www.ajopred.com

*Author for correspondence: E-mail address: chimafrankduff@yahoo.com ; frankline.kenechukwu@unn.edu.ngTel: +234-8038362638, Fax:+234-42-771709.

Antihypertensive Effect of Methanol Leaf Extract of Andrographis paniculata inExperimental Cats

Mshelbwala Kubili1, Ofokansi KC2 and Kenechukwu FC2*1Department of Pharmaceutics and Pharmaceutical Microbiology, Faculty of Pharmaceutical Sciences, Almadu BelloUniversity, Zaria, Kaduna State, Nigeria2Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, University ofNigeria, Nsukka 410001, Enugu State, Nigeria.

ABSTRACTThe leaves of Andrographis paniculata (Family Acanthaceae) are used locally in Northern Nigerian for the treatment ofhypertension. This work was primarily set out to find justification for the local medicinal use of this plant and to scientificallystudy the pharmacological activity of the plant. Phytochemical analyses of methanolic extract of the plant leaves werecarried out using standard methods. The extract was tested for antihypertensive activity in cats by monitoring changes inblood pressure following administration of the extract. The antihypertensive activity was compared with Propranolol(control). Toxicity and histopathological studies were also carried out on the extract. Results of the Phytochemical testshowed that the plant extract contained alkaloids, tannins, cardiac glycosides, flavonoids and terpenes. The plant isrelatively safe, with an LD50 of 1.90 x 104mg/kg body weight which is much higher than those of 0.81mg/kg body weighttaken by the local people. Pharmacological studies showed that the methanol extract exhibited greater antihypertensiveactivity than Propranolol, a standard anti-hypertensive drug. This study suggests that the methanolic leaf extract ofAndrographis paniculata contains bioactive constituents that may be beneficial in hypertension and lend pharmacologicalcredence to the ethnomedical claim for the use of the plant in the management of hypertension.

KEYWORDS: Andrographis paniculata; Anti-hypertensive effect; Propranolol; Anaesthezied cats.

INTRODUCTIONHypertension, defined as a disburbance inhemodynamic function in which there is persistentabnormal elevation of systemic blood pressure,whether it is systolic or diastolic, above the arbitrarylevel of normal pressure of 140/90 mmHg, is acommon disease that cut across all races and theprevalence rate increases with age. [1, 2]. A silentkiller among the most vibrant and productive classof the society hypertension has no cure and whendiscovered the treatment is life-long [3]. Manydrugs are available for the control of hypertensionbut some are not affordable for majority of thepeople in Africa [4, 5]. Orthodox drugs used in thetreatment of hypertension are associated with sideeffects and drug interactions [6]. Herbal medicinesare widely used due to their therapeutic efficacycoupled with least side effects, which initiate thescientific research regarding herbs with theantihypertensive activity. In addition, herbal

preparations are most assessable to the majority ofthe population who cannot afford orthodox drugs [7].Andrographis paniculata (Fig. 1) (familyAcanthaceae), commonly known as “King ofBitters”, is an annual branched erect plant up to 1 mtall that grows abundantly in South Eastern Asia,India and Sri Lanka, Pakistan and Indonesia. It iscultivated extensively in China and Thailand [8],East and West Indies and Mauritius [9]. Due to itsubiquitous nature, AP grows in pine, evergreen anddeciduous forest areas and along the roads invillages; it grows in all type of soil, even wherealmost no other plant can be cultivated. Thisruggedness of the plant accounts for its widedistribution. It is therefore not surprising to find itgrowing in some parts of Northern Nigeria and WestAfrica. Specifically in Nigeria, it is found inAdamawa and Kaduna states, and the FederalCapital Territory (FCT), Abuja. The plant is known tohave proven biological activities and that may be

Vol. 5 No.2 pp.109-120 (2013)

African Journal of PharmaceuticalResearch & Development

www.ajopred.com

*Author for correspondence: E-mail address: chimafrankduff@yahoo.com ; frankline.kenechukwu@unn.edu.ngTel: +234-8038362638, Fax:+234-42-771709.

