Tetracyclic triterpenoids from the leaves of Azadirachta indica and their insecticidal activities. (1/64)

A new tetranortriterpenoid, meliatetraolenone [24,25,26,27-tetranor-apotirucalla-(apoeupha)-6alpha-O-methyl, 7alpha-senecioyl(7-deacetyl)-11alpha,12alpha,21,23-tetrahydroxy-21,23-epoxy-2,14, 20(22)-trien-1,16-dione] (1) was isolated from the methanolic extract of fresh leaves of Azadirachta indica along with the known compound odoratone (3) which was hitherto unreported from this source. Their structures have been elucidated by spectral studies including 2D NMR. The insecticidal activities of 1 as well as those of odoratone (3) are reported. 1 and odoratone both showed mortality on fourth instar larvae of mosquitoes (Anopheles stephensi) with LC(50) values of 16 and 154 ppm, respectively.  (+info)

Anti dermatophytic activity of Azardirachta indica (neem) by invitro study. (2/64)

The leaf and seed extracts of the Plant Azardirachta indica were tested for antidermatophytic activity against dermatophytes such as Trichophyton ruberum, Trichophyton, Mentagrophytes, Trichophyton violaceum, Microsporum nanum and Epidermophyton floccosum by tube dilution technique. The minimum Inhibitory concentration (MIC) of neem seed extract was found to be lower tan that of neem leaf when tested against different species of Dermatophytes.  (+info)

Ethanolic neem leaf extract protects against N-methyl -N'-nitro-N-nitrosoguanidine-induced gastric carcinogenesis in Wistar rats. (3/64)

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.  (+info)

Bioefficacy and mode-of-action of some limonoids of salannin group from Azadirachta indica A. Juss and their role in a multicomponent system against lepidopteran larvae. (4/64)

Biological activities of the salannin type of limonoids isolated from Azadirachta indica A. Juss were assessed using the gram pod borer Helicoverpa armigera (Hubner) and the tobacco armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae. All three compounds exhibited strong antifeedant activity in a choice leaf disc bioassay with 2.0, 2.3 and 2.8 microg/cm(2) of 3-O-acetyl salannol, salannol and salannin, respectively deterring feeding by 50% in S. litura larvae. In nutritional assays, all three compounds reduced growth and consumption when fed to larvae without any effect on efficiency of conversion of ingested food (ECI), suggesting antifeedant activity alone. No toxicity was observed nor was there any significant affect on nutritional indices following topical application, further suggesting specific action as feeding deterrents. When relative growth rates were plotted against relative consumption rates, growth efficiency of the H. armigera fed diet containing 3-O-acetyl salannol, salannol or salannin did not differ from that of starved control larvae (used as calibration curve), further confirming the specific antifeedant action of salannin type of limonoids. Where the three compounds were co-administered, no enhancement in activity was observed. Non-azadirachtin limonoids having structural similarities and explicitly similar modes of action, like feeding deterrence in the present case, have no potentiating effect in any combination.  (+info)

Extracts of Azadirachta indica and Melia azedarach seeds inhibit folliculogenesis in albino rats. (5/64)

The seed oil of Azadirachta indica A. Juss (neem) is used in traditional medicine for its antidiabetic, spermicidal, antifertility, antibacterial, and wound healing properties. The present study was undertaken to investigate the quantitative aspects of follicular development in cyclic female albino rats (135 +/- 10 g; 8 groups with 6 animals in each group) after oral administration of polar (PF) and non-polar (NPF) fractions of A. indica seed extract at 3 and 6 mg kg body weight-1 day-1 and Melia azedarach Linn. (dharek) seed extract at 24 mg kg body weight-1 day-1 for 18 days. The extracts were prepared using a flash evaporator at 35 degrees C and then dissolved in olive oil to prepare doses on a per kg body weight basis. There was a significant reduction (P = 0.05) in the number of normal single layered follicles (A. indica: 0.67 +/- 0.33 and 4.67 +/- 2.03 after 3 and 6 mg/kg NPF, and 3.33 +/- 1.67 and 1.00 +/- 1.00 after 3 and 6 mg/kg PF vs control: 72.67 +/- 9.14 and M. azedarach: 0.60 +/- 0.40 and 1.80 +/- 1.2 after 24 mg/kg PF and NPF, respectively, vs control: 73.40 +/- 7.02) and follicles in various stages (I-VII) of follicular development in all treatment groups. These extracts also significantly reduced (P = 0.05) the total number of normal follicles in the neem (14.67 +/- 5.93 and 1.00 +/- 1.00 after 3 and 6 mg/kg PF and 3.67 +/- 0.88 and 5.33 +/- 2.03 after 3 and 6 mg/kg NPF) and dharek (13.00 +/- 3.58 and 14.60 +/- 2.25 after 24 mg/kg NPF and PF) treatments compared to control (216.00 +/- 15.72 and 222.20 +/- 19.52, respectively). Currently, indiscriminate use of persistent and toxic rodenticides to control rodent populations has created serious problems such as resistance and environmental contamination. Therefore, it becomes necessary to use ecologically safe and biologically active botanical substances that are metabolized and are not passed on to the next trophic level, and that interfere with the reproductive potential particularly growth and differentiation of follicles. This may help elevate the socio-economic status of the country. Thus, the present study is an attempt to investigate the effects of A. indica and M. azedarach seed extracts on reproduction of albino rats.  (+info)

