Indian Journ al of Experimental Biology Vo l. 39, Janu ary 200 1, pp. 63-67

Evaluation of methanolic extract of Ficus platyphylla on gastrointestinal activity

S Amos"*, L Binda•, B Chindo•, P Akah", M Abdurahmanb, H U Danmall amb, C Wambebe• & K Gamaniel•

"Department of Pharmacology and Toxicology, Nati onal Institute fo r Pharmaceutical Research and Development , P. M. B. 2 1, Ahuja, Nigeria

Fax: 2349523 1 043; e. mail : samsonamos @yahoo.co.uk

hDcpartment of Pharmacognosy and Drug Development , Ahmadu Bello Uni versity, Zaria

Received II November 1999; revised 27 September 2000

Methanolic extract of Ficus platyphy/la was tested on isolated rabbit jejunum, rat duodenum and gastrointestinal motility in mice. The extrac t showed a hi phasic effect on isolated smooth muscle. Lower concentration or extract caused contract ion, while higher concentrations produced relaxation. The cont ractil e phase was attenuated by atropine , whi le relaxant phase attenuated histamine induced contraction or guinea pig ileum. The ext ract also exh ibited a dose-dependent inhib ition of gastrointestinal mot ility. Acu te toxic it y test in mice establi shed LD 511 value (ip) or the ex tract to be 2000 mg/kg. Preliminary phytochemical screening or the extract gave positive tes t fo r fl avonoids, tannins and saponins.

Majority of the populati on in developing count ries remains dependent on medicinal pl ants for health care. Based on thi s fact, scienti sts and WHO are focussing attention on medicinal plants, because of great potential that these plants carry in combating various di seases. Ficus platyphylla (Moraceae) is a tree commonl y found in Savannah region, West Africa. In northern Ni geri a, where it is commonl y known as gamji , the latex heated or chewed is used as a birdlime 1

• Our previous studies revealed that the plant possesses analgesic and anti-infl ammatory effects2 and has behavioural effects in rodents3

. To the best of our knowledge, no report has been made on its acti vity on the gastrointestinal tract. This study was carried out to evaluate the effects of the methanolic extract of F. platyphylla on gastro intestinal tract.

Materials and Methods Plant collection and identification-The plant

materi al was collected from Hong, Adamawa State, Nigeri a in September 1998. Botanical identity was confirmed by Messers. A. Ohaeri and I. Muazzam, Department of Pharmacognosy and Alternati ve Medicine, NIPRD, Abuj a, Ni geri a. A voucher specimen of the plant has been depos ited in NIPRD herbarium fo r future reference.

Extraction of plant material-The stem bark was cleaned, air-dri ed fo r 7 days and then reduced to coarse powder by grinding. The powder (80 g) was extracted with I L of methanol using a sox hlet extractor. The extract was subsequentl y concentrated

to dryness in vacuo using a rotary evaporator and it gave a mean yield of 8.2% (w/w). This was stored at 4 °C unti I used for the study.

Animals-Swiss albino mice (20-25 g), rats ( 180-220 g), guinea pigs (250-400 g) and rabbits ( 1.5-3 kg) bred in the Animal Fac ility Centre, NIPRD were used in these studies. The animals were kept under standard conditions of temperature, re lative humidity and light/dark cycle. The animals were fed with Ladokun animal feeds and water ad libitum.

Acute toxicity determination-Eight groups, each consisting of 5 mice of both sexes were used for the test. Groups 1-7 were injected int raperitoneall y (ip) with varying doses ( I 00-4000 mg/kg) of the extract in normal saline, while group 8 which served as control received equi valent vo lume of normal saline. After treatment, the animals were observed fo r clin ical signs and symptoms of tox icity over a period of 24 hr. Death within thi s period were recorded. LD50 (with 95% confidence limits) was estimated using probit

I 0 4 ana ys1s .

Phytochemical test- Phytochemical analys is of the extract was performed according to the methods of Clarke5

, Odebiyi & Sofowora6, and Trease & Evans7

.

Test for alkaloids, saponins, tannins, flavonoids, etc. were carried out.

