheter tubes was observed. Our data suggest that anacardic acid-impregnated silicon catheters may help in preventing catheter-related staphylococcal infections. This study opens new directions for designing antimicrobial phytochemical-coated surfaces with ideal antibiofilm properties and could be of great interest for biomedical research scientists.

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

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.

Anxiolytic effect of anacardic acids from cashew (Anacardium occidentale) nut shell in mice

Antianxiety drugs currently in use are associated with a number of serious side effects. Present study was designed to evaluate the efficacy of anacardic acids (AAs) isolated from cashew nut (Anacardium occidentale L.) shell liquid (CNSL) to treat anxiety as well as its role in oxidative stress in mice model. Anxiolytic effect of AA was evaluated using rota-rod and a set of behavioral tests in male Swiss albino mice at the doses of 10, 25, and 50 mg/kg. Flumazenil was used to evaluate the possible involvement of GABAergic system in the mechanism of action of AA. The effect of AA on oxidative stress in mice was evaluated by determining the concentration of malondialdehyde (MDA), reduced glutathione, and catalase (CAT) activity. The detection of DNA damage of the treated animals was performed using alkaline comet test in the hippocampus and frontal cortex of the animals. The results demonstrated that AA did not produce myorelaxant and sedative effects, nor did it cause a decrease in locomotor activity. The anxiolytic effect of AA was well-evident in all tests, especially at higher dose levels (25 and 50 mg/mg). Flumazenil reversed the anxiolytic effect of AA at all doses. In addition, AA reduced oxidative stress by decreasing the concentration of MDA and increasing the levels of reduced glutathione (GSH) and CAT activity. Statistical analysis by Pearson's correlation indicated a positive correlation between anxiolytic effect of AA to its antioxidant and lipid peroxidation inhibitory activity. Furthermore, increased CAT activity and GSH concentrations in the hippocampus and frontal cortex of mice was also complementary to the reduced genotoxic damage observed in the study. In comet assay, AA did not increase in DNA damage. In conclusion, the results supported that AA possesses GABAA receptor mediated anxiolytic activity with the lack of myorelaxation and genotoxicity. © 2018 IUBMB Life, 70(5):420-431, 2018.

Anacardic Acids from Cashew Nuts Prevent Behavioral Changes and Oxidative Stress Induced by Rotenone in a Rat Model of Parkinson’s Disease

Anacardic acids (AAs) are alkyl phenols mainly presenting in cashew nuts. The antioxidant effects of these compounds have been an area of interest in recent research, with findings suggesting potential therapeutic use for certain diseases. Nevertheless, none of these studies were performed in order to test the hypothesis of whether anacardic acids are capable of preventing behavioral changes and oxidative stress induced by the pesticide rotenone in experimental model of Parkinson's disease. In our research, adult male rats were treated orally with AAs (1, 3, 10, 25, 50, or 100mg/kg/day) 1h before rotenone (3mg/kg; s.c.) for five consecutive days. The behavioral testing strategies, including tests for general locomotor activity (open field), motor coordination (rotarod), and spatial memory performance (elevated T-maze), were carried out. Lipoperoxidation levels and total superoxide dismutase (t-SOD) activity, as well as cytoplasmic and mitochondrial SOD gene expression, were assessed in the substantia nigra (SN), striatum, and cerebral cortex. The results showed that AAs dose-dependently prevented the rotenone-induced learning and motor impairment from 10mg/kg/day. AAs also precluded rotenone-induced lipoperoxidation in all doses, acting directly on the mitochondria, and improved the t-SOD activity in the doses 25-100mg/kg/day. AAs per se (100mg/kg/day) increased SOD gene expression and t-SOD activity. Our findings indicate that the oral administration of AAs prevents rotenone-induced behavioral changes and oxidative stress, in part due to a modulatory action on the mitochondria and SOD gene expression. These data suggest that AAs have promising neuroprotective action against degenerative changes in Parkinson's disease.

