Cashew Plant Summary:
The cashew plant is more than just those salted nuts you often find in the supermarket. The plant behind the nuts has much more to offer. The cashew plant comes from the Amazon rainforest, and thrives in the slightly drier central plains of Brazil.
The nut grows at the end of a swollen, juicy "peduncle" (shown as the red part in the photo below). This peduncle is juiced to make a delicious, sweet-tasting drink with a wide range of medicinal actions. It is also a great source of Vitamin C. Its sweet flavor and apple-like appearance has led to its common name as the "cashew apple". The short shelf life has prevented it from becoming mainstream outside of South America however.
The nuts are separated from their resinous shell (the resin is also a powerfully medicinal substance), roasted and salted, and then eaten. They provide a potent dose of trace minerals, vitamins, fats, and proteins. This is the part we are most familiarized with when it comes to the cashew plant.
The leaves and bark contain similar chemicals to each other, but the leaves have the added benefit of being powerfully antioxidant. Similar antioxidant chemicals can be found in tea plant leaves and are very well known for their health promoting effects. Benefits of the cashew plant include: anti diabetic, antidiarrheal, and anti-inflammatory actions, as well as having the ability to lower blood pressure, fight cancer, kill infecting bacteria, viruses, and fungus, and has been used effectively for dental and skin complaints.
Fruit (drupe), pseudo-fruit juice, bark, leaves, resin (toxic)
- Antiviral (HCV)
Dosage varies widely depending on treatment goals and part used.
A note on dosage
Traditional dosage for diarrhea and dysentery is 125ml (½ cup), of standard (1:20) decoction of leaves, twigs taken 2-3 times per day (Taylor L. 2005). If using for diabetes, take with meals.
Currently, the fruit is used mainly in South America in its raw juice form, however fruit extracts are being used in cosmetic applications, valued mainly for its high mineral salts, and vitamin C concentrations, although is relatively unstable, and requires the addition of antioxidant agents to help in preservation. It is often used for premature aging to the skin, and to remineralize the skin. Other cosmetic uses of the fruit extract include shampoos, lotions, and scalp creams. [7, 15].
The leaves, and bark can be infused, decocted, or extracted with ethanol and drunk to treat diarrhea, and colic (even for children), diabetes, urinary tract infections, hepatitis C infection, mouth ulcers, stomach ulcers, throat problems, hypertension, cardiovascular disease, [5, 9, 10, 15].
The pseudo-fruit is often used for its anti-tumor effects and as a supportive for radiation therapy for cancer, as a prebiotic, antimicrobial, to inhibit urease, and lipoxygenase activity, as an antioxidant .
The author suggests that the urease inhibiting activity may play a role in the treatment of various kidney, and bladder stones, and may play a role in the treatment of gout. More research is needed.
Can be used as an oral rinse to prevent periodontal disease, and to treat toothaches, and sore gums, and various other results from the accumulation of pathogenic biofilm in the oral cavity.
Anacardium occidentale can be used as an antimicrobial topically, against a number of organisms, including MRSA and may have systemic effects as well but more research is needed. The mechanism of action for this is considered to be in the polyphenol content (tannins) which are known to have a low absorption rate into the body, and thus may not provide significant systemic antimicrobial activity. These chemicals bind and precipitate proteins which may be responsible for the antimicrobial effects, as well as the anacardic acid that has been shown in various studies to inhibit various enzymatic processes.
- Jocote maranon
- Noix d’acajou
- Pomme cajou
- Jambu golok
- Jambu mete
- Jambu monyet
- Jambu terong
Indigenous cultures of the Amazon rain forest, have used A. occidentale medicinally for hundreds of years, and has been cultivated by them for use as well. Amazonian indigenous cultures have used this plants various parts for different uses. The bark was used for diarrhea, colic for infants, as a douche, astringent, tooth extraction post treatments, diabetes, weakness, muscular debility, urinary disorders, asthma .
The leaves were used most commonly as a tea referred to as casho, and was employed for such uses as diarrhea treatment, mouth ulcers, tonsillitis, throat problems, washing wounds. Both the leaves and the bark were used interchangeably for such uses as treating eczema, psoriasis, scrofula, dyspepsia, genital problems and STIs, impotence, bronchitis, colic, diarrhea, and as a general tonic .
