ANTIOXIDANT COMPOUNDS IN NEEM
Antioxidants are compounds that protect cells against reactive oxygen cells – or free radicals -- in the body. Although they are created as part of the body's normal metabolic functions, free radicals react with other cells and may interfere with their ability to function. Free radicals are believed to play a role in many health conditions, ranging from cancer and atherosclerosis to wrinkles caused by too much sun.
Ongoing research in universities around the world details the antioxidant compounds in neem as well as their impact on animals with chemically induced cancers. A single study reported in indicates that antioxidant compounds in neem helped to prevent brain damage in rats who had suffered a stroke by enhancing lipid peroxidation and increasing ascorbic acid (Vitamin C) in the brain. Rats pre-treated with neem seemed to complete standard tests, including a water maze, better than the control group. Unpublished data from Brunswick Laboratories, one of the nation's leading laboratories specializing in the science of antioxidants and oxidative stress, shows that neem is extraordinarily high in antioxidants as measured by the industry-standard ORAC (oxygen radial absorbance capacity).
ORAC (oxygen radical
absorbance capacity) /gram
Extract (8% in sesame oil)
2008 Mar 18 [Epub ahead of print] Evaluation of Azadirachta indica leaf fractions for in vitro antioxidant
potential and in vivo modulation of biomarkers of chemoprevention in the
hamster buccal pouch carcinogenesis model.
Manikandan P, Letchoumy PV, Gopalakrishnan M, Nagini S.
Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University,
Annamalainagar 608 002, Tamil Nadu, India.
We evaluated the chemopreventive potential of Azadirachta indica (neem) leaf fractions based
on in vitro antioxidant assays, and in vivo inhibitory effects on 7,12-
dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. In
addition we also identified the major constituents in neem leaf fractions by HPLC. Analysis of
the free radical scavenging activities and reducing potential of crude ethanolic extract (CEE),
ethyl acetate fraction (EAF) and methanolic fraction (MF) of neem leaf revealed a
concentration-dependent increase in antioxidant potential that was in the order EAF>MF>CEE.
Administration of neem leaf fractions reduced the incidence of DMBA-induced HBP
carcinomas at a lower concentration compared to the crude extract. Chemoprevention by neem
leaf fractions was associated with modulation of phase I and phase II xenobiotic-metabolising
enzymes, lipid and protein oxidation, upregulation of antioxidant defences, inhibition of cell
proliferation and angiogenesis, and induction of apoptosis. However, EAF was more effective
than MF in terms of antiproliferative and antiangiogenic effects, and expression of CYP
isoforms. The greater efficacy of EAF may be due to higher content of constituent
phytochemicals as revealed by HPLC analysis. The results of the present study suggest that the
antioxidant properties of neem leaf fractions may be responsible for modulating key hallmark
capabilities of cancer cells such as cell proliferation, angiogenesis and apoptosis in the HBP
PMID: 18442880 [PubMed - as supplied by publisher]
2006 Jul-Sep;7(3):467-71. Antioxidative and modifying effects of a tropical plant Azadirachta indica
(Neem) on azoxymethane-induced preneoplastic lesions in the rat colon.
Tumor Pathology, University of the Ryukyus Faculty of Medicine, Okinawa 903-0215, Japan.
The purpose of the present study was to examine whether Neem leaf (Azadirachta indica) has
short-term chemopreventive effects on endpoint preneoplastic lesions involved in rat colon
carcinogenesis and might also exert antioxidative activity. Forty- two male F344 rats were
randomly divided into 6 experimental groups. Groups 1 to 4 were given a subcutaneous
injection of azoxymethane (AOM, 20 mg/kg body weight) once a week for 2 weeks. Starting
one week before the first injection of AOM, rats in groups 2 to 4 received an aqueous extract of
Neem leaf (20, 100, and 250 mg/kg, respectively) by gavage 3 times per week, for 5 weeks.