Studies on rat duodenum- The method of Schlemper et a/. 8 was foll owed and in brief. Wistar rats weighing 180-220 g of either sex were killed by a blow on the head and exsanguinated. The abdominal

64 INDIAN J EXP BIOL, JANUARY 2001

cavity was exposed and the intestine removed . After di scarding a part of I 0 em nearest the gastrointestinal junction, the duodenum was removed and place in a petri dish containing Tyrode's solution. The intestinal content was removed by flu shing with Tyrode' s containing (mM) NaCI, 136.8; KCI , 2.7; CaCI2. 1.3; NaHCO,, 12; MgCh, 0.5; Na2P04, 0.14; glucose, 5.5. The duodenum was cut into segments (3 em) and each segment was mounted in a 20 mL organ bath containing Tyrode' s solution at 37° ± I °C and aerated with air. An initi al tension of 1.0 g was applied to the tissue for 60 min . During that time the physiological solution was changed every 15 min , after which the effect of the extract at final bath concentration of 0.05-3 .2 mg/mL and acetylcholine (2.75 x I o·'0-8.8 x I o·9 M ) were evaluated. Effects of the extract and acetyl choline on the tissue incubated with atropine (5x I o-9 M) were evaluated. Responses were recorded isometrically on Ugo Basile Unirecorder 7050.

Studies on rabbit jejunum- The rabbits were killed by a blow on the head, exsanguinated and abdomen opened. Segments of the jejunum (about 2-3 em long) were removed and dissected free of adhering mesentery. The tissue was mounted in an organ bath (20 mL) containing Tyrode' s solution at 37° ± I °C and aerated with air. A tension of 0.5 g was applied for 60 min (equilibration period) during which the physiological solution was changed every 15 min . At the end of the equilibration period, the effect of acetylcholine (ACh) and extract were evaluated.

Studies on guinea pig ileum- Adult guinea pigs (250-400 g) of either sex were starved overnight but had free access to water. Animals were killed by a blow on the head, exsanguinated and the abdomen was opened. Ileum was removed and cut into segments of 2-3 em long. The segments were dissected free of adhering mesentery and mounted in an organ bath (20 mL) containing Tyrode's solution, gassed with air and maintained at 37°C. The tissue was equi librated for 60 min during which the bathing solution was replaced every I 0 min . At the end of the equilibration period, the effect of increasing concentration of the extract on hi stamine induced contraction of guinea pig ileum was evaluated. Responses were recorded on Ugo Bas ile Unirecorder 7050. Determinations were done in quadruplicates.

Studies on gastrointestinal motility in mice--To test the effects of the extract on gastrointestinal motility adu lt Swi ss albino mice (20-25 g) were randomly divided into 5 groups of 5 mice each. The animals were starved for 24 hr prior to the experiments, but

were allowed access to water. One group of animals was given 20 mL/kg of normal sal ine, while the remaining other 3 groups received ip the extract at doses of 25, 50 and I 00 mg/kg. The last group received atropine (0.1 mg/kg; ip). After 5 min of drug administration, 0.5 mL of charcoal suspension(5%) in aqueous solution of tragacanth powder (I 0% )was admini stered to each animal orally. The animals were killed 30 min later and the abdomen was opened. Percentage di stance of the small intestine (from pylorus to caecum) travelled by the charcoal plug in both the extract and the normal sal ine treated groups were determined9

'10

.

Studies on castor oil induced diarrhoea-Swi ss albino mice of either sex ( 18-22 g) were used for the experiment. The mice were fasted for 18 hr prior to commencement of the experiment and were randomly divided into 4 groups of 5 mice each. The animals in group I received normal saline (30 mL/kg; i.p)., while those animals in groups II , III and IV received the extract (doses of 25, 50 and 100 mg/kg; i.p). The last group received Ioperamide (5 mg/kg i.p). After 30 min of drug pre-treatment, castor oil (0.2 mL/mouse) was admini stered intragastrically. The animals were placed in individual cages over clean filter paper. After 3 hr of oil challenge, mouse cages were inspected (by an observer unaware of the particular treatment) for the presence of characteristic diarrhoea droppings; their absence was recorded as a protection from diarrhoea 11.1

2

and the percentage protection was calculated 13.

Drugs-Acetylcholine chloride, histamine, atropine (all from Sigma Chemical Company, USA), mepyramine (M & B) were used. All drugs were freshly prepared to desired concentrations with di stilled water just before use. The extract was also fresh ly prepared using distilled water. Parallel control experiments were also carried out in order to correct possible effects caused by vehicle alone.

Statistical analysis-Results were expressed as mean± SEM. The significance of difference between the means was determined by Student's t test and resu lts were regarded as significant at P < 0.05 (Ref. 14).

Results Fresh extract of F. platyphylla gave pos1tJve

reactions fo r saponins, tannins and flavonoids. In the preliminary acute toxici ty test in mice, LD50 va lues of the extract given ip was 2000 mg/kg.

