Neem

INTRODUCTION:

COMMON NAME:
Nim (Tag., Engl.) [1]
Margosa tree (Engl.) [1]
Indian Lilac (Engl.) [1]

SCIENTIFIC NAME:
 Azadirachta indica [2]

FAMILY NAME:
Meliaceae [3]

DESCRIPTION OF THE PLANT AND ITS PARTS:

•  The Neem Tree is evergreen and can reach heights of about 15 -30 m. The trunk of the Neem Tree is straight. The texture of the trunk is hard and scaly. It has wide spreading branches with dense clusters of leaves. During extreme dry conditions the Neem Tree sheds all the leaves.[3]

• The leaves of the Neem Tree are arranged in a comb like structure called as the “pinnate” arrangement. The pinnate leaves are arranged opposite to each other on a long stalk. The leaves of the Neem Tree are 20-30 cm long.[3]
• The flowers are found in large clusters called “inflorescence”. Each inflorescence bears about 150 -250 flowers. The individual flower itself is very small. They are white in color and have a strong fragrance.[3]
• The fruit of the Neem Tree is oval to round in shape and smooth just like the Olive fruit. This fruit is edible but bitter in taste. It has one elongated seed and rarely two to three seeds. [3] Neem is a tree. The bark, leaves, and seeds are used to make medicine. Less frequently, the root, flower, and fruit are also used.

• 
  Neem leaf is used for leprosy,eye disorders, bloody nose, intestinal worms,stomach upset, loss of appetite,skin ulcers, diseases of the heart and blood vessels (cardiovascular disease), fever,diabetes, gum disease (gingivitis), and liver problems. The leaf is also used for birthcontrol and to cause abortions.                                                                                                                                                        The bark is used for malaria, stomach and intestinal ulcers, skin diseases, pain, and fever.
  
  The flower is used for reducing bile, controlling phlegm, and treating intestinal worms.
  
  The fruit is used for hemorrhoids , intestinal worms, urinary tract disorders, bloody nose, phlegm, eye disorders, diabetes, wounds, and leprosy.
  
  Neem twigs are used for cough, asthma, hemorrhoids, intestinal worms, low sperm levels, urinary disorders, and diabetes. People in the tropics sometimes chew neem twigs instead of using toothbruseh, but this can cause illness; neem twigs are often contaminated with fungi within 2 weeks of harvest and should be avoided.
  
  The seed and seed oil are used for leprosy and intestinal worms. They are also used for birth control and to cause abortions.
  
  The stem, root bark, and fruit are used as a tonic and astringent.
  
  Some people apply neem directly to the skin to treathead lice, skin diseases, wounds, and skin ulcers; as a mosquito repellent; and as a skin softener.
  
  Inside the vagina neem is used for birth control.
  
  Neem is also used as an insecticide.[4]

 PICTURE OF THE PLANT AND IMPORTANT PARTS

NEEN TREE (figure1) [5]

BARK  (figure2) [6]

    

LEAVES (figure3) [7]

      

    SEEDS(figure4) [8]

  FLOWERS(figure5) [9]

                                                                          

                                                      
                                                                                       

  FRUITS(figure6) [10]

                                                             
                                                                                      



ACTIVE CONSTITUENTS:


From the seed is produced a bitter fixed oil, nimbidin, known as "Oil of Margosa" or neem oil. Neem seeds yield a fix oil of glycerides and bitter compounds including nimbin, nimbinin and nimbidol. Neem bark and leaves contain tannin and oil.Azadirachtin, the insecticide constituent of the seeds, is biodegradable, non-mutagenic, and nontoxic to birds, fish, and warm-blooded animals. The EPA has approved a neem formulation (Margosan-O) as a pesticide for limited use on nonfood crop Antiinflammatory (nimbidin, sodium nimbidate, gallic acid, catechin, polysaccharides) Antiarthritic, hypoglycemic, antipyretic, hypoglycemic, diuretic, anti-gastric ulcer (nimbidin) Antifungal (nimbidin, gedunin, cyclic trisulfide) Antibacterial (nimbidin, nimbolide, mahmoodin, margolone, margolonone, isomargolonone) Spermicidal (nimbin, nimbidin) Antimalarial (nimbolidfe, gedunin, azadirachtin) Antitumor (polysaccharides)Immunomodulatory (NB-II peptoglycan, gallic acid, epicatechin, catechin) Hepatoprotective (aqueous extract of neem leaf)Antioxidant (neem seed extract)[1]

