Cashew Nut Shell Research Articles

Structural Analysis of Cardanol and Its Biological Activities on Human Keratinocyte Cells

Background/Objectives: Cashew nutshell liquid (CNSL) is obtained during the industrial processing of cashew nuts. It contains anacardic acid (2-hydroxy-6-n-pentadecylbenzoic acid) and cardanol (3-n-pentadecylphenol). Therefore, CNSL provides a rich source of phenolic lipids serving as natural antioxidants or precursors for industrial uses. Here, we have analyzed in detail a commercial sample of cardanol by nuclear magnetic resonance (NMR) spectroscopy and its biological activities in the human keratinocyte cell line (HaCaT cells). Methods: The cytotoxic effects, genotoxicity, cell proliferation, and healing properties on HaCaT cells were studied using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, comet assay, proliferation assay, and scratch assay, respectively. Additionally, the modulatory effect of cardanol on the cellular fatty acid profile of HaCaT cells was analyzed by gas chromatography. Results: NMR showed the structure of cardanol as a mixture of the 8′-monoene (42%), the 8′,11′-diene (22%), and the 8′,11′,14′-triene (36%) for the pentadecyl side chain with all double bonds in Z configuration. The cytotoxic effects on HaCaT cells only occurred at high concentrations of cardanol (>10 µg/mL), which caused significant reductions in cell viability. Using the comet assay, a dose-dependent increase in DNA damage was found at concentrations above 10 µg/mL. Scratch assays revealed that cardanol achieved 99% wound closure of HaCaT cells treated with 1 µg/mL cardanol after 48 h. Cardanol at 1 and 0.1 µg/mL significantly enhanced HaCaT cell proliferation and promoted migration, contributing to accelerated wound healing processes. As shown by gas chromatography, 1 µg/mL cardanol increased the total amount of polyunsaturated fatty acids (PUFA), including ω-3, ω-6, and ω-9 fatty acids. Conclusions: Together, these findings suggest that concentrations of <10 µg/mL cardanol are safe and exhibit beneficial biological activities, particularly wound-healing effects on HaCaT cells. Further studies are necessary to explore additional potential applications of cardanol, to refine its formulations for clinical use, and to ensure its safety and action in other target cells and species.

Revolutionary bamboo crash barriers utilizing sustainable materials for enhanced road safety

Road accidents are a growing concern worldwide, and crash barriers have significantly reduced the severity of these incidents. In its pursuit of developing an eco-friendly crash barrier, India installed the world’s first 200 m bamboo crash barrier, on Bombay–Pune Highway. Although its eco-friendly and recyclable design is commendable, using Bambusa balcooa infused with creosote oil and covered with High-density polyethylene (HDPE) raises substantial health and environmental issues due to the presence of toxic and carcinogenic Polycyclic aromatic hydrocarbons (PAHs). To address these concerns, a novel eco-friendly design has been proposed, utilizing Pseudoxytenanthera bamboo species treated with Cashew nutshell liquid (CNSL). This study rigorously characterizes these bamboo species through mechanical testing at both nodes and internodes, evaluating critical strength parameters such as axial tensile modulus, ultimate strength, compression strength, flexural strength, and impact strength. Scanning electron microscopy is employed to examine fracture morphology, linking the natural fiber characteristics to their mechanical properties. The results indicate that Pseudoxytenanthera stocksii exhibits superior Tensile strength (496.73 MPa), flexural (235.57 MPa), Impact strength (4.8 kJ/m2) and compressive strength (68.66 MPa), with a direct correlation between density, particularly in nodal regions. The final phase involves chemically validating the bamboo treated with CNSL to enhance its environmental friendliness, presenting a viable alternative to steel for sustainable infrastructure. This study presents a high-strength sustainable and non-toxic alternative to conventional crash barriers by utilising Pseudoxytenanthera bamboo species treated with CNSL, replacing the toxic creosote-treated Bambusa balcooa, and offering a robust solution for safer road infrastructure while advancing green engineering practices.