Subcritical water extraction of phenolic and antioxidant constituents from pistachio (Pistacia vera L.) hulls

Pistachio hulls, important by-products of pistachio processing, were extracted using an environmentally friendly process with subcritical water (SCW) at a pressure of 6.9 MPa in the range of 110 and 190 °C, and a flow rate of 4 ml/min. Detailed HPLC-DAD-ESI/MSn analyses allowed the identification of 49 phenolic compounds in the SCW extracts. Total gallotannin yields up to 33 g/kg were reached at 150–170 °C, where gallic acid (22.2 g/kg) and penta-O-galloyl-β-d-glucose (9.77 g/kg) levels were 13.2- and 10.6-fold higher than those in the aqueous methanol extracts. Flavonols were also effectively extracted at 110–150 °C (4.37–5.65 g/kg), while anacardic acid recovery was poor (1.13–2.77 g/kg). Accordingly, high amounts of anacardic acids (up to 50.7 g/kg) were retained in the extraction residue, revealing that SCW extraction allowed selective extraction of gallotannins and flavonols. Antioxidant capacities ranged from 0.68 to 1.20 mmol Trolox equivalents (TE)/g for SCW extracts increasing with temperature up 190 °C.

Inhibition of angiotensin I converting enzyme by anacardic acids isolated from Cashew nut (Anacardium occidentale Linn.) shell liquid

ABSTRACTHypertension represents one of the most common maladies of western civilizations caused by bad dietary practices and lack of exercise. Angiotensin-I-converting enzyme inhibitors (ACEi) have been shown to be very efficient in the prevention of hypertension. ACEi are also implicated (by their ability to reduce the product of ACE activity namely angiotensin-II levels, which has oncogenic and increased cell proliferation effects) to be efficient anticancer agents. Therefore, we evaluated the potential antihypertension capacities of anacardic acids purified from Cashew (Anacardium occidentale Linn.) nut shell liquid by inhibition of ACE using analytical reverse-phase high performance liquid chromatography. The ability to inhibit ACE showed the following relation: anacardic-3 (IC50 = 12 µM) > anacardic acid-4 (IC50 = 20 µM) > anacardic acid-2 (IC50 = 33 µM) > anacardic acid-1 (IC50 = 39 µM) as compared to the positive control captopril (IC50 = 6.85 nM). Salicylic acid lacking a phytyl side chain was negative. The capacity of purified anacardic acids to inhibit ACE thereby represents the most potent naturally available plant chemicals described so far, as a potential means of reducing hypertension. The inhibition of angiotensin II production indicated that anacardic acids could also have utility in cancer prevention and recurrence, and reduction of cardiotoxicity during chemotherapy.

Development and Validation of a Reversed Phase HPLC Method for Determination of Anacardic Acids in Cashew (Anacardium occidentale) Nut Shell Liquid

Cashew nut shell liquid (CNSL) contains phenolic lipids with aliphatic chains that are of commercial interest. In this work, a chromatographic method was developed to monitor and quantify anacardic acids (AnAc) in CNSL. Samples containing AnAc were analyzed on a high-performance liquid chromatograph coupled to a diode array detector, equipped with a reversed phase C18 (150 × 4.6 mm × 5 μm) column using acetonitrile and water as the mobile phase both acidified with acetic acid to pH 3.0 in an isocratic mode (80:20:1). The chromatographic method showed adequate selectivity, as it could clearly separate the different AnAc. To validate this method, AnAc triene was used as an external standard at seven different concentrations varying from 50 to 1,000 μg mL-1. The Student's t-test and F-test were applied to ensure high confidence for the obtained data from the analytical calibration curve. The results were satisfactory with respect to intra-day (relative standard deviation (RSD) = 0.60%) and inter-day (RSD = 0.67%) precision, linearity (y = 2,670.8x - 26,949, r2 > 0.9998), system suitability for retention time (RSD = 1.02%), area under the curve (RSD = 0.24%), selectivity and limits of detection (19.8 μg mg-1) and quantification (60.2 μg mg-1). The developed chromatographic method was applied for the analysis of different CNSL samples, and it was deemed suitable for the quantification of AnAc.

Chemical characterization and pharmacological assessment of polysaccharide free, standardized cashew gum extract (Anacardium occidentale L.)

