- Open Access
Azadirachta indica ethanolic extract protects neurons from apoptosis and mitigates brain swelling in experimental cerebral malaria
© Bedri et al.; licensee BioMed Central Ltd. 2013
Received: 1 February 2013
Accepted: 20 August 2013
Published: 29 August 2013
Cerebral malaria is a rapidly developing encephalopathy caused by the apicomplexan parasite Plasmodium falciparum. Drugs currently in use are associated with poor outcome in an increasing number of cases and new drugs are urgently needed. The potential of the medicinal plant Azadirachta indica (Neem) for the treatment of experimental cerebral malaria was evaluated in mice.
Experimental cerebral malaria was induced in mice by infection with Plasmodium berghei ANKA. Infected mice were administered with Azadirachta indica ethanolic extract at doses of 300, 500, or 1000 mg/kg intraperitoneally (i.p.) in experimental groups, or with the anti-malarial drugs chloroquine (12 mg/kg, i.p.) or artemether (1.6 mg/kg, i.p.), in the positive control groups. Treatment was initiated at the onset of signs of brain involvement and pursued for five days on a daily basis. Mice brains were dissected out and processed for the study of the effects of the extract on pyramidal cells’ fate and on markers of neuroinflammation and apoptosis, in the medial temporal lobe.
Azadirachta indica ethanolic extract mitigated neuroinflammation, decreased the severity of brain oedema, and protected pyramidal neurons from apoptosis, particularly at the highest dose used, comparable to chloroquine and artemether.
The present findings suggest that Azadirachta indica ethanolic extract has protective effects on neuronal populations in the inflamed central nervous system, and justify at least in part its use in African and Asian folk medicine and practices.
Cerebral malaria is a rapidly developing encephalopathy that represents the most severe neurological complication of infection with Plasmodium falciparum. Cerebral malaria mainly occurs in resource-poor tropical countries, and mostly affects children[1, 2]. Surviving patients display neurologic and cognitive deficits, including consciousness impairment, cerebellar ataxia, seizures, and coma, making cerebral malaria a major cause of childhood neurodisability in endemic areas[3–6]. The pathogenesis of neuro-cognitive sequelae is poorly understood.
Experimental models of cerebral malaria have been providing new mechanistic insights that will help develop efficient neuro-protective interventions. The non-human pathogenic parasite Plasmodium berghei has been used to induce experimental cerebral malaria in mice that has some features comparable to the human disease[7–9]. Experimental evidence suggests that the vast array of pro-inflammatory molecules released by the host to fight the infection and alterations due to parasite sequestration in the microvessels cause leakage of plasma into the parenchyma resulting in brain oedema, and may contribute to the subsequent blood–brain barrier breakdown[10, 11]. Brain parenchyma infiltration by danger or pathogen-associated molecules would trigger a sustained detrimental neuroinflammatory response leading to the recruitment of circulating immune cells. The latter cells would induce death through cell-mediated apoptosis in sensible neuronal populations, by triggering pathways such as caspase 3 and Fas-Fas ligand[12–14]. Previous studies and reports have shown that such inflammation-triggered apoptosis can induce cerebellar ataxia when affecting Purkinje cells in the cerebellum[15–17]. Similarly, apoptosis affecting cortical neurons may explain many other neurologic deficits observed in experimental cerebral malaria, such as cognitive impairment or seizures[18–21]. Overall, these findings corroborate the alterations reported in humans[9, 14, 22, 23]. New effective drugs are urgently needed for cerebral malaria treatment due to the development of parasite chemoresistance, and to improve current drugs’ poor treatment outcome[24–26].
Azadirachta indica is a plant commonly used in the African and Asian folk medicine and practices[27–31]. Anti-malarial effects of A. indica extracts have been demonstrated[32–36], as well as the neuro-protective effects on Purkinje cells of P. berghei- infected mice successfully mitigating cerebellum malaria. The present study addresses the potential of A. indica extract for the protection of cortical and sub-cortical pyramidal neurons of P. berghei-infected mice, considering the implications for the treatment of cerebral malaria-associated cortical deficits.