TRADITIONAL USE
Various parts of the neem tree have been used as traditional Ayurvedic medicine in India. Neem oil and the bark and leaf extracts have been therapeutically used as folk medicine to control leprosy, intestinal helminthiasis, respiratory disorders, constipation and also as a general health promoter. Its use for the treatment of rheumatism, chronic syphilitic sores and indolent ulcer has also been evident. Neem oil finds use to control various skin infections. Bark, leaf, root, flower and fruit together cure blood morbidity, biliary afflictions, itching, skin ulcers, burning sensations and pthysis.[11]

PHAMACOLOGICAL ACTIVITIES:

• Biological and pharmacological activities attributed to different parts and extracts of these plants include antiplasmodial, antitrypanosomal, antioxidant, anticancer, antibacterial, antiviral, larvicidal and fungicidal activities. Others include antiulcer, spermicidal, anthelminthic, antidiabetic, anti-implantation, immunomodulating, molluscicidal, nematicidal, immunocontraceptive, insecticidal, antifeedant and insect repellant effects.[12]

• Neem leaf and its constituents have been demonstrated to exhibit immunomodulatory, anti-inflammatory, antihyperglycaemic, antiulcer, antimalarial, antifungal, antibacterial, antiviral, antioxidant, antimutagenic and anticarcinogenic properties.[13]
•  

  » Introduction

  
  
  Azadirachta indica A. Juss. synonymous with Melia azadirachta and Melia indica (A. Juss) belongs to the family Meliaceae. In English, it is called the Indian Lilac, neem tree or margosa. Vernacular names are neem or nim (Hindi, Urdu), neeb (Arabic), azad dirakht (Persian) and Nimba (Sanskit). Azadirachta indica is indigenous to the Indo-Pakistan subcontinent. Medicinal properties of the oil are attributed to the presence of bitter principles of the odorous compounds. The seeds contain about 20% oil.
  
  Our study aimed at testing the antifungal effects of 10 different solvent extracts of the neem seed kernels against Candida sps. This yeast like fungus is part of the normal flora of the mucous membranes, in the respiratory, gastrointestinal and female genital tracts. Under conditions like immunosuppression, diabetes mellitus, indwelling urinary or intravenous catheters, intravenous narcotic abuse, administration of corticosteroids or antimicrobials that alter the normal flora, infection with Candida occurs. Most commonly infection occurs in the mouth (oral thrush), female genitalia (vulvovaginitis), nails (paronychia) and skin, principally warm moist parts of the body such as the axillae, intergluteal folds, groin, or inframammary folds.
  
  The 15 isolates of Candida species tested were those from patients infected with Human Immunodeficiency Virus (HIV).
  
  
  

  » Materials and Methods

  
  
  Dried neem seeds were obtained from native medical shops. The seeds were authenticated as those of Azadirachta indica A. Juss by the Department of Botany, Presidency college, University of Madras. The solvents chosen to extract the neem seeds were hexane, methanol, chloroform, water, petroleum ether, 5% dimethylsulfoxide, dichloromethane, acetone, methanol: chloroform: water (12:5:3) and absolute alcohol. The seed kernels of healthy neem seeds were surface sterilized with spirit and dried. They were then cut with sterile scissors and dropped into the solvent. The seed weight:solvent ratio was taken as 1:10.The seeds were allowed to soak in the solvent for 8 days at room temperature. The solvent was then filtered through a Whatman filter paper (No.1) to remove the coarse seed material, into pre-weighed sterile containers. The vials were covered with filter paper and the solvent was allowed to evaporate. The weight of the residue was calculated (weight of the vial plus extract minus the weight of the empty vial) and the extracts were refrigerated. A successive extraction procedure was also attempted with the seed kernels in hexane, followed by chloroform and finally extraction with methanol each for 48 h, respectively.
  
