The plant of neem beautifully illustrates the need and value of delving deep into the treasures pointed out by our ancient wisdom. There are two aspects on which modern research and studies on neem have been particularly fruitful; they are: the additive role of neem oil and fats in pharmaceutical and other industries and the importance of neem as a source of pest control material. It is impressive to note and reflect on a short summary on both of these aspects as given below:
Scientists concede that neem is one of the most valuable and yet the least exploited of all the tropical trees. Importance of this realisation becomes much emphasised when we realise that this glorious plant is simply luxuriously available in India. It grows in almost any soil, arid regions and even on nutrient deficient soil and also happens to be a very fast growing source of fuel wood.
It can survive high temperature, altitudes between 5 to 1000 metres, as little rainfall as 130 mm per year and long stretches of drought. Its cultivation is the easiest, it makes almost no demand. The roots possess an unusually great capacity to secure nutrients and moisture even from highly leached (drained away) and sandy soil.
Its propagation is by seeds which need no pretreatment and 9 to 12 months old seeddings are good enough for transplanting. The whole tree is a good and quickly regenerating source of fuel wood and its heart wood is an exploitable timber. The Indian neem tree grown in Sudan of African continent is moderately heavy, stable and resembles the most valuable timber of Mahogony. It is teak like in strength and properties.
The following are some of the properties of medicinal value that modern studies have brought to light:
1. Antitubercular Activity: The dreaded disease of tuberculosis is due to a bacterial organism called Mycobacterium. Neem oil has been found to Inhibit the growth of all the three strains of Mycobacterium and it does so in such a low concentration of 12.5 mg/ml.
When tested for effect in tuberculosis infected mice, neem oil and nimbidol showed partial inhibitory effect. In higher concentrations nimbidin prolonged their survival duration. Tested on guineapigs, neem oil depressed their very sensitivity to this disease.
2. Antifungal Activity: Diseases caused by fungus in man are quite many and most of them once they start tend to become chronic quite soon, almost defying any medicine. Nimbidin, nimbin, nimbidol and neem oil-all of these have been demonstrated to be very effective against many fungi causing disease in man such as Tinea rubrum, the ring worm fungus, Trichophyton interdigitale, Coccidiosis immitis and other species of Trichophyton causing superficial skin infections.
And, they are so effective at very low concentrations even. The other fungi over which neem oil has been found to be quite efficiently active are: Microsporum gypsum Aspergillus fumigatus and Penicillium lilanicum
3. Anti Protozoal Activity: Apart from fungi which are plants there are many microscopic animals called protozoans, some of which do caiise diseases in man for eg. amoebic dysentery. Nimbidin and sodium nimbidinate have been found to kill Paramecium caudatum, a very common protozoan within a minute and in such a low dilution as 1500. Nimbidol when given orally to chicks suffering from the infection by another protozoan called Plasmodium gellinaceum suppressed the infection.
4. Antiallergic Activity: Allergy is supposed to be a modern disease, though it is only its recognition that is modern. The speciality of this disease is that it is not due to any pathogenic or disease causing organism. Instead it represents an adverse reaction shown peculiarly by individuals to an entry of some specific foreign protein. It is purely a special reaction of the individual or it is just an idiosyncrasy. For eg. some people are allergic to onion; others are not. The reaction may manifest itself in many ways such as skin rashes, or immediate running nose.
This is usually violent and immediate. Histamine is one of the very potent chemical known to cause allergy. When tested in guinea pigs, nlmbin has been shown to inhibit the stimulation produced by guinea pig. due to allergy. Eosiniophilia is an allergic reaction manifesting itself in persistent and rather prolonged bout of coughing that leaves the individual highly depressed and rather weak. Nimbidin is reported to be effective against this affliction and gives marked symptomatic relief.
5. Skin Diseases: It may be recalled that references in Ayurveda for the use of neem in various forms against many skin diseases are abundant. Modern studies have confirmed this remarkable efficacy in several ways. Nimbidin has been shown to be effective against many skin diseases such as furunculosis (infection of hair follicles), arsenical dermatitis, eczema, scabies and seborrhoeic dermatitis (inflammation regions next to the sweat glands). An easy way to secure this effect is to extract it from dried leaves of neem with 70% alcohol, evaporate, disolve the residue in propylene glycol in a ratio of 4:6 and apply the solution locally.
6. Dental Diseases: Gargle and dentifrices (i.e tooth pastes and tooth powders) of nimbidin have been demonstrated to be effective in bleeding gums and pyorrhoea (pus in teeth sockets). There are patented extracts of the bark of neem in the market that form the active ingredient in tooth paste and other oral hygienic preparations.
7. Miscellaneous Activities: Various neem products either alone or in mutual combination have shown many useful medicinal activities such as antibacterial, antiviral and sperm killing activity. They are also ulcer destructive and countering inflammation and fever. They increase urine flow and regulate cardio vascular functions.