Thirty five mice, divided into seven groups (five animals per group), were used in this study. These groups were: i) a disease control group made of untreated P. berghei- infected mice; ii) two positive control groups made of P. berghei- infected mice treated with the commercially available anti-malarial drugs chloroquine (12 mg/kg in distilled water, i.p.) and artemether (1.6 mg/kg in olive oil, i.p.); iii) three experimental groups made of P. berghei- infected mice treated with A. indica ethanolic extract at doses 300, 500, or 1000 mg/kg (i.p.); iv) and a group of uninfected healthy animals. Parasitaemia, body weight, core body temperature, and signs of brain involvement were monitored. Treatment was started when the number of parasitized red blood cells was >5% (severe malaria indicator) and was associated with signs of brain involvement. Treatment was pursued for five days on a daily basis. Mice either died spontaneously or were sacrificed by ether inhalation-induced deep anesthesia once signs of disease terminal stage (hypothermia, ptosis, and convulsion), were observed. Uninfected mice were sacrificed concomitantly with the last animals to check for disease terminal stage signs. For all animals, brains were dissected out and processed for histopathological analysis.
Animals and infection
Male Swiss albino mice (weighing 26.5 ± 3.0 g, aged 6 ± 1 week) were donated by Sudan National Health Laboratory (Khartoum, Sudan). Mice were maintained at a 12:12 light/dark cycle and were given ad libitum access to food (standard diet) and water. For infection, mice were administered (i.p.) with a load of 10 × 106 parasitized red blood cells containing P. berghei ANKA. The parasitaemia was checked by blood smear Giemsa-staining. All procedures received approval from the Ethical Committee of the Institute of Endemic Diseases of the University of Khartoum and animals were handled according to institutional guidelines. Plasmodium berghei ANKA blood-stage cryostabilates were kindly donated by Dr. C.R. Pillai (National Institute of Malaria, New Delhi, India).
Preparation of the extract
Fresh leaves of A. indica were collected in Khartoum region, where they are commonly used in folk medicine to treat malaria, and shade-dried. Dry leaves were grinded, and 1500 g of powder were macerated in 15 L of ethanol for three consecutive days at room temperature. A 1 mg/mL stock solution was obtained by filtration and boiling of the supernatant, and was stored at 4°C until use. Three doses of A. indica, i.e. 300, 500, and 1,000 mg/kg, were administered to the respective experimental groups once a day for five days. These regimens were chosen in accordance with previous pharmacological studies in malaria models[16, 28].
Pyramidal neuron density and brain oedema
Brains dissected out were fixed in 10% neutral buffered formaldehyde, then paraffin-embedded and cut sagittally (section thickness: 5 μm). Sections were deparaffinized in xylene, rehydrated, and processed for haematoxylin-eosin (H&E) staining. The pyramidal neuron volumetric density, i.e. the proportion of brain subfield that is occupied by pyramidal neuronal cell bodies, was determined as described by Highley and colleagues. Pyramidal neurons were counted on five consecutive sections, in the medial temporal lobe, using a light microscope with a fixed 1 cm grid eyepiece under 40× objective. Brain oedema was assessed by giving a severity score integrating histopathological parameters, such as the importance (how big) and frequency (how numerous) of fluid built up in the brain parenchyma, on the H&E stained sections[39, 40].