Quinone reductase inducers in Azadirachta indica A. Juss flowers, and their mechanisms of action. (6/64)

We have previously shown that the flowers of neem tree (Azadirachta indica A. Juss, family Meliaceae), Thai variety, strongly induced the activity of glutathione S-transferase (GST) while resulting in a significant reduction in the activities of some cytochrome P(450)-dependent monooxygenases in rat liver, and possess cancer chemopreventive potential against chemically-induced mammary gland and liver carcinogenesis in rats. In the present study, 2 chemicals possessing strong QR inducing activity were fractionated from neem flowers using a bioassay based on the induction of QR activity in mouse hepatoma Hepa 1c1c7 cultured cells. Spectroscopic characteristics revealed that these compounds were nimbolide and chlorophylls, having CD (concentration required to double QR specific activity) values of 0.16 and 3.8 mug/ml, respectively. Nimbolide is a known constituent of neem leaves, but was found for the first time here in the flowers. Both nimbolide and chlorophylls strongly enhanced the level of QR mRNA in Hepa 1c1c7 cells, as monitored by northern blot hybridization, indicating that the mechanism by which these constituents of neem flowers induced QR activity is the induction of QR gene expression. These findings may have implication on cancer chemopreventive potential of neem flowers in experimental rats previously reported.  (+info)

Ethanolic neem (Azadirachta indica) leaf extract induces apoptosis in the hamster buccal pouch carcinogenesis model by modulation of Bcl-2, Bim, caspase 8 and caspase 3. (7/64)

Induction of apoptosis is one of the most active strategies in cancer chemoprevention and the ability of medicinal plants in this regard has attracted major research interest. The present study was designed to investigate the apoptosis inducing capacity of an ethanolic neem leaf extract (ENLE) during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis using the apoptosis-associated proteins Bcl-2, Bim, caspase 8 and caspase 3 as markers. Topical application of DMBA to the hamster cheek pouch for 14 weeks resulted in well developed squamous cell carcinomas associated with increased expression of Bcl-2 and decreased expression of Bim, caspase 8 and caspase 3. Administration of ENLE inhibited DMBA-induced hamster buccal pouch (HBP) carcinogenesis, as revealed by the absence of neoplasms, with induction of Bim and caspases 8 and 3 and inhibition of Bcl-2 expression. Our results suggest that the chemopreventive effects of ENLE may be mediated by induction of apoptosis.  (+info)

Enhancement of immune responses to neem leaf extract (Azadirachta indica) correlates with antineoplastic activity in BALB/c-mice. (8/64)

An aqueous plant extract from Azadirachta indica and its chromatographic fraction F1 (neem extract) exerted immunomodulating and antimetastatic activities in BALB/ c-mice. Regular subcutaneous administration of neem extract yielded significantly increased spleen weight and significant enhancement of peritoneal macrophage activity in the chemiluminescence assay, and activation marker CD-44 expression. The thymus weight and thymocyte counts did not show significant differences in the control and neem extract-treated groups, however, determination of peripheral blood cells revealed significant up-regulations of leukocyte subsets, the lymphocytes and monocytes. Flow cytometric analaysis of lymphocyte supopulations documented increased counts of CD-4 and CD-8 cells and an inreased activation marker expression on lymphocytes (CD-25) and monocytes (MAC-3) in neem-treated mice compared to the control animals. To evaluate the antimetastatic activity of neem extract, sarcoma L-1 cells and lymphosarcoma RAW cells were intravenously inoculated into BALB/c-mice. In these model systems the number of experimental lung and liver metastases decreased relevantly, however, biometrically non-significantly in neem extract-treated animals, as compared to the control mice which received injections of saline solutions. Neem extract can be regarded as an immunomodulating and antimetastatic substance which holds promise for further experimental and clinical investigation.  (+info)

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