Eurycoma longifolia in Radix for the Treatment of Ethanol-induced Gastric Lesion in Rats
The effect of treatment with Radix on ethanol-induced gastric lesions was investigated. The main ingredient of Radix is Eurycoma longifolia. Twenty-four rats of the Sprague-Dawley species were randomly divided into four groups. Three groups were given 0.5 mL 100% ethanol orally. Another group was used as a control and was given only distilled water orally (control). After 6 h all the rats were fed with normal diet. One group that was administered with ethanol was only given distilled water orally (no treatment). Another two groups that were administered with ethanol were treated with oral Radix 0.128 mg g-1 b.wt. (Radix) and oral ranitidine 21.4 mg kg-1 b.wt. (Ranitidine), respectively. After one week, all the rats were fasted overnight and sacrificed. The stomach was isolated and examined for the presence and severity of gastric lesions. Measurements for malondialdehyde content and gastric acid concentration were also done. It is found that the ulcer index was lower in the Radix and ranitidine group compared to the no treatment group whereas in the control group there was no lesion. There was no difference in ulcer index between the Radix and ranitidine group. The gastric MDA content was significantly higher in all the groups that were induced with ethanol compared to the control group but no difference between all the ethanol-induced groups. There was no difference in the gastric acid concentration in all groups. Hence it is concluded that Eurycoma longifolia in Radix is as effective as ranitidine in the treatment of ethanol-induced gastric lesions in rats.
Received: January 15, 2013;
Accepted: March 05, 2013;
Published: May 16, 2013
About 80% of the population is still using traditional medicine to treat health
problem (Diallo et al., 1996). Traditional medicine
includes consuming herbs, plants, animals or minerals and also practices according
to religious belief and norms. It is often termed alternative, complementary
or non-conventional medicine. Radix is a product by HPA Industries from
Malaysia. The main ingredient of Radix is Eurycoma longifolia,
which is also known as Tongkat Ali, Long jack, pasak bumi, Piak or tung saw.
Its usage is mainly focused on its aphrodisiac characteristic. Among the active
components in Eurycoma longifolia are alkaloid, saponins, erycomanone
and eurycomalactone which are able to stimulate testosterone production in male.
Tada et al. (1991) revealed the presence of
quassinoids in Eurycoma longifolia which has anti-ulcer effect. Ulcer
is a break on an organ surface or tissue due to superficial tissue inflammation.
Peptic ulcer is ulcer that occur at the gastrointestinal tract either stomach
(gastric ulcer) and duodenum (duodenal ulcer).
The mechanism of ethanol-induced gastric lesion is complicated and multifactorial.
Ethanol causes oedema, hyperemia especially to the superficial epithelial cells,
venoconstriction, arteriol dilatation, necrosis and hemorrhage on gastric mucosal
and submucosal surface (Dinoso et al., 1976;
Guth et al., 1984). A few studies relate the
lesion formation due to its free radicals and lipid peroxidation (Hernandez-Munoz
et al., 2000; Pan et al., 2008; Salim,
1990). Malondialdehyde (MDA) is the end product of lipid peroxidation. Oxyradical
produced during ischaemia-reperfusion causes severe changes at the cellular
level. It causes cell death because it attacked the cell component which is
essential such as nucleic acid, protein and lipid. The oxy-radical also stimulates
the membrane lipid peroxidation process forming toxic products such as epoxide,
aldehyde and new free radicals (Glavin and Szabo, 1992).
This study was carried out to determine the effects of Eurycoma longifolia
in Radix for the treatment of ethanol-induced gastric ulcer in rats considering
the importance and widespread usage of traditional and complementary medicine
in the community.
MATERIALS AND METHODS
In this study, twenty-four rats of the Sprague-Dawley species (200-250 g) were randomly divided into four groups. Three groups were given 0.5 mL 100% ethanol by oral gavage. Another group was used as a control and was given only distilled water by oral gavages (control). After six hours all the rats were fed with normal rat diet. One group that was administered with ethanol was only given distilled water by oral gavage (no treatment). Another two groups that were administered with ethanol were treated with Radix 0.128 mg g-1 b.wt. diluted in distilled water (Radix) given by oral gavage and ranitidine 21.4 mg kg-1 b.wt. (Ranitidine) given by oral gavage, respectively. Food and water were given ad libitum throughout the experiment. After one week, all the rats were fasted overnight and sacrificed. The stomachs were isolated and examined for the presence and severity of gastric lesions. Measurements for MDA and gastric acid concentration were also done. This study was conducted in the Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia and has been approved by the Universiti Kebangsaan Malaysia Animal Ethics Committee.
Measurement of gastric lesion: The lower end oesophagus and pylorus
were clamped and the stomach was removed. It was then opened up and the gastric
lesions was assessed using semi quantitative scale by Berry
et al. (1988) which have been modified by Nafeeza
et al. (1999) (Table 1).
Measurement of malondialdehyde: Gastric tissue MDA content was measured
using a method modified by Ledwozyw et al. (1986).
The gastric tissue was homogenised in distilled water, centrifuged and the diluted
supernatant was added with trichloroacetic acid.
After 15 min at room temperature, thiobarbituric acid was added and the samples
were incubated in 100°C water bath for 30 min. After cooling, n-butanol
was added and the absorbency of the upper phase was read.