  As the extracts were mostly oily or waxy, they were immiscible in the test broth. Several methods were tried to make a uniform suspension of the oil in broth using Tween 20, chloroform, petroleum ether: ethanol, gum acacia, benzene and methanol.
  
  The 15 isolates of Candida species tested were those from patients infected with HIV.
  
  Anticandidal activity of the extracts was tested by measuring the minimum inhibitory concentration (MIC) by the broth dilution method. An amount of 2 ml of diluent solvent (petroleum ether:alcohol) was added to each vial containing extract and from this stock solution various volumes were drawn for the MIC assay such that in each volume the concentration of extract was 1, 0.5, 0.25, 0.125 and 0.0625 mg. Mueller Hinton broth was used in this assay. The highest dilution of extract, at which inhibition of test organism was observed, was recorded as the MIC. Aliquots from each of the tubes were subcultured onto Saboraud's dextrose agar (SDA) and incubated overnight. Minimum fungicidal concentration (MFC) of the extracts was read as the highest dilution of extract that showed no growth on SDA. Fluconazole was used as the antifungal control and the MIC breakpoints of which are ( < 8 µg sensitive, 16-32 µg susceptible dose-dependent, > 64 µg resistant).
  
  
  

  » Results

  
  
  During extraction, we encountered repeated contamination of aqueous and 5% DMSO extracts on overnight soaking of the seed material in solvent. Hence, these extracts were not used. Extracts with hexane, chloroform and acetone gave pale yellow oil. Thick yellow oil was obtained from dichloromethane and methanol:chloroform:water extracts and waxy or greasy extracts were obtained with methanol. Pale yellowish white extracts were obtained on extraction with ethanol. The w/w yield of the extract fell in the range of 30-40% of the dried seed weight.
  
  Oil or wax, dissolved best in equal quantities of petroleum ether: ethanol (1:1) and was uniformly distributed in the broth. The solvent control was non-toxic to Candida sps. The disc diffusion method was not a reliable antimicrobial testing method, as the oil did not diffuse well into the medium.
  
  The direct hexane and ethanol extracts of the seed kernels were the best, inhibiting more than 13 out of 15 strains. [Table1] The ethanol extract of the neem seed kernel and that of the commercial oil showed similar activity. All strains were resistant to chloroform obtained by the successive extraction method and methanol: chloroform: water extracts. However, 9 out of 15 strains were inhibited by a direct chloroform extract. All other extracts showed satisfactory inhibition at concentrations at or below 1 mg/ml. Out of the 15 strains tested against the antifungal control fluconazole, 8 were sensitive, 2 were resistant and 5 were susceptible-dose dependent. A comparison of the activities of all the extracts has been made in.
  
  

  » Discussion

  
  
  The neem seed kernel yields an acrid bitter greenish yellow to brown fixed oil (40-48.9%) known as 'Oil of Margosa' with a strong disagreeable garlic odor. Oil is extracted in local presses from the seeds and is sold for native medicine purposes.
  
  Medicinal properties of the oil are attributed to the presence of bitter principles and odorous compounds. Neem oil is used to treat certain chronic skin diseases, ulcers, different types of metritis, leprosy, gum and dental troubles. Some studies have shown that neem has antifungal properties especially against dermatophytes. The seed oil is said to be non-mutagenic. However, seed oil intoxication has been reported at oral doses of 5-30 ml displaying symptoms of Reyes syndrome ruling out ingestion of the oil for medicinal purposes.
  