The sections processed for immunohistochemical labeling were deparaffinized in xylene, rehydrated, and endogenous peroxidase activity was extinguished. Sections were then pre-incubated in normal serum buffer solution (Diagnostic BioSystems, Serpentine, CA, USA), and incubated for 3 h in either rabbit anti-caspase-3, anti-FAS, anti-FAS ligand, anti-tumor necrosis factor (TNF), or anti-nitric oxide synthase (NOS) primary antibody buffer solution (dilution factor 1:40, Lica Biosystem Newcastle Ltd, UK), followed by a biotinylated secondary antibody and streptavidin-conjugated horseradish peroxidase (Vision Biosystems Novocastra, Novocastra Laboratories Ltd., Newcastle, UK) prepared according to the kit instructions. The sections were incubated with 3,3′-diaminobenzidine hydrochloride (DAB) chromogen substrate (Vision Biosystems Novocastra) according to the manufacturer’s instructions, and counterstained with H&E. P value < .05 was considered significant. Thorough washes between steps were performed using immune wash buffer (Vision Biosystems Novocastra). Sections were dehydrated through a graded ethanol series, cleared in xylene, and covered with a thin glass coverslip. The fraction of pyramidal neurons expressing each of the studied markers, i.e. the markers of apoptosis caspase 3, Fas, and Fas ligand, and the markers of neuroinflammation-triggered apoptosis TNF and NOS, was determined using a light microscope under 40× objective.
Data obtained from infected treated or uninfected groups were compared to those obtained from the infected untreated group using one-way ANOVA followed by LSD test. Differences with a p value < .05 were considered statistically significant. All data were expressed as a percentage of the value obtained in the infected untreated group. Data are presented as mean ± SEM (n = 5).
The early signs of disease started five days after infection in the majority of P. berghei- infected animals, i.e. in the disease control group and in animals treated with chloroquine, artemether, or one of the three doses of A. indica extract. Cerebral malaria signs appeared at day 6 ± 1 post-infection. The most recurrent ones were a ruffled fur, locomotor impairments, and sickness behavior (anorexia, cachexia, fever) associated with body weight loss. Animals treated with A. indica, chloroquine or artemether did not displayed fever (as evaluated by increases in core body temperature), and from dose 500 mg/kg of extract locomotor disturbances and body weight loss were improved. Parasitaemia was decreased in infected mice following treatment with chloroquine or arthemether (from 6.1 ± 1.8% to 1.2 ± 0.4%, P < 0.05), but no significant change was observed in A. indica-treated animals, as previously reported.
Azadirachta indica extract did not protected infected mice from death, unlike chloroquine and artemether, although the highest doses slightly (not significantly) delayed death time. Infected untreated mice spontaneously died at day 9 ± 1 post-infection, A. indica- treated mice treated with the highest doses started to die at day 11, whereas no animal died in groups treated with chloroquine and artemether during the time of observation. However, about all the survivors in groups treated with the extract were sacrificed two days after (day 13 post-infection) as terminal signs of cerebral malaria, i.e. hypothermia, ptosis, ataxia, and convulsion, were observed. All other animals, including those treated with chloroquine or artemether as well as uninfected ones were also sacrificed then.
Extract effect on pyramidal neuron density
Extract effect on caspase 3 expression
Extract effect on Fas and Fas ligand expression
Extract effect on TNF expression
Extract effect on NOS expression
Extract effect on brain oedema severity
The present study points out the protective effects of A. indica extract on pyramidal neurons in experimental cerebral malaria induced by P. berghei-infection in mice.
Protective effects on pyramidal neurons
Pyramidal neuron density study revealed comparable values between P. berghei-infected mice treated with the extract of A. indica and uninfected mice, which were significantly different from untreated P. berghei-infected mice (disease control group) where a significant decrease in pyramidal neuron density, characteristic of cerebral malaria insult[14, 18–20], was observed. These findings suggest that the extract protected pyramidal neurons from cerebral malaria-induced apoptosis. In order to further characterize these effects, the expression of apoptosis markers was studied, considering the importance of this phenomenon in cerebral malaria-associated encephalopathy[7–9].