Antihypertensive Effect of Methanol Leaf Extract of Andrographis paniculata inExperimental Cats

Mshelbwala Kubili1, Ofokansi KC2 and Kenechukwu FC2*1Department of Pharmaceutics and Pharmaceutical Microbiology, Faculty of Pharmaceutical Sciences, Almadu BelloUniversity, Zaria, Kaduna State, Nigeria2Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, University ofNigeria, Nsukka 410001, Enugu State, Nigeria.

ABSTRACTThe leaves of Andrographis paniculata (Family Acanthaceae) are used locally in Northern Nigerian for the treatment ofhypertension. This work was primarily set out to find justification for the local medicinal use of this plant and to scientificallystudy the pharmacological activity of the plant. Phytochemical analyses of methanolic extract of the plant leaves werecarried out using standard methods. The extract was tested for antihypertensive activity in cats by monitoring changes inblood pressure following administration of the extract. The antihypertensive activity was compared with Propranolol(control). Toxicity and histopathological studies were also carried out on the extract. Results of the Phytochemical testshowed that the plant extract contained alkaloids, tannins, cardiac glycosides, flavonoids and terpenes. The plant isrelatively safe, with an LD50 of 1.90 x 104mg/kg body weight which is much higher than those of 0.81mg/kg body weighttaken by the local people. Pharmacological studies showed that the methanol extract exhibited greater antihypertensiveactivity than Propranolol, a standard anti-hypertensive drug. This study suggests that the methanolic leaf extract ofAndrographis paniculata contains bioactive constituents that may be beneficial in hypertension and lend pharmacologicalcredence to the ethnomedical claim for the use of the plant in the management of hypertension.

KEYWORDS: Andrographis paniculata; Anti-hypertensive effect; Propranolol; Anaesthezied cats.

INTRODUCTIONHypertension, defined as a disburbance inhemodynamic function in which there is persistentabnormal elevation of systemic blood pressure,whether it is systolic or diastolic, above the arbitrarylevel of normal pressure of 140/90 mmHg, is acommon disease that cut across all races and theprevalence rate increases with age. [1, 2]. A silentkiller among the most vibrant and productive classof the society hypertension has no cure and whendiscovered the treatment is life-long [3]. Manydrugs are available for the control of hypertensionbut some are not affordable for majority of thepeople in Africa [4, 5]. Orthodox drugs used in thetreatment of hypertension are associated with sideeffects and drug interactions [6]. Herbal medicinesare widely used due to their therapeutic efficacycoupled with least side effects, which initiate thescientific research regarding herbs with theantihypertensive activity. In addition, herbal

preparations are most assessable to the majority ofthe population who cannot afford orthodox drugs [7].Andrographis paniculata (Fig. 1) (familyAcanthaceae), commonly known as “King ofBitters”, is an annual branched erect plant up to 1 mtall that grows abundantly in South Eastern Asia,India and Sri Lanka, Pakistan and Indonesia. It iscultivated extensively in China and Thailand [8],East and West Indies and Mauritius [9]. Due to itsubiquitous nature, AP grows in pine, evergreen anddeciduous forest areas and along the roads invillages; it grows in all type of soil, even wherealmost no other plant can be cultivated. Thisruggedness of the plant accounts for its widedistribution. It is therefore not surprising to find itgrowing in some parts of Northern Nigeria and WestAfrica. Specifically in Nigeria, it is found inAdamawa and Kaduna states, and the FederalCapital Territory (FCT), Abuja. The plant is known tohave proven biological activities and that may be

Vol. 5 No.2 pp.109-120 (2013)

African Journal of PharmaceuticalResearch & Development

www.ajopred.com

*Author for correspondence: E-mail address: chimafrankduff@yahoo.com ; frankline.kenechukwu@unn.edu.ngTel: +234-8038362638, Fax:+234-42-771709.