Effect on rabbit jejunum-Extract of F.platyphylla ex hibited biphasic effect on rabbit jejunum with lower

AMOS eta/.: EVALUATION OF METHANOLIC EXTRACT OF FICUS PLA TYPHYLLA 65

concentrations (0.05-0.4 mg/mL) producing contraction and higher concentrations (0.8-1 .6 mg/mL) producing relaxation (Fig. I) .

Effect on rat duodenum-Extract of F. platyphylla exhibited a biphasic effect on rat duodenum. Lower concentrations (0.1-0.4 mg/mL) evoked a

• • • • o.os 0.1 0.2 0.4

concentration dependent contraction of duodenum, whi le higher concentrations (0.8-1.6 mg/mL) showed relaxation on smooth muscle. The extract induced contraction was blocked by atropine mid relaxant phase did not attenuate ACh induced contractions of duodenum (Fig. 2).

0.5g

min

• • 0 . 8 1.6 Ficus pla typh y lla (mg/ ml ) ----'----

Fig. 1-Biphasic effects of methanolic extract of F. platyphylla on the spontaneous activity of rabbit jejunum .

.. ·/-- / -·-

j I !

. ;-

'·

A

i I i . . , ./-· -·., --·/ ·-/:' -.. /-log J· ... r ----: ... ·- -- ·- . --

j

! i i

1.6 (mg/ml)

.· min ·

Atr

mg/ml A

E 0.8mg/ml

---r - - "--;·--- - -- --.. .

__ :r~.~ 1

---L_

Fig. 2-Effect of methnnolic extract of F. platyphylla (E; 0. 1- 1.6 mg/mL); acetylcholine (A); and atropine (Atr; 5x l o-~ M) on the rat duodenum.

66 IND IA N J EXP BIOL, JAN UARY 2001

Effect on guinea pig ileum-Extract of F. platyphylla was devoid of contractile e ffect on guinea pig ileum. However the extract inhibited hi stamine evoked responses of ilea l segment in a concentration dependent manner (Fig. 3).

Effect Oil gastrointestinal transit in mice-The results of charcoal meal test showed that the extract of F. platyphylla caused a significant decrease in gut motility when compared with normal sa line. Average percentage di stance trave lled by the charcoa l plug has been shown in Table I .

Effect on castor oil induced dia rrhoea- The ext ract (25, 50 and I 00 mg/kg) and loperamide (5 mg/kg) protected mice aga inst diarrhoea induced by castor oil significantly as co mpared to contro l. (Table 2).

Discussion The present study has provided a preliminary data,

which suggested that methano lic ex tract of F. platyphylla contains biologica lly acti ve components . The contractile response of the extract at lower concentrations was similar to those of acetylcholine on choline rgic receptors 15

• Atropi ne a known cho linergic antagonist16 blocked the effect of this contractile phase of the extract, in a s imil ar way it blocked Ach induced sub-maximal contracti ons of the smooth muscle. The contractions evoked by the

I ·• . -9

3.3X10

H

I ! i

!· --·-; . .

I

.·. ! . --1 I

I

M E

0.1

mg/ml

. I I

0.2

mg/ml

: min ·

0.4

mg/m l

Table !- Percentage di stance travelled by charcoal plug in mice treated wi th F. platyphy/la and atropine

[Values are mean ± SE of 5 mice]

Treatment (mg/kg)

Normal Saline 20 mUkg

F. platyphy/la 25

50

100

Atropine 0. 1

Maxi mum di stance trave ll ed (%)

71.2 ± 5.3

66 ± 2.4

44.7 ± 3.2*

40.5 ± 2.6*

32.5 ± 6.5*

Signili cant at *?<0.05 treat ment group vs normal sa line.

Table 2-EfTect of F. platyphylla on castor oil (0.2 mUkg) induced diarrhoea in mi ce

Treatment (mg/kg)

Castor oi l (0.2 mUkg)

F. platyphy /la +Castor oil 25 50 100 5

o. of mice with diarrhoea

5/5

5/5 115* 0/5 * 0/5 *

n = 5 signilicant at *?<0.05 treatment group vs normal saline

-- · -·--/

..... . ;·--

i i

0.8

mg/ml

• H

r ·- , - ·- . . I .:

7~~) 7. I

--1--- -/ ---' .. I I : . I -. ·j

"1 -~ 1---~i -i I i i - I . -- I -

.... ! --! ·-·-·-l --i I I

_\ ! .. . I

\ H

Mep w -6

2.5X10 M

Fig. 3-lnhibitory effect of extrac t of F. f'latvphylla !E; 0.1 -0.8 mg/mL) on hi stamine (H; 3.3x I o-~ M) induced contraction of the guinea pig ileum.