Striking decrease in the expression of apoptosis markers
The markers of apoptosis studied were caspase 3, Fas, and Fas ligand, which are commonly used for the detection of apoptosis in neuronal populations[13, 19]. Azadirachta indica extract induced a striking decrease in caspase 3, Fas, and Fas ligand expressions on pyramidal neurons of P. berghei-infected mice, particularly at the highest dose used. Considering that these markers are associated with the risk for neuron apoptosis[13, 19], the present finding indicates that A. indica extract has anti-apoptotic effects on pyramidal neurons in experimental cerebral malaria. The latter effects probably account for at least part of the protective effects of the extract against pyramidal neuron death in treated P. berghei-infected mice. Considering that the pro-inflammatory environment, and particularly infiltrating immune cells, contribute to the detrimental effects of cerebral malaria on neurons, including apoptosis in sensible neuronal populations[12, 14, 42], through extrinsic mediators of apoptosis such as TNF and NOS[12, 43, 44], we have addressed the effect of A. indica extract on these inflammatory triggers of apoptosis in P. berghei-infected mice.
Mitigation of neuroinflammatory triggers of apoptosis and brain oedema severity
Treatment with A. indica extract induced decreases in pyramidal neuron expression of TNF and NOS in P. berghei-infected mice as compared with disease control group, suggesting that the extract modulated inflammation in the brain parenchyma. Besides, considering that brain oedema is a major causative of the inflammatory response in the brain parenchyma (through infiltrating danger or pathogen-associated molecules[10, 11]), the decrease in oedema severity observed in groups treated with the extract in the present study, indicate that the aforementioned anti-inflammatory effects may be mediated, at least in part, by protective effects on brain vessels. These findings are in agreement with our precedent observations in Purkinje cells of P. berghei- infected mice, where A. indica also displayed neuroprotective effects. Comparable effects of A. indica extract have been reported in other models of detrimental neuroinflammation associated with brain oedema, including cerebral post-ischemic reperfusion and hypoperfusion in rats[45, 46]. Thus, the findings herein reported confirm that A. indica extract has neuroprotective effects in experimental cerebral malaria, and indicate that such effect may be mediated through protective effects on brain vessels and the consequent decrease in neuroinflammation severity. Not surprisingly and interestingly, chloroquine and artemether, drugs in use for cerebral malaria treatment in the field[37, 47], also induced similar effects, corroborating their beneficial effects reported in humans, and pointing out at least part of the mechanisms accounting for these effects. It appears, therefore, that future studies aiming at unraveling the active principle(s) accounting for the beneficial effects of A. indica extract reported may provide key elements for the development of new drugs for cerebral malaria. Subjecting the bioactive agents of Azadirachta indica which have already been characterized, such as gedunin,, to a similar study may provide better insights into the neuroprotective effects herein described.
Azadirachta indica extract did not protected infected mice from death from cerebral malaria, although the highest doses slightly delayed death time. However, A. indica extract displayed neuroprotective effects mediated probably by mitigating oedema build up, and modulating both neuroinflammatory triggers of apoptosis and apoptosis signaling pathways. The use of extracts of A. indica in African and Asian folk medicine and practices for the treatment of malaria and cerebral malaria is justified. Characterization of the active principle(s) accounting for these effects will probably provide new drugs, which are particularly needed in the current context of increased chemoresistance to chloroquine.
The authors would like to acknowledge the Qassim University and Ministry of Higher education for funding this project as well as Dr. C. R. Pillai, National Malaria Institute, New Delhi, India for donation of the parasite. The authors would like to acknowledge the critical thinking and brainstorming of Professor Mustafa Idris. The authors would like to acknowledge the help of Dr. Imran Ulhag for providing a second opinion in analyzing the immunohistochemistry results; the technical support of Ali Yousif, Mohammed Awad and Said Yousif in the study and the help of Dr. Mohsin Shaik and Dr. Mgdy Abdelsalam in the statistical analysis.
Special thanks are due to the Institute of Endemic Diseases of the University of Khartoum and to the College of Applied Medical Sciences of Qassim University for the logistic support, and to Prof. Bunyamin Shahin for his insightful suggestions.