Rats in group 5 also were given the Neem extract by gavage feeding 3 times per week for 5
weeks, while group 6 served as untreated controls. The experiment was terminated 5 weeks
after the start. Dietary feeding of the Neem extract at all dose levels significantly inhibited the
induction of aberrant crypt foci (ACF) (P<0.0002), when compared to the AOM-treated group
(group 1). In groups 2 to 4, treatment of rats with the Neem extract also significantly decreased
the proliferating cell nuclear antigen (PCNA) labeling indices (P<0.0006) of colon epithelium
and ACF. Moreover, the Neem extract also showed antioxidative activity. The finding that
dietary Neem has possible chemopreventive effects in the present short-term colon
carcinogenesis bioassay suggests that longer-term exposure may cause suppression of tumor
PMID: 17059347 [PubMed - indexed for MEDLINE]
Comparison of free radical scavenging activity of Siamese neem tree
(Azadirachta indica A. Juss var. siamensis Valeton) leaf extracts prepared by
different methods of extraction.
Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand.
OBJECTIVE: The aim of this study was to investigate the antioxidant activity of the aqueous
extracts of leaves of Siamese neem tree (Azadirachta indica A. Juss var. siamensis Valeton)
from several extracting and drying methods using 2,2-diphenyl-1-picrylhydrazyl (DPPH)-
scavenging assay. MATERIALS AND METHODS: The leaves of Siamese neem tree were
extracted using percolation, decoction, maceration, soxhlet extraction, freeze drying or spray
drying methods. The extract was tested for antioxidant activity using DPPH-scavenging assay.
Thin-layer chromatography of the extract from decoction was also investigated. RESULTS:
The freeze drying method gave the highest yield (51.50%, w/w) of crude extract, while
decoction gave the most effective DPPH-scavenging activity (EC(50): 31.4 microg/ml). Thin-
layer chromatography analysis was used to screen the leaf extract obtained using decoction,
and the chromatogram showed spots corresponding to quercetin and rutin flavonoids which
exhibited antioxidant activities (EC(50): 2.29 and 34.67 microg/ml, respectively).
CONCLUSION: Siamese neem tree leaf extracts possessed free radical scavenging activity
against the DPPH radical. The most active extract was obtained with the leaf decoction
method. It showed antioxidant activity with EC(50) of 31.4 microg/ml. Copyright 2006 S.
Karger AG, Basel.
PMID: 16651839 [PubMed - in process]
Chemomodulatory effects of Azadirachta indica on the hepatic status of skin
tumor bearing mice.
Department of Biophysics, Basic Medical Sciences Block, Panjab University, Chandigarh-
The liver plays an important role in the modulation of the process of carcinogenesis, as it is the
primary site for the biotransformation of xenobiotics including carcinogens as well as
anticancer drugs. The present study was designed to evaluate the biochemical alterations
occurring in the liver of 7,12-dimethylbenz(a)anthracene (DMBA) induced skin tumor bearing
male Balb/c mice and their modulation by aqueous Azadirachta indica leaf extract (AAILE). It
was observed that skin tumor induction caused hepatic damage characterized by a decreased
hepatosomatic index and significantly increased (p < 0.001) activities of the hepatic tissue
injury marker enzymes, namely alkaline phosphatase, alanine aminotransferase and aspartate
aminotransferase. However, upon treatment with AAILE, the above-mentioned alterations,
including the increased activities of hepatic tissue injury marker enzymes, were significantly
reversed, which signified the hepato-protective efficacy of Azadirachta indica. Increased
oxidative stress was also observed in the hepatic tissue of skin tumor bearing mice as revealed
by a significant increase (p < 0.001) in lipid peroxidation levels and a decrease in reduced
glutathione contents and activities of various antioxidant enzymes studied, namely glutathione-
S-transferase, glutathione peroxidase and glutathione reductase. The AAILE treatment reduced
oxidative stress by decreasing lipid peroxidation levels and enhancing the reduced glutathione
contents and activities of various antioxidant enzymes. The activities of the xenobiotic
biotransformation enzymes, namely cytochrome P450, cytochrome b5 and glutathione-S-
transferase, were found to be decreased in the hepatic tissue of tumor bearing mice. Treatment
with AAILE further caused a decrease in the activity of cytochrome P450 and cytochrome b5,
whereas it up-regulated the activity of glutathione-S-transferase. The significance of these
observations with respect to the progress of the process of carcinogenesis is explained in the
present research article. Copyright 2006 John Wiley & Sons, Ltd.