Antihypertensive Effect of Methanol Leaf Extract of Andrographis paniculata inExperimental Cats

Mshelbwala Kubili1, Ofokansi KC2 and Kenechukwu FC2*1Department of Pharmaceutics and Pharmaceutical Microbiology, Faculty of Pharmaceutical Sciences, Almadu BelloUniversity, Zaria, Kaduna State, Nigeria2Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, University ofNigeria, Nsukka 410001, Enugu State, Nigeria.

ABSTRACTThe leaves of Andrographis paniculata (Family Acanthaceae) are used locally in Northern Nigerian for the treatment ofhypertension. This work was primarily set out to find justification for the local medicinal use of this plant and to scientificallystudy the pharmacological activity of the plant. Phytochemical analyses of methanolic extract of the plant leaves werecarried out using standard methods. The extract was tested for antihypertensive activity in cats by monitoring changes inblood pressure following administration of the extract. The antihypertensive activity was compared with Propranolol(control). Toxicity and histopathological studies were also carried out on the extract. Results of the Phytochemical testshowed that the plant extract contained alkaloids, tannins, cardiac glycosides, flavonoids and terpenes. The plant isrelatively safe, with an LD50 of 1.90 x 104mg/kg body weight which is much higher than those of 0.81mg/kg body weighttaken by the local people. Pharmacological studies showed that the methanol extract exhibited greater antihypertensiveactivity than Propranolol, a standard anti-hypertensive drug. This study suggests that the methanolic leaf extract ofAndrographis paniculata contains bioactive constituents that may be beneficial in hypertension and lend pharmacologicalcredence to the ethnomedical claim for the use of the plant in the management of hypertension.

KEYWORDS: Andrographis paniculata; Anti-hypertensive effect; Propranolol; Anaesthezied cats.

INTRODUCTIONHypertension, defined as a disburbance inhemodynamic function in which there is persistentabnormal elevation of systemic blood pressure,whether it is systolic or diastolic, above the arbitrarylevel of normal pressure of 140/90 mmHg, is acommon disease that cut across all races and theprevalence rate increases with age. [1, 2]. A silentkiller among the most vibrant and productive classof the society hypertension has no cure and whendiscovered the treatment is life-long [3]. Manydrugs are available for the control of hypertensionbut some are not affordable for majority of thepeople in Africa [4, 5]. Orthodox drugs used in thetreatment of hypertension are associated with sideeffects and drug interactions [6]. Herbal medicinesare widely used due to their therapeutic efficacycoupled with least side effects, which initiate thescientific research regarding herbs with theantihypertensive activity. In addition, herbal

preparations are most assessable to the majority ofthe population who cannot afford orthodox drugs [7].Andrographis paniculata (Fig. 1) (familyAcanthaceae), commonly known as “King ofBitters”, is an annual branched erect plant up to 1 mtall that grows abundantly in South Eastern Asia,India and Sri Lanka, Pakistan and Indonesia. It iscultivated extensively in China and Thailand [8],East and West Indies and Mauritius [9]. Due to itsubiquitous nature, AP grows in pine, evergreen anddeciduous forest areas and along the roads invillages; it grows in all type of soil, even wherealmost no other plant can be cultivated. Thisruggedness of the plant accounts for its widedistribution. It is therefore not surprising to find itgrowing in some parts of Northern Nigeria and WestAfrica. Specifically in Nigeria, it is found inAdamawa and Kaduna states, and the FederalCapital Territory (FCT), Abuja. The plant is known tohave proven biological activities and that may be

Vol. 5 No.2 pp.109-120 (2013)

