Toxins in Mango Trees

With pinkish new leaf growth and producing edible crops of sweet juicy fruits, the mango (Mangifera indica) is an ornamental fruit tree of tropical fame. A member of the cashew family, Anacardiaceae, it is related to poison ivy (Rhus radicans), and reveals that the sap of mango's stems, leaves and fruit skins contain a toxic irritant that causes dermatitis.

Anacardiaceae

The cashew family, Anacardiaceae, includes roughly 70 genera, or botanical groupings, across the world that share similar flower structures. Mostly found growing in the tropics, there are some species in temperate regions. Some members of this plant family are known to secrete a resinous sap that can cause mild to severe allergic skin and/or mouth reactions when touched or placed in the mouth.

Containing phenolic substances, such as alkyl catechols or alykl resorcinols, that may be insoluble in water, contact with the sap can cause contact dermatitis. Reaction to these substances varies per individual. Poison ivy (Rhus radicans, formerly Toxicodendron radicans), cashew nut (Anacardium occidentale), some sumac (Rhus spp.) and Brazilian pepper tree (Schinus molle) are plants in Anacardiaceae that are known to cause allergic skin reactions. Mango (Mangifera indica) also contains irritants that may lead to contact dermatitis.

Toxins in the Mango

The toxins in the mango plant are distributed in its milky sap. It contains mangiferen, resinous acid, mangiferic acid, and the resinol, mangiferol. Contact with cut stems, leaves will directly expose people to the sap. However, depending on the level of sensitivity, merely touching the foliage or skin of the mango fruit can cause a rash and discomfort in some individuals. However, the edible flesh of the mango itself lacks the toxic and irritating phenolic substances that are present in the fruit's skin.

Effects of Exposure

After touching the sap, leaf or fruit skin, a red rash on the skin is the usual reaction in sensitive people. It appears immediately in irritant contact dermatitis, but if allergic contact dermatitis, the rash does not appear for 1-2 days after the exposure. Blistering may occur or a raised red rash called hives may develop in extreme cases of sensitivity. Overall, the skin will itch and have a burning sensation that is the source of pain.

Irritant contact dermatitis normally affects the hands, which have been exposed by resting in or dipping into a container (sink, pail, tub) containing the irritant. Thus, paring knife handles or shaking the hands of people who have peeled mango skins or pruning foliage or branches of the mango tree can be a source of dermatitis.

Avoiding Exposure

People with mild hypersensitivity to mango skin toxins can peel the skin while wearing latex gloves, making sure in the clean-up process no skin peels or other sap-laced utensils touch their skin. Thoroughly wash hands with warm soapy water.

Highly susceptible individuals should simply avoid touching mangoes. The flesh of mango does not contain the problematic phenolic substances so you can still enjoy the fruit, especially if canned or prepared by someone else.

Medicinal Uses

Historically, nearly all parts of the mango plant have been employed for medicinal purposes in eastern Asia. The bark is an astringent, used to treat diarrhea and hemorrhages. The foliage alleviates coughs, skin irritations and tooth aches. The flowers are claimed to be an aphrodisiac and also repel mosquitoes.