Anti-diarrhoeal evaluation of some medicinal plants used ...

Journal of Ethnopharmacology 79 (2002) 53 – 56

www.elsevier.com/locate/jethpharm

Anti-diarrhoeal evaluation of some medicinal plants used by Zulu
traditional healers

J. Lin a,*, T. Puckree b, T.P. Mvelase a

a Department of Biochemistry and Microbiology, Uni6ersity of Zululand, Pri6ate Bag X1001, Kwa Dlangezwa 3886, South Africa
b Department of Physiotherapy, Uni6ersity of Durban-West6ille, Pri6ate Bag X 54001, Durban 4000, South Africa
Received 8 April 2001; received in revised form 3 September 2001; accepted 20 September 2001

Abstract

Aqueous and methanolic extracts of several medicinal plants, Psidium guaja6a (leaves), Aristea spp., Iridaceae family (stem),
Bridelia micrantha (bark) and Eleutherina bulbosa (bulb), used by Zulu traditional healers were evaluated for anti-diarrhoeal
activity against different experimental models of diarrhoea in rats as well as for anti-microbial activity against different pathogenic
microorganisms that cause diarrhoea. The methanolic extract of P. guaja6a (leaves) was the only agent showing significant
inhibitory activities against the growths of Salmonella spp. (two isolates), Shigella spp. (S. flexneri, S. 6irchow and S. dysenteriae)
and enteropathogenic Escherechia coli (two isolates). The methanolic extract of B. micrantha (Bark) demonstrated weak inhibitory
activities against S. flexneri and S. plesiomonas. Based on the results in experimental rat models, there were significant reductions
in faecal output and frequency of droppings when plant extracts were administered compared with castor-oil treated rats. All plant
extracts also significantly retarded the propulsion of charcoal meal and significantly inhibited the PGE2-induced enteropooling.
The results have confirmed the effectiveness of all these Zulu medicinal plants as anti-diarrhoeal agents. © 2002 Elsevier Science
Ireland Ltd. All rights reserved.

Keywords: Medicinal plants; Anti-diarrhoeal activity; Anti-microbial activity

1. Introduction 1992; Ahsan et al., 1996; Rao et al., 1997; Menezes and
Rao, 1998; Mukherjee et al., 1998; Zavala et al., 1998;
Diarrhoea continues to be one of the leading causes Das et al., 1999; Offiah and Chikwendu, 1999; Rani et
of mortality and morbidity especially in children in al., 1999; Tona et al., 1999). South Africa has a great
developing countries (Black et al., 1982) including environmental and biological (genomic) diversity com-
South Africa. The emergence of multiple drug resistant pared with the rest of the world. A range of medicinal
strains of diarrhoeagenic pathogens has made the treat- plants with anti-diarrhoeal properties has been widely
ment of dysentery more difficult (Munshi et al., 1987; used by the traditional healers of difficult tribes in
Bennish et al., 1984). In developing countries, the ma- South Africa. The effectiveness of many of these antidi-
jority of people living in rural areas almost exclusively arrhoeal traditional medicines, however, has not been
use traditional medicines in treating all sorts of diseases scientifically evaluated. Aristea spp., Iridaceae family
including diarrhoea. has been used to treat cold, flu, malaria, toothache and
bruise and Eleutherina bulbosa to treat burns. However,
Due to these facts, the World Health Organization anecdotal evidence suggests that the above two medici-
(WHO) incorporates studies of traditional medicinal nal plants can also be used to treat gastro-intestinal
practice in its diarrhoeal disease control program. Sev- diseases. Bridelia micrantha is also used by traditional
eral studies have evaluated the effectiveness of some healers for the treatment of gastro-intestinal diseases,
traditional medicines in treating diarrhoea in all differ- paralysis and painful joints. Psidium guaja6a originally
ent continents (Chowdhury et al., 1991; Ferdous et al., from Mexico is also widely used by local traditional
healers. P. guaja6a is also a relatively well studied
* Corresponding author. Tel.: + 27-35-902-6095; fax: +27-35-902- species with respect to diarrhoea (Lutterodt, 1989;
6750. Ghosh et al., 1993; Tona et al., 1999).

E-mail address: [email protected] (J. Lin).

0378-8741/02/$ - see front matter © 2002 Elsevier Science Ireland Ltd. All rights reserved.
PII: S 0 3 7 8 - 8 7 4 1 ( 0 1 ) 0 0 3 5 3 - 1

54 J. Lin et al. / Journal of Ethnopharmacology 79 (2002) 53–56

This study reports on the anti-diarrhoeal effects of in each group. All rat studies described below were
some medicinal plants used by traditional Zulu herbal- followed using the method of Mukherjee et al. (1998)
ists using different experimental models in rats. It also with modifications.
looks at the anti-microbial activities of these medicinal
plants against different pathogenic microorganisms that 2.4. Castor oil-induced diarrhoea in rats
cause diarrhoea.
Rats were fasted for 18 h. Each of the plant extracts
2. Methodology at a dose of 400 mg/kg was administered orally to each
group of the experimental animals. The control group
2.1. Preparation of plants extracts received 1 ml of DMSO only. After 1 h of treatment,
each animal was fed with 1 ml of castor oil orally. The
P. guaja6a (leaf), Aristea spp., Iridaceae family treated rats were observed for defecation overnight.
(stem), B. micrantha (bark) and E. bulbosa (bulb) were The total defecate for each animal was weighed and
collected from the campus of the University of Zulu- means obtained for each group for comparison.
land, identified by A. Hutchings from the Botany De-
partment and confirmed by the National Botanical 2.5. Gastrointestinal motility tests
Institute. The plant extracts were prepared as described
by Lin et al. (1999). In brief, dry plant materials were One ml of charcoal meal (3% deactivated charcoal,
extracted using distilled water in a Soxhlet extractor for 10% distilled water and 87% of commercial rat food)
24 h. The aqueous extracts were concentrated in vacuo, was administered orally to the rats after a fast for 18 h.
at 40 °C, using a Rotary evaporator (Bu¨ chi). Methano- Immediately after the administration of charcoal meal,
lic (MeOH) crude plant extracts were extracted three each experimental group of rats was then fed orally
times in MeOH at 150 rpm for 24 h at room tempera- with different plant extracts (400 mg/kg). And the
ture. The combined extracts were then evaporated to control groups received either 1 ml of DMSO or no
dryness as above. The yields of 9.9, 11.7, 14.1, 8.6% treatment. All rats were sacrificed 30 min later. The
(w/w) from aqueous extracts, and 11.6, 7.0, 11.2 and intestinal distance that the charcoal meal had moved
9.1% (w/w) from MeOH extracts with respect to dry from the pylorus was measured and the value was
powdered material of P. guaja6a, Aristea spp., Iridaceae calculated as a percentage of the whole length of the
family, B. micrantha and E. bulbosa were obtained. The intestine.
final residues of each extract were re-dissolved in 100%
Dimethyl sulfoxide (DMSO) and stored in sterile brown 2.6. PGE2 induced enteropooling test
glass bottles in a freezer at − 20 °C until further
processing for bioassay. Each experimental group of rats was treated with
different plant extracts at a dose of 400 mg/kg after an
2.2. Anti-microbial assays 18-h fast. One control group received 1 ml of DMSO.
About 100 mg/kg of Prostaglandin E2 (PGE2) was im-
The disk diffusion method of Salie et al. (1996) was mediately administrated orally to all rats to induce the
used to evaluate anti-microbial activities against 17 enteropooling. Then, 30 min after the PGE2 administra-
isolates of diarrheagenic E. coli, 13 isolates of tion, all rats were sacrificed and the whole length of
Salmonella spp. and nine isolates of Shigella spp. Each intestine from pylorus to the caecum was dissected. The
extract was tested in triplicate. Control discs contained contents of the intestine were collected and the total
10 ml pure DMSO (100%). Standard antibiotics, volume was measured.
Nalidixic acid (30 mg per disc), tetracycline (30 mg per
disc), and chloramphenicol (30 mg per disc) were used 2.7. Statistical analysis
as positive controls.
The experimental results are expressed as the mean9
2.3. Animal used standard deviation (S.D.). Student’s t-test was used to
determine the statistical significance (PB 0.05).
The rats, Rattus nor6egicus, of either gender (adults,
\ 200 g or adolescence, B100 g) were used. All ani- 3. Results
mals were acclimatized to uniform laboratory condi-
tions for at least 1 week before performing an The methanolic extract of P. guaja6a (leaves) was the
experiment. Depending on the experiment, animals only agent showing significant inhibitory activities (in-
were divided into five or six groups with three animals

J. Lin et al. / Journal of Ethnopharmacology 79 (2002) 53–56 55

hibitory zone ]10 mm) against the growths of Table 2
Salmonella spp (two isolates), Shigella spp. (S. flexneri, Inhibition of gastro-intestinal motility by some Zulu medicinal plant
S. 6irchow and S. dysenteriae) and enteropathogenic E. extracts (n =3)
coli (two isolates). (Data not shown) All aqueous, etha-
nol and acetone medicinal plant extracts showed no Control Movement of charcoal meal as percentage of
significant inhibitory activity against all tested microor- full intestinal length (%)
ganisms. The methanolic extract of B. micrantha (bark)
demonstrated weak inhibitory activities against S. 91.29 94.15 92.71 9 4.71
flexneri and S. plesiomonas (10 mm \ inhibition zone] (−DMSO) (+DMSO)
7 mm).
Methanolic extract H2O extract
In all rat models, there were no significant differences
in the effects of medicinal plant extracts based on either Medicinal plant used 53.25 9 1.49*
gender or age of rats. Both methanolic and aqueous 57.60 9 7.10*
extracts of the same plant showed similar effects in all P. guaja6a 71.45 92.22*
cases. 69.02 9 5.17*
Aristea spp. 72.06 92.64* 51.88 92.44*
In the castor oil induced diarrhoea experiment, the
rats that did not receive the medicinal plant extracts (Iridaceae)
showed typical diarrhoeal signs: watery and frequent
defecation. The average weight of defecate in the con- B. micrantha 38.97 93.66**
trol group was 10.53 g. Treatment with each of the
medicinal plant extracts significantly reduced the weight E. bulbosa 70.66 98.74*
of defecate to 30–40% (Table 1) as well as reduced the
frequency of defecation compared with the control **PB0.005; *PB0.05.
group. All defecates from the plant extracts-treated
groups were dry or semi-dry. 4. Discussion

Administration of either methanolic or aqueous plant The methanolic extract of P. guaja6a (leaves) was the
extracts significantly slowed down the propulsion to- only agent that showed significant inhibitory activities
ward the caecum of the charcoal meals. Distance trav- against the growths of some diarrhoeagenic pathogens
eled by the charcoal meal was reduced to 50– 70% of in this study. Several studies (Lutterodt, 1989; Ghosh et
the full intestine in the experimental groups compared al., 1993; Tona et al., 1999) have also demonstrated
with 91–92% in the control group (Table 2). that P. guaja6a possesses antidiarrhoeal and antimicro-
bial activities. In addition, leaf extract of P. guaja6a
As shown in Table 3, PGE2 induced a significant contains anticough (Jaiarj et al., 1999), antiamoebic
increase in the fluid volume of rat intestine com- and antispasmodic properties (Lozoya et al., 1994;
pared with that in the control group that received 5% Tona et al., 1999). Lutterodt (1989) showed that
ethanol in normal saline. All aqueous and methanolic quercetin from the leaf extract inhibits acetylcholine
extracts of individual medicinal plants demonstrated release in the gastrointestinal tract that might account
their abilities to inhibit PGE2-induced enteropooling in for the antidiarrhoeal activity of the plant. Further-
rats. more, several chemical compounds isolated from guava
leaves possess antibacterial activities against different
strains of gram negative bacteria (Caceres et al., 1990)
as well as gram positive bacteria (Jaiarj et al., 1999). All

Table 3
Anti-enteropooling effect of some Zulu medicinal plant extracts in
rats (n = 3)

Table 1 Volume of intestinal fluid
Effect of some Zulu medicinal plant extracts on castor-oil induced (ml)
diarrhoea in rats (n =3)
Ethanol in saline 0.85 9 0.15

Control Mean defections per rat (10.53 9 0. 94 mg) PGE2 in ethanol 2.65 90.30
(100%) (100 mg/kg)

Methanolic extract, H2O extract, Methanolic extract Aqueous extract
mg (%) mg (%)

Medicinal plant used

Medicinal plant used P. guaja6a 1.44 90.20* 1.25 90.23*
1.35 90.17*
P. guaja6a 3.53 90.68* (33.55) 4.059 1.13* (38.49) Aristae spp. 1.22 90.15*
3.12 9 0.05* (29.69) 1.45 90.21*
Aristae spp. (Iridaceae) 3.78 9 0.34* (36.02) 3.82 9 1.24* (36.25) (Iridaceae) 1.05 9 0.22*
2.969 0.78* (28.11)
B. micrantha 4.11 9 1.01* (39.03) B. micrantha 1.55 90.23*

E. bulbosa 3.82 90.88* (36.25) E. bulbosa 1.15 9 0.10*

*PB0.005. *PB0.005.

56 J. Lin et al. / Journal of Ethnopharmacology 79 (2002) 53–56

plant extracts significantly reduced castor-oil induced granatum seed extract in rats. Journal of Ethnopharmacology 68
diarrhoea, slowed the propulsion of charcoal meal and (1), 205 – 208.
significantly inhibited the PGE2-induced enteropooling. Ferdous, A.R., Islam, S.N., Ahsan, M., Hasan, C.M., Ahmed, Z.U.,
It is well known that the administration of PGE2 or 1992. In vitro antibacterial activity of the volatile oil of Nigella
PGE1 induces the signs of inflammation, swelling and sati6a seeds against multiple drug resistant isolates of Shigella, V.
edema resulting from increased capillary permeability. cholerae and E. coli. Phytotherapy Research 6, 137 – 140.
Our results suggest that these plant extracts can reduce Ghosh, T.K., Sen, T., Das, A., Dutta, A.S., Nag Chaudhuri, A.K.,
the capillary permeability and, therefore, decrease mu- 1993. Antidiarrhoeal activity of the methanolic fraction of the
cocal inflammation. extract of unripe fruits of Psidium guaja6a Linn. Phytotherapy
Research 7, 431 – 433.
Compared with the leaf extract of P. guaja6a, the Jaiarj, P., Khoohaswan Pm Wongkrajang, Y., Peungvicha, P.,
extracts of Aristea spp., Iridaceae family (stem), B. Suriyawong, P., Saraya, M.L., Ruangsomboon, O., 1999. Anti-
micrantha (bark) and E. bulbosa (bulb) produced a cough and antimicrobial activities of Psidium guaja6a Linn. leaf
similar level of antidiarrhoeal effects in all animal mod- extract. Journal of Ethnopharmacology 67 (2), 203 – 212.
els. The inhibitory effects of other medicinal extracts Lin, J., Opoku, A.R., Geheeb-Keller, M., Hutchings, M.A.,
from the above results prove that these plant materials Terblanche, S.E., Jager, A.K., van Staden, J., 1999. Preliminary
used by Zulu traditional healers can be considered as screening of traditional Zulu medicinal plants for anti-inflamma-
potent antidiarrhoeal agents. tory and anti-microbial activities. Journal of Ethnopharmacology
68, 267 – 274.
Acknowledgements Lozoya, X., Meckes, M., Abou-Zaid, M., Tortoriello, J., Nozzolillo,
C., Arnason, J.T., 1994. Quercetin glycosides in Psidium guaja6a
We would like to thank the Medical Research Coun- L. leaves and determination of a spasmolytic principle. Archives
cil (SA) and the University of Zululand for the financial of Medical Research 25 (1), 11 – 15.
support. We also would like to thank A. Hutchings Lutterodt, G.D., 1989. Inhibition of gastrointestinal release of acetyl-
from the Botany Department at the University of Zulu- choline by quercetin as a possible mode of action of Psidium
land for the collection and the identifications of these guaja6a leaf extract in the treatment of acute diarrhoea. Journal
medicinal plants. of Ethnopharmacology 25, 235 – 238.
Menezes, A.M., Rao, V.S., 1998. Effect of Astronium urundeu6a
References (aroeira) on gastrointestinal transit in mice. Brazilian Journal of
Medical and Biological Research 21 (3), 531 – 533.
Ahsan, M., Chowdhury, A.K.A., Islam, S.N., Ahmed, Z.N., 1996. Munshi, M.H., Haider, K., Rahman, M.M., Sack, D.A., Ahmed,
Garlic extract and allicin: broad spectrum antibacterial agents Z.U., Morshed, M.G., 1987. Plasmid mediated resistance to
effective against multiple drug resistant strains of Shigella dysente- nalidixic acids in Shigella dysenteriae type I. Lancet ii, 419 –421.
riae type 1 and Shigella flexneri, enterotoxigenic Escherichia coli Mukherjee, P.K., Saha, K., Murugesan, T., Mandal, S.C., Pal, M.,
and Vibrio cholerae. Phytotherapy Research 10, 329 –331. Saha, B.P., 1998. Screening of antidiarrhoeal profile of some plant
extracts of a specific region of West Bengal, India. Journal of
Bennish, M., Eusof, A., Kay, B., Wierzba, T., 1984. Multi-resistant Ethnopharmacology 60 (1), 85 – 89.
Shigella infections in Bangladesh. Lancet ii, 441. Offiah, V.N., Chikwendu, U.A., 1999. Antidiarrhoeal effects of Oci-
mum gratissimum leaf extract in experimental animals. Journal of
Black, R.E., Brown, K.H., Becker, S., Yunus, M., 1982. Longitudinal Ethnopharmacology 68 (1), 327 – 330.
studies of infectious diseases and physical growth of children in Rani, S., Ahamed, N., Rajaram, S., Saluja, R., Thenmozhi, S.,
rural area of Bangladesh. American Journal of Epidemiology 115 Murugesan, T., 1999. Antidiarrhoeal evaluation of Clerodendrum
(3), 305 – 314. phlomidis Linn. leaf extract in rats. Journal of Ethnopharmacol-
ogy 68 (1), 315 – 319.
Caceres, A., Cano, O., Samayoa, B., Agnilar, C., 1990. Plants used in Rao, V.S., Santos, F.A., Sobreira, T.T., Souza, M.F., Melo, C.L.,
Guatemala for the treatment of GI disorders 1. Screening of 84 Silveira, E.R., 1997. Investigations on the gastroprotective and
plants against enterobacteria. Journal of Ethnopharmacology 38, antidiarrhoeal properties of ternatin, a tetramethoxyflavone from
55 – 73. Egletes 6iscose. Planta Medica 63 (2), 146 – 149.
Salie, F., Eagles, P.F.K., Leng, H.M.J., 1996. Preliminary antimicro-
Chowdhury, A.K.A., Ahsan, M., Islam, S.N., Ahmed, Z.N., 1991. bial screening of four South African Asteraceae species. Journal
Efficacy of aqueous extract of garlic and allicin in experimental of Ethnopharmacology 52, 27 – 33.
shigellosis in rabbits. Indian Journal of Medical Research [A] 93, Tona, L., Kambu, K., Mesia, K., Cimanga, K., Apers, S., De Bruyne,
33 – 36. T., Piters, L., Totte, J., Vlietinck, A.J., 1999. Biological Screening
of traditional preparations from some medicinal plants used as
Das, A.K., Mandal, S.C., Banerjee, S.K., Sinha, S., Das, J., Saha, antidiarrhoeal in Kinshasa, Congo. Phytomedicine 6 (1), 59 –66.
B.P., Pal, M., 1999. Studies on antidiarrhoeal activity of Punica Zavala, M.A., Perez, S., Perez, C., Vargas, R., Perez, R.M., 1998.
Antidiarrhoeal activity of Waltheria americana, Commelina
coelestis and Alternanthera repens. Journal of Ethnopharmacology
61 (1), 41 – 47.