Measurement of gastric acid concentration: Samples of gastric juice
were collected and centrifuged at 3000 rpm for 10 min. Aliquots of each sample
were titrated with 0.01N NaOH to a pH of 7.0. The concentration of hydrogen
ion was calculated as described by Shay et al. (1954).
Statistical analysis: All results were expressed as Mean±SEM. Statistical analysis was performed using SPSS version 12.0 and Excel by student t-test and two-way ANOVA. A p-value of less than 0.05 was considered statistically significant for all parameters.
Measurement of gastric lesion: The ulcer index was significantly lower in the Radix (0.17±0.11) (p = 0.041) and ranitidine group (0.08±0.08) (p = 0.013) compared to no treatment (0.67±0.11) group. There was no lesion in the control group. There was no difference in ulcer index between the Radix and ranitidine group (Fig. 1).
Measurement of malondialdehyde (MDA): The gastric MDA content was significantly higher in all the groups that were induced with ethanol i.e., no treatment (0.3273 nmol mg-1 protein±0.04), Radix (0.4107 nmol mg-1 protein±0.07) and ranitidine (0.3341 nmol mg-1 protein±0.02) compared to the control group (0.1776 nmol mg-1 protein±0.02). There was no difference in the gastric tissue MDA concentration between all the ethanol-induced groups (Fig. 2).
Measurement of gastric acid concentration: There was no significant
difference in the gastric acid concentration among all the groups i.e., control
group (3.073 mEq L-1 ±0.56), no treatment (3.47 mEq L-1±0.59),
Radix (5.1717 mEq L-1±0.91) and ranitidine (2.832 mEq L-1±0.39)
||Effects of Radix on gastric ulcer index after one week
of treatment, The data is expressed as Mean±S.E.M (n = 6), *p<0.05
compared to control
||Effects of Radix on gastric tissue MDA, content after
one week of treatment. The data is expressed as Mean±SEM (n = 6).
*p<0.05 compared to control
||Effects of Radix on gastric acid concentration after
one week of treatment, The data is expressed as Mean±SEM (n = 6)
This study showed that Radix was able to reduce 75% of the gastric ulcer index compared with no treatment group. Radix is as good as ranitidine in the treatment of ethanol-induce gastric lesion as there is no significant difference between the ulcer index in the Radix and ranitidine group.
In this current study, we found that MDA was increased after challenged with
ethanol. Elevated gastric MDA reflects an intensification of lipid peroxidation
process and further prove the involvement of free radical in ethanol-induced
gastric lesions. Antioxidant such as Eurycoma longifolia used in this
study is expected to retard lipid peroxidation process but this was not the
case in this study. Amongst the factors causing the lack of antioxidant effects
of Eurycoma longifolia could be the dose of ethanol used. If, in fact
the dose of ethanol used is high and ethanol increases the production of free
radical, it is highly possible that the amount of Eurycoma longifolia in
Radix used is insufficient to scavenge the excessive free radical. Even
with no reduction in the lipid peroxidation process, Radix is able to
reduce the gastric lesion; most probably the mechanism is not via its antioxidant
This study showed that 100% ethanol did not increase gastric acid concentration.
Previous study also showed that ethanol at higher concentration has either no
effect or mildly inhibits gastric acid concentration whereas lower concentration
up to 5% stimulates gastric acid secretion (Chari et
al., 1993). We found that Radix has no effect on gastric acid
concentration. No study has shown the effect of Eurycoma longifolia on
gastric acid. It could be that Eurycoma longifolia in Radix has
no effect on gastric acid. Ranitidine is a competitive H2 histamine
receptor antagonist to parietal cell. As expected it has no effect on the gastric
tissue MDA content. Dose used in this study is according to the oral dose given
to human (4.3 mg kg-1 day-1). Ranitidine inhibits basal,
nocturnal and food stimulated acid secretion depending on the dose given (Segawa
et al., 1991; Yeomans, 2000). Study done
by Segawa et al. (1991) using ranitidine 100
mg kg-1 day-1 subcutaneously was able to inhibit basal
gastric acid secretions. This study showed that ranitidine was unable to inhibit
gastric acid secretion. It could be that one week duration is not enough to
reduce gastric acid significantly. Previous study done by Jaarin
et al. (1999) reported that after one week of treatment there is
no reduction of gastric acid but the reduction occurred after three weeks of
treatment with ranitidine. If the dose is increased or use a longer treatment
period with ranitidine, there could be a reduction in the gastric acid.
In conclusion, Eurycoma longifolia in Radix given as oral gavages at 0.128 mg g-1 b.wt. was able to treat ethanol-induced gastric lesions in rats. The mechanism for the ulcer healing is not through reduction of the MDA or gastric acid. There could be other mechanism for the ulcer healing such as increased in gastric blood flow, gastric mucous production or prevention in prostaglandin inhibition. Further study needs to be carried out to determine its mechanism for ulcer healing and further assess its potential as an anti-ulcer agent.
Authors wish to thank Miss Nor Nazilah binti Mohamad Zuldin and all the staffs in Pharmacology Department, Universiti Kebangsaan Malaysia for their assistance in this study.
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