  Candida sps. are opportunistic fungal pathogens that usually infect immuno-compromised, immunosuppressed and diabetic patients causing a spectrum of infections like oral thrush, intestinal candidiasis, vaginal thrush, onychomycosis, etc.
  
  This study aimed at assaying the efficacy of 10 different solvent extracts of the seed kernels against 15 strains of Candida isolated from immunocompromised patients. The extracts were rated based on the number of strains of Candida inhibited at concentrations of 1 mg/ml or less. Among the extracts tested, the best activities were observed using direct ethanol extracts of the seed and the commercially available seed oil. Alcohol extraction done after hexane extraction showed lesser activity. Direct chloroform extracts were also inhibitory but chloroform extraction of the seed after hexane extraction showed no activity indicating that an active component was extracted by hexane. Dichloromethane, acetone and petroleum ether extracts inhibited fewer strains. Methanol: chloroform:water extracts showed no activity. Direct ethanol extracts of neem seed and ethanol extract of the commercial neem oil obtained from native medicine suppliers inhibited similar number of strains.
  
  Neem seed extracts such as those of hexane and ethanol could be potential anticandidal agents. In vivo studies could show whether they could be useful in treating nail and skin infections with Candida sps. Since neem oil is used intravaginally as an abortifacient, spermicide, and antimicrobial agent in sexually transmitted diseases, studies could also be done on the use of these seed extracts in treating vaginal candidiasis. NIM-76 a fraction of neem seed oil has been shown to have spermicidal and antimicrobial activities. However, neem seed oil is toxigenic when given orally. Further studies might throw light on the systemic toxicity of the solvent extracts of the neem seed.
  
  
  

  » Conclusion

  
  
  Azadirachta indica is a valuable plant source of medically useful compounds that has been used in several traditional drug preparations. The antimicrobial activities of the plant have not been extensively documented. Three of our solvent-derived extracts showed good anticandidal activity. Further ethnopharmacognostic studies and antimicrobial investigations might identify newer compounds which may have better antimicrobial properties.[20]

•  Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of neem (Azadirachta indica A. Juss) leaf extract against plaque formation was assessed in males between the age group of 20–30 years over a period of 6 weeks. Present study includes formulation of mucoadhesive dental gel containing Azadirachta indica leaf extract (25 mg/g). A 6-week clinical study was conducted to evaluate the efficacy of neem extract dental gel with commercially available chlorhexidine gluconate (0.2% w/v) mouthwash as positive control. Microbial evaluation of Streptococcus mutans and Lactobacilli species was carried out to determine the total decrease in the salivary bacterial count over a period of treatment using a semi-quantitative four quadrant streaking method. The results of the study suggested that the dental gel containing neem extract has significantly (P<0.05) reduced the plaque index and bacterial count than that of the control group.[21]

