Cashew Tree

Overview

Originating in South America, cashew is now one of the world's most widely grown nut crops. It is widely cultivated in many tropical regions, especially in India, Brazil, and East Africa. The plant also has a wide variety of other applications, including as a drug and a source of different commodities.

Vernacular Names

Jambu monyet (Indonesia), Yao kuo (Chinese), Acajou (French, German), Acagia (Italian), Kashu nattsu (Japanese), Kacang monyet (Malay), Kasuy (Philippines), Manao (Thai).

Agroecology

A plant for tropical and subtropical lowland areas, reaching elevations of up to 1,000 m. It grows well in humid, semi-arid, frost-free climates, fruiting well with 500 - 900 mm of annual precipitation. It occurs with an annual rainfall of 1,000 - 3,500 mm in warm and humid climates. A well-drained sandy soil and a place in full sun is favored. Tolerates a pH within the 4.5 - 6.5 range.

Morphology

• Roots - a very prominent taproot and a well-developed and extensive network of lateral and sinker roots.
• Stems - a short and usually irregularly-shaped trunk. It has spreading branches and a canopy that can spread up to 12 m.
• Leaves - arranged in an alternate pattern, pale green in colour but shiny, with fine veins, and are relatively large but narrows towards its base.
• Flowers - small, 5-6 mm in diameter, crowded at the tips of the branches, and yellow to yellowish-white, the petals usually with pink stripes.
• Fruits - the true fruit of the tree is the cashew nut resembling a miniature boxing-glove; consisting of a double shell in honey comb-like cells, enclosing the edible kidney-shaped kernel.
• Seeds - kidney-shaped with reddish-brown testa, two large white cotyledons and a small embryo.

Cultivation

• Generative propagation is by seeds and is usually sown in situ.
• Vegetative propagation is by stem cuttings and by layering.

Chemical Constituents

Leaves: flavonoids, tannin, anakardat acid, phenol compounds, glycoside. Bark: ellagat acid, cathekin. Seeds: anacardic acid, cardanol, cardol, carotenoid, volatile, lutein, thiamin, stearic acid, oleic acid, linoleic acid, palmitic acid.

Traditional Medicinal Uses

• The leaves are febrifuge.
• The bark is vesicant, astringent, and rubefacient.
• Studies have shown that it is also hypoglycaemic, with the potential to lower blood sugar levels.
• The fruit is anti-scorbutic, diuretic, and astringent, and is also used to treat cholera and kidney problems.
• It is a beneficial medication for reducing craving, depressive symptoms, sadness,
  disappointment, anxious, shortcoming, scurvy, paleness, and treatment of stomach, chest, urinary and liver problems.
• The bark is used for detoxifying snake bites in Ayurvedic medicine. The bark is harvested fresh or dried as required and used.
• A good remedy for coughs and colds is cashew syrup. It is said that cashew apple juice is effective for syphilis treatment and is also used in the treatment of cholera and kidney problems.
• The fresh, acrid juice inside the shell is vesicant. It has been used to remove warts and the treatment of ringworm, corn, and leprosy and is applied to the soles of the feet to heal skin cracks. For many disease-causing organisms, such as the bacteria Staphylococcus, it is toxic.
• An excellent purgative is an infusion of the root.
• It is considered that the sap or bark extract is a contraceptive. The gum is bactericidal, fungicidal, and kills protozoa and worms. In the treatment of leprosy, and for corn and fungal conditions, it is used externally.