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Articles:

Protective effects of ethanolic neem leaf extract on N-methyl-N'-nitro-N-nitrosoguanidine-induced genotoxicity and oxidative stress in mice.

Subapriya R, Kumaraguruparan R, Abraham SK, Nagini S.

Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar-608 002, Tamil Nadu, India.

We evaluated the effects of pretreatment with ethanolic neem leaf extract on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced genotoxicity and oxidative stress in male Swiss albino mice. The frequency of micronuclei (MN), concentrations of lipid peroxides and the status of the antioxidants, reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were used as intermediate biomarkers of chemoprotection. Animals were divided into four groups of five animals each. Animals in group 1 were given MNNG (40 mg/kg body weight) by intragastric intubation. Animals in group 2 received intragastric administration of ethanolic neem leaf extract at a concentration of 200 mg/kg body weight for 5 days followed by MNNG 1.5 h after the final feeding. Group 3 animals received ethanolic neem leaf extract alone for five days. Group 4 received the same volume of normal saline and served as control. The animals were sacrificed by cervical dislocation 27 h after the carcinogen exposure. In MNNG-treated mice, enhanced lipid peroxidation with compromised antioxidant defences in the stomach, liver and erythrocytes was accompanied by increase in bone marrow micronuclei. Pretreatment with ethanolic neem leaf extract significantly reduced MNNG-induced micronuclei and lipid peroxides and enhanced GSH-dependent antioxidant activities. The results of the present study demonstrate that ethanolic neem leaf extract exerts protective effects against MNNG-induced genotoxicity and oxidative stress by augmenting host antioxidant defence mechanisms.

Neem (Azadirachta indica) leaf mediated immune activation causes prophylactic growth inhibition of murine Ehrlich carcinoma and B16 melanoma.

Baral R, Chattopadhyay U.

Department of Immunoregulation and Immunodiagnostics, Chittaranjan National Cancer Institute (CNCI), 37, S.P. Mookherjee Road, Kolkata 700026, India.

Conditional growth inhibition of murine Ehrlich carcinoma (EC) and B16 melanoma (B16Mel) was observed, following treatment of mice (Swiss and C57BL/6) with aqueous extract of neem (Azadirachta indica) (1 unit/mice/week for 4 weeks) either before or after inoculation of 1x10(6) tumor cells. Tumor inoculation after weekly injections for 4 weeks with neem leaf preparation (NLP) induced significant reduction of tumor growth (both EC and B16Mel) and increased survivability of mice. On the other hand, NLP treatment after tumor inoculation demonstrated no tumor growth inhibition in the NLP treated group in comparison to the PBS treated control. No direct cytotoxic effect of NLP towards EC and B16Mel tumor cells was observed in vitro. The spleen cells of NLP treated mice when mixed with inoculum of B16Mel tumor cells and injected into a group of mice, tumor growth was found to be significantly reduced and survivability of the tumor hosts increased remarkably in comparison to mice inoculated with tumor along with normal spleen cells. Concanavalin A (ConA) induced proliferation of lymphocytes from NLP treated mice was significantly higher than the lymphocytes of untreated mice. In in vitro, NLP by itself had no proliferative effects on lymphocytes but it co-stimulated ConA induced mitogenesis. NLP induced lymphocytosis as evidenced by increased lymphocyte count in blood as well as spleen. Flow cytometric evidence suggested that increase in CD4+ and CD8+ T cells accounted for lymphocytosis. The conditional tumor growth retardation, observed in mice treated with NLP before tumor inoculation, may be regulated by NLP mediated immune activation, having prominent role in the cellular immune function of the tumor host.

Evaluation of antiplaque activity of Azadirachta indica leaf extract gel--a 6-week clinical study.

Pai MR, Acharya LD, Udupa N.

Department of Pharmaceutics, College of Pharmaceutical Sciences, Manipal Academy of Higher Education, 576119, Manipal, India

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.

N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced in vivo clastogenicity: protective effects of aqueous neem leaf extract.

Arivazhagan S, Nagini S, Santhiya ST, Ramesh A.

Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar, Tamil Nadu, India.

We evaluated the modifying effects of aqueous neem leaf extract on the in vivo clastogenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a potent gastric carcinogen by quantitation of micronuclei and chromosomal aberrations in metaphase cells from the bone marrow of male Wistar rats. Intraperitoneal injection of MNNG (40 mg/kg body weight) induced a significant increase in the frequency of micronuclei and chromosomal aberrations. Pretreatment with aqueous neem leaf extract (100 mg/kg body weight) significantly reduced MNNG-induced increase in micronuclei and chromosomal aberrations. These results reveal the chemoprotective potential of aqueous neem leaf extract against the clastogenic effects of MNNG.