•  In our experiments 30 hypoglycaemic medicinal plants (known and less known) have been selected for thorough studies from indigenous folk medicines, Ayurvedic, Unani and Siddha systems of medicines. In all the experiments with different herbal samples (vacuum dried 95% ethanolic extracts), definite blood glucose lowering effect within 2 weeks have been confirmed in alloxan diabetic albino rats. Blood glucose values are brought down close to normal fasting level using herbal samples at a dose of 250 mg/kg once, twice or thrice daily, as needed. While evaluating comparative hypoglycaemic activity of the experimental herbal samples, significant blood glucose lowering activities are observed in decreasing order in the following 24 samples—Coccinia indica, Tragia involucrata, G. sylvestre, Pterocarpus marsupium, T. foenum-graecum, Moringa oleifera, Eugenia jambolana, Tinospora cordifolia, Swertia chirayita, Momordica charantia, Ficus glomerata, Ficus benghalensis, Vinca rosea, Premna integrifolia, Mucuna prurita, Terminalia bellirica, Sesbenia aegyptiaca, Azadirachta indica, Dendrocalamus hamiltonii, Zingiber officinale, Aegle marmelos, Cinnamomum tamala, Trichosanthes cucumerina and Ocimum sanctum. Present studies besides confirming hypoglycaemic activities of the experimental herbal samples, help identify more potent indigenous hypoglycaemic herbs (in crude ethanolic extract) from the comparative study of the reported experimental results.[22]
•  
  The effect of Azadirachta indica extract on gastric ulceration was studied in albino rats. Azadirachta indica extract (100–800 mg/kg p.o., 100–250 mg/kg i.p.) significantly inhibited gastric ulceration induced by indomethacin (40 mg/kg). Administration of 800 mg/kg p.o. and 250 mg/kg i.p. caused 100% cytoprotection against indomethacin (40 mg/kg, i.p.)-induced gastric ulceration. This action was accompanied by a dose-dependent decrease in total gastric acidity. In order to investigate the probable mechanism of Azadirachta indica antiulcer activity, the effect of the extract alone and in combination with histamine (1 mg/kg) and cimetidine (0.12 mg/kg) on gastric acid secretion in situ was studied. Azadirachta indica (250 mg/kg) significantly inhibited the basal and histamine-induced gastric acid secretion. Cimetidine seemed to augment Azadirachta indica inhibition of gastric acid secretion.
  The results suggest that the stem bark extract of Azadirachta indica possesses antiulcer agents, which probably act via histamine H₂ receptor.[23]

•  We have shown earlier that Neem (Azadirachta indica) bark aqueous extract has potent antisecretory and antiulcer effects in animal models and has no significant adverse effect (Bandyopadhyay et al., Life Sciences, 71, 2845–2865, 2002). The objective of the present study was to investigate whether Neem bark extract had similar antisecretory and antiulcer effects in human subjects. For this purpose, a group of patients suffering from acid-related problems and gastroduodenal ulcers were orally treated with the aqueous extract of Neem bark. The lyophilised powder of the extract when administered for 10 days at the dose of 30 mg twice daily caused a significant (p < 0.002) decrease (77%) in gastric acid secretion. The volume of gastric secretion and its pepsin activity were also inhibited by 63% and 50%, respectively. Some important blood parameters for organ toxicity such as sugar, urea, creatinine, serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, albumin, globulin, hemoglobin levels and erythrocyte sedimentation rate remained close to the control values. The bark extract when taken at the dose of 30–60 mg twice daily for 10 weeks almost completely healed the duodenal ulcers monitored by barium meal X-ray or by endoscopy. One case of esophageal ulcer (gastroesophageal reflux disease) and one case of gastric ulcer also healed completely when treated at the dose of 30 mg twice daily for 6 weeks. The levels of various blood parameters for organ toxicity after Neem treatment at the doses mentioned above remained more or less close to the normal values suggesting no significant adverse effects. Neem bark extract thus has therapeutic potential for controlling gastric hypersecretion and gastroesophageal and gastroduodenal ulcers.[25]

•  Hypoglycaemic effect was observed with Azadirachta indica when given as a leaf extract and seed oil, in normal as well as diabetic rabbits. The effect, however, was more pronounced in diabetic animals in which administration for 4 weeks after alloxan induced diabetes, significantly reduced blood glucose levels. Hypoglycaemic effect was comparable to that of glibenclamide. Pretreatment with A. indica leaf extract or seed oil administration, started 2 weeks prior to alloxan, partially prevented the rise in blood glucose levels as compared to control diabetic animals. The data suggests that A. indica could be of benefit in diabetes mellitus in controlling the blood sugar or may also be helpful in preventing or delaying the onset of the disease.[26]
•  

TOXICITY:

•  Study of neem oil by oral route in rats and rabbits showed dose-related pharmacotoxic symptoms along with biochemical and histopathological indices of toxicity, with the changes in the lungs and CNS as target organs of toxicity.[1]