High-performance and promising biolubricants from agro-waste cashew nut shell liquid

Purpose This study aims to replace petroleum-based lubricating oils with sustainable biomaterials, addressing issues associated with existing alternatives, such as poor performance, high cost and limited availability. Design/methodology/approach The transformation of agricultural waste cardanol, a nonedible vegetable oil that is abundantly available, into green cardanyl acetate (CA) biolubricating ester oil. The potential of CA as a base stock for lubricants is validated by assessing its lubrication performance. Findings CA exhibited a higher viscosity index, flash point and thermal stability than commercially available mineral-based (CTL3, coal-to-liquid) and synthetic (PAO2, poly-alpha-olefin) lubricant base stocks. Moreover, CA exhibits excellent anticorrosivity properties as well as PAO2 and CTL3. The tribological properties of CA were evaluated, and the results show that CA exhibits a smaller average wear scar diameter (WSD) of 0.54 mm than that of PAO2 (0.85 mm) and CTL3 (0.90 mm). In extreme pressure tests, acylated CA demonstrated the highest last nonseizure load capacity at 510 N, outperforming commercial CTL3 (491 N) and PAO2 (412 N). All results demonstrate that CA displays an excellent series of base stock properties. Originality/value The novelty of this work lies in the utilization of renewable agricultural waste, cashew nut shell liquid, to produce a high-value biolubricant as an alternative to commercial fossil-based lubricants. The renewable nature, low cost, and large-scale availability of raw materials pave a new path for the production and application of biolubricants, showcasing the immense potential of converting agricultural waste into high-value products. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0064/

Comparative studies of composites based on commercial epoxy resin with renewable resources-based tetra functional epoxy resin

This research distinguishes itself by synthesizing a novel epoxy resin from three distinct renewable resources, moving beyond the conventional reliance on a single source found in many studies. The innovative epoxy resin was synthesized through a chemical reaction involving cardanol, resorcinol, furfural, and epichlorohydrin. Notably, resorcinol and a component of cashew nutshell liquid (CNSL) cardanol were incorporated as a partial substitute for up to 50% of the phenol in the synthesis process. This multifaceted approach not only enhances sustainability but also demonstrates the potential of eco-friendly materials in developing advanced composites while optimizing the resin performance characteristics. The modified tetrafunctional epoxy resin based composites were prepared from sustainable synthesized bio-based epoxy resin. This study compared the varied characterization data of cardanol-based tetra functional epoxy resin with conventional epoxy resin using Aromatic and aliphatic hardeners such as triethylenetetramine, phenalkamine, low viscous phenalkamine, and polyamide. The adhesive strength and curing properties of a modified epoxy resin with hardeners are examined in this study. Strong adhesive bonding of matrix with wood and metal substrates was demonstrated by lap shear strength (LSS). The Brookfield viscosity, volatile content, epoxy equivalent weight (EEW), hydrolyzable chlorine content, weight average molecular weight, and Fourier transform infrared spectroscopy were used to characterize the tetrafunctional modified epoxy resin. Thermal analysis using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) showed a cure index and decomposition temperature of resin systems. Chemical resistance, and mechanical properties (Rockwell hardness, Izod impact strength, tensile strength, and flexural strength) were determined for every composite.

Assessment of embryotoxicity and teratogenic effects of Anacardium occidentale L. cashew nutshell extracts on zebrafish (Danio rerio) embryos

Herbal extracts of therapeutic relevance are of great importance as they have the capability of being used as lifesaving medicines. Anacardium occidentale L. is one such herb that is widely used in a variety of pharmaceutical preparations. The cashew nutshells have several medicinal uses, including the treatment of urinary and metabolic issues. Investigating its teratogenic risks during the early stages of development is necessary to prevent the health problems that could arise from its excessive usage. Therefore, the goal of the current study was to assess the developmental toxicity of cashew nutshell extracts on the embryos of zebrafish (Danio rerio). The study examined four extracts of cashew nutshells: aqueous, chloroform, organic, and ethyl acetate obtained by Soxhlet extraction. Of these, the aqueous extract exhibited the highest LC50 value with no visible teratogenic abnormalities. However, treatment with higher concentrations of the aqueous extract resulted in altered cardiac systole, decreased protein content, elevated lipid, and cholesterol levels, as well as elevated AST and ALT activity in treated embryos. All these teratogenic effects were found to be prominent at dosages greater than 62.5 μg/ml. Therefore, it can be concluded that the cashew nutshell aqueous extract is nonteratogenic, when utilized at concentrations lower than 62.5 μg/ml.

Enhancement of Green Composite Performance Through the Synergistic Influence of Cashew Nut Shell Liquid and Nanoclay on Natural Fiber Reinforcement

ABSTRACTNatural fiber‐reinforced biocomposites are emerging as viable alternatives to conventional thermoplastics; however, low mechanical and physical properties limit their broad applications. This study addresses these limitations by developing a nanoclay and cashew nut shell liquid (CNSL)‐modified novel soy resin‐based jute composites by enhancing mechanical and physical performance. CNSL, rich in phenolic compounds, chemically interacts with the soy matrix, improving interfacial bonding and imparting resistance to environmental degradation. Nanoclay dispersion within the matrix optimizes load transfer, as confirmed through density functional theory (DFT) calculations of interaction energies, resulting in a synergistic effect on composite strength. The optimized composite exhibited a remarkable storage modulus of 8697 MPa at 35°C and 1 Hz, a flexural modulus of 3288 MPa, tensile strength of 61.3 MPa, and flexural strength of 62.7 MPa. X‐ray diffraction and transmission electron microscopy analyses revealed a well‐integrated nano‐biocomposite structure, confirming successful reinforcement dispersion. Thermal stability up to 290°C, a contact angle of 61.4°, and water absorption of 49.5% indicate its suitability for diverse conditions. Additionally, cytotoxicity tests demonstrated the material's biocompatibility, while soil burial tests showed a mass loss of 74.2% over 75 days, verifying its biodegradability. These biocomposites can replace nondegradable thermoplastics in various applications.

Effects of Polyol Types on Underwater Curing Properties of Polyurethane.

This study aims to develop castable polyurethane suitable for applications on wet substrates or underwater construction. Polyurethanes were synthesized using various polyols with similar hydroxyl values, including poly(tetrahydrofuran) polyol, polyester polyol, castor oil-modified polyol, soybean oil-modified polyol, and cashew nut shell oil-modified polyol. The corresponding polyurethane curing products were evaluated for their underwater curing characteristics by volume expansion ratios and adhesion strength on dry and wet substrates, combined with analyses of reaction exothermic behavior, wetting properties on dry and wet substrates, interfacial tension, and microstructure characterization from the perspectives of reaction activity and water solubility. The results indicate that polyols with higher hydrophobicity and reactivity to isocyanates lead to reduced side reactions during underwater curing, making them more suitable for underwater applications. Soybean oil-based and cashew nut shell oil-based polyurethanes exhibited fast curing (gel times of 1.15 and 1.35 min, respectively), minimal volume change (within 2.5% after 7 days underwater), and strong wet adhesion (1.95 MPa and 2.38 MPa with minimal loss, respectively). The two polyols showed different mechanical properties, providing tailored options for specific underwater engineering applications.

Structural Characterization and In Vitro and In Silico Studies on the Anti-α-Glucosidase Activity of Anacardic Acids from Anacardium occidentale.

The growing focus on sustainable use of natural resources has brought attention to cashew nut shell liquid (CNSL), a by-product rich in anacardic acids (AAs) with potential applications in diabetes treatment. In this study, three different AAs from CNSL, monoene (15:1, AAn1), diene (15:2, AAn2), and triene (15:3, AAn3), and a mixture of the three (mix) were evaluated as α-glucosidase inhibitors. The samples were characterized by combining 1D and 2D NMR spectroscopy, along with ESI-MS. In vitro assays revealed that AAn1 had the strongest inhibitory effect (IC50 = 1.78 ± 0.08 μg mL-1), followed by AAn2 (1.99 ± 0.76 μg mL-1), AAn3 (3.31 ± 0.03 μg mL-1), and the mixture (3.72 ± 2.11 μg mL-1). All AAs significantly outperformed acarbose (IC50 = 169.3 μg mL-1). In silico docking suggested that polar groups on the aromatic ring are key for enzyme-ligand binding. The double bond at C15, while not essential, enhanced the inhibitory effects. Toxicity predictions classified AAs as category IV, and pharmacokinetic analysis suggested moderately favorable drug-like properties. These findings highlight AAs as a promising option in the search for new hypoglycemic compounds.

Seedling Production in Eco-Friendly Tubes Manufactured with Beeswax and Cashew Nutshell

The disposal of polypropylene plastic tubes generated by producing seedlings of forest species promotes negative impacts on the environment and human health. These factors have motivated the search for biodegradable and environmentally friendly materials. Thus, the present study aims to evaluate the efficiency and quality of tubes made from particulate waste from cashew nut shells and beeswax in the development of Mimosa caesalpiniifolia Benth. The sustainable tubes were produced using a natural beeswax matrix with proportions of 10, 20, 30, 40, and 50% cashew nut particles. The chemical characterization of the material was performed. The tubes were made in a handmade cardboard mold and P80 wood sandpaper, 35 mm × 125 mm (diameter × length). The quality of the seedlings was evaluated using the Dickson quality index (DQI). The results showed that the cashew nutshell particles present in their chemical composition have values of 6.83 g kg−1 of nitrogen (N), 0.60 g kg−1 of phosphorus (P), and 1.93 g kg−1 of potassium (K). The quality assessment found that all biodegradable tubes had higher DQI values than polypropylene tubes, emphasizing the treatment with 40% of cashew peel particles, which showed a DQI of 0.14, while the polypropylene tube presented a value of 0.09. Therefore, biodegradable tubes seem a sustainable and efficient alternative for replacing polypropylene tubes in cultivating forest seedlings.

Pyrolysis-derived activated carbon from Colombian cashew (Anacardium occidentale) nut shell for valorization in phenol adsorption

Pyrolysis-derived activated carbon from Colombian cashew (Anacardium occidentale) nut shell for valorization in phenol adsorption

Zinc adsorption from synthetic wastewater using activated carbons from sugarcane bagasse and Cashew nut shells before determination by flame atomic absorption spectrometry

Zinc adsorption from synthetic wastewater using activated carbons from sugarcane bagasse and Cashew nut shells before determination by flame atomic absorption spectrometry

Effect of Alkaline Activated Cashew Nut Shell Ash in the Stabilization of Weak Clayey Soil—An Experimental Study

Effect of Alkaline Activated Cashew Nut Shell Ash in the Stabilization of Weak Clayey Soil—An Experimental Study

Effects of cashew nutshell extract inclusion into a high-grain finishing diet on methane emissions, nutrient digestibility, and ruminal fermentation in beef steers.

By 2050, the U.S. beef industry must produce an extra 40 million tons of beef to satisfy the global demand. Such an increase in inventory will undoubtedly enhance methane (CH4) production from livestock, which should be reduced by over 20%. The addition of plant secondary metabolites, such as anacardic acid present in cashew nutshell extract (CNSE), has shown promising results in reducing CH4 yield, although its effects seemed to be diet dependent. This study evaluated the addition of CNSE to a high-grain diet (85:15 Grain: forage) on in vivo CH4 emissions, nutrients digestibility, performance, feeding behavior, and ruminal fermentation parameters of beef steers. Sixteen Angus crossbred steers [599 ± 40kg of bodyweight (BW)] and six ruminally cannulated crossbred steers (490 ± 51kg of BW) were utilized in a crossover design with 2 experimental periods of 56 d each, composed by 14 d of adaptation, 35 d of measurement, and 7 d of washout. Following adaptation, steers were sorted by BW, and assigned to receive no additive (CON) or CNSE at 5g/steer/d. Data were analyzed using the MIXED procedure of SAS. Inclusion of CNSE increased (P < 0.05) propionate concentration and molar proportion (MP; mol/100mol), tended to decrease acetate MP (P = 0.10), reduced the acetate: propionate (A:P) ratio (P = 0.05), and MP of branched chain volatile fatty acids (P < 0.01). Neither in vitro organic matter digestibility nor in vitro CH4 yield were affected by CNSE inclusion (P > 0.05). Steers receiving CNSE exhibited greater (P < 0.05) final BW, dry matter intake (DMI), and average daily gain (ADG) but lesser (P < 0.05) in vivo CH4 emission rate (g/d), yield (g/kg of DMI), and intensity (g/kg of ADG). Meal length, bunk visit duration, and apparent total tract digestibility of DM increased (P < 0.05) after CNSE addition. Considering CNSE-supplemented steers spent more time in the feedbunk and exhibited higher DMI, CH4 mitigation was unlikely associated with intake reduction. The addition of CNSE to a high-grain diet in beef steers demonstrated significant improvements in animal performance and reduced CH4 emissions, as the result of shifts in ruminal fermentation patterns, favoring propionate instead acetate concentration, leading to a reduction in the A:P ratio. CNSE shows promise as a strategy to enhance beef industry sustainability.

Sulfonic Acid-Functionalized Solid Polymer Catalyst from Crude Cashew Nut Shell Liquid: Synthesis of Tetra(indolyl)methanes and Bis(indolyl)methanes from Xylochemicals.

Xylochemistry presents a sustainable solution to the depletion of petroleum resources, contributing to the success of the circulatory economy. The development of reusable carbonaceous materials as heterogeneous acid catalysts has garnered significant attention in both research community and industry. Catalysis research has an intrinsic connection with low-cost synthetic routes, sustainable raw materials, and chemical and thermal stability. We designed and made a solid acid catalyst that can be used more than once from cheap, naturally occurring, crude cashew nut shell liquid (CNSL). Identification of practical applications for waste biomass is a component of the objectives of sustainable development. We treated the black-colored crude CNSL with varying amounts of formaldehyde and further sulfonated the resulting crude resins with chlorosulfonic acid. The solid with the most sulfonic acid groups was used as a Bronsted acid catalyst (CNSLF-SO3H) for the Friedel-Craft reactions of indoles and furfuraldehydes. We synthesized 15 novel di[bis(indolyl)methane] derivatives from secondary xylochemical 2,5-diformylfuran (DFF) and 15 bis(indolyl)methanes from 5-hydroxymethylfurfural (5-HMF).

Effects of cashew nutshell biofillers on the mechanical and thermal behaviour of Basalt/Hibiscus vitifolius hybrid fabrics reinforced polymer biocomposites

Basalt-based natural fiber hybrid composites with fillers are always the most anticipated composite material candidates for lightweight structural applications. Current work focusses on the preparation, characterization and testing of Basalt (B)/Hibiscus vitifolius (HV) based epoxy biocomposites with and without cashew nutshell fillers. Individual fiber reinforced composites (with 40 vol% of fibers) and hybrid composites (with 40 vol% of fibers in the ratio 1:1) filled with 10–30 vol% of fillers were manufactured using compression moulding techniques. The X-ray diffraction spectrum showed the crystal size and crystallinity index for all biocomposites. It showed a monoclinic crystal structure with an irregular surface of the fiber and filler. The FTIR spectrum showed the chemical composition presented in the biocomposites. The presence of filler and fibers was confirmed by different spectral peaks. Hybrid biocomposites were then subjected to mechanical and thermal investigations. The mechanical properties of the biocomposites showed that the tensile, flexural, and impact strength of the biocomposites varies with the concentration of the cashew nutshell filler. The surface morphology of the fractured sample showed the presence of fabric layer, fiber fracture and pull out, and homogenous dispersion of the fillers in the biocomposites. Thermal degradation curves showed that the thermal stability of biocomposites is improved by adding filler up to 20 vol% because the filler acted as a barrier element for the thermal degradation of biocomposites. From the results, it could be understood that these biocomposites find their applications probably in lightweight structures.