The fruit and fruit juice were used for influenza, diarrhea, syphilis, as a stimulant, diuretic, and aphrodisiac, and in the 1600s, in Brazil, Europeans were taking cashew juice to treat fever, to sweeten the breath, and to “conserve the stomach” .
The toxic seed oil has been used traditionally as a topical remedy for botfly larvae .
Brazil uses the leaves for eczema, psoriasis, scrofula, dyspepsia, genital problems, and venereal diseases, as well as for impotence, bronchitis, cough, intestinal colic, leishmaniasis, and syphilis-related skin disorders .
There are 10 species in the Anacardium genus, with the species of focus being Anacardium occidentale. This tree is a large, aromatic, evergreen tree growing up to 15m high in the Amazon rainforest [13, 15].
The leaves are described as clustered (at shoot apex), simple, entire, and usually have a rounded apex. .
The inflorescences are either terminal or axillary, and paniculate. Anacardium spp. contains both bisexual, and unisexual flowers on the same tree. The flowers are 5 petaled, 6-12 stamens, with 1 or 4 of them much longer than the others with the shorter stamens below fused to form a short tube. The flowers may or may not have anthers .
The cashew nut, as found in grocery stores across North America, Australia, and Europe, are botanically classified as the fruit (drupe), and has many uses in nutrition, medicine, as well as in the plastic and resin industries . This nut is encased in a shell that is filled with cardol, a very caustic, toxic oil which must be cleaned off, and roasted in order to be safe for consumption . Behind this fruit lies the pseudo-fruit (or hydrocarp), which is a swollen peduncle. This is where the juice is taken from. The juice offers a very sweet flavor, and is fairly common in South America as a beverage, however due to its short shelf life it is not commonly shipped to American, European, or other markets [13, 15].
Medicinally, the bark, leaves, pseudo-fruit, and seed (nut/fruit) are all used .
A. microcarpum, is also edible, and is starting to gain interest for this purpose in Brazil, and other South American countries, the author at this time however has not found any quality research suggesting its use as a safe alternative, for the known medicinal A. occidentale.
Habitat, Ecology, Distribution:
Anacardium spp, is indigenous to the Amazon rainforest, specifically, from Honduras to Paraguay and southern Brazil, with A. occidentale favouring the drier, sandy soils in the central Plains of Brazil, and northern South America, [13, 15]. Currently, A. occidentale is widely cultivated in Peru, and other lowland Amazonia, mostly for its hydrocarp, and fruit . The cultivation of A. occidentale is estimated to cover approximately 700 000 hectares (7000 square kilometers), with nut production at about 280 000 tons/year (255000 metric tonnes) . In Brazil, the vast majority of production (96%) takes place in the northeast region of the country . This plant has huge economical impact on the regions cultivating it, due to the large labor force required to cultivate, and process it .
Upon discovery by the Europeans, the cashew tree was exported to India, and East Africa where it has since become naturalized .
Harvesting, Collection, and Preparation:
Still compiling research.
The pseudo-fruit, contains rich amounts of minerals, vitamins, esters, terpenes, and carboxylic acids .
The bark and leaves contain tannins, which have been the subject of much scientific study, and due to the astringency associated with this chemical, may account for the antidiarrheal effects of this plant .
The nutshells contain anacardic acids in high amounts, which have been shown to produce cytotoxicity to certain cancer cells, and curb the darkening effect of aging through tyrosinase inhibition .
The pseudo-fruit (cashew apple) contains volatile compounds, resorcinolic acid, anacardic acids, carotenoids (α-carotene, β-carotene and β-cryptoxanthin), vitamin C, phenols, tannin and two flavonoid aglycones. Phenolic constituents include anacardic acids, cardols, and cardanols .
