Revista Anatomy ok - European Journal of Anatomyeurjanat.com/data/pdf/eja.100014da.pdf ·...

SUMMARY

Datura has been documented as a plant withhallucinogenic properties. Although it has areputation as one of the ‘darker’ hallucino-gens, historically it has been widely used bysocieties in both the Old and New World, andindeed continues to be used today. It is one ofthe drugs of abuse in Nigeria; young peopleadd the decoction (of the leaves or the fruit) ofthe plant to their drinks in order to get“high”. This is because it is cheap and readilyavailable in comparison with to marijuana.The alkaloids present in the plant have been indemand in the past and its application as asubject for botanical and medical research isvast.

The aim of this study is to highlight someof the effects of aqueous leaf extracts of Daturametel on the frontal cortex of adult Wistar rats.Twenty wistar rats were used for this study.The treatment groups consisted of 3 sub-groups designated A, B, and C and these weregiven 200 mg/kg, 150 mg/kg and 100 mg/kgbwt of the extract respectively, while the con-trol group, designated D, received equal vol-umes of phosphate buffered saline (PBS).Administration was performed once daily overseven days using an orogastric tube. Twenty-four hours after the last administration, all the

animals were sacrificed by cervical dislocation.The brains were carefully extracted from theskulls of the animals and fixed in 10% formolcalcium for histological examination. Specialstaining techniques such as Cresyl fast violet(CFV) and Feulgen DNA were employed fol-lowed by routine hematoxylin and eosin(H&E) stain. It was observed from this studythat the administration of aqueous extracts ofDatura metel (at the doses administered) haddeleterious effects on the frontal cortex ofadult albino Wistar rats. There were vacuola-tions in the stroma of the brains of the rats inthe extract treatment group and the degree ofvacuolation was dose-dependent.

Key words: Datura metel – Cresyl fast violet –Frontal cortex – Vacuolations – Alkaloids

INTRODUCTION

Datura metel belongs to the familySolanaceae, also known as the nightshade fam-ily. This plant is widely distributed all overthe world (Duke, 1985; Hussein, 1985;Zamora and Pola, 1992). The genus Daturaconsists of five species. These include D.arborea, D. fastuosa, D. innoxia, D. metel and D.stramonium.

Eur J Anat, 14 (2): 83-89 (2010)

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Some effects of the aqueous leaf extractof Datura metel on the frontal cortex ofadult Wistar rats (Rattus norvegicus)

Damilare A. Adekomi, A.A. Tijani, O.K. Ghazal

Department of Human Anatomy, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin, Nigeria.

Correspondence to:Adekomi Damilare Adedayo. Department of Human Anatomy, Faculty of BasicMedical Sciences, P.M.B. 1515, University of Ilorin, Ilorin, Nigeria.Phone: +23480-3844-1671/ +23480-7656-3746. E-mail: [email protected]

Submitted: July 17, 2010Accepted: August 27, 2010

Revista Anatomy ok 19/7/11 09:48 Página 83

The alkaloids content of the different partsof the Datura plants has been studied byinvestigators studying the chemical composi-tion of the plant. In a study conducted byBerkov and Zayed (2004), it was observed thatthe leaves, fruits and root of D. innoxia containabout 38 alkaloids. According to Checke andShull (1985), Xu et al. (1985) and Shonle and

Bergelson (2000), phytochemical analysis ofall species of the genus Datura revealsatropine, hyoscyamine and scopolamine(hyoscine) as the main tropane alkaloids buttheir concentrations depend on the species andon the part of the plant used. These tropanealkaloids are of great importance in the phar-maceutical industry.


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Fig. 1. Images of the frontal cortex of the animals in groups A, B, C and D. (CFV, x1920). V= vacuolations, P= pyramidal cells, Bv =Bloodvessels, N= neurons. Note the extent and degree of vacuolations in the treatment groups A, B, C compared with the control group D. Thedistortion in the arrangement and shape of the neurons in the sections of the treatment group compared vis-à-vis the control.


