Inhibition of NorA efflux pump of Staphylococcus aureus by anacardic acids isolated from the cashew nutshell liquid of Anacardium occidentale L.

The rising of diseases caused by multidrug-resistant bacteria has encouraged researchers to explore more antimicrobial substances, as well as chemicals capable of potentiating the action of existing ones against multidrug-resistant bacteria. Anacardium occidentale produces a fruit known as cashew nut, filled with a dark, almost black, caustic, and flammable liquid called cashew nutshell liquid (CNSL). The goal of the study was to evaluate the intrinsic antimicrobial activity of the major compounds present in CNSL, called anacardic acids (AA), as well as their possible modulatory action as an adjuvant of Norfloxacin against a Staphylococcus aureus strain overproducing the NorA efflux pump (SA1199B). Microdilution assays were performed to determine the minimum inhibitory concentration (MIC) of AA against different microbial species. Norfloxacin and Ethidium Bromide (EtBr) resistance modulation assays were performed in the presence or absence of AA against SA1199-B. AA showed antimicrobial activity against Gram-positive bacterial strains tested but no activity against Gram-negative bacteria or yeast strains. At subinhibitory concentration, AA reduced the MIC values for Norfloxacin and EtBr against the SA1199-B strain. Furthermore, AA increased the intracellular accumulation of EtBr in this NorA overproducer strain, indicating that AA are NorA inhibitors. Docking analysis showed that AA probably modulates Norfloxacin efflux by spatial impediment at the same binding site of NorA.

Phenolic Lipids Derived from Cashew Nut Shell Liquid to Treat Metabolic Diseases.

Metabolic diseases are increasing at staggering rates globally. The peroxisome proliferator-activated receptors (PPARα/γ/δ) are fatty acid sensors that help mitigate imbalances between energy uptake and utilization. Herein, we report compounds derived from phenolic lipids present in cashew nut shell liquid (CNSL), an abundant waste byproduct, in an effort to create effective, accessible, and sustainable drugs. Derivatives of anacardic acid and cardanol were tested for PPAR activity in HEK293 cell co-transfection assays, primary hepatocytes, and 3T3-L1 adipocytes. In vivo studies using PPAR-expressing zebrafish embryos identified CNSL derivatives with varying tissue-specific activities. LDT409 (23) is an analogue of cardanol with partial agonist activity for PPARα and PPARγ. Pharmacokinetic profiling showed that 23 is orally bioavailable with a half-life of 4 h in mice. CNSL derivatives represent a sustainable source of selective PPAR modulators with balanced intermediate affinities (EC50 ∼ 100 nM to 10 µM) that provide distinct and favorable gene activation profiles for the treatment of diabetes and obesity.

JNK signaling-dependent regulation of histone acetylation are involved in anacardic acid alleviates cardiomyocyte hypertrophy induced by phenylephrine.

Cardiac hypertrophy is a complex process induced by the activation of multiple signaling pathways. We previously reported that anacardic acid (AA), a histone acetyltransferase (HAT) inhibitor, attenuates phenylephrine (PE)-induced cardiac hypertrophy by downregulating histone H3 acetylation at lysine 9 (H3K9ac). Unfortunately, the related upstream signaling events remained unknown. The mitogen-activated protein kinase (MAPK) pathway is an important regulator of cardiac hypertrophy. In this study, we explored the role of JNK/MAPK signaling pathway in cardiac hypertrophy induced by PE. The mice cardiomyocyte hypertrophy model was successfully established by treating cells with PE in vitro. This study showed that p-JNK directly interacts with HATs (P300 and P300/CBP-associated factor, PCAF) and alters H3K9ac. In addition, both the JNK inhibitor SP600125 and the HAT inhibitor AA attenuated p-JNK overexpression and H3K9ac hyperacetylation by inhibiting P300 and PCAF during PE-induced cardiomyocyte hypertrophy. Moreover, we demonstrated that both SP600125 and AA attenuate the overexpression of cardiac hypertrophy-related genes (MEF2A, ANP, BNP, and ß-MHC), preventing cardiomyocyte hypertrophy and dysfunction. These results revealed a novel mechanism through which AA might protect mice from PE-induced cardiomyocyte hypertrophy. In particular, AA inhibits the effects of JNK signaling on HATs-mediated histone acetylation, and could therefore be used to prevent and treat pathological cardiac hypertrophy.

Lipid and color stability of the meat and sausages of broiler fed with calcium anacardate.