African Journal of PharmaceuticalResearch & Development

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the basis of its wide use for various ailments indifferent parts of the world. Andrographis paniculatais a plant with a wide application in traditionalmedicine especially in Asia and Indonesia. [10]. Theplant has been shown to possess anti-clotting,antimicrobial, anti-malarial, anti-filarial, anti-tubercular, anti-inflammatory and immune-stimulantactivities as well as Protection on the Liver and GallBladder [11-20]. It has been used for centuries inAsia to treat gastrointestinal tract and upperrespiratory tract infections, fever, herpes, sorethroat and a variety of chronic and infectiousdiseases [21]. In India it is called ‘Kalmeh’ It is foundin the Indian Pharmacopoeia and is prominent in atleast 26 Ayurvedic formula. In traditional Chinesemedicine (TCM), it is an important “cold remedy”herb [10]. It is used to rid the body of heat as infevers and also dispel toxins from the body. In theScandinavian countries, it is commonly used to treatand prevent common colds. It has been found to bean immune-stimulant [22] and used in treatment ofcold and colic pains in children [23]. In folkloricmedicine, it has been proved to possessantihypertensive properties. This study wasundertaken to substantiate its traditional use by thenatives in Garkida, Adamawa state of Nigeria. Thenatives usually take ten to fifteen of the fresh leavesof Andrographis paniculata to chew once or twice aday with a glass of cold water and this dose isenough to lower blood pressure continuously.Orthodox drugs used for the treatment ofhypertension for example propranolol at variousdosage forms e.g. 40mg and 80 mg. The use oftraditional medicine as substitute or complementaryto modern medicine has been documented byseveral authors [24]. Herbs such as Andrographispaniculata are also employed to treat mildhypertension at dose of 500mg of the crude leafwhich is equivalent to 60 - 70 mg per daily dose.Medicinal plants used for the therapy ofhypertension, in traditional medicine have beenshown to possess promising antihypertensiveactivities in animal models of antihypertensivescreening [10, 25-30].The objective of this study was to evaluate theantihypertesnsive effect of methanol leaf extract ofAndrographis paniculata in experimental cats.

EXPERIMENTALMaterialsThe following reagents were used as procuredwithout further purification: Methanol (BDHChemicals Ltd., Poole England), Ferric chloridesolution (BDH Chemicals Ltd., Poole, England),

Mayers reagent (BDH Chemicals Ltd, Poole,England), Vanillin Sulphuric Acid spray reagentBDH Chemicals Ltd England, Dragendoff’s reagent(BDH Chemicals Ltd, Poole, England), Fehling’ssolution A and B (BDH Chemicals Ltd, Poole,England), Potassium carbonate, Sodium Chloride(Dangote Nigeria), Chloroform (Prolab. 12 RuePelle, Paris,France), Petroleum ether (Hopkins andWilliams, Chadwell Health, Sussex, U.K), Ethanol(BDH Chemicals Ltd., Poole, U.K.), Tween 80 (BDHChemicals Ltd., Poole, U.K), ConcentratedHydrochloric acid (BDH Chemicals Ltd., Poole,U.K.), Lead Acetate (BDH Chemicals Ltd., Poole,U.K.) and Distilled water (Sterile laboratory, Facultyof Pharmaceutical Sciences, Ahmadu BelloUniversity, Zaria).Experimental animalsThe animals were procured from the Animal House,Faculty of Pharmaceutical Sciences, Ahmadu BelloUniversity, Zaria, Nigeria, and were allowed toacclimatize to the new environment for a period oftwo weeks prior to the study. The mice, maintainedon standard rodent feed and water ad libitum, werehoused in metalic cages at room temperaturethroughout the study and were maintained understandard conditions of humidity, room temperatureand 12 h light/12h darkness cycle. The animalexperiments were conducted in accordance withEthical Guidelines of Animal Care and UseCommittee (Research Ethics Committee) of theFaculty of Pharmaceutical Sciences, Ahmadu BelloUniversity, Zaria, Nigeria.Preparation of plant material and extractsThe leaves of Andrographis paniculata werecollected from Zaria, Kaduna State of Nigeria andproperly identified. The voucher specimens weredeposited in the herbarium of the National Institutefor Pharmaceutical Research and Development(NIPRD). The herbarium number is NIPRD 5558.The leaves of Andrographis paniculata were shade-dried and pulverized using an electrically operatedmill. A 0.5 kg of shade-dried pulverized leaves wasextracted with 2 L of methanol using a soxhletapparatus, concentrated under vacuum and kept inan airtight container until further use.