Bio-inspired sustainable benzoxazine based composites containing aniline derivatives: A comprehensive study on anti-microbial, advanced coatings, oil-water separation and electronic utilizations

A comprehensive study of benzoxazines derived from magnolol and five different substituted aniline moieties through Mannich condensation was carried out. The structural confirmation was ascertained using different spectral analyses. Mg-a exhibited a lowest polymerization temperature of 220 °C than that of other monomers. Whereas, poly (Mg-ea) showed relatively the higher initial thermal stability until 411 °C with char yield of 56 % at 850 °C and enhanced values of limiting oxygen index (LOI) and statistic heat resistance index (HRI) than rest of polybenzoxazines. The Mg-pfa benzoxazine monomer exhibits significant antibacterial behavior with a maximum of 22 mm zone of inhibition and less cytotoxicity with IC50 value of 162 μg/ml as well as better corrosion resistant properties with 99 % corrosion inhibition efficiency. The hydrophobic studies indicated that poly (Mg-tfa) exhibited the highest water contact angle (CA) value of 143°. Poly (Mg-tfa) coated cotton fabric was resistant to chemical and UV treatments along with the 97 % of oil water separating efficiency. Polybenzoxazine composites were derived from poly (Mg-fa) matrix and cashew nut shell residue ash (CNA) and cashew nut shell carbon (CNC) fillers to ascertain influence on thermal, dielectric and hydrophobic properties. Poly (Mg-fa) composites reinforced with 15 wt% of CNA and 15 wt% of CNC exhibited dielectric constant values of 2.71 and 6.91 respectively at a frequency of 1 MHz. Findings from multifaceted studies indicate that the polybenzoxazines and composites reported in the present work can be utilized for anti-corrosion, anti-microbial, oil-water separation and electronic applications for improved performance and enhanced longevity.

Charcoal Residue from Cashew Nutshells as a Bioadsorbent in Fixed Bed Column for Produced Water

Charcoal Residue from Cashew Nutshells as a Bioadsorbent in Fixed Bed Column for Produced Water

Fabrication and characterization of polyvinyl alcohol/biowaste cashew nut shells powder-based hybrid biocomposite films

Fabrication and characterization of polyvinyl alcohol/biowaste cashew nut shells powder-based hybrid biocomposite films

Effect of Cashew Nutshell Extract, Saponins and Tannins Addition on Methane Emissions, Nutrient Digestibility and Feeding Behavior of Beef Steers Receiving a Backgrounding Diet.

The beef industry contributes to greenhouse gas emissions through enteric methane emissions, exacerbating climate change. Anacardic acid in cashew nutshell extract (CNSE), saponins and tannins (ST) are plant secondary metabolites that show promise in methane mitigation via antimicrobial effects, potentially exerting changes in ruminal fermentation patterns. This study examined the impact of CNSE, ST, and their combination on methane emissions, digestibility, intake, and performance of sixteen Angus crossbred steers (347 ± 30 kg) receiving a backgrounding diet (70:30 corn silage: cottonseed burrs). The study used a 4 × 4 Latin square design (4 steers, 4 treatments, 4 periods) with a 2 × 2 factorial arrangement, including the main effects of additive (CNSE or ST) fed individually or combined. Thus, steers received the following treatments: (1) no additive, (2) CNSE only, (3) ST only, or (4) both (CNSEST). Non-supplemented steers registered eight more feedbunk visits/d than ST-steers and spent an extra 10 min/d on the feedbunk. The addition of ST tended to increase dry matter, organic matter, and neutral detergent fiber intake. Additives fed individually reduced CP digestibility. Intake of the carrier containing CNSE only was lesser and coincided with a greater methane yield in that treatment. Digestibility and methane mitigation were improved after CNSEST compared with individual inclusion, suggesting synergistic reactions enhanced methane mitigation effects in fibrous diets without affecting the digestibility of nutrients nor animal growth performance.

An experimental investigation on enhancing diesel engine performance and emissions with cashew nut shell oil biodiesel and hydrogen fumigation

An experimental investigation on enhancing diesel engine performance and emissions with cashew nut shell oil biodiesel and hydrogen fumigation