- Mishra SK, Newton CR: Diagnosis and management of the neurological complications of falciparum malaria. Nat Rev Neurol. 2009, 5: 189-198. 10.1038/nrneurol.2009.23.PubMed CentralView ArticlePubMedGoogle Scholar
- Idro R, Marsh K, John CC, Newton CR: Cerebral malaria: mechanisms of brain injury and strategies for improved neurocognitive outcome. Pediatr Res. 2010, 68: 267-274.PubMed CentralView ArticlePubMedGoogle Scholar
- Idro R, Ndiritu M, Ogutu B, Mithwani S, Maitland K, Berkley J, Crawley J, Fegan G, Bauni E, Peshu N, Marsh K, Neville B, Newton C: Burden, features, and outcome of neurological involvement in acute falciparum malaria in Kenyan children. JAMA. 2007, 297: 2232-2240. 10.1001/jama.297.20.2232.PubMed CentralView ArticlePubMedGoogle Scholar
- Kihara M, Carter JA, Holding PA, Vargha-Khadem F, Scott RC, Idro R, Fegan GW, de Haan M, Neville BG, Newton CR: Impaired everyday memory associated with encephalopathy of severe malaria: the role of seizures and hippocampal damage. Malar J. 2009, 8: 273-10.1186/1475-2875-8-273.PubMed CentralView ArticlePubMedGoogle Scholar
- Kariuki SM, Ikumi M, Ojal J, Sadarangani M, Idro R, Olotu A, Bejon P, Berkley JA, Marsh K, Newton CR: Acute seizures attributable to falciparum malaria in an endemic area on the Kenyan coast. Brain. 2011, 134: 1519-1528. 10.1093/brain/awr051.PubMed CentralView ArticlePubMedGoogle Scholar
- Gwer S, Thuo N, Idro R, Ndiritu M, Boga M, Newton C, Kirkham F: Changing trends in incidence and aetiology of childhood acute non-traumatic coma over a period of changing malaria transmission in rural coastal Kenya: a retrospective analysis. BMJ Open. 2012, 2: e000475-10.1136/bmjopen-2011-000475.PubMed CentralView ArticlePubMedGoogle Scholar
- Kaiser K, Texier A, Ferrandiz J, Buguet A, Meiller A, Latour C, Peyron F, Cespuglio R, Picot S: Recombinant human erythropoietin prevents the death of mice during cerebral malaria. J Infect Dis. 2006, 193: 987-995. 10.1086/500844.View ArticlePubMedGoogle Scholar
- Combes V, Coltel N, Faille D, Wassmer SC, Grau GE: Cerebral malaria: role of microparticles and platelets in alterations of the blood–brain barrier. Int J Parasitol. 2006, 36: 541-546. 10.1016/j.ijpara.2006.02.005.View ArticlePubMedGoogle Scholar
- Faille D, El-Assaad F, Alessi MC, Fusai T, Combes V, Grau GE: Platelet-endothelial cell interactions in cerebral malaria: the end of a cordial understanding. Thromb Haemost. 2009, 102: 1093-1102.PubMedGoogle Scholar
- Pino P, Taoufiq Z, Nitcheu J, Vouldoukis I, Mazier D: Blood–brain barrier breakdown during cerebral malaria: suicide or murder?. Thromb Haemost. 2005, 94: 336-340.PubMedGoogle Scholar
- Bisser S, Toure FS, Taoufiq Z, Bouteille B, Buguet A, Mazier D, ON O-M-O-B: Harbouring in the brain: a focus on immune evasion mechanisms and their deleterious effects in malaria and human African trypanosomiasis. Int J Parasitol. 2006, 36: 529-540. 10.1016/j.ijpara.2006.02.001.View ArticlePubMedGoogle Scholar