Phytochemical tests of the plant extractsVarious phytochemical tests were carried out on theextract using standard procedures to determine thepresence of saponins, flavonoids, glycosides,steroids, triterpenes, alkaloids, cardenolideaglycone and tannins following standard procedures[31-33]. Each test was qualitatively expressed as

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negative (-) or positive (+); the intensity of thecharacteristic colour was expressed as (++) or(+++).

Anti-hypertensive effects of the extract onanaesthesized catsThe anti-hypertensive effect of the extract wascarried out on anaesthesized cats. Briefly, aconcentrated solution of the extract was preparedby dissolving 100 mg in

Fig. 1: A mature shrub of Andrographis paniculata grownin a garden in GRA Zaria, Kaduna State, Nigeria.

10ml of normal saline to obtain a 10mg/ml stockconcentration. The cats were stabilized in thelaboratory for 24 hours before the experiment. Ineach case, the cat was anaesthetized withpentobarbitone sodium BP (Vet) 60-mg/ml at a doseof 27.5mg/kg body weight for the generalanaesthesia. 1.35ml of the 60mg/ml wasadministered intraperitoneally. Heparin sodium 6.8mg/ml and 0.2 ml which was equivalent to 1.3mg/1.8kg body weight was given to prevent bloodclot. The anaesthetized cat was placed on thedissecting board and secured in a supine position tothe board using threads. A midline incision wasmade in the neck and the vagus vein and rightcarotid artery were separated and short ligatured.An incision was made in the carotid artery largeenough to insert a cannula. The cannula was heldand secured in the artery by a second ligature. Thecannula from the artery was connected to the oneend to a microdynamometer for the measurement ofthe mean arterial blood pressure. Another incisionwas made in the left femur, the left femoral vein was

exposed, cannualated and ligated as was done forthe carotid artery. The cannulated femoral vein wasthe site for the administration of the drug and testsamples. Blood clotting was prevented by theinjection of heparinised normal saline (N/S)intravenously into the femoral venous cannula. Afterabout 30 min equilibrium, the control blood pressurewas recorded after which 2ml of normal saline wasadministered and the mean arterial blood pressurerecorded.Thereafter, the following studies were carried out onthe anaesthetised cat and the point ofadministration was the femoal vein.

i. The effect of Acetylechodline (Ach) in the doseof 2.0 x 10-4 mg/kg and 4.0 x 10-4 mg/kg wereadministered respectively and the response onthe blood pressure was observed.

ii. Adrenaline of 8.0 x 10-3 mg/kg was alsoadministered and the response on the cat bloodpressure was observed.

iii. The effect of the extract on the cat bloodpressure was also observed. Various doses ofthe extract (0.04, 0.083, 0.330, 0.412, 0.826and 1.651 mg/kg) were administered and theresponse on the cat blood pressure recorded.

iv. The antagonistic effect of the extract againstAtropine was also observed at dose of 4 x10-3

mg/kg, followed immediately with dose of1.615mg/kg of the extract and the response onthe cat blood pressure observed.

v. The comparism of the extract with standarddrug, Propranolol was determined on the catblood pressure. The same doses of both theextract and Propranolol were administered. Theresponse of the drug on the cat blood pressurewas observed.

Toxicological and histopathological studiesThe safety of the extract to the animals (rats) wasevaluated using the probit method [34]. Autopsywas carried out on animal groups where death wasrecorded. The organs examined were the kidneys,livers and heart. Histopathology was also carriedout on these organs and also on the control group.Briefly, small pieces of each tissue in each groupwere collected in 10 % neutral buffered formalin forproper fixation for 24 h. These tissues wereprocessed and embedded in paraffin wax. Sectionsof 5- 6 μm in thickness were cut and stained withhematoxylin and eosin (H & E). These sectionswere examined photomicroscopically at amagnification of x400.