Anacardic acid (found in high amounts in the nutshell), has been found to inhibit the activity of various cellular enzymes, including histone acetyltransferases (HATs) . Anacardic acid can also be found in Ginkgo biloba, Amphipterygeum adstringens, and Ozoroa insignis . This compound has been shown to produce numerous medicinal actions such as anti inflammatory, antimicrobial, antioxidant, and antitumor activities . It has also been shown to inhibit numerous other enzymes, including tyrosinase (also associated with cytotoxicity), xanthine oxidase (likely cause for low shelf life of juice), phosphatidylinositol-specific phospholipase C, tissue factor VIIa, lipoxygenase, and cyclooxygenase (COX) . The nut shell liquid, contains high amounts of cardol, and cardanol as well.
A. De Sousa Leite et al, (2015), reports the concentrations in the natural cashew nut shell liquid extracted via solvents (referred to as iCNSL) (highest temperature reached in the making of this extract was 45C) as 62.9% anacardic acid, 23.98% cardol, and 6.99% cardanol. A different extraction process referred to as technical cashew nut shell liquid (tCNSL) is achieved by burning the nuts at high temperatures (195C bath for 3 hours), which in turn changes these amount to 60-65% cardanol, 15-20% cardol, 10% polymeric material, and small amounts of melticardol. This process of burning the nuts decarboxylates the anacardic acid (removes acid group), and converts this compound into cardanol. .
Interestingly, E.S. De Brito et al., (2007) reports that both cashew apple (pseudo-fruit) and cranberry contained the same set of 12 glycosylated flavonols, namely, 3-O- galactoside, 3-O-glucoside, 3-O-xylopyranoside, 3-O-arabinopyranoside, 3-O- arabinofuranoside and 3-O-rhamnoside of myricetin and quercetin. .
It would be interesting to examine the comparative effects of these two botanicals to determine possible effects of these chemicals and their synergy.
Taylor L. (2005), describes the main chemicals contained within A. occidentale as follows: alanine, alpha-catechin, alpha-linolenic acid, anacardic acids, anacardol, antimony, arabinose, caprylic acid, cardanol, cardol, europium, folacin, gadoleic acid, gallic acid, ginkgol, glucuronic acid, glutamic acid, hafnium, hexanal, histidine, hydroxybenzoic acid, isoleucine, kaempferol-epicatechin, lauric acid, leucine, leucocyanidin, leucopelargonidine, limonene, linoleic acid, methyl-glucuronic acid, myristic acid, naringenin, oleic acid, oxalic acid, palmitic acid, palmitoleic acid, phenylalanine, phytosterols, proline, quercetin-glycoside, salicylic acid, samarium, scandium, serine, squalene, stearic acid, tannin, and trans-hex-2-enal tryptophan. .
Pharmacology and Medical Research:
L. A study done on Anacardium occidentale and its effects on diabetes, and found that the long term efficacy of a hexane extract (leaves) acted as a hypoglycemic agent in diabetic rats. .
An ethanol extract of the stem bark showed no hypoglycemic effects on type 1 diabetic rats, or type 2 diabetic rats in fasting condition, however did show significant hypoglycemic effects in type 2 diabetic rats when fed glucose simultaneously. These results were suggested to be due to insulin stimulating actions in a glucose dependant manner in the pancreas, as well as possible inhibition of glucose absorption in the gastrointestinal tract (Ramnik Singh, 2010). These findings suggest the best time to take this herb for treatment in diabetes, may be with meals.
Anacardium humile stems have also been shown to produce significant antidiabetic effects, regulating blood sugar levels in diabetic rats, though did not alter insulin secretion. This extract (aqueous) also showed no toxicity . This species needs closer examination to identify how it compares to A. occidentale.
Tannins have been found in the bark, and leaves of the cashew tree . These chemicals have a proven effect on astringing the digestive tract, and therefore produce anti-diarrhea actions.
Anacardic acid is associated with A. occidentales antitumor effects . One study  suggested that “one possible mechanism by which anacardic acid exerts its effects is by modulating the nuclear factor-κB”. Various inflammatory agents induce activation of this protein complex, including cytokines, carcinogens, cigarette smoke, stress, and environmental pollutants. Due to the various negative effects associated with the activation of this complex (such as various tumor cell promoting effects), suitable inhibitors are actively being researched, including A. occidentale extracts.