- Lovegrove FE, Gharib SA, Patel SN, Hawkes CA, Kain KC, Liles WC: Expression microarray analysis implicates apoptosis and interferon-responsive mechanisms in susceptibility to experimental cerebral malaria. Am J Pathol. 2007, 171: 1894-1903. 10.2353/ajpath.2007.070630.PubMed CentralView ArticlePubMedGoogle Scholar
- Lackner P, Burger C, Pfaller K, Heussler V, Helbok R, Morandell M, Broessner G, Tannich E, Schmutzhard E, Beer R: Apoptosis in experimental cerebral malaria: spatial profile of cleaved caspase-3 and ultrastructural alterations in different disease stages. Neuropathol Appl Neurobiol. 2007, 33: 560-571.PubMedGoogle Scholar
- Toure FS, Ouwe-Missi-Oukem-Boyer O, Bisvigou U, Moussa O, Rogier C, Pino P, Mazier D, Bisser S: Apoptosis: a potential triggering mechanism of neurological manifestation in Plasmodium falciparum malaria. Parasite Immunol. 2008, 30: 47-51.PubMedGoogle Scholar
- Teo JT, Swayne OB, Silber E: Cerebellar ataxia after malaria. Neurology. 2009, 73: 73-74. 10.1212/WNL.0b013e3181aae9e6.View ArticlePubMedGoogle Scholar
- Farahna M, Bedri S, Khalid S, Idris M, Pillai CR, Khalil EA: Anti-plasmodial effects of Azadirachta indica in experimental cerebral malaria: Apoptosis of cerebellar Purkinje cells of mice as a marker. N Am J Med Sci. 2010, 2: 518-525.PubMed CentralView ArticlePubMedGoogle Scholar
- Duque V, Seixas D, Ventura C, Da CS, Melico-Silvestre A: Plasmodium falciparum malaria, bilateral sixth cranial nerve palsy and delayed cerebellar ataxia. J Infect Dev Ctries. 2012, 6: 290-294.PubMedGoogle Scholar
- Potter S, Chan-Ling T, Ball HJ, Mansour H, Mitchell A, Maluish L, Hunt NH: Perforin mediated apoptosis of cerebral microvascular endothelial cells during experimental cerebral malaria. Int J Parasitol. 2006, 36: 485-496. 10.1016/j.ijpara.2005.12.005.View ArticlePubMedGoogle Scholar
- Potter SM, Chan-Ling T, Rosinova E, Ball HJ, Mitchell AJ, Hunt NH: A role for Fas-Fas ligand interactions during the late-stage neuropathological processes of experimental cerebral malaria. J Neuroimmunol. 2006, 173: 96-107. 10.1016/j.jneuroim.2005.12.004.View ArticlePubMedGoogle Scholar
- Wiese L, Kurtzhals JA, Penkowa M: Neuronal apoptosis, metallothionein expression and proinflammatory responses during cerebral malaria in mice. Exp Neurol. 2006, 200: 216-226. 10.1016/j.expneurol.2006.02.011.View ArticlePubMedGoogle Scholar
- Schmutzhard J, Kositz CH, Glueckert R, Schmutzhard E, Schrott-Fischer A, Lackner P: Apoptosis of the fibrocytes type 1 in the spiral ligament and blood labyrinth barrier disturbance cause hearing impairment in murine cerebral malaria. Malar J. 2012, 11: 30-10.1186/1475-2875-11-30.PubMed CentralView ArticlePubMedGoogle Scholar
- Mackintosh CL, Beeson JG, Marsh K: Clinical features and pathogenesis of severe malaria. Trends Parasitol. 2004, 20: 597-603. 10.1016/j.pt.2004.09.006.View ArticlePubMedGoogle Scholar
- Medana IM, Idro R, Newton CR: Axonal and astrocyte injury markers in the cerebrospinal fluid of Kenyan children with severe malaria. J Neurol Sci. 2007, 258: 93-98. 10.1016/j.jns.2007.03.005.View ArticlePubMedGoogle Scholar