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0.1ml 10mg/mlMethanolic extractN/S 0.9% w/v

percent

(as control)

0.2ml 10mg/mlMethanolic extract

0.8ml 10mg/mlMethanolic extract

0.4ml 10mg/mlMethanolic extract

Statistical analysisThe experimental results were expressed as theMean ± SEM for the animals in each group.Difference between means were determinedstatistically using one-way analysis of variance(ANOVA) followed by Dunnett’s multiple comparisontest (DMCT). P value of < 0.05 was considered asstatistically significant.

RESULTS AND DISCUSSIONThe present study was undertaken to evaluate theanti-hypertensive effect of Andrographis paniculata,a commonly used plant in Nigerian traditionalmedicine for treatment of hypertension.Ethnopharmacological data has been one of theuseful ways for the discovery of biologically activecompounds from plants [35]. Ethnopharmacologicaluse of plants could form the basis for phytochemical

and phytopharmacological investigation. Preliminaryphytochemical tests of the extracts of Andrographispaniculata revealed the presence ofphytoconsituents as presented in Table1.Phytochemistry of the extract showed that itcontains high amounts of tannins, flavonoids,alkaloids, saponins, anthraquinones, terpenes andsteroids. Phytoconstituents like triterpenoids andsteroids are known to possess anti-hypertensiveactivity [36]. Perhaps the anti-hypertensive effect ofthe extract could be attributed to the presence ofthese phytoconstituents present in the plant extract.These are the sources of the most activecomponent of the leaves which contain theandrographolide [37].

Fig. 2: Effect of the various concentrations of Methanoli extrac on cat blood pressure

Fig. 3: Effect of the various concentrations of Propranolol on cat blood pressure.

2.0ml 1mg/mlPropranolol1.0ml 1mg/ml

Propranolol4.0ml 1mg/mlPropranolol

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Fig. 4: Comparison of the effect of Methanolic extract and Propranolol on cat blood pressure.

Fig. 5: Effect of the various concentrations of Acetylcholine (Ach) on cat blood pressure.

Fig. 6: Effect of the various concentrations of Adrenaline on cat blood pressure.

Fig. 7: Effect of the concentrations Atropine and Methanolic extract of Andrographis paniculata on cat blood pressure

0

1

2

3

4

0.041 0.083 0.33 0.412 0.826 1.651

Bloo

d pr

essu

re lo

wer

ing

(cm

)

Dose (mg/kg)

Propranolol Methanolic extract (ME)

0.1ml 5µg/ml Ach

0.1ml Adrenaline 100µg/ml 0.2ml Adrenaline100µg/ml

0.1ml Atropine 100µg/ml +0.8ml 10mg/ml Methanolic extract

0.2ml Atropine 100µg/ml +0.8ml 10mg/ml Methanolicextract

0.2ml 5µg/ml Ach

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Table 1: Qualitative chemical tests forphyto-constituents in Andrographispaniculata methanolic extractConstituent ObservationAlkaloids +Steroids +++Terpenoids +++Glycosides +++Flavonoids +Tannins +Saponins -KEYS:+++ = relatively high abundance of compound, ++= moderate abundance of compound, + = relative lowpresence of compound, - = not detected.

Effect of the extract on anaesthesised Cat’s bloodpressureFigs. 2 and 3 showed the reaction of the extract andPropranolol on cats blood pressure lowering. The resultsshowed that the extract dose-dependently lowered theblood pressure of the cats (Fig. 2). Normal saline wasused to wash off the extract, and there was no change inthe blood pressure when normal saline (0.9 %w/v) wasintroduced. Comparing the effects of the extract withPropranolol, the two gave graded decrease in the catblood pressure up to the highest dose of 1.651mg/kg(Fig. 4). Propranolol acts by blocking the antogonizingeffect of noradrenaline on β adrano receptors [1-4]. Thisaccounts for the lowering of blood pressure observed.The study suggests that the extract may cause adecrease in blood pressure through -receptorsmediated inhibition since Propranolol is a -receptorantagonist. Figs. 5 and 6 show the effect of the variousconcentrations of Acetylcholine and Adrenalinerespectively on cat blood pressure while Fig. 7 shows theeffect of the concentrations Atropine and methanolicextract of Andrographis paniculata on cat blood pressure.Atropine did not block the effect of the extract as couldbe seen in Fig. 7 indicating that the mechanism of actionof the extract could not be parasympathetic system-mediated [5, 6]

Toxicological and histopathogical studiesTable 2 and Fig. 8 showed the graph of acute toxicity ofthe extract given intra-peritoneally from which the LD50(1.9 ×104 mg/kg body weight) was extrapolated. Thisimplies that doses below this could be safe while dosesabove it could be detrimental to the human system [38].The LD50 was higher than the dose used by the nativeswhich was approximately 0.8mg/kg body weight of thecrude extract. This is in agreement with previous studies[16, 17]. The acute toxicity results indicated that theextract was practically non-toxic acutely [38] and thusprovided a guide in the choice of doses for further in vivostudies. This high safety profile might have contributed tothe widespread use of Andrographis paniculata indifferent ethno-therapeutic interventions, particularly asan anti-hypertensive agent. Behavioural signs of toxicityobserved in treated rats include increased breathing rate,ataxia and muscular fatigue, reduced activity and pawlicking. However, in the negative control group thatreceived normal saline, none of the rats changed theirbehaviour and none died either.Histopathological results (Table 3 and Figs. 9-14)indicate that all of extract used were hepatotoxic,nephrotoxic and were also toxic to the heart and lungsonly at very high concentration. However these doseswere extremely very high as compared with the doseused by the natives to reduce Blood Pressure which wasfound to be about 0.81mg/kg body weight and the LD50was 1.9 x 104mg/kg body weight. In the control group(Group 9) no significant histological findings wereobserved in the major organs. These results areconsistent with previous reports on Andrographispaniculata [9, 13-15, 17, 18]. Intravenousandrographolide (a constituent of Andrographispaniculata) showed no abnormal cardiovascularresponse; liver enzyme test and the heart, liver, kidneyand spleen were normal [15, 36]. More so,it has a veryshort half life, 80% of it is removed within eight hours viathe kidney and gastro intestinal tract and 90% iseliminated within forty-eight hours [37].

Table 2: Results of determination of the LD50 of aqueous extracts of AP in rats using Probit method.Group Dose (mg/kg) Concentration

(mg/ml)Dead Survival Dead

%Corrected % Probit

123456789

5.6x103

1.1x104

1.4x104

1.7x104

1.9x104

2.2x104

2.5x104

2.8x104

6.923 x101

1.0x103

2.0x103

2.5x103

3.0x103

3.5x1034.0x103

4.5x1035.0x103

9.0

023566912-

121097663012

016.62541.650.050.075.0100-

2.0816.625.041.650.050.07597.91-

2.954.0264.3264.7865.05.05.05.6747.054

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0

1

2

3

4

5

6

7

8

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Prob

it

Log Dose

Fig. 8: Graph of acute toxicity of methanol extract of Andrographis paniculata after intra-peritoneal (IP) administration on rats

Table 3: Histopathological studies of the various organs of the ratsGroup OBSERVATION ON

LIVER KIDNEY HEART

1, 2 & 3 The liver had diffuse areasof necrosis withmononuclear cellularinfiltration, haemosiderosis,dilated sinusoids andcongested blood vessels.

Necrosis of the glomerulus; proximaland distal convoluted tubules andcollecting tubules with mononuclearcellular infiltration; there was purplishpigment in the medulla of the kidney.

Necrosis; fibrosis andmonounclear cellular infiltration;myocarditis.

4 Areas of necrosis withmononuclear cellularinfiltration, dilated sinosoidsand congested bloodvessels.

Necrosis of glomerulus, proximal anddistal convoluted tubules involving thecollecting tubules; mononuclear cellularinfiltration and proliferation of fibrousconnective tissue; fibrosis in medullarand pelvis.

Necrosis in the heart withmononuclear cellular infiltrationand myocarditis.

5 & 6 Had areas of necrosis;mononuclear cellularinfiltration, dilated sinusoidsand haemosiderosis.