Ethnopharmacological relevanceThe cashew gum (Anacardium occidentale L.) is used in traditional Brazilian medicine in the treatment of inflammatory conditions, asthma, diabetes, and gastrointestinal disturbances. Aim of the studyIn the present study, we aimed at forming a chemical characterization and investigation of the antinociceptive and anti-inflammatory activities of the aqueous extract of cashew gum without the presence of polysaccharides in its composition (CGE). Materials and methodsThe CGE was obtained after the precipitation and removal of polysaccharides through the use of acetone. After, the acetone was removed by rotaevaporation, and the concentrated extract was lyophilized. The chemical characterization of CGE was performed by liquid chromatography mass spectrometry (LC-MS) and tandem mass spectrometry (MS/MS) analyses. Mice were used for the evaluation of the antinociceptive and anti-inflammatory activities. CGE was analyzed via the Irwin test, acetic acid-induced writhing test, formalin-induced pain test, and carrageenan-induced paw edema test. The motor activity or probable sedation was verified through the chimney, open-field, and sodium pentobarbital-induced sleep tests. We investigated if the analgesic and anti-inflammatory effects of CGE depend of reduction in PGE2 levels, were performed the carrageenan or PGE2-induced hyperalgesia tests. ResultsThe chemical characterization of CGE showed the presence of anacardic acids as the predominant phytoconstituents. The treatment with CGE (75, 150, and 300mg/kg, p.o.) inhibited the number of writhing in a dose-dependent manner. With an intermediate dose, CGE did not cause motor impairment with the chimney test or alterations in either the open-field or sodium pentobarbital-induced sleep. In the formalin-induced pain test, CGE (150mg/kg, p.o.) produced an antinociceptive effect only in the first phase of the test, suggesting anti-inflammatory activity. With the same dosage, CGE also reduced the carrageenan-induced paw edema at all hours of the test, confirming its anti-inflammatory effect. Furthermore, CGE (150mg/kg, p.o.) presented an antihyperalgic effect at all hours of the carrageenan-induced hyperalgesia test. However, this dose of CGE was not able to reduce the hyperalgesia induced by PGE2, suggesting that the anti-inflammatory effect of this extract depends on the reduction in the PGE2 levels. ConclusionThe anacardic acids are the predominant phytoconstituents identified in the CGE. The action mechanisms of CGE suggest the reduction in the PGE2 levels. These findings support the use of cashew gum in popular medicine and demonstrate that part of its antinociceptive and anti-inflammatory effects should also be attributed to the presence of anacardic acids in its composition, independent of the presence of polysaccharides.

Effects of industrial cashew nut processing on anacardic acid content and allergen recognition by IgE

Cashew nuts are important both nutritionally and industrially, but can also cause food allergies in some individuals. The present study aimed to assess the effect(s) of industrial processing on anacardic acids and allergens present in cashew nuts. Sample analyses were performed using liquid chromatography coupled with mass spectrometry, SDS-PAGE and immunoassay. The anacardic acid concentration ranged from 6.2 to 82.6mg/g during processing, and this variation was attributed to cashew nut shell liquid incorporation during storage and humidification. Dehydrated and selected samples did not significantly differ in anacardic acid content, having values similar to the raw sample. SDS-PAGE and immunoassay analysis with rabbit polyclonal sera and human IgE indicated only minor differences in protein solubility and antibody binding following processing steps. The findings indicate that appreciable amounts of anacardic acid remain in processed nuts, and that changes to cashew allergens during industrial processing may only mildly affect antibody recognition.

Determination of pistachio (Pistacia vera L.) hull (exo- and mesocarp) phenolics by HPLC-DAD-ESI/MSn and UHPLC-DAD-ELSD after ultrasound-assisted extraction