• The seed oil of Azadirachta indica (neem oil) is well known for its medicinal properties in the indigenous Indian system of medicine. Its acute toxicity was documented in rats and rabbits by the oral route. Dose-related pharmacotoxic symptoms were noted along with a number of biochemical and histopathological indices of toxicity. The 24-h LD50 was established as 14 ml/kg in rats and 24 ml/kg in rabbits. Prior to death, animals of both species exhibited comparable pharmacotoxic symptoms in order and severity, with lungs and central nervous system as the target organs of toxicity. Edible mustard seed oil (80 ml/kg) was tested in the same manner to document the degree to which the physical characteristics of an oil could contribute to the oral toxicity of neem oil.[24]

•  The toxic effects of neem extract and azadirachtin on the brown planthopper,
  Nilaparvata lugens (Stal) (BPH) (Homoptera: Delphacidae).
  Senthil Nathan S, Choi MY, Paik CH, Seo HY, Kim JD, Kang SM.
  Plant Environment Division, Honam Agricultural Research Institute (HARI),
  National Institute of Crop Science (NICS), Rural Development Administration
  (RDA), #381 Songhak-dong, Iksan, Chonbuk, 570-080, Republic of Korea.
  senthilkalaidr@hotmail.com
  Extracts of neem (Azadirachta indica A. Juss) are used in the developing world
  for many purposes including management of agricultural insect pests. The effects
  of different neem extracts (aqueous (NSKEaq), ethanol (NSKEeth) and hexane
  (NSKEhex)) on mortality, survival and weight of the brown planthopper,
  Nilaparvata lugens (Stal) (BPH) (Homoptera: Delphacidae) third and fourth
  nymphal instars were investigated. When fed rice plants treated with neem
  derivatives in bioassays, the survival of BPH nymphs is affected. Comparisons
  were made with the pure neem limonoid, azadirachtin (AZA) to ascertain its role
  as a compound responsible for these effects. AZA was most potent in all
  experiments and produced almost 100% nymphal mortality at 0.5 ppm and higher
  concentrations. When higher concentrations were applied, the effects appeared
  shortly after treatment and mortality was higher. Many insects died after
  remaining inactive for several days or during prolonged moulting. At lower
  concentrations, if moulting was achieved, disturbed growth and abnormalities
  were then likely to occur in the moulting process. Nymphs that were chronically
  exposed to neem extract showed a reduction in weight (45-60%). The results
  clearly indicate the simple NSKE (aqueous, ethanolic or both), containing low
  concentrations of AZA, can be used effectively to inhibit the growth and survival of BPH.[14]
  
  
  • Toxicity of neem (Azadirachta indica A. Juss) formulations for twospotted
  spider mite and Euseius alatus de leon and Phytoseiulus macropilis (Banks)
  (Acari: Phytoseiidae)]
  [Article in Portuguese]
  Brito HM, Gondim MG Jr, de Oliveira JV, da Camara CA.
  Depto. Agronomia, Univ. Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros
  s/n, Recife, PE.
  The toxicity of selected commercial formulations of neem on Tetranychus urticae
  Koch (Acari: Tetranychidae) and two predatory mites Euseius alatus De Leon and
  Phytoseiulus macropilis (Banks) was studied. Topical toxicity was tested with
  the commercial formulations (Natuneem, Neemseto and Callneem) and extract of
  neem's seeds at concentration 1%, compared to the standard acaricide abamectin
  at concentration of 0.3 ml/L and the control treatment (distilled water). Based
  on the best performance against T. urticae through topical contact, the
  formulation Neemseto was selected to be evaluated using different concentrations
  against eggs, and residual and repellent effects on adults of the mites. Egg
  treatment consisted of dipping eggs into Neemseto dilutions and control
  treatment for five seconds. In addition, residual and repellent effects of
  Neemseto for adult mites consisted of using leaf discs dipped into the dilutions
  for five seconds. The toxicity of Neemseto on eggs and adults was greater for T.
  urticae compared to the toxicity observed for the predatory mites. Neemseto was
  repellent for T. urticae and E. alatus when tested at the concentrations of
  0.25, 0.50 and 1.0%, and did not affect P. macropilis. Neemseto using all
  concentrations, while for the predatory mites significant reduction of mite
  fecundity was only observed at the largest concentrations reduced the fecundity
  of T. urticae significantly. So Neemseto, among tested neem formulations,
  performed better against the twospotted spider mite and exhibited relatively low
  impact against the predatory mites studied.[15]
  