Lucio Neto et al., (2013) reports that “anacardic acid has been shown to be cytotoxic to lung, liver and gastric tumor cells through epigenetic mechanisms by inhibiting histone acetyl-transferases (HATs)” .
Anacardic acid has also been shown to potentiate apoptosis induced by TNF .
This constituent, which can be found in a variety of plants, has been shown to also exhibit actions that sensitize tumors to radiation , which may increase the efficacy of radiation therapy cancer treatment.
A. De Sousa Leite et al, (2015), investigated the effects of natural cashew nut shell liquid (iCNSL) (only heated to 45C), and technical cashew nut shell liquid (tCNSL) (heated to 195C for 3 hours), on genotoxicity. They discovered that the lowest concentrations of iCNSL and all concentrations of tCNSL provided preventive, antimutagenic, and reparative effects on micronuclei and on chromosomal aberration. The tCNSL was reported to be not toxic, cytotoxic, or mutagenic in any of the concentrations .
These combined effects, may prove Anacardium occidentale efficacious in the treatment of various cancers.
A bark stem extract of A. occidentale was shown to produce anti hypotensive effects in vivo .
Listed in the Nigerian, and Brazilian traditional pharmacopoeia for its anti inflammatory effects . These effects are at least partly due to its anacardic acid content, which has been demonstrated to produce anti inflammatory actions, as well as many more effects . These effects are thought to be due to modulation of nuclear factor-κB  which plays a key role in the process of inflammation.
A. occidentale fruit has been shown to produce antimicrobial effects against Helicobacter pylori . Anacardic acid, contained in this plant, have demonstrated antimicrobial effects , and may at least in part be responsible for this action from the plant or plant extract.
Cosmetically, extracts from A. occidentale pseudo-fruits, demonstrated antimicrobial actions, however were considered unstable, forming crusts on the surface of the formulas. Researchers in this study suggested the addition of antioxidant substances may ameliorate this instability but suggested more research in this area was required .
In a study done by G. Anand et al., (2015), identifying the antimicrobial effects of A. occidentale in the form of an oral mouthwash, noted the significant antifungal, and antibacterial effects that were considered equal, or greater than povidone-iodine rinses currently used today. Some of the pathogens of note in oral health are Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Candida albicans due to the common resistance these pathogens have against normal oral care products. This study showed that the ethanol extract of A. occidentale showed significant in vitro activity against all of these organisms, as well as MRSA .
A stem bark extract has been shown to produce cardio-inhibitory effects in vitro and was suggested to be due to either calcium channel blockage, or hindrance of calcium release from internal storages, or a combination of both . More research is needed in this area to determine the exact mechanism of action, however it is clear that A. occidentale bark stem extract has a positive effect on hypertension, and CVD.
+ Hepatitis C
Hepatitis C is a virus in the genus Hepacivirus contained within the Flaviviridae family. This infection can become chronic, and will eventually lead to cirrhosis of the liver, hepatocarcinoma, and eventually death by liver failure. The World Health Organization suggests more than 120-150 million people worldwide are infected with this virus,and the numbers are growing. About 500 000 people die each year as a result of this infection .
Anacardic acid has been shown to inhibit HCV entry, replication, translation, and virion secretion in a dose dependant action and has no reported toxicity, or measurable effects on cell viability . These researchers suggested the mechanism of action be due to anacardic acids ability to inhibit histone acetyltransferases (HATs). The dose focused specifically on anacardic acid (>5µM) and needed to be administered over multiple hours (12h) to produce the significant effects noted in the study. These researchers did not specify how the anacardic acid was administered, however it is most likely intravenous. This brings up the question of how long, and in what concentrations anacardic acid will remain active in the system from oral administration, and if these demonstrated therapeutic effects can be recreated through oral ingestion of A. occidentale extract. More research is needed to better understand this mechanism of action. Researchers need to investigate further whether these effects can be translated to other members of the Flaviviridae family, or other viruses in general.
Other members of this family (Flaviviridae), include yellow fever, dengue fever, and arboviruses .