A method for the simultaneous extraction and quantitation of gallotannins, flavonoids and anacardic acids from pistachio hulls is presented. After screening of various extraction parameters and solvent systems with variable polarity and acidity, a three-fold repeated extraction with methanol/water/formic acid (80/19/1, v/v/v) at a sample-to-solvent ratio of 1/20 (w/v) under probe-sonication was found to be most suitable for extracting ≥95% of the abovementioned phenolics. A newly developed UHPLC-DAD-ELSD method was compared to an HPLC method for compound separation and quantitation. While analyses by UHPLC were 3.7 times faster, the core-shell particle HPLC column used allowed a superior peak resolution, particularly regarding anacardic acids. While phenolic acids were virtually undetectable by ELSD, it may be applicable for the determination of anacardic acids. However, ELSD sensitivity was inferior to that of the DAD used. Furthermore, validation parameters such as signal linearity, detection and quantitation limits, extraction recoveries, intra- and inter-day repeatability are presented. The new method was applied to pistachio hulls of three different varieties. Phenolic contents ranged from 61.2±0.45 to 100±0.48g/kg dry matter. Among phenolic constituents, anacardic acids prevailed (64.6–80.4% of total phenolics) followed by gallotannins (13.4–21.2%), such as β-glucogallin, gallic acid, and penta-O-galloyl-β-d-glucose, and flavonol glycosides (5.7–16.3%).

Anacardic Acid Constituents from Cashew Nut Shell Liquid: NMR Characterization and the Effect of Unsaturation on Its Biological Activities.

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.

UPLC-qTOF-MS/MS-based phenolic profile and their biosynthetic enzyme activity used to discriminate between cashew apple (Anacardium occidentale L.) maturation stages.

Cashew immature and ripe peduncles (Anacardium occidentale L.) from orange- and red-colored clones CCP 76 and BRS 189, respectively, were prepared as juice or fibrous fraction and submitted to UPLC-MS analyses, while the soluble fraction was also submitted to enzymatic evaluation. Cinnamoyl glucoside was present in ripe juice samples from both cashew clones, while monogalloyl diglucoside and digalloyl glucoside were present in immature juice samples from both cashew clones. Four compounds were found at immature fiber of both clones, anacardic acids (1, 2, 3) and GA19. The phenolic biosynthetic pathway was evaluated in juice samples and phenylalanine ammonia-lyase activity decreased significantly during the development, although it was much higher in ripe CCP 76. UDP-glycosyltransferases activity differed between clones, however its product cinnamoyl glucoside was a possible chemical marker of ripe juice samples from both clones. Flavonol synthase showed the highest specific activity in both cashew clones and its product, flavonols were identified in cashew apple at immature and ripe stages.

Ginkgo fruit extract as an additive to modify rumen microbiota and fermentation and to mitigate methane production

Ginkgo fruit, an unused byproduct of the ginkgo nut industry, contains antimicrobial compounds known as anacardic acids. Two major cultivars of ginkgo, Kyuju (K) and Tokuro (T), were evaluated for their potential as a feed additive for ruminants. In batch culture, we incubated a mixture of hay and concentrate in diluted rumen fluid with or without 1.6% (fruit equivalent) ginkgo fruit extract. We conducted another series of batch culture studies to determine the dose response of fermentation. We also conducted continuous culture using the rumen simulation technique (RUSITEC) with cultivar K and carried out a pure culture study to monitor the sensitivity of 17 representative rumen bacterial species to ginkgo extract and component phenolics. Although both K and T extracts led to decreased methane and increased propionate production, changes were more apparent with K extract, and were dose-dependent. Total gas production was depressed at doses ≥3.2%, suggesting that 1.6% was the optimal supplementation level. In RUSITEC fermentation supplemented with 1.6% ginkgo K, methane decreased by 53% without affecting total gas or total VFA production, but with decreased acetate and increased propionate. Disappearance of dry matter, neutral detergent fiber, and acid detergent fiber were not affected by ginkgo, but ammonia levels were decreased. Quantitative PCR indicated that the abundance of protozoa, fungi, methanogens, and bacteria related to hydrogen and formate production decreased, but the abundance of bacteria related to propionate production increased. MiSeq analysis (Illumina Inc., San Diego, CA) confirmed these bacterial changes and identified archaeal community changes, including a decrease in Methanobrevibacter and Methanomassiliicoccaceae and an increase in Methanoplanus. Pure culture study results supported the findings for the above bacterial community changes. These results demonstrate that ginkgo fruit can modulate rumen fermentation toward methane mitigation and propionate enhancement via microbial selection.