Spermicidal activity of Azadirachta indica (neem) leaf extract.

Khillare B, Shrivastav TG.

Department of Reproductive Biomedicine, National Institute of Health and Family Welfare, Munirka, New Delhi, India-110067.

The present study was carried out to evaluate the effective concentration of aqueous extract of old and tender Azadirachta indica (neem) leaves to immobilize and kill 100% human spermatozoa within 20 s. Sander-Cramer test was used to study the spermicidal activity of neem leaf extract. Under the test conditions, minimum effective spermicidal concentrations for tender and old leaf extracts were 2.91 +/- 0.669 mg/million sperm and 2.75 +/- 0.754 mg/million sperm, respectively. The effect of extracts on morphology and viability of sperm was also studied and no change was observed in morphology of head, mid-piece and tail and no viable sperm seen. The leaf extracts were found to be water soluble and carbohydrate in nature. The effect of different concentrations of extracts (old and tender) on percentage motility of the sperm was also studied. With an increase in concentration, there is a linear decrease in percentage motility, becoming zero at a 3-mg dose within 20 s.

Ethanolic neem leaf extract protects against N-methyl -N'-nitro-N-nitrosoguanidine-induced gastric carcinogenesis in Wistar rats.

Subapriya R, Nagini S.

We evaluated the effects of ethanolic neem leaf extract on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis in Wistar rats. The extent of lipid peroxidation and the status of the antioxidants superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) in the stomach, liver and erythrocytes were used as biomarkers of chemoprevention. Animals were divided into four groups of six animals each. Rats in group 1 were given MNNG (150 mg/kg bw) by intragastric intubation three times with a gap of 2 weeks in between the treatments. Rats in group 2 administered MNNG as in group 1, in addition received intragastric intubation of ethanolic neem leaf extract (200 mg/kg bw) three times per week starting on the day following the first exposure to MNNG and continued until the end of the experimental period. Group 3 animals were given ethanolic neem leaf extract alone, while group 4 served as controls. All the animals were killed after an experimental period of 26 weeks. Diminished lipid peroxidation in the stomach tumour tissue was associated with enhanced antioxidant levels. In contrast to tumour tissue, enhanced lipid peroxidation with compromised antioxidant defences was found in the liver and erythrocytes of tumour bearing animals. Administration of ethanolic neem leaf extract significantly reduced the incidence of stomach tumours, modulated lipid peroxidation and enhanced antioxidant status in the stomach, liver and blood. From the results of our study, we suggest that ethanolic neem leaf extract may exert its chemopreventive effects by modulating lipid peroxidation and enhancing the antioxidant status in the stomach, liver and erythrocytes.

Chemoprotective effects of ethanolic extract of neem leaf against MNNG-induced oxidative stress.

Subapriya R, Kumaraguruparan R, Chandramohan KV, Nagini S.

Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar, Tamil Nadu, India.

We evaluated the modifying effects of ethanolic extract of neem leaves (Azadirachta indica A. Juss) on oxidative stress induced by the potent gastric carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in male Wistar rats. The extent of lipid peroxidation and the status of the antioxidants superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were used as intermediate endpoints of chemoprevention. Three different concentrations of ethanolic neem leaf extract (100, 200 and 400 mg kg(-1) body weight) were administered by intragastric intubation (i.g) for five consecutive days followed by MNNG (i.g) 1.5 h after the final administration. Enhanced lipid peroxidation was accompanied by compromised antioxidant defences in the stomach, liver and erythrocytes of MNNG-treated rats. Pretreatment with ethanolic neem leaf extract at a dose of 200 mg/kg body weight (bw) significantly lowered the concentration of lipid peroxides and increased antioxidant levels. Our results demonstrate that neem leaf exerts its chemoprotective effects on MNNG- induced oxidative stress by decreasing lipid peroxidation and enhancing the antioxidant status.

A study of cardiovascular effects of Azadirachta indica (neem) on isolated perfused heart preparations.

Khosla P, Gupta A, Singh J.

Department of Pharmacology, Pt. B.D. Sharma PGIMS, Rohtak-124 001.

The effects of aqueous leaf extract of Azadirachta indica were evaluated on isolated prefused frog and rabbit heart. Dose dependent negative inotropic and chronotropic effects were observed in both the heart preparation. An increase in coronary blood flow in isolated rabbit heart was observed. The effects were not blocked by atropine and mepyramine in both the preparations. The data suggests that A. indica could be of benefit in coronary artery disease and arrhythmias.