Medicinal folklore use of the flowers ofDatura plants as a source of analgesic mixturesby the Ancient Chinese (Xu et al., 1985),Indians (Duke, 1985) and Mexicans (Zamoraand Pola, 1992) has been documented. Thecontents of the Datura plant have beenemployed in treating clinical conditions relat-ing to the nervous system as well as other sys-tems. These have been outlined by severalauthors such as Perry, (1980); Duke, (1985);Hussein, (1985); Weiss, (1996); Al-Gadi,(1997); Henry and Wiseman, (1997);Guarrera, (1999); Rojas et al., (1999) andPeredery and Persinger (2004). Such clinicaldeviations include: Parkinson’s disease, paral-ysis, psychological and sleeping disorders,epilepsy, headache, spasms, shock, motionsickness, asthma, tuberculosis, breast cancer,glaucoma, arthritis, rheumatism, intestinalparasitic infestation, hydrocele, hemorrhoids,boils, hair loss, ringworm and depression ofsexual desire. Induced diabetes mellitus inrodents can also be treated with seed extractsof D. metel (Krishna et. al., 2004).

The brain is the center of the nervous systemin all vertebrates and most invertebrate animals(Shepherd, 1994). In vertebrates, the brain islocated in the head, protected by the skull andclose to the primary sensory systems of vision,hearing, balance, taste, and smell. Brains areextremely complex in structure and function.

The brain controls the other organ systemsof the body, either by activating muscles or bycausing the secretion of chemicals such as hor-mones. This centralized control allows rapidand coordinated responses to changes in theenvironment. Some basic types of responsesare possible without a brain: even single-celled organisms may be capable of extractinginformation from the environment and actingin response to it (Gehring, 2005). Sponges,which lack a central nervous system, are capa-ble of coordinated body contractions and evenlocomotion (Nickel, 2002).

Van de Graaff (2001) observed that thefrontal lobe is responsible for responses relat-ing to memory, emotions, reasoning, judg-ment, planning, and verbal communication.Owing to the significant functions of thefrontal cortex, any structural alteration in thisstructure is vital to health.

This present study was undertaken toobserve some of the effects of aqueous leafextracts of Datura metel on the frontal cortex ofadult Wistar rats.

MATERIALS AND METHODS

Collection of plants and preparation of plant extracts

Fresh leaves of Datura metel were collectedalong the Agbo-Oba axis, Ilorin, Kwara Stateand were authenticated at the Department ofPlant Science University of Ilorin, Nigeria.The leaves of the plant were air-dried at 50°C.The dried plant material was weighed usingGallenkamp (FA2104A, England) electronicweighing balance and ground withBlender/Miller III, (model MS -223, China).Sixty grams (60 g) of the ground plant samplewas then soaked in 600 ml of phosphatebuffered saline (PSB) for 24 hours at roomtemperature with constant shaking (StuartScientific Orbital Shaker, UK), and then fil-tered through silk cloth. The filtrate was con-centrated using a rotary evaporator(Rotavapor® R-210) at 42-47°C. The residueof the extract obtained was kept in a cappedsample bottle and stored in a refrigerator untiluse.

Animal care and experimental design

Twenty (20) male albino Wistar rats of thefirst filial generation were randomly assignedto three (3) treatment groups identified as; A,B, and C (n=15), and a control group D (n=5).The body weights of the animals were record-ed on daily basis using a digital weighingscale (Saltun® EK5055Max).

The animals in the treatment groups desig-nated as A, B, and C were administered orally(through an orogastric tube) with 200 mg,150 mg and 100 mg per kilogram bodyweight of the aqueous extract of Datura metelfor seven days respectively, while the animalsin the control group (group D) were adminis-tered an equal amounts of phosphate bufferedsaline (PBS).

All the animals were housed in clean cageswith dimensions of 33.0 x 20.5 x 19.0 cmunder in well ventilated standard housingconditions (temperature: 28-31oC; humidity:50-55%) (Yakubu et al., 2008). Their cageswere cleaned daily. All animals were checkedfor illness, abnormal behavior, and morpho-logical anomalies.