Inhibitory effects of Azadirachta indica on DMBA-induced skin carcinogenesis
in Balb/c mice.
Department of Biophysics, Basic Medical Sciences Block, Panjab University, Chandigarh,
Male Balb/c mice were divided into four groups on the basis of their respective treatments
wherein mice of Group I served as controls. For induction of skin tumors, mice of Group II and
IV were injected sub-cutaneously with 7,12-dimethylbenz(a)anthracene (DMBA). Mice of
Group III and IV were administered aqueous Azadirachta indica leaf extract (AAILE) thrice a
week throughout the experiment. After 14 weeks of the first DMBA injection, Group II and IV
mice developed tumors. In the tumor-bearing mice that received AAILE (Group IV), a
significant reduction in mean tumor burden and tumor volume was observed. The tumors were
confirmed to be papillomas and interestingly, the extent of hyper-chromatia was observed to be
much more in skin tumors of Group II mice vis a vis the mice receiving AAILE. An increase in
the extent of lipid peroxidation was observed in tumorous tissue of Group IV when compared
to that of Group II mice. Glutathione (GSH) content and the activities of GSH-based
antioxidant enzymes viz. glutathione peroxidase (GPx) and glutathione reductase (GR)
increased significantly in the skin tissues of all the groups of mice when compared to control
counterparts. Catalase activity was found to decrease significantly in the skin of mice, which
received AAILE treatment only (Group III). Activity of super-oxide dismutase (SOD)
decreased significantly in all the tumorous tissues (Group II and IV mice). In light of the above
observations, the role of AAILE in inhibition of DMBA-induced skin carcinogenesis is
discussed in the present study.
Ethanolic leaf extract of neem (Azadirachta indica) inhibits buccal pouch
carcinogenesis in hamsters.
Department of Biochemistry, Faculty of Science, Annamalai University, Tamil Nadu, India.
We evaluated the chemopreventive effects of ethanolic neem leaf extract in the initiation and
post-initiation phases of 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal
pouch (HBP) carcinogenesis. The frequency of bone marrow micronuclei as well as the
concentrations of lipid peroxides, ratio of reduced to oxidized glutathione (GSH/GSSG), and
the activities of the GSH-dependent enzymes glutathione peroxidase (GPx) and glutathione-S-
transferase (GST) in the buccal pouch, liver and erythrocytes were used as biomarkers of
chemoprevention. All the hamsters painted with DMBA alone for 14 weeks developed buccal
pouch carcinomas that showed diminished lipid peroxidation and enhanced antioxidant status
associated with increased frequencies of bone marrow micronuclei. In the liver and
erythrocytes of tumour-bearing animals, enhanced lipid peroxidation was accompanied by
compromised antioxidant defences. Administration of ethanolic neem leaf extract effectively
suppressed DMBA-induced HBP carcinogenesis as revealed by the absence of tumours in the
initiation phase and reduced tumour incidence in the post-initiation phase. In addition,
ethanolic neem leaf extract modulated lipid peroxidation and enhanced antioxidant status in the
pouch, liver and erythrocytes and reduced the incidence of bone marrow micronuclei. The
results of the present study, demonstrate that ethanolic neem leaf extract inhibits the
development of DMBA-induced HBP tumours by protecting against oxidative stress.
Copyright 2004 John Wiley & Sons, Ltd.
PMID: 15473007 [PubMed - indexed for MEDLINE]
2005 May 13;99(1):109-12.
Antioxidant activity of Siamese neem tree (VP1209).
Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayuthaya
Rd., Ratchatewi, Bangkok 10400, Thailand.
Leaves, fruits, flowers and stem bark extracts from the Siamese neem tree (Azadirachta indica
A. Juss var. siamensis Valeton, Meliaceae) were assessed for antioxidant activity in vitro using
the 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging assay, total antioxidant activity and
inhibition of lipid peroxidation in Chago K1 cancer cell culture by the thiobarbituric acid
reactive substances (TBARS) method. The results showed that leaf aqueous extract, flower and
stem bark ethanol extracts exhibited higher free radical scavenging effect on the DPPH assay
with 50% scavenging activity at 26.5, 27.9 and 30.6 microg/ml, respectively. The total
antioxidant activity of these extracts was found to be 0.959, 0.988 and 1.064 mM of standard
trolox, respectively. At 100 microg/ml, the flower ethanol and leaf aqueous extracts
significantly decreased malondialdehyde (MDA) levels (46.0 and 50.6%, respectively) by the
TBARS method. The results suggest that extracts from leaf, flower and stem bark of the
Siamese neem tree have strong antioxidant potential. This report supports the ethnomedical use
of young leaves and flowers of this plant as a vegetable bitter tonic to promote good health.
PMID: 15848028 [PubMed - indexed for MEDLINE]
2005 Feb 4;76(12):1325-38. Epub 2005 Jan 18.
Neuroprotective effect of Azadirachta indica on cerebral post-ischemic
reperfusion and hypoperfusion in rats.
Department of Pharmacology, Institute of Medical Sciences, Banaras Hindu University,
Varanasi, Uttar Pradesh 221 005, India.
We assessed the effect of Azadirachta indica (A. indica), a plant that has been reported to
possess antioxidant, anti-inflammatory and anxiolytic properties, on cerebral reperfusion injury
and long term cerebral hypoperfusion. When blood flow to brain region that has undergone
critical period of ischemia is re-established, additional injury is to be expected from the
reperfusion. In the present study, bilateral common carotid artery (BCCA) occlusion for 30 min
followed by 45 min reperfusion resulted in increase in lipid peroxidation, superoxide dismutase
(SOD) activity and fall in total tissue sulfhydryl (T-SH) groups. A. indica pretreatment (500
mg/kg/day x 7 days) attenuated the reperfusion induced enhanced lipid peroxidation, SOD
activity and prevented fall in T-SH groups. Moreover, A.indica per se increased brain ascorbic
acid level, which was unchanged during reperfusion insult. Long-term cerebral hypoperfusion
induced by permanent BCCA occlusion has been reported to cause behavioral and
histopathological abnormalities. In the present study, as tested by open field paradigm and
Morris' water maze, a propensity towards anxiety and disturbances of learning/memory were
observed in animals subjected to hypoperfusion for 2 weeks. A. indica (500 mg/kg/day x 15
days) significantly reduced these hypoperfusion induced functional disturbances. Reactive
changes in brain histology like gliosis, perivascular lymphocytic infiltration, recruitment of
macrophages and cellular edema following long term hypoperfusion were also attenuated
effectively by A. indica. We conclude that our study provides an experimental evidence for
possible neuroprotective potentiality of A. indica.
PMID: 15670613 [PubMed - indexed for MEDLINE]
Protective Effects of Ethanolic Neem Leaf Extract on DMBA-Induced
Genotoxicity and Oxidative Stress in Mice.
Faculty of Science, Annamalainagar, Tamil Nadu, 608 002, India.
We evaluated the effects of pretreatment with ethanolic neem leaf extract on 7,12-
dimethylbenz[a]anthracene (DMBA)-induced genotoxicity and oxidative stress in male Swiss
albino mice. The frequency of bone marrow micronuclei, the extent of hepatic lipid
peroxidation and the status of antioxidants-reduced glutathione (GSH), glutathione peroxidase
(GPx) and glutathione-S-transferase (GST) were used as intermediate biomarkers of
chemoprotection. In DMBA-treated mice, the increases in micronuclei and lipid peroxides
were accompanied by compromised antioxidant defenses. Pretreatment with ethanolic neem
leaf extract (200 mg/kg body weight) significantly reduced DMBAinduced micronuclei and
lipid peroxides and enhanced GSH-dependent antioxidant activities. The results of the present
study suggest that ethanolic neem leaf extract exerts protective effects against DMBA-induced
genotoxicity and oxidative stress by enhancing the antioxidant status.
PMID: 16635967 [PubMed - in process]
Effects of aqueous extracts of garlic (Allium sativum) and neem (Azadirachta
indica) leaf on hepatic and blood oxidant-antioxidant status during
experimental gastric carcinogenesis.
Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar,
Tamil Nadu, India.
The modifying effects of aqueous extracts of garlic and neem leaf during the pre-initiation and
post-initiation phases of gastric carcinogenesis induced by N-methyl-N'-nitro-N-
nitrosoguanidine were investigated in male Wistar rats. The extent of lipid peroxidation and the
status of phase II biotransformation enzymes such as glutathione peroxidase and glutathione-S-
transferase that use reduced glutathione (GSH) as substrate were used to biomonitor the
chemopreventive potential of these extracts. Enhanced lipid peroxidation in the liver and blood
of tumor-bearing animals was accompanied by significant decreases in the activities of GSH-
dependent antioxidants in the pre-initiation as well as in the post-initiation phases. Our results
suggest that the modulatory effects of garlic and neem leaf on hepatic and blood oxidant-
antioxidant status may play a key role in preventing cancer development at extrahepatic sites.
PMID: 15383228 [PubMed - indexed for MEDLINE]
The effect of Azadirachta indica on distribution of antioxidant elements and
glutathione S-transferase activity in the liver of rats during
Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra,
The liver is often the first organ to be infected by metastasizing cancer. Hepatocarcinogenesis
is one of the most prevalent and deadly cancers worldwide, which ranks seventh among
cancers in order of frequency of occurrence. Numbers of natural and synthetic antioxidants are
known to treat initiation and promotion of chemical carcinogenesis in experimental animal
models. The effect of 5% w/v of Azadirachta indica extract in diethylnitrosamine and
acetylaminofluorene induced hepatocellular carcinoma, which is a vital mechanism in cancer
treatment, was studied in male Sprague dawly rats. The result of microscopic observation of
the lesion score during hepatocarcinogenesis revealed that cells of cancer group without
treatment were severely necrotic at week 12. However, cells of cancer group with Azadirachta
indica treatment appeared nearly normal. The tracking of the elements during
hepatocarcinogenesis was done using energy filtering transmission electron microscope
(EFTEM). According to EFTEM results, some of antioxidant elements such Na, Ca, and P is
highly distributed in Azadirachta indica treated normal and cancer group. However, the
distribution is too low in normal control and cancer control group without Azadirachta indica
treatment. The obtained results have shown a significant, decrease (P=0.05) of liver cytosol
Glutathione S-transferase in cancer control group rats. Meanwhile, treatment with Azadirachta
indica caused overall increase in liver GST activity nearly to control group. Distinct evidence
from this study contribute that oral administration of 5% Azadirachta indica extract
demonstrated anticancer activity by increasing the distribution of antioxidant elements and
GST activity may to protect cells in preneoplastic nodules in cancer treated groups. However,
there was no evidence of side effects of Azadirachta indica towards normal cells indicating
Azadirachta indica as a potential preventive agent for cancer.
PMID: 15294745 [PubMed - in process]
2004 May;59 Suppl B:208-9.
The effect of neem (Azadirachta indica) extract and dietary selenium on
distribution of selenium in hepatocarcinogenesis induced rat.
Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Institute of
Bioscience, Universiti Putra Malaysia 43400, Serdang.
Neem, Azadirachta indica, is a plant from the family Meliaceae, known as "Pokok Semambu"
in Malay community. It has been extensively used in India as traditional Ayurvedic and
folklore minedicine for the treatment of various diseases. This study aimed to determine the
distribution of selenium in the liver of rats during hepatocarcinogenesis when neem aqueous
extract and dietary selenium was supplemented.
PMID: 15468891 [PubMed - indexed for MEDLINE]
Chemopreventive potential of Azadirachta indica (Neem) leaf extract in murine
carcinogenesis model systems.
Cancer Biology and Applied Molecular Biology Laboratories, School of Life Sciences,
Jawaharlal Nehru University, New Delhi 110067, India.