Cashew nuts nutritional profile per 100g is as follows: 2314 kJ of energy, 46.4g of fat, 9.2g saturated fatty acids, 27.3g monounsaturated fatty acids, and 7.8g polyunsaturated fatty acids, 7.7g linoleic acid, 0.15g α-linolenic acid, 18.2g protein, 5.9g fiber, 25μg folate, 158 mg plant sterols, 37mg Ca, 292 mg Mg, 12 mg Na, 660 mg K .
Nuts in general are considered an energy dense food, and have been reported to positively affect coronary heart disease, high cholesterol, and diabetes with their consumption. Nutritionally, cashews in particular contain significant amounts of plant protein, α-linolenic acid, plant sterols (not including cholesterol), Mg, Na, and K as compared to other nuts .
In order to be considered a prebiotic oligosaccharide, it must:
- Not be absorbable by the upper GI tract
- Be a selective substrate for beneficial bacteria in the gut
- Promote healthy intestinal biota
With this in mind, A. occidentale fermented pseudo-fruit juice has been shown to meet these requirements to be considered as a prebiotic source .
The leaf extract has been shown to be non toxic in therapeutic doses (about 100 mg/kg minimum), and remains non toxic until at least 14g/kg . Other studies have confirmed this as well such as Tchikaya et al., (2011) , who reported that a hydroethanolic extract obtained from Anacardium Occidentale leaves, is non toxic at a dose of 2 g/kg.
Cardol contained within the cashew nut shell has documented caustic, and toxic effects . Other components in various parts of the plant (nut, bark, leaves, fruit, fruit oil) may also cause allergic response in certain individuals.
There is potential for toxicity through contamination of cashew (and other) nuts with mycotoxins, particularly aflatoxin, which may result in mild-severe allergic response. The nuts themselves may produce an allergic response as well, as nuts are a well known cause of food allergies. The estimated prevalence rate is approximately 1% in the general population .
The raw resin of the cashew nut can be irritating to the skin, and gastrointestinal mucosa.
A combination of Anacardium occidentale (stem bark, and leaf extract), Eucalyptus globulus, Psidium guajava (leaves), and Xylopia aethiopaca (fruits), were found to produce synergistic action on the treatment of diabetes .
The Sunlight Experiment
Updated: June 2017
Recent Blog Posts:
- Aracelli de Sousa Leite, Alisson Ferreira Dantas, George Laylson da Silva Oliveira, Antonio L. Gomes Júnior, Sidney Gonçalo de Lima, Antônia Maria das Graças Lopes Citó, Rivelilson M. de Freitas, Ana Amélia de C. Melo-Cavalcante, and José Arimateia Dantas Lopes. (2015). Evaluation of Toxic, Cytotoxic, Mutagenic, and Antimutagenic Activities of Natural and Technical Cashew Nut Shell Liquids Using the Allium cepa and Artemia salina Bioassays. BioMed Research International. Volume 2015, Article ID 626835.
- Bokyung Sung, Manoj K. Pandey, Kwang Seok Ahn, Tingfang Yi, Madan M. Chaturvedi, Mingyao Liu, and Bharat B. Aggarwal. (2008). Anacardic acid (6-nonadecyl salicylic acid), an inhibitor of histone acetyltransferase, suppresses expression of nuclear factor-κB–regulated gene products involved in cell survival, proliferation, invasion, and inflammation through inhibition of the inhibitory subunit of nuclear factor-κBα kinase, leading to potentiation of apoptosis. Blood. 111(10): 4880–4891. doi: 10.1182/blood-2007-10-117994
- Emilio Ros. (2010). Health Benefits of Nut Consumption. Nutrients. Vol 2. 652-682. doi:10.3390/nu2070652
- E.S. Brito, M.C. Araújo, L. Lin, & J. Harnly, (2007). Determination of the flavonoid components of cashew apple ( Anacardium occidentale) by LC-DAD-ESI/MS.Food Chemistry. doi:10.1016/j.foodchem.2007.02.009
- Francis Olivier Tchikaya , Guy Bernard Bantsielé , Gisèle Kouakou-Siransy , Jacques Yao Datté , Paul Angoue Yapo, Noel Guedé Zirihi , Michel Atté Offoumou. (2011). Anacardium occidentale LINN. (Anacardiaceae) Stem Bark Extract Induces hypotensive And Cardio-inhibitory Effects In Experimental Animal Models. Afr J Tradit Complement Altern Med. 8(4):452‐461
- Geethashri Anand, Manikandan Ravinanthan,1 Ravishankar Basaviah,2 and A. Veena Shetty. (2015). In vitro antimicrobial and cytotoxic effects of Anacardium occidentale and Mangifera indica in oral care. J Pharm Bioallied Sci. Jan-Mar; 7(1): 69–74. doi: 10.4103/0975-7406.148780
- Gisele Mara Silva Gonçalves and Juliana Gobbo. (2012). Antimicrobial Effect of Anacardium Occidentale Extract and Cosmetic Formulation Development. Braz. Arch. Biol. Technol. v.55 n.6: pp. 843-850.
- Isabel Moreira da Silva & Maria Cristiane Rabelo & Sueli Rodrigues. (2014). Cashew juice containing prebiotic oligosaccharides. J Food Sci Technol. 51(9):2078–2084. DOI 10.1007/s13197-012-0689-9
- Jana Hundt, Zhubing Li, Qiang Liu. (2015). The Inhibitory Effects of Anacardic Acid on Hepatitis C Virus Life Cycle. PLOS ONE. DOI:10.1371/journal.pone.0117514
- L. Tedong, P.D. Djomeni Dzeufiet, T. Dimo, E.A. Asongalem, S.N.Sokeng, J-F. Flejou, P. Callard, P. Kamtchouing. (2007). Acute and subacute toxicity of Anacardium ocidentale LINN (Anacardiaceae) leaves hexane extract in mice. Afr. J. Trad. CAM. 4 (2). 140-147.
- Lucio Neto, Nayara Matos, Wellington Gonzaga, Luiz Romeiro, Maria Santos, Damaris Santos, Andrea Motoyama. (2014). Characterization of cytotoxic activity of compounds derived from anacardic acid, cardanol and cardol in oral squamous cell carcinoma. Neto et al. BMC Proceedings 2014, 8(Suppl 4):P30.
- Márcio A. Urzêda, Silvana Marcussi, Luciana L. Silva Pereira, Suzelei C. França,Ana Maria S. Pereira, Paulo S. Pereira, Saulo L. da Silva, César L. S. Guimarães, Leonardo A. Calderon, Rodrigo G. Stábeli, Andreimar M. Soares, and Lucélio B. Couto. (2013). Evaluation of the Hypoglycemic Properties of Anacardium humile Aqueous Extract. Evidence-Based Complementary and Alternative Medicine. Vol 2013.
- Pennington, T. D., Reynel, C., Daza, A., & Wise, R. (2004). Illustrated guide to the trees of Peru. Sherborne, England: D. Hunt. Pg 429-430.
- Ramnik Singh. (2010). Antihyperglycemic effect of Ethanol Extract And Fractions Of Anacardium occidentale L. Stem Bark In Streptozotocin-Induced Diabetic Rats. Journal of Basic and Clinical Pharmacy. Vol 1. 1.
- Taylor, L. (2005). The healing power of rainforest herbs: A guide to understanding and using herbal medicinals. Garden City Park, NY: Square One Publishers.
- Victor Eshu Okpashi, Bayim Peter-Robins Bayim, and Margaret Obi-Abang. (2014). Comparative Effects of Some Medicinal Plants: Anacardium occidentale, Eucalyptus globulus, Psidium guajava, and Xylopia aethiopica Extracts in Alloxan-Induced Diabetic Male Wistar Albino Rats. Biochemistry Research International. Vol 2014. http://dx.doi.org/10.1155/2014/203051
- Wilks, D., Farrington, M., & Rubenstein, D. (2008). Infectious Diseases Manual. Chichester, GBR: Wiley. Retrieved from http://www.ebrary.com
- World Health Organization. (2015, July). WHO | Hepatitis C. Retrieved November 2015, from http://www.who.int/mediacentre/factsheets/fs164/en/