All experimental procedures followed therecommendations provided in the “Guide forthe Care and Use of Laboratory Animals” pre-pared by the National Academy of Sciencesand Published by the National Institute ofHealth (NIH, 1985).

Some effects of the aqueous leaf extract of Datura metel on the frontal cortex of adult Wistar rats (Rattus norvegicus)

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The rats were fed with standard rat chow ata recommended dose of 100 g/kg as advised bythe International Centre of Diarrheal DiseaseResearch, Bangladesh (ICDDR, B) daily.Drinking water was supplied ad libitum.

Twenty-four hours after the last adminis-tration, all the animals were sacrificed by cer-vical dislocation, the brains were carefullyextracted from the skulls of the animals, blot-ted dry on a filter paper, and placed in speci-men bottles containing 10% formol calciumfor histological processing.

Neurohistological parametersAfter fixing the brains of both the treated

and control animals, the tissues were laterprocessed for Cresyl fast violet, Feulgen DNAand Hematoxylin and Eosin (Bancroft andSteven, 1992; Feulgen and Rossenbeck, 1924;Drury et al., 1967). After fixation, the tissueswere embedded in paraffin wax; serial sectionsof 5 μm thick were produced using the LeitzRotary microtome (Leitz 1512 Microtome).The sections were mounted in DPX andexamined with the aid of Olympus binocular


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Fig. 2. Graph showing the body weight changes in grams (p<0.05).


light microscope (XSZ-107BN, No. 071771).The photomicrographs of each slide was takenwith a Nikon Digital Camera DXM1200F(Nikon, Japan) for subsequent histologicalanalysis.

Statistical analysis

Data were evaluated statistically usingStudent’s t-test with SPSS/14.0 software (SPSSInc, Chicago, USA) and Excel 2007 (MicrosoftCorporation, USA) and were expressed asmeans ± standard error of mean (SEM). Avalue of p<0.05 was considered to indicate asignificant difference between groups.

RESULTS

Behavioral responses of the treated animals

The animals in the treatment groups dis-played aggressive and erratic resistance to han-dling throughout the duration of this study.The animals of extract-treated group Ashowed restlessness and excitation for a muchlonger period, followed by animals in group Band then by the animals in group C. At about20 to 30 minutes after administration, theanimals in the treatment groups began toshow sign of calmness. The animals isolatedthemselves and avoided response to externalevents. Dilatation of the pupil was noted uponobserving the eyes. Mydriasis is a commonconsequence of the anticholinergic activity ofthe biochemical components of the plant, assuggested by Thabet et al., (1999) andPekdemir et al., (2004). The animals in boththe treatment and control groups were fre-quently checked for any alteration or changesin their behavioral responses.

Body weight

Following the administration of D. metelextract to the experimental animals in thetreatment groups, the average body weight(Fig. 2) in each of the experimental groups A,B, C, and D were calculated on day 7 of theexperimental procedures. Anorexia (a reduc-tion in food consumption and body weight)was observed in all the rats in the treatmentgroups administered 200, 150, and 100mg/kg bwt of the plant extract respectively.Food intake was significantly reduced follow-ing the administration of the plant extract ina dose-dependent pattern. Since food con-sumption was reduced, similar reductions inbody weight were observed during the study

for all three treatment groups. All controlgroup rats showed an increase in body weight.Gross observations

No gross alterations were observed in thecytoarchitecture and morphology of thefrontal cortex of the animals in the treatmentgroups or those in the control groups twenty-four hours after the termination of the experi-mental procedure. The frontal cortex (with allits component parts) of the animals in boththe treatment and control groups appearedmorphologically normal.

Histological observations of the frontal cortex tissues

Neurohistological assessment of the righthalves of the frontal lobes of the animals in thetreatment groups showed varying degrees ofdegenerative and deleterious effects on theneurons of the frontal cortex. Also observed inthe neurohistological slides were changes inthe appearances of the DNA, chromatolysis ofthe Nissl bodies, vacuolations of the neuronsin the stroma of the brain, and degeneration ofthe glial cells. Such damage indicates neu-ropathologic lesions, chromatolysis and necro-sis of the neurons.