  
  
  
  • Prophylactic dose of neem (Azadirachta indica) leaf preparation restricting
  murine tumor growth is nontoxic, hematostimulatory and immunostimulatory.
  Haque E, Mandal I, Pal S, Baral R.
  Department of Immunoregulation and Immunodiagnostics, Chittaranjan National
  Cancer Institute, Kolkata, India.
  Significant restriction of growth of Ehrlich's carcinoma was observed following
  prophylactic treatment on Swiss albino mice with neem leaf preparation (NLP-1
  unit) once weekly for four weeks. Toxic effects of this particular dose (1
  unit), along with 0.5 unit and 2 units of NLP doses, were evaluated on different
  murine physiological systems. One hundred percent of mice could tolerate 4
  injections of 0.5 and 1 unit NLP doses. Body weight, different organ-body weight
  ratios and physical behavior of treated mice remained completely unchanged
  during treatment with different NLP doses. All of these NLP doses were observed
  to stimulate hematological systems as evidenced by the increase in total count
  of RBC, WBC and platelets and hemoglobin percentage. As histological changes as
  well as elevation in serum alkaline phosphatase, SGOT, SGPT were not observed in
  mice treated with three different doses of NLP, the nonhepatotoxic nature of NLP
  was proved. The level of serum urea remained unaltered and normal architecture
  of the cortical and medullary parts of the kidney were also preserved after NLP
  treatment. Increased antibody production against B16 melanoma antigen was
  detected in mice immunized with 0.5 unit and 1 unit of NLP. Number of splenic T
  lymphocytes (CD4+ and CD8+) and NK cells were also observed to be increased in
  mice injected with 0.5 unit and 1 unit of NLP. However, NLP dose of 2 units
  could not exhibit such immunostimulatory changes; NLP mediated immunostimulation
  was correlated well with the growth restriction of murine carcinoma. In other
  words, tumor growth restriction was observed only when mice were injected with
  immunostimulatory doses of NLP (0.5 unit and 1 unit).[16]
  
  
  
  • The toxicity and behavioural effects of neem limonoids on Cnaphalocrocis
  medinalis (Guenee), the rice leaffolder.
  Senthil Nathan S, Kalaivani K, Sehoon K, Murugan K.
  Department of Environmental Engineering, Chonbuk National University, 664-14 1ga
  Duckjin-Dong Duckjin, Jeonju City, Chola buktho, Chonbuk 561 756, Republic of
  Korea. senthilkalaidr@hotmail.com
  Meliaceae plant products have been shown to exert pesticidal properties against
  a variety of insect species. In agricultural pest control programs, such
  products may have the potential to be used successfully as botanical
  insecticides. The effect of the neem (Azadirachta indica) limonoids
  azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and
  deacetylnimbin on the biology and mortality of rice leaffolder larvae was
  investigated. In laboratory experiments, treatment with neem limonoids
  suppressed leaf folding behaviour of C. medinalis. Biological parameters (larval
  duration, pupal duration adult longevity and fecundity) were also affected by
  the treatment. Azadirachtin, salannin, and deacetylgedunin showed high
  bioactivity at all doses, while the rest of the neem limonoids were less active,
  and were only biologically active at high doses. Azadirachtin was most potent in
  all experiments and produced almost 100% larval mortality at 1 ppm
  concentration. These results indicate neem limonoids affect the larval
  behaviour. These effects are most pronounced in early instars.[17]
  
