It is a tree that can reach 30 m and live 2 centuries, but is generally smaller (5 to 10 m), its evergreen foliage is imparipinnate (5 to 8 pairs of falciform leaflets with very unequal base), flowers in panicles are white or yellowish, the fruit is a drupe of 1 to 2 cm, yellow when ripe
The Neem grows very well in tropical and subtropical regions even in the dry season because it has a very deep root system, but it can not withstand prolonged cold.
It is widespread in India and Southeast Asia and has been introduced to Australia, Africa, the West Indies, and tropical America. In the southern US and Europe, varieties from northern India have been acclimatized and are more resistant to frost.
It is a "sacred" tree in the Indian sub-continent, used for over 2000 years in Ayurvedic medicine and considered a "protective" tree in the traditional culture of India.
Modern studies have shown that all parts of this tree contain substances with interesting pharmacological properties (about 50 oxidized tetranortriterpenoid), but it is especially in the fight against insect pests that neem seems the most promising.
US agrochemical companies backed by the US government very quickly (1995) "patented" this tree, but it seems that after an international campaign denouncing these processes, Europe has decided not to recognize the legality of these abusive patents .
The leaves, bark and wood, and especially the fruits that contain oil are medicinal.
CHEMICAL COMPOSITION AND PROPERTIES
The fruit kernel contains 40 to 48% of oil whose fatty acid composition is as follows:
myristic acid: 2 to 3%
palmitic acid: 13 to 15%
stearic acid: 15 to 19%
oleic acid: 50 to 62%
linoleic acid: 8 to 16%
The oil also contains potentially active terpenoids in large quantities:
azadirachtin, nimbine, nimbidine, azadirone, but also meliacines.
Azadirachtin, the most active compound against insects, is actually a mixture of 7 isomeric compounds (A to G); the isomer A is the most abundant but it is the isomer E which is the most active as insecticide.
It would act both on the growth and development of the insect (larval growth, moulting) and as an antinutrient factor.
Other compounds present in the neem (leaves, wood or oil) also have an insecticidal power mainly of the "hormonal" or antinutrient type.
One study reports 24, which for these authors reduces the risk of development of resistance or addiction by insects. The most active compounds are azadirachtin already mentioned, salanin, melantriol, and nimbine.
The neem oil would be:
purgative, antihelminthic, external parasite (louse), antimycotic, and antidiabetic.
It contains antiviral compounds (some active on the AIDS virus), and antimalarials.
All these pharmacological properties are not always supported by clinical trials.
In Sanskrit Azadirachta indica is called Nimba which derives from a word meaning "to stay healthy"; in the ancient religious texts the neem is "the one who heals all the evils", a panacea, a pharmacy tree.
He is still very present in many current Ayurvedic preparations.
It is considered one of the most powerful means to "purify and detoxify blood".
In village medicine:
• The leaf tea (10 sheets in one liter of water) is used to lower fever, calm gastric pain due to ulcers, control non-insulin-dependent moderate diabetes type 2.
• The decoction of leaves (50 leaves in a liter of water) or bark (a handful of bark in a liter of water) is used to clean wounds, mouthwash in case of gingivitis, gargle in case angina, in vaginal irrigation in case of leucorrhea, by mouth in case of ordinary diarrhea or directly in the bath water in case of diffuse cutaneous infection (acne, furunculosis).
• Dry leaf powder may be added to the toothpaste in case of slight inflammation of the gums.
• Neem oil is used directly on cutaneous mycosis and on the scalp in case of mycosis or lice (leave one hour and rinse with shampoo, once a week for 3 weeks)
• neem oil is spermicide, it is also lubricating, it is used as a local contraceptive
• a mixture of coconut oil and neem oil is an effective protection against several types of mosquitoes: anopheles, aedes, culex:
• 1 to 4% of neem oil in coconut oil applied to the skin reduces the number of anopheline bites by 80 to 90%, in some studies the protection is complete.
• An oily lotion with 2% neem oil completely protects against phlebotomy (Phlebotomus argentipes) bites that transmit the agent of the leshmaniosis
• by putting 1% of neem oil in kerosene lamps it reduces the incidence of malaria, it keeps anopheles away (it is less repulsive for culex). After one year, no adverse side effects were observed in a sample of 266 people who used this protection.
Neem is used in traditional agriculture to control insect pests (including flying locusts), and to treat soil against larvae of insects and other pests; peasants use wood, leaves, crushed fruit, oil in aqueous solution with a little detergent, deoiled fruit cake.
Neem fruit or neem oil can be used to destroy or reduce the number of intestinal or external parasites of livestock and domestic animals.
Several Indian companies market different extracts of Azadirachta indica:
• For "rational" or organic agriculture: neem oil, pesticides dosed with azadirachtin, neem fertilizer.
• Cosmetics based on neem oil: anti-dandruff shampoo or to get rid of lice, acne lotion but also to improve certain dermatological conditions (eczema, psoriasis), antiseptic lotion.
• Azadirachta indica or neem extract medicines: against malaria, helminthiases, bacterial, fungal, viral and even tuberculosis infections, or to "detoxify, cleanse" the body.
• In veterinary medicine: internal and external deworming, to prevent infection of wounds including flies that lay eggs directly on wounds.
To my knowledge, there is no use of Azadarichta indica, Neem tree, in Western medicine.
Melia azedarach,( chinaberry tree, Pride of India, bead-tree, Cape lilac, syringa berrytree, Persian lilac, or Indian lilac) is botanically very close to Neem tree ; native to the Himalayan foothills, it is now widespread throughout the world, from tropical to temperate to moderately severe winter
(It is present in the south of France and in the Iberian peninsula).
It is planted in parks, squares, gardens and along roads and is easily naturalized because its fruits are eaten and transported by birds.
Unlike Azadirachta indica, Melia azedarach has two and sometimes three pinnate foliage, purple or mauve fragrant flowers and it loses its leaves in autumn, its fruits almost identical to those of neem persist on the tree during Winter.
It contains many triterpenoids like neem but has been little studied from a chemical point of view and does not have the reputation of neem in India, although it is known to have insecticidal properties; a hydro-alcoholic extract of its leaves would depress the central nervous system and be analgesic.
Cuban researchers have considered the possibility of using its fruits in the fight against molluscs vectors of the liver fluke (fasciola hepatica).
It should be known that the ALMOND FRUIT of this tree, common in public places, is considered as TOXIC, poisoning at low doses not only insects but also mammals (including humans).
The fruit, which could attract children, is fortunately very hard to break.
A PANACEA FROM INDIA
Azadirachta indica, or nimba, is known around the world as the Neem tree.
For thousands of years this common tree in the Indo-Malayan region is the "pharmacy" of the village.
It contains several substances that are naturally insecticidal
and others interesting at the pharmacological level.
Melia azedarach, which resembles Neem, is planted in southern Europe,
its fruits are considered potentially toxic.
Copyright 2019 : Dr Jean-Michel Hurtel