Necrosis of glomerulus, proximal anddistal convoluted tubules involving thecollecting tubules with mononuclearcellular infiltration.

Had focal areas of necrosis withmononuclear cellular infiltration.

7&8 The liver of the rats hadareas of necrosis, dilatedsinusoids, mononuclearinfiltration and congestedblood vessels.

The kidneys had necrosis of theglomerulus and distal convolutedtubules involving the collecting tubuleswith mononuclear cellular infiltration andcongested blood vessels.

The hearts had areas of necrosisand mononuclear cellularinfiltration.

9Control

No significanthistopathological findings.

No significant histopathological findings. No significant histopathologicalfindings.

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Fig. 9: Photomicrograph of a section of untreated liver of cat which served as control [Note the normal sinusoids (S) andnormal hepatic cords (H). H&E stain x400].

Fig. 10: Photomicrograph of a section of a liver from a cat treated with methanol extract of Andrographispaniculata at 2.2 x 104 mg/kg for two hours. [Note the areas of necrosis of the hepatic cells (arrow heads) thedilated sinusoidal spaces the atrophied (shrinked) hepatic cords (A) and the central vein (CV). H & E stain X400].

CVH

S

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Fig. 9: Photomicrograph of a section of untreated liver of cat which served as control [Note the normal sinusoids (S) andnormal hepatic cords (H). H&E stain x400].

Fig. 10: Photomicrograph of a section of a liver from a cat treated with methanol extract of Andrographispaniculata at 2.2 x 104 mg/kg for two hours. [Note the areas of necrosis of the hepatic cells (arrow heads) thedilated sinusoidal spaces the atrophied (shrinked) hepatic cords (A) and the central vein (CV). H & E stain X400].

CVH

S

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Fig. 9: Photomicrograph of a section of untreated liver of cat which served as control [Note the normal sinusoids (S) andnormal hepatic cords (H). H&E stain x400].

Fig. 10: Photomicrograph of a section of a liver from a cat treated with methanol extract of Andrographispaniculata at 2.2 x 104 mg/kg for two hours. [Note the areas of necrosis of the hepatic cells (arrow heads) thedilated sinusoidal spaces the atrophied (shrinked) hepatic cords (A) and the central vein (CV). H & E stain X400].

CVH

S

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Fig. 11: Photomicrograph of a section of untreated kidney of cat which served as control. [Note: The normal glomerular (G)and normal Renal tubular epithelial cells (RT)].

Fig. 12: Photomicrograph of a section of the kidney of a cat treated with methanol extract of Andrographis paniculata at 2.2x 104 mg/kg from two hours. [Note the glomenular(g) and renal tubular arrow head (necrosis). H & E stain x400].

G

RT Bowman’sspace

G

NR

NR

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Fig. 13: Photomicrograph of a section of untreated heart of cat which served as control. [Note: Distinct nuclei ofmyocardial cells (N). H & E stain x 400].

Fig. 14: Photomicrograph of a section of the heart treated with methanol extract of Andrographis paniculata at 2.5 x 104mg/kg from 10 minutes. [Note the areas of necrosis of the myocardial cells (arrow heads) and the mononuclear cells (M). H& E stain x 400].

N

M

M

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CONCLUSIONSThe present investigation has shown thatAndrographis paniculata methanolic leaf extractexerted significant dose-dependent reduction of theblood pressure of anaesthesized cats. This justifiesthe continuous folkloric use of Andrographispaniculata leaf as a remedy for hypertension by thenatives in Garkida, Adamawa state of Nigeria. Thenatives usually take ten to fifteen of the fresh leavesof Andrographis paniculata to chew once or twice aday with a glass of cold water and this dose isenough to lower blood pressure continuously. Theantihypertensive effect of the extracts wassignificantly higher than that of Propranolol, astandard antihypertensive drug. Theantihypertensive effect of the plant extract may beattributed to the cardiac glycosides, terpenes andsteroids principles present in the plant, possiblyandrogropholide. However, further identification andelucidation of the structures of the actualconstituents responsible for this activity isunderway.

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