Inhibitory potential of neem (Azadirachta indica Juss) leaves on dengue virus type-2 replication.

Parida MM, Upadhyay C, Pandya G, Jana AM.

Division of Virology, Defence Research and Development Establishment, Gwalior 474 002, MP, India.

In the present study we report in vitro and in vivo inhibitory potential of crude aqueous extract of neem leaves and pure neem compound (Azadirachtin) on the replication of Dengue virus type-2. In vitro antiviral activity of aqueous neem leaves extract assessed in C(6/36) (cloned cells of larvae of Aedes albopictus) cells employing virus inhibition assay showed inhibition in dose dependent manner. The aqueous extract of neem leaves at its maximum non-toxic concentration of 1.897 mg/ml completely inhibited 100-10,000 TCID(50) of virus as indicated by the absence of cytopathic effects. The in vivo protection studies with neem leaves extract at its maximum non-toxic concentrations 120-30 mg/ml resulted in inhibition of the virus replication as confirmed by the absence of Dengue related clinical symptoms in suckling mice and absence of virus specific 511 bp amplicon in RT-PCR. The pure neem i.e. Azadirachtin did not reveal any inhibition on Dengue virus type-2 replication in both in vitro and in vivo systems.

A study of hypoglycaemic effects of Azadirachta indica (Neem) in normaland alloxan diabetic rabbits.

Khosla P, Bhanwra S, Singh J, Seth S, Srivastava RK.

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.

Effect of Azadirachta indica (Neem) leaf aqueous extract on paracetamol-induced liver damage in rats.

Bhanwra S, Singh J, Khosla P.

Department of Pharmacology, Pt. B.D. Sharma P.G.I.M.S., Rohtak.

The effect of aqueous leaf extract of Azadirachta indica (A. indica) was evaluated in paracetamol induced hepatotoxicity in rats. Liver necrosis was produced by administering single dose of paracetamol (2 g/kg, p.o.). The liver damage was evidenced by elevated levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transpeptidase (gamma-GT) and by histopathological observations of liver sections. Aqueous A. indica leaf extract (500 mg/kg, p.o.) significantly (P < 0.01) reduced these elevated levels of AST, ALT and gamma-GT. Paracetamol induced liver necrosis was also found to be reduced as observed macroscopically and histologically.

Garlic and neem leaf extracts enhance hepatic glutathione and glutathione dependent enzymes during N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis in rats.

Arivazhagan S, Balasenthil S, Nagini S.

Department of Biochemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India.

The protective effect of garlic (Allium sativum L.) and neem leaf (Azadirachta indica A. Juss.) was investigated on hepatic lipid peroxidation and antioxidant status during N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis in male Wistar rats. Enhanced lipid peroxidation in the liver of tumour-bearing animals was accompanied by significant decreases in the activities of glutathione peroxidase (GPx), glutathione-S-transferase (GST), gamma-glutamyl transpeptidase (GGT) and reduced glutathione (GSH) levels. Administration of garlic and neem leaf extracts significantly lowered lipid peroxidation and enhanced the hepatic levels of glutathione and glutathione dependent enzymes. We speculate that garlic and neem leaf significantly alter cancer development at extrahepatic sites by influencing hepatic biotransformation enzymes and antioxidants.

'In vitro' antiviral activity of neem (Azadirachta indica. A. Juss) leaf extract against group B coxsackieviruses.

Badam L, Joshi SP, Bedekar SS.

National Institute of Virology, Pune, India.

The antiviral and virucidal effect of methanolic extract fraction of leaves of neem (Azadirachta indica A. Juss) (NCL-11) was studied regarding its activity and possible mechanism of action against Coxsackie B group of viruses. NCL-11 inhibited plaque formation in 6 antigenic types of Coxsackie virus B at a concentration of 1000 micrograms/ml at 96 hrs. 'in vitro'. Additionally virus inactivation, yield reduction and effect of time of addition assays suggested that NCL-11 was most effective against coxsackie virus B-4 as a virucidal agent besides interfering at an early event of its replicative cycle. The evidence suggested that presence of a battery of compounds besides flavonoids, triterpenoids and their glycosides in NCL-11 have antiviral action for coxsackie B group of viruses 'in vitro.' The minimal inhibitory concentrations were not toxic to Vero (African green monkey kidney), cells; subtoxic concentration was 8,000 micrograms/ml and cytotoxic concentration 10,000 micrograms/ml, which was confirmed by trypan blue dye exclusion test.