Numerous laboratory studies reveal that various naturally occurring dietary substances can
modify the patho-physiological process of various metabolic disorders and can be an effective
preventive strategy for various diseases, including cancer. Indian Neem tree, Azadirachta
indica A. Juss. (family: Meliaceae), contains at least 35 biologically active principles and is
widely grown all over the tropics. The effect of two different doses (250 and 500 mg per
kilogram body weight) of 80% ethanolic extract of the leaves of Azadirachta indica were
examined on drug metabolizing Phase-I and Phase-II enzymes, antioxidant enzymes,
glutathione content, lactate dehydrogenase, and lipid peroxidation in the liver of 7-week-old
Swiss albino mice. Also anticarcinogenic potential of Azadirachta indica leaf extract was
studied adopting protocol of benzo(a)pyrene-induced fore-stomach and 7,12-dimethyl
benz(a)anthracene (DMBA)-induced skin papillomagenesis. Our primary findings reveal its
potential to induce only the Phase-II enzyme activity associated mainly with carcinogen
detoxification in liver of mice. The hepatic glutathione S-transferase (P < 0.005) and DT-
diaphorase specific activities (P < 0.01) were elevated above basal level. With reference to
antioxidant enzymes the investigated doses were effective in increasing the hepatic glutathione
reductase (GR), glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase
(CAT) activities significantly (from P < 0.005 to P < 0.001). Reduced glutathione measured as
non-protein sulphydryl was found to be significantly elevated in liver (P < 0.005) and in
extrahepatic organs (from P < 0.005 to P < 0.001) examined in our study. Glutathione S-
transferase (GST) and DT-diaphorase (DTD) showed a dose-dependent increase in
extrahepatic organs. Chemopreventive response was measured by the average number of
papillomas per mouse, as well as percentage of tumor-bearing animals. There was a significant
inhibition of tumor burden, in both the tumor model system studied (from P < 0.005 to P <
0.001). Tumor incidence was also reduced by both the doses of Azadirachta indica extract.
Copyright 2003 Elsevier Ireland Ltd.
PMID: 15099843 [PubMed - indexed for MEDLINE]
Protective effects of ethanolic neem leaf extract on N-methyl-N'-nitro-N-
nitrosoguanidine-induced genotoxicity and oxidative stress in mice.
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.
PMID: 15038245 [PubMed - indexed for MEDLINE]
Comment in: Ethanolic neem leaf extract protects against N-methyl -N'-nitro-N-
nitrosoguanidine-induced gastric carcinogenesis in Wistar rats.
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.
PMID: 14507242 [PubMed - indexed for MEDLINE]
Chemoprotective effects of ethanolic extract of neem leaf against MNNG-
induced oxidative stress.
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.
PMID: 12889539 [PubMed - indexed for MEDLINE]
2002 Nov 1;71(24):2845-65.
Gastroprotective effect of Neem (Azadirachta indica) bark extract: possible
involvement of H(+)-K(+)-ATPase inhibition and scavenging of hydroxyl
Department of Physiology, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick road,
Kolkata 700032, India.
The antisecretory and antiulcer effects of aqueous extract of Neem (Azadirachta indica) bark
have been studied along with its mechanism of action, standardisation and safety evaluation.
The extract can dose dependently inhibit pylorus-ligation and drug
(mercaptomethylimidazole)-induced acid secretion with ED(50) value of 2.7 and 2 mg Kg(-1)
b.w. respectively. It is highly potent in dose-dependently blocking gastric ulcer induced by
restraint-cold stress and indomethacin with ED(50) value of 1.5 and 1.25 mg Kg(-1) b.w.
respectively. When compared, bark extract is equipotent to ranitidine but more potent than
omeprazole in inhibiting pylorus-ligation induced acid secretion. In a stress ulcer model, it is
more effective than ranitidine but almost equipotent to omeprazole. Bark extract inhibits H(+)-
K(+)-ATPase activity in vitro in a concentration dependent manner similar to omeprazole. It
offers gastroprotection against stress ulcer by significantly preventing adhered mucus and
endogenous glutathione depletion. It prevents oxidative damage of the gastric mucosa by
significantly blocking lipid peroxidation and by scavenging the endogenous hydroxyl radical
((z.rad;)OH)-the major causative factor for ulcer. The (z.rad;)OH-mediated oxidative damage
of human gastric mucosal DNA is also protected by the extract in vitro. Bark extract is more
effective than melatonin, vitamin E, desferrioxamine and alpha-phenyl N-tert butylnitrone, the
known antioxidants having antiulcer effect. Standardisation of the bioactive extract by high
pressure liquid chromatography indicates that peak 1 of the chromatogram coincides with the
major bioactive compound, a phenolic glycoside, isolated from the extract. The
pharmacological effects of the bark extract are attributed to a phenolic glycoside which is
apparently homogeneous by HPLC and which represents 10% of the raw bark extract. A single
dose of 1g of raw extract per kg b.w. (mice) given in one day and application of 0.6g raw
extract per kg b.w. per day by oral route over 15 days to a cumulative dose of 9g per kg was
well tolerated and was below the LD(50). It is also well tolerated by rats with no significant
adverse effect. It is concluded that Neem bark extract has therapeutic potential for the control
of gastric hyperacidity and ulcer.
PMID: 12377267 [PubMed - indexed for MEDLINE]
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.
Department of Biochemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu,
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. Copyright 2000 John Wiley & Sons, Ltd.
PMID: 10861977 [PubMed - indexed for MEDLINE]
Modulatory effects of garlic and neem leaf extracts on N-methyl-N'-nitro-N-
nitrosoguanidine (MNNG)-induced oxidative stress in Wistar rats.
Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar 608
002, Tamil Nadu, India.
The effects of garlic and neem leaf extracts on lipid peroxidation and antioxidant status during
administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a carcinogenic nitrosamine
were evaluated in male Wistar rats. Extracts of garlic and neem leaf were administered orally
for five consecutive days before intraperitoneal injection of MNNG. Enhanced lipid
peroxidation in the stomach, liver and circulation of MNNG-treated rats was accompanied by a
significant decrease in glutathione (GSH) and the activities of glutathione peroxidase (GPx),
glutathione-S-transferase (GST) and gamma glutamyl transpeptidase (GGT). Administration of
garlic and neem leaf extracts significantly decreased the formation of lipid peroxides and
enhanced the levels of antioxidants and detoxifying enzymes in stomach, the primary target
organ for MNNG, as well as in the liver and circulation. The results of the present study
suggest that garlic and neem may exert their protective effects by modulating lipid
peroxidation and enhancing the levels of GSH and GSH-dependent enzymes.
PMID: 10686579 [PubMed - indexed for MEDLINE]
1999 Nov 1;67(2):189-95.
Chemopreventive potential of neem (Azadirachta indica) on 7,12-
dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch
Department of Biochemistry, Faculty of Science, Annamalai University, Tamil Nadu, India.
The inhibitory effect of the aqueous extract of neem (Azadirachta indica A. Juss.) on 7,12-
dimethylbenz[a]anthracene (DMBA) induced buccal pouch carcinogenesis was investigated in
Syrian male hamsters. All hamsters painted on their buccal pouch with DMBA for 14 weeks
developed squamous cell carcinoma. Administration of neem leaf extract effectively
suppressed oral carcinogenesis initiated with DMBA as revealed by the reduced incidence of
neoplasms. Lipid peroxidation, glutathione (GSH) content and the activities of glutathione
peroxidase (GPx), glutathione S-transferase (GST) and gammaglutamyl transpeptidase (GGT)
were used to biomonitor the chemopreventive potential of neem. Lipid peroxidation was found
to be significantly decreased, whereas GSH, GPx, GST and GGT were elevated in the oral
mucosa of tumour bearing animals. Our data suggest that neem may exert its chemopreventive
effects in the oral mucosa by modulation of lipid peroxidation, antioxidants and detoxification
PMID: 10619383 [PubMed - indexed for MEDLINE]
Mechanism of action of NIM-76: a novel vaginal contraceptive from neem oil.
Defense Institute of Physiology and Allied Sciences, Timarpur, Delhi, India.
