Neem leaf extract is a very highly concentrated liquid form of the leaves of the herb neem, and it is approximately 10 times more potent than a tincture. An infusion, decoction or tincture technically also is a form of an extract, but because of the much milder strength and shorter storage life of an infusion and a decoction, they seldom are referred to as extracts. If neem leaf, however, is allowed to steep in boiling hot water, a mild aqueous neem leaf extract is achieved. The same can be said if alcohol, glycerin or some other solvent is employed to extract the therapeutic properties of this herb.
Commercially prepared neem extract might involve methods that use high pressure, evaporation by heat or a process known as cold percolation. Homemade extracts generally are prepared with a natural grain alcohol. They tend to be less potent than their commercial counterparts.
The Latin name for neem is Azadirachta indica, and its name in Sanskrit is nimba. Sanskrit is an ancient language of India, one of the lands to which the tree is native. The plant also grows in other parts of southern Asia and is cultivated in arid regions of Africa, the Middle East, Central and South America, Hawaii and southern Florida in the United States.
Some form of neem leaf extract has been used through the centuries with positive results. For example, the young and tender twigs of the tree have been employed as "chewing sticks" that served as primitive toothbrushes in India. This probably encouraged the addition of neem leaf extract to formulations for dentifrice that sometimes are called neem toothpaste.
Some cases of dental diseases such as gingivitis and mild mouth infections have been treated successfully with neem leaf extract or products containing the extract, a success usually attributed to the antiviral and antimicrobial properties of neem. Other neem leaf extract benefits are because of the antiseptic and antibacterial properties of the herb, making it useful as an active ingredient in all natural herbal beauty products such as neem shampoo or soap.
Itching of the scalp and head lice are two conditions known to respond very well to the extract. Skin diseases, ulcers and even leprosy are still externally treated with neem in many parts of the world because of the cleansing and healing action that this all-natural medicine has on wounds and open sores. The herb, however, should not be relied upon to cure leprosy.
Neem leaf extract is quite potent, so it can be dangerous if taken internally for periods longer than two consecutive weeks or in high dosages. There have been unconfirmed reports of people in Africa suffering kidney damage from the prolonged internal use of neem to treat malaria. The reputation of being one of the world's most effective mosquito repellants, however, has kept neem on the list of all-natural agents employed in the fight against deadly diseases such as malaria that are spread by mosquitoes.