BACKGROUND: Anacardic acid, a phenolic compound, represents 90% of cashew nut shell liquid, which is a byproduct from the industrial processing of cashew nuts. This study aimed to add calcium anacardate (CA) to broilers' diets as a source of anacardic acid, to evaluate its antioxidant effect in breast meat and in processed meat products (sausages). For this purpose, birds were fed according to the following treatments: diet without antioxidant and diets containing 2.5, 5.0, 7.5, or 10.0 g kg-1 CA. Chicken breast meat was stored frozen for 90 days. The thigh and drumsticks were used to produce chicken sausages that were kept in refrigerated conditions for 90 days. Lipid oxidation and color stability were assessed every 30 days. RESULTS: For breast meat, a 2.5 g kg-1 concentration of CA was insufficient to retard lipid oxidation, whereas 10.0 g kg-1 gave rise to a pro-oxidant effect and 5.0 g kg-1 slowed the oxidation up to 50 days. A level of 7.5 g kg-1 of CA was effective in retarding oxidation, favoring colour stability during the 90-days frozen storage. For sausages, 2.5 g kg-1 of calcium anacardate in broiler diets was sufficient to retard lipid oxidation. Calcium anacardate 7.5 g kg-1 provided greater redness in the sausages compared with the control and with the other treatments containing 5.0 and 10.0 g kg-1 . CONCLUSIONS: Calcium anacardate is a potential natural antioxidant for breast meat and sausages in storage when added to broilers' diets. © 2018 Society of Chemical Industry.

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.

Chemical biology of histone acetyltransferase natural compounds modulators.

Histone acetyltransferases (HATs) are a class of epigenetic enzymes crucial for chromatin restructuring and transcriptional regulation in eukaryotic cells, thus being a promising target for therapeutic development. Nonetheless, differently from histone deacetylases (HDACs) inhibitors, there is still paucity of small-molecule modulators of HAT activity. After a decline during past decade, natural products and their derivatives could be once again a valuable tool in the lead discovery process and meet such need of Novel Chemical Entities (NCEs). In this review, we will provide a comprehensive summary on the discovery of small-molecule HAT modulators from naturally occurring molecular scaffolds.

Ginkgolic acid inhibits protein SUMOylation by blocking formation of the E1-SUMO intermediate.

Protein modification by small ubiquitin-related modifier proteins (SUMOs) controls diverse cellular functions. Dysregulation of SUMOylation or deSUMOylation processes has been implicated in the development of cancer and neurodegenerative diseases. However, no small-molecule inhibiting protein SUMOylation has been reported so far. Here, we report inhibition of SUMOylation by ginkgolic acid and its analog, anacardic acid. Ginkgolic acid and anacardic acid inhibit protein SUMOylation both in vitro and in vivo without affecting in vivo ubiquitination. Binding assays with a fluorescently labeled probe showed that ginkgolic acid directly binds E1 and inhibits the formation of the E1-SUMO intermediate. These studies will provide not only a useful tool for investigating the roles of SUMO conjugations in a variety of pathways in cells, but also a basis for the development of drugs targeted against diseases involving aberrant SUMOylation.

Enzymatic polymerization of natural anacardic acid and antibiofouling effects of polyanacardic acid coatings.

Anacardic acid, separated from cashew nut shell liquid, is well known for its strong antibiotic and antioxidant activities. Recent findings indicate that phenolic compounds from plant sources have an effect on Gram-negative bacteria biofilm formation. In this work, a polyphenolic coating was prepared from anacardic acid using enzymatic synthesis and tested for its effects on biofilm formation of both Gram-negative and Gram-positive bacteria. Natural anacardic acid was enzymatically polymerized using soybean peroxidase. Hydrogen peroxide and phenothiazine-10-propionic acid were used as an oxidizing agent and redox mediator, respectively. Nuclear magnetic resonance and Fourier transform infrared (FTIR) analyses showed the formation of oxyphenylene and phenylene units through the phenol rings. No linkage through the alkyl chain was observed, which proved a high chemo-selectivity of the enzyme. Aqueous solvents turned out to play an important role in the polymer production yield and molecular weight. With 2-propanol, the highest production yield (61%) of polymer (molecular weight = 3,900) was observed, and with methanol, higher-molecular-weight polymers (5,000) were produced with lower production yields (43%). The resulting polyanacardic acid was cross-linked on a solid surface to form a permanent natural polymer coating. The FTIR analysis indicates that the cross-linking between the polymers took place through the unsaturated alkyl side chains. The polyanacardic acid coating was then tested for its antibiofouling effect against Gram-negative and Gram-positive bacteria and compared with the antibiofouling effects of polycardanol coatings reported in the literature. The polyanacardic acid coating showed more reduction in biofilm formation on its surface than polycardanol coatings in the case of Gram-positive bacteria, while in the case of Gram-negative bacteria, it showed a similar reduction in biofilm formation as polycardanol.

Lipoxygenase inhibitory activity of anacardic acids.

6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor.