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Native to the northeast coast of Brazil, cashew was domesticated long before the arrival of Europeans at the end of the fifteenth century. It was "discovered" by European traders and explorers and first recorded in 1578. It was taken to India and East Africa, where it soon became naturalized.

Recorded Medicinal history:

The cashew tree and its nuts and fruit have been used for centuries by the indigenous tribes of the rainforest (Peruvian and Brazilian), and it is a common cultivated plant in their gardens.

In Africa, the bark and leaves of the tree are used medicinally; fruit juice and a bark tea are very common diarrhoea remedies used by curandeiros and indigenous people alike. Caju infusions and teas of the bark are used to treat diabetes, weakness, urinary disorders, and fevers.

In South America, the leaves and/or the bark are used in for eczema, psoriasis, scrofula, dyspepsia, genital problems, and venereal diseases, as well as for impotence, bronchitis, cough, asthma, vaginitis, intestinal colic and syphilis-related skin disorders.

North American practitioners use cashew for diabetes, coughs, bronchitis, tonsillitis, intestinal colic, and diarrhoea, and as a general tonic.

Traditional Medicinal Uses:

Caju contains naturally occurring analogs of the latest diabetes drugs pioglitazone (Actos) and rosiglitazone (Avandia), without their potential for liver damage or weight gain.

Benefits of caju for specific health conditions include the following:

Diabetes. Laboratory tests suggest that cajueiro lowers blood sugar by inhibiting the action of an enzyme known as tyrosinase. When tyrosinase is blocked, receptor sites on cells in the intestines become more sensitive to insulin. Insulin "instructs" the cells to absorb more of the amino acids leucine, phenylalanine, tyrosine, and valine. With higher concentrations of these amino acids in the body, the body suffers less protein breakdown and wasting caused by uncontrolled diabetes. This protects against kidney damage. While animal studies show caju to have only a weak anti-diabetic effect, the herb is useful because it carries no risk of toxic damage to cell DNA.

Parasitic infection. In the Barna region of Brazil, 65 percent of cases of leishmaniasis, an ulcerating skin disease, are successfully treated with caju.

Caju extracts are over 90 percent effective against the parasites that cause schistosomiasis (bilharzia).


The bark and leaves of cashew are a rich source of tannins, a group of plant chemicals with documented biological activity. These tannins, in a 1985 rat study, demonstrated anti-inflammatory and astringent effects, which may be why cashew is effective in treating diarrhoea.

Biological Activities and Clinical Research:

Caju’s anti-microbial properties were first documented in a 1982 in vitro study. In 1999, another study was published indicating it had good in vitro antibacterial activity against E. coli and Pseudomonas. Most recently, a 2001 study reported that a bark extract exhibited in vitro anti-microbial activity against 13 of 15 microorganisms tested. In 1999, researchers reported that cashew fruit exhibited antibacterial activity against the Gram-negative bacterium Helicobacter pylori, which is now considered to cause acute gastritis and stomach ulcers. Its effectiveness against leishmanial ulcers also was documented in two clinical studies. Finally, two studies (one in mice and the other in rats) in 1989 and 1998 document the protective quality of a leaf extract against lab-induced diabetes, although the extract did not act as hypoglycaemic as some others, it did stabilize blood glucose levels near pre-test levels.

Properties/Actions Documented by Research:

Anti-diabetic, antibacterial, anti-inflammatory, anti-ulcerous, astringent.

Other Properties/Actions Documented by Traditional Use:

Anti-diabetic, cough suppressant, decongestant, digestive stimulant, diuretic, febrifuge (reduces fever), hypotensive (lowers blood pressure), purgative (strong laxative), refrigerant (reduces body temperature), tonic (tones, balances, strengthens), wound healer.

Pubmed Extracts:

1. Journal of Ethnopharmacology

Volume 62, Issue 2, September 1998, Pages 95-99

Protective role of Anacardium occidentale extract against streptozotocin-induced diabetes in rats.
Kamtchouing P, Sokeng SD, Moundipa PF, Watcho P, Jatsa HB, Lontsi D.

Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1, Cameroon.

The protective effect of Anacardium occidentale aqueous extract against streptozotocin-induced diabetes was evaluated in rats. The rats were treated with 175 mg/kg of the extract per os, twice daily; beginning 2 days before streptozotocin (STZ) injection. A total of 3 days after STZ administration, there was a 48% increase in blood glucose level in pretreated rats, compared with a 208% increase in diabetic control rats treated with STZ alone. Furthermore, these pretreated animals presented no glycosuria, a normal weight gain and a non-significant increase in food and fluid intake at the end of the treatment compared with the normal control. Diabetic control animals showed a positive glycosuria, body weight loss, a real polyphagia and polydypsia. These results indicate the protective role of Anacardium occidentale extract against the diabetogenic action of STZ.

PMID: 9741880 [PubMed - indexed for MEDLINE]

2. Methods Find Exp Clin Pharmacol. 2003 Apr; 25(3): 199-204.

Laboratory evaluation of the hypoglycaemic effect of Anacardium occidentale Linn (Anacardiaceae) stem-bark extracts in rats.

Ojewole JA.

Department of Pharmacology, Faculty of Health Sciences, University of Durban-Westville, Durban, South Africa.

This study evaluated the hypoglycaemic effect of stem-bark extracts of Anacardium occidentale Linn., of the Anacardiaceae family, in normal (normoglycemic) and in streptozotocin-treated diabetic rats.

… Both insulin (5 microU/kg s.c.) and glibenclamide (0.2 mg/kg p.o.) produced significant reductions (p< 0.01-0.001) in the blood glucose concentrations of the fasted normal and fasted diabetic rats. At single doses of 800 mg/kg p.o., A. occidentale stem-bark aqueous and methanolic extracts significantly reduced (p< 0.001) the mean basal blood glucose concentrations of fasted normal and fasted diabetic rats. The hypoglycaemic effect of the methanolic plant extract was found to be slightly more pronounced than that of the aqueous plant extract in both the normal and diabetic rats examined.  Although A. occidentale stem-bark aqueous or methanolic extract is less potent than insulin as an anti-diabetic agent, the results of this experimental animal study indicate that it possesses hypoglycaemic activity, and thus lends credence to the folkloric use of the plant in the management and/or control of adult-onset, type-2 diabetes mellitus among the Yoruba-speaking people of Western Nigeria.

PMID: 12743624 [PubMed - indexed for MEDLINE]



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