  
  
  
  
  • Cytotoxic and antiproliferative effects induced by a non terpenoid polar extract
  of A. indica seeds on 3T6 murine fibroblasts in culture.
  Di Ilio V, Pasquariello N, van der Esch AS, Cristofaro M, Scarsella G, Risuleo
  G.
  Biotechnology Biological Control Agency, V. del Bosco, 10--00060 Sacrofano,
  Roma, Italy.
  Neem oil is a natural product obtained from the seeds of the tree Azadirachta
  indica. Its composition is very complex and the oil exhibits a number of
  biological activities. The most studied component is the terpenoid azadirachtin
  which is used for its insecticidal and putative antimicrobial properties. In
  this report we investigate the biological activity of partially purified
  components of the oil obtained from A. indica. We show that the semi-purified
  fractions have moderate to strong cytotoxicity. However, this is not
  attributable to azadirachtin but to other active compounds present in the
  mixture. Each fraction was further purified by appropriate extraction procedures
  and we observed a differential cytotoxicity in the various sub-fractions. This
  led us to investigate the mode of cell death. After treatment with the oil
  fractions we observed positivity to TUNEL staining and extensive
  internucleosomal DNA degradation both indicating apoptotic death. The
  anti-proliferative properties of the neem oil-derived compounds were also
  assayed by evaluation of the nuclear PCNA levels (Proliferating Cell Nuclear
  Antigen). PCNA is significantly reduced in cells treated with a specific
  fraction of neem oil. Finally, our results strongly suggest a possible
  involvement of the mitochondrial pathway in the apoptotic death.[18]
  
  
  
  
  
  
  • Anti-plasmodial activity and toxicity of extracts of plants used in traditional
  malaria therapy in Meru and Kilifi Districts of Kenya.
  Kirira PG, Rukunga GM, Wanyonyi AW, Muregi FM, Gathirwa JW, Muthaura CN, Omar
  SA, Tolo F, Mungai GM, Ndiege IO.
  Department of Chemistry, School of Pure & Applied Sciences, Kenyatta University,
  P.O. Box 43844, Nairobi 00100 GPO, Kenya.
  The methanol and aqueous extracts of 10 plant species (Acacia nilotica,
  Azadirachta indica, Carissa edulis, Fagaropsis angolensis, Harrissonia
  abyssinica, Myrica salicifolia, Neoboutonia macrocalyx, Strychnos heningsii,
  Withania somnifera and Zanthoxylum usambarensis) used to treat malaria in Meru
  and Kilifi Districts, Kenya, were tested for brine shrimp lethality and in vitro
  anti-plasmodial activity against chloroquine-sensitive and chloroquine-resistant
  strains of Plasmodium falciparum (NF54 and ENT30). Of the plants tested, 40% of
  the methanol extracts were toxic to the brine shrimp (LD(50)<100micro/ml), while
  50% showed in vitro anti-plasmodial activity (IC(50)<100microg/ml). The methanol
  extract of the stem bark of N. macrocalyx had the highest toxicity to brine
  shrimp nauplii (LD(50) 21.04+/-1.8microg/ml). Methanol extracts of the rest of
  the plants exhibited mild or no brine shrimp toxicity (LD(50)>50microg/ml). The
  aqueous extracts of N. macrocalyx had mild brine shrimp toxicity (LD(50)
  41.69+/-0.9microg/ml), while the rest were lower (LD(50)>100microg/ml). The
  methanol extracts of F. angolensis and Zanthoxylum usambarense had IC(50) values
  <6microg/ml while the aqueous ones had values between 6 and 15microg/ml, against
  both chloroquine-sensitive and resistant P. falciparum strains. The results
  support the use of traditional herbs for anti-malarial therapy and demonstrate
  their potential as sources of drugs.[19]
  
  

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COMPILED BY: CHERRY MAE A. DE LA TORRE