DISCUSSION

The effects of oral administration of aque-ous extracts of Datura metel on the frontal cor-tex of adult albino Wistar rats were investigat-ed to explore the possible neurohistologicalimplications that could result following itsuse. Using an Olympus binocular light micro-scope (XSZ-107BN, N?. 071771), the resultsobtained from the sections of the frontal cor-tex of the animals in the treatment groupsstained with Cresyl fast violet (CFV) for Nisslbodies, Feulgen DNA (FDNA) for deoxyri-bonucleic acid, and hematoxylin and eosin(H&E) staining techniques revealed that oraladministration of aqueous extracts of Daturametel had deleterious effects on the frontal cor-tex of the animals in the extract-treatedgroups since histological derangement, degen-erative changes, and apoptosis and/or necrosisof neurons were observed within the cerebraltissues of the brains of the animals in thetreatment groups when compared with thecontrol group.

Fig. 1 A-C shows the neurohistology of thefrontal cortex of the animals in the experimen-tal groups (A, B, and C). It may be seen fromthe sections of the treatment groups A and B


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that oral administration of aqueous leafextracts of Datura metel brings about chroma-tolysis of Nissl bodies, which may occur as aresult of trauma or other exogenous agents orfactors (Lowe and Cox, 1992; Snell, 2001).However, chromatolysis usually results in aloss of normal functioning of Nissl bodies andimpaired functioning, and may ultimatelylead to cellular death.

DNA clustering was also observed in theextract treated groups. The DNA was alsocompromised, suggesting an alteration in itsintegrity, and this may cause impairment inthe normal functioning of the frontal cortex.

The decrease in body weight of the animalsin all the treatment groups as recorded in thisstudy could have been aa result of anorexia fol-lowing oral administration of the aqueous leafextracts of Datura metel. Akinlolu andShokunbi (2010) suggested that decreases inbody weight could also occur as a result of thenegative impacts of drugs on the normal bio-logical, biochemical, physiological and meta-bolic processes, with consequent depletion ofbody protein in the treated animals.

The decrease in body weight of the extract-treated animals reflected the possible changesin function of the organs that are regulated bythe nervous system and metabolic activities.The active constituents of the aqueous leafextract, mainly tropane alkaloids, prevent theaction(s) of the essential neurotransmitter(acetylcholine) in the brain through blockadeof its receptors (Henry and Wiseman, 1997).Brain tissue has two subtypes of acetylcholinemuscarinic receptors: M4 and M5 (Yasuda etal., 1993). Atropine and other related alka-loids are effectively functional on the mus-carinic receptors, and have limited effects onnicotinic receptors (Bloom, 1992; Brown,1992). Nielsen et al. (2004) demonstrated thehigh affinity of aqueous extracts of Daturaferox leaves to reuptake the transport proteinof the neurotransmitter serotonin, leading to aprominent inhibition of reuptake.

Although the plant has been reported tohave many beneficial and medicinal proper-ties, its side effects (such as hallucinations,psychiatric derangement, disorientation withagitated behavior, etc.) could have been aresult of the insults of the chemical compo-nents of the plant to the cells of the nervoussystem. It was observed that the plant has thepotential to cause cerebral damage and thismay lead to trauma and impaired functions ofthe brain.

CONCLUSION

This study has demonstrated some of theeffects of aqueous leaf extracts of Datura metelin rats. People often consume herbal remediesand/or decoctions (either in aqueous form or asa tincture) with orthodox medication with noprescription either from a pharmacist or aphysician. Considering some of the deleteriouseffects of Datura metel leaf extracts on the bodyweight and the cellular components of thefrontal cortex in rats, herbal practitioners anddrug abusers (particularly young people)should be properly educated about the use of theplant, in particular in view of the negativeimpact it has on body weight and the fontalcortex in the extract-treated animals in thisstudy. Further studies should be directedtowards isolating the specific component(s) ofthe plant responsible for the deleterious effectsin order to standardize the plant preparationfor maximum therapeutic benefit.

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