- Newton PN, Green MD, Mildenhall DC, Plancon A, Nettey H, Nyadong L, Hostetler DM, Swamidoss I, Harris GA, Powell K, Timmermans AE, Amin AA, Opuni SK, Barbereau S, Faurant C, Soong RC, Faure K, Thevanayagam J, Fernandes P, Kaur H, Angus B, Stepniewska K, Guerin PJ, Fernandez FM: Poor quality vital anti-malarials in Africa - an urgent neglected public health priority. Malar J. 2011, 10: 352-10.1186/1475-2875-10-352.PubMed CentralView ArticlePubMedGoogle Scholar
- Cheeseman IH, Miller BA, Nair S, Nkhoma S, Tan A, Tan JC, Al SS, Phyo AP, Moo CL, Lwin KM, McGready R, Ashley E, Imwong M, Stepniewska K, Yi P, Dondorp AM, Mayxay M, Newton PN, White NJ, Nosten F, Ferdig MT, Anderson TJ: A major genome region underlying artemisinin resistance in malaria. Science. 2012, 336: 79-82. 10.1126/science.1215966.PubMed CentralView ArticlePubMedGoogle Scholar
- Nayyar GM, Breman JG, Newton PN, Herrington J: Poor-quality antimalarial drugs in southeast Asia and sub-Saharan Africa. Lancet Infect Dis. 2012, 12: 488-496. 10.1016/S1473-3099(12)70064-6.View ArticlePubMedGoogle Scholar
- Ekanem OJ: Has Azadirachta indica (Dogonyaro) any anti-malarial activity?. Niger Med J. 1978, 8: 8-11.Google Scholar
- El Tahir A, Satti GM, Khalid SA: Antiplasmodial activity of selected Sudanese medicinal plants with emphasis on Maytenus senegalensis (Lam.) Exell. J Ethnopharmacol. 1999, 64: 227-233. 10.1016/S0378-8741(98)00129-9.View ArticlePubMedGoogle Scholar
- Hashmat I, Azad H, Ahmed A: Neem (Azadirachta indica A. Juss) - A nature’s drugstore: an overview. Int Res J Biol Sci. 2012, 1: 76-79.Google Scholar
- Dike IP, Obembe OO, Adebiyi FE: Ethnobotanical survey for potential anti-malarial plants in south-western Nigeria. J Ethnopharmacol. 2012, 144: 618-626. 10.1016/j.jep.2012.10.002.View ArticlePubMedGoogle Scholar
- Belayneh A, Asfaw Z, Demissew S, Bussa NF: Medicinal plants potential and use by pastoral and agro-pastoral communities in Erer Valley of Babile Wereda, Eastern Ethiopia. J Ethnobiol Ethnomed. 2012, 8: 42-10.1186/1746-4269-8-42.PubMed CentralView ArticlePubMedGoogle Scholar
- Obaseki O, Fadunsin J: The antimalarial activity of Azadirachta indica. Fitoterapia. 1986, 57: 247-251.Google Scholar
- Khalid SA, Duddeck H, Gonzalez-Sierra M: Isolation and characterization of an antimalarial agent of the neem tree Azadirachta indica. J Nat Prod. 1989, 52: 922-926. 10.1021/np50065a002.View ArticlePubMedGoogle Scholar
- Isah AB, Ibrahim YK, Iwalewa EO: Evaluation of the antimalarial properties and standardization of tablets of Azadirachta indica (Meliaceae) in mice. Phytother Res. 2003, 17: 807-810. 10.1002/ptr.1231.View ArticlePubMedGoogle Scholar
- Udeinya JI, Shu EN, Quakyi I, Ajayi FO: An antimalarial neem leaf extract has both schizonticidal and gametocytocidal activities. Am J Ther. 2008, 15: 108-110. 10.1097/MJT.0b013e31804c6d1d.View ArticlePubMedGoogle Scholar
- Lucantoni L, Yerbanga RS, Lupidi G, Pasqualini L, Esposito F, Habluetzel A: Transmission blocking activity of a standardized neem (Azadirachta indica) seed extract on the rodent malaria parasite Plasmodium berghei in its vector Anopheles stephensi. Malar J. 2010, 9: 66-10.1186/1475-2875-9-66.PubMed CentralView ArticlePubMedGoogle Scholar