The present study was undertaken to elucidate the mechanism of spermicidal action of NIM-
76, a fraction isolated from neem oil. The spermicidal activity of NIM-76 was confirmed using
a fluorescent staining technique. NIM-76 was found to affect the motility of the sperm in a
dose-dependent manner. Supplementation of pentoxifylline, which is known to enhance the
motility of the sperm, could not prevent the spermicidal action of NIM-76. There was a gradual
leakage of cytosolic LDH from the sperm in the presence of NIM-76. Electron microscopic
studies revealed the formation of pores and vesicles over the sperm head, indicating the
damage to the cell membrane. Membrane fluidization studies did not reveal any significant
change in the fluidity of sperm cell membrane structure.
PIP: Neem oil, an extract of a native plant of India, has been demonstrated to have anti-
fertility, anti-implantation, and abortifacient properties. An active fraction, termed NIM-76,
was extracted that eliminates its abortifacient properties while retaining spermicidal activity.
This fraction kills all human sperm in vitro in under 20 seconds at a concentration of 25 mg/ml. With increases in NIM-76 concentrations from 10 to 1000 mcg/ml, there was a linear decrease in percentages of motile as well as progressively motile sperm with time; also recorded were decreases in percentages of rapid, medium, and slow moving sperm, mean track speed, progressive velocity, mean linearity, and lateral head displacement and an increase in the percentage of static sperm. Electron microscopy revealed the formation of pores and vesicles over the sperm head, indicating damage to the cell membrane. Membrane fluidization studies did not reveal any significant change in the fluidity of sperm cell membrane structure. Since calcium supplementation did not relieve the sperm from the spermicidal action, it was determined that NIM-76 does not cause any depletion of intracellular calcium. The capability of NIM-76 to selectively kill sperm without affecting normal cells makes it a highly desirable potential vaginal contraceptive agent. PMID: 8968666 [PubMed - indexed for MEDLINE]
Most of this research data was compiled from the National Library of Medicine at the National Institutes of Health
website and is presented here as a service. Using Neem does not sell neem products.
ORIGINAL SUBMISSION Spirulina platensis GRAS self affirmation 7-1-2011 Executive Summary The objective of this Generally Recognized as Safe (GRAS) determination is to summarize the available safety information on Spirulina platensis, which is used as an ingredient in foods and beverages. We, the undersigned expert panel members, Susan Cho, Ph.D., Joanne Slavin, Ph.D., and George C. Fahey, Jr., Ph.D., have individually and collectively critically evaluated the materials summarized in the Spirulina platensis GRAS report. We conclude that Spirulina platensis is safe and GRAS for its intended use in food. There is broad-based and widely disseminated knowledge concerning the chemistry and health benefits of Spirulina platensis in both human and animals. Pursuant to 21 CFR § 170.30, this GRAS determination for Spirulina platensis is based on scientific procedures. There are no indications of significant adverse effects related to Spirulina platensis in the publicly available literature, and the manufacturing process of Spirulina platensis does not employ any treatments with organic solvents. In the United States, Spirulina platensis has been already recognized as a GRAS substance since 2003 (FDA, GRN 000127). Since that time, several toxicity and human clinical studies have been published to report higher values of safe intake levels than the previously reported. This GRAS notice captures the findings from recent studies.
Recent Trends in Class Action and Aggregate Litigation in the Life Sciences Industry www.morganlewis.com © 2013 Morgan, Lewis & Bockius LLP For the last several years, the life sciences industry has been fertile ground for class action and aggregate litigation. Developments in this area have driven several trends, including state consumer fraud claims, securities class actions, antitrust class actions, and aggregate litigation brought by private healthcare insurers and state attorneys general. These recent trends have been driven, in part, by legislative and doctrinal developments. For example, in 2005—based on legislative findings of abuse in class action practice in state courts—Congress enacted the Class Action Fairness Act (CAFA), permitting defendants to remove to federal court putative class actions that previously may have been subject to less stringent standards in state court. In Standard Fire Insurance Co. v. Knowles,1 the U.S. Supreme Court held that a plaintiff's stipulation that he would not accept more than $5 million in damages could not be used to avoid CAFA's amount in controversy requirement. In other words, a class representative may not agree to seek less money to try to keep a case in state court.