AMOS et a/.: EVALUATION OF METHANOLIC EXTRACT OF FICUS PLATYPHYLLA 67

extract, therefore, might have resulted from activation of muscarinic receptors17

.18

. On the other hand , relaxant phase of the extract on smooth musc le did not attenuate Ach induced contraction, but was found to inhibit hi stamine induced contractions 111 a concentration dependent manner. Activity of the extract in this regard was similar to that of mepyramine, a known H 1 receptors blocker19

·20

, which also blocks the contractile response evoked by histamine. Thus, it is proposed that the relaxant phase mi ght be mediating its effects through blockade of hi staminergic receptors.

The charcoal meal test, which allows for comparative evaluation of the degree of inhibition/stimulation of gastrointestinal motility in laboratory animals21

, the finding th at F. platyphylla decreased peri staltic movement in the charcoal mea l study corroborated with some of the results of in vitro studies. Phytochemical screening of the extract revealed the presence of flavonoids, tannins and saponins. These constituents are known to be bioactivc principles . Flavonoids are known to inhibit contractions induced by spasmogensn 2

:; and inhibit small intestinal transie 4

. Properties such as thi s may underlie the observed pharmacological effects. The results provided useful guide for isolation of ac ti ve principles in thi s plant.

Acknowledgement This work was supported by a gran t from NJPRD,

Abuja, Nigeria. The technical assistance of Adamu Mohammed, David Akumka, Martins Emeje and Hauwa Abdullahi is acknowledged. The authors are grateful to Charles Balogun for typing the manuscript.

References I Dalziel J M, The useful plants of West tropical Africa. (Crown

agents for the Co lonies, London) 1955, 281.

2 Amos S, Chindo B, Edmond I, Akah P, Wambebe C & Gamaniel K, Herbs, Spices Me d. Plant, ( 1999); In press .

3 Gam:llliel K, Amos S, Cl1indo B, Wambebe C, Vongtau H. Olusola A, Abdu lrahman E M, Odutola A A, Akah P A & Adamu S S. Behav. Pharmacal. ( 1999). (In press).

4 Mill er L C & Tainter M L, Proc Soc EXJ! Bioi Ma l, 57, (1944) 26 1.

5 Clarke E G C (Ed), Isolation and identification of drugs. Vol. 2, edited by E G C Clarke (Pharmaceutical Press London) 1975, 905.

6 Odebiyi 0 0 & Sofowora E A, Phytochemical Screening of Nigerian Medicinal Plants. Lloydia, 41 ( 1978) 234.

7 Trease G E & Evans W C. Pharmacognosy, 13' 11 editi on (Engli sh Language Book Society. Baillicre, Tindall , London) 1989, 683 .

8 Schlemper V, Ribas Nicol an M & Ccchinel Filho V, Phytomedicine, 3 ( 1996) 2 1 I.

9 Akah P A, Fitoterapia, 60 ( 1989) 45 . 10 Akah P A & Offiah V N, lnt J Phannacog, 30 (1992) 21 3. II lzzo A A, Mascolo N, Dicarl o G & Capasso F, Eur J

Pharmacal, 27 1 ( 1994) 3 1. 12 Diurno M V, lzzo A A, Mazzoni 0 , Bolognese 0 & Capasso

F, J Pharm Pharmacal, 48 ( 1996) 760. 13 Bolton S, Phannacelllica/ statistics - Practical afl(/ clinical

application. 3'J edition. (Marcel Dekker Inc. New York , USA) 1997.

14 Edi th Heilbronn & Tamas Banfai , Prog Neurobiol, II (1978) 11 7

15 Pharmacology 3rd edit ion edited by H P Rang, M M Dale & J M Ritter (Churchi ll Livingstone UK) 1995, 226.

16 Bolton T B, Physiol Rev, 59 ( 1979a) 606. 17 Bolton T B, Br Med Bull, 35 ( 1979b) 275 . 18 Black J W, Duncan W A M & Durant G J, Nature, ~36

(1972) 385. 19 Ganellin C R, Phannacologv of histamine receptor, edited by

C R Ganellin , M E Parson, (Wright Bristol) 1982, I I. 20 Olliah V N, Akah P A & lstzoh A 0, Phytotherapy Res, 10

(1996) 322. 2 1 Capasso F, Pinto A, Maascolo N, Autore G & France M P,

Phannacol Res Comm, 20 ( 1988) 20 I. 22 Macauder P J, Prog Clin Bioi Res, 213 ( 1986) 489. 23 Viswanathan S, Thirugnana S P & Bapltn J S, Arch /!11

Phannacodyn, 270 ( 1984) 151.