- de Miranda AS, Brant F, Machado FS, Rachid MA, Teixeira AL: Improving cognitive outcome in cerebral malaria: insights from clinical and experimental research. Cent Nerv Syst Agents Med Chem. 2011, 11: 285-295. 10.2174/1871524911106040285.View ArticlePubMedGoogle Scholar
- Highley JR, Walker MA, McDonald B, Crow TJ, Esiri MM: Size of hippocampal pyramidal neurons in schizophrenia. Br J Psychiatry. 2003, 183: 414-417. 10.1192/bjp.183.5.414.View ArticlePubMedGoogle Scholar
- Basir R, Rahiman SF, Hasballah K, Chong W, Talib H, Yam M, Jabbarzare M, Tie T, Othman F, Moklas M, Abdullah W, Ahmad Z: Plasmodium berghei ANKA infection in ICR mice as a model of cerebral malaria. Iran J Parasitol. 2012, 7: 62-74.PubMed CentralPubMedGoogle Scholar
- Lekic T, Rolland W, Manaenko A, Krafft PR, Kamper JE, Suzuki H, Hartman RE, Tang J, Zhang JH: Evaluation of the hematoma consequences, neurobehavioral profiles, and histopathology in a rat model of pontine hemorrhage. J Neurosurg. 2013, 118: 465-477. 10.3171/2012.10.JNS111836.PubMed CentralView ArticlePubMedGoogle Scholar
- Spriet A, Beiler D: When can ‘non significantly different’ treatments be considered as ‘equivalent’?. Br J Clin Pharmacol. 1979, 7: 623-624. 10.1111/j.1365-2125.1979.tb04653.x.PubMed CentralView ArticlePubMedGoogle Scholar
- Hunt NH, Golenser J, Chan-Ling T, Parekh S, Rae C, Potter S, Medana IM, Miu J, Ball HJ: Immunopathogenesis of cerebral malaria. Int J Parasitol. 2006, 36: 569-582. 10.1016/j.ijpara.2006.02.016.View ArticlePubMedGoogle Scholar
- Alvarez S, Blanco A, Fresno M, Munoz-Fernandez MA: TNF-alpha contributes to caspase-3 independent apoptosis in neuroblastoma cells: role of NFAT. PLoS One. 2011, 6: e16100-10.1371/journal.pone.0016100.PubMed CentralView ArticlePubMedGoogle Scholar
- Bienvenu AL, Gonzalez-Rey E, Picot S: Apoptosis induced by parasitic diseases. Parasit Vectors. 2010, 3: 106-10.1186/1756-3305-3-106.PubMed CentralView ArticlePubMedGoogle Scholar
- Yanpallewar S, Rai S, Kumar M, Chauhan S, Acharya SB: Neuroprotective effect of Azadirachta indica on cerebral post-ischemic reperfusion and hypoperfusion in rats. Life Sci. 2005, 76: 1325-1338. 10.1016/j.lfs.2004.06.029.View ArticlePubMedGoogle Scholar
- Vaibhav K, Shrivastava P, Khan A, Javed H, Tabassum R, Ahmed ME, Khan MB, Moshahid KM, Islam F, Ahmad S, Siddiqui MS, Safhi MM, Islam F: Azadirachta indica mitigates behavioral impairments, oxidative damage, histological alterations and apoptosis in focal cerebral ischemia-reperfusion model of rats. Neurol Sci. 2013, 34 (8): 1321-1330. 10.1007/s10072-012-1238-z.View ArticlePubMedGoogle Scholar
- Ibezim EC, Odo U: Current trends in malarial chemotherapy. Afr J Biotechnol. 2008, 7: 349-356.Google Scholar
- Khalid SA, Farouk A, Geary TG, Jensen JB: Potential antimalarial candidates from African plants: and in vitro approach using Plasmodium falciparum. JEthnopharmacol. 1986, 15: 201-209. 10.1016/0378-8741(86)90156-X.View ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.