Ecofriendly Neem tree
Dr. Banarsi Lal & Dr. Pawan SharmaDr
Neem (Azadirachta indica) is considered as a valuable source of unique natural products for development of medicines against various ailments and also for the development of various industrial products. This is said to be a divine tree and mainly cultivated in the Indian subcontinent. It is a member of mahogany family, Meliaceae. It is considered as one of the most versatile medicinal plants having a wide spectrum of biological properties. Each part of this tree is used as a traditional medicine for house hold remedy against various human ailments. Neem has been extensively used in Ayurveda, Unani and Homeopathic medicines and become a cynosure of modern medicine. The Sanskrit name of the neem tree is “Arishtd’ meaning “Reliever” and it is still regarded as village dispensary in the rural areas. Azadirachtin belongs to an organic molecule class called tetranotriterpenoids. lt is a crystalline yellow to amber coloured chemical with a boiling point 155-158 C. This is an incredible tree that has been declared as the “Tree of 21st century” by the United Nations. For centuries, millions have cleaned their teeth with neem twigs, smeared skin disorders with neem leaf juice, taken neem tea as a tonic and placed neem leaves in their grain bins, beds, books and closets to keep away troublesome bugs. This tree has relieved different pains, infections, fevers etc. and deserves to be called a wonder plant.
Azadirachtin is relatively harmless to spiders, butterflies and insects such as bees that pollinate crops and trees and ladybugs that consume aphids and wasps that act as parasites on various crops pests. Thus, it is eco friendly in nature. The oil from the neem leaves, seeds and bark possesses a wide spectrum of antibacterial action against Gram-negative and Grampositive microorganism including M. tuberculosis and streptomycin resistant strains. lt also inhibits Vibriocholera, Klebsiella pneumoniae, M.tuberculosis and M. pyogenes. Anti microbial effect of neem extract have been demonstrated against Streptococcus mutans and S. faecalis. Azadirachtin has been found to enhance the efficient use of nitrogen by restricting microbial activity. Thus, it plays a key role to increase the fertiliser use efficiency. The indiscriminate use of fertiliser for increasing food production has led to discernible concerns of environmental pollution due to the hazardous chemical residue in the soil. The high fertiliser consumption is also due to loss of fertilizer as ammonia (volatilisation), N20, N2 and leaching. The ammonium nitrogen is converted to nitrate nitrogen (by Nitrosomonas and Nitrobacter bacteria), called nitrification, which ultimately transforms to N2O, N2-gases through denitrification. The importance of the neem tree has been recognized by the U.S. National Academy of Sciences, which published a report in 1992 entitled “Neem-A tree for solving global problems”. Various parts of the neem tree are used as traditional Ayurvedic medicine in lndia as well as in abroad. Neem oil, bark and leaf extract has been therapeutically used at folk medicine to control leprosy; intestinal helminthiasis, respiratory disorders, constipation and also as a general health promoter. It is also used for treatment of rheumatism, chronic syphilitic sores and indolent ulcer. It has also been evident Bark, leaf, root, flower and fruit together cure morbidity’ itching, bilary afflictions and skin, ulcer and burning sensations. The aqueous leaf extract offers antiviral activity against Vaccina virus, Ckikungunya and measles virus in vitro. The anti viral and virucidal effect of the methanolic extract of neem leaves have recently been demonstrated against group-B coxsackic viruses.
The Aqueous extract of neem leaves significantly decreases blood sugar level and prevents adrenalin as well as glucose induced hyperglycomla. Aqueous leaf extract also reduces hyperglycemia in streptozotoc in diabetes and the effect is possible due to presence of a flavonoid, quercetin. The Neem oil proved spermicidal against rhesus monkey and humanspermatozoa in vitro. ln vitro studies showed that intravaginal application of Neem oil prior to coitus could prevent pregnancy. Anti fertility effect of Neem oil has been studied and suggested to be novel method of contraception. Purified Neem seed extract (praneem) has also been demonstrated to abrogate pregnancy in both baboons and bonnet monkeys, when administrated orally. The effect is possible due to activation of cell mediated immune reaction. The mechanism of action of neem oil appears to be non-humoral, probably mediated through its spermicidal effect and may have fewer side effects than steroidal contraceptives. The Neem seed and leaf extract are effective against malarial parasites; components of alcoholic extract of leaves and seeds are effective against both chloroquin, resistant and sensitive strains’ of malarial parasites. Recently, Neem seed extract and purified reaction have been shown to inhibit growth and development of asexual stages of drug sensitive and resistant strains of the human malarial parasite Plasmodium falciparum. The extract of neem leaf neem oil and seed kernels are effective against certain human fungi including Trichophyton, Epidermophyton, Microsporium, Trichosporon, Geotricum and Condida. Neem extract has also mycotic
The Neem leaf aqueous extract produces antiulcer effect to restraint coldstress by preventing mucous depletion. An aqueous extract of Neem bark has also shown in laboratory to possess highly potent antacid secretary and anti ulcer activity and the bioactive compound has been attributed to a glycoside. The aqueous extract of stem, bark and leaf also possesses potent immunostimulant property as evidence by both humoral and cell-mediated responses. Neem oil has also stimulated the activity by selectively activating the cell mediated immune mechanism to elicit an enhanced response to subsequent mutagenic oranttgenic challenge. The crude ethanolic extracts of stem and root bark showed hypertensive, spasmolytic and diuretic activities.
The antioxidant activity of Neem seed extract has been demonstrated in vivo during horse grain germination, which is associated with low level of lipooxygenase activity and lipid peroxides. It can completely inhibit the growth of Mycobacteerium tuberculosis and was also found to be bactericidal Diuretic activity was also reported for sodium nimbidinate in dogs. Nimbolide has been shown to exert antimalarial activity by inhibiting the growth of Plasmodium lalciparum. Nimbolide also shows antibacterial activity against S. aureus and S. coagulase. Gedunin lsolated from neem seed oil has been reported lo possesses both antifungal and Antimalaria activities. Azadirachtin is highly oxygenated and having strong antifeedant activity has been demonstraled to have antimalarial property as well. It is inhibitory to the development of malarial parasites. Mahmoodin a deoxygedunin isolated from seed oil, has been shown to possess moderate antibacterial action against some strains of human pathogenic bacteria Condensed tannins from the bark contain gallic acid’ (+)gallocatechin, (-) epicatechin, (+) catechin and epigallocatechin.
Neem, the versatile medicinal plant is the unique source of various types of compounds having diverse chemical structure. Very little work has been done on the biological properties and plausible medicinal applications of these compounds and hence extensive research is needed to exploit their therapeutic utility to combat diseases. A drug development programme should be undertaken to develop modern drugs with the compounds isolated from Neem. Although crude extracts from various parts of Neem have medicinal application from time immemorial, modern drugs can be developed after extensive investigation of its bioactivity, mechanism of action, pharmacotherapeutics, toxicity and after proper standardisation and clinical trials. As the global scenario is now changing towards the use of nontoxic plant products having traditional medicinal use, development of modern drugs from neem should be emphasised tor the control of various ailments. ln fact, time has come to good use of centuries-old knowledge on neem through modern approaches of drug development. For the last few years there has been an increasing trend and awareness in neem research. Quite a significant amount of research has already been carried out during the past few decades in exploring the chemistry of different parts of Neem. Several therapeutically and industrially useful preparations and compounds have also been researched which generate enough encouragement among the scientists in exploring more information on Neem and its