INTRODUCTION
The use of medicinal plants and animal-derived remedies for treating illness
by Africans goes back many years. Traditionally, rural African communities have
relied mainly on the invaluable spiritual and practical skills of traditional
medicine practitioners (TMPs) for their healthcare (Busia,
2005).
Traditional herbal medicine has often be used side by side western medicine
more so when herbal medicine is of lower cost than western medicine. Literature
has documented that Piliostigma thonningii plant has diverse ethnomedical
applications (Togola et al., 2005).
Piliostigma thonningii is a leguminous plant which belongs to the family of trees or shrubs called Caesalpiniacea.
Piliostigma thionningii is a perennial tree that is between 4-15 m in height with a rounded crown and a short but often cooked bole.
In Nigeria, the seed of P. thonningii is called Abefe in the Yoruba
land, Kalgo in Hausa and Okpoatu in Ibo. The roots of the plant have been used
for the treatment of dysentery, fever, infections, snake bites, hookworm and
skin diseases (Jimoh and Oladiji, 2005).
Various parts of the plant have been used to arrest bleeding, in the treatment
of fever as well as bacterial infections, it has also been used as laxatives
and as an anthelmintic and as anti-inflammatory agents (Igoli
et al., 2005; Fakae et al., 2000).
The plant has also been observed to exhibit potency against five bacterial
and three fungi at 25 mg mL-1 concentration and the leaves are a
good source of some minerals, antioxidant-vitamins and efficient source of energy
(Ighodaro et al., 2012).
The liver has the unique capacity to regulate its growth and mass (Fausto
and Campbell, 2003). In rodents and humans, it grows rapidly after resection
of more than 50% of its mass. This growth process, as well as that following
acute chemical injury is known as liver regeneration, although growth takes
place by compensatory hyperplasia rather than true regeneration. Fausto
and Campbell (2003) also observed that in addition to hepatocytes and non-parenchymal
cells, the liver contains intra-hepatic "stem" cells which can generate a transit
compartment of precursors named oval cells. Liver regeneration after partial
hepatectomy does not involve intra or extra-hepatic (hemopoietic) stem cells
but depends on the proliferation of hepatocytes. Transplantation and repopulation
experiments have demonstrated that hepatocytes which are highly differentiated
and long-lived cells, have a remarkable capacity for multiple rounds of replication.
The liver is known for the detoxification of substances that enter into the
body. In the event of liver damage or alteration of function the liver enzymes
are found to increase.
The consumption of herbal medicine does not have a defined dosage; hence one may consume what may be too much for the system.
This study investigates the effect of chronic consumption of Piliostigma
thonningii on activities of Alanine Aminotransferase (ALT) and Aspartate
Aminotransferase (AST) in serum and liver in Rattus novergicus.
MATERIALS AND METHODS
Animal care ethics: Twelve Rattus novergicus (Wister rats) of both sexes with average weight of 200 g were randomly assigned into two groups A and B. Group A served as treatment group while group B served as the control group. The rats were obtained and maintained in the Animal Holdings of the department of Anatomy, School of Basic Medical Sciences, University of Benin. The animals were fed with grower’s mash obtained from Top feeds and flower mills Limited, Sapele, Delta State with batch number 023465 and given water liberally.
Preparation and administration of aqueous piliostigma thonningii:
Piliostigma thonningii stem bark sample used for the experiment were
harvested within the University of Benin premises. The samples were then identified
by Dr. A.B. Bamidele of the Department of Pharmacognocy, Faculty of Pharmacy,
University of Benin. The stem bark were washed clean free from debris and dust
particles and were air dried at ambient and sun room temperature for two weeks.
The samples were reduced in size using wooden mortar and pestle. The smaller
size sample was pre-dried in drying oven at 25°C for five hours. It was
immediately pulverized using plant milling machine available in the Department
of Pharmacognocy, University of Benin. Each of the samples was accurately weighed
(100 g) with a Top loading balance. It was packed in giant size thimble of a
soxhlet and subjected to ethanolic extraction for ten (10) h. This procedure
was repeated four times. The Piliostigma thonningii powder (37 g) was
then dissolved in 530 mL of distilled water, it was then transferred into suitable
container and freeze dried ready for the experiment.
R. novergicus were then sacrificed by cervical dislocation on the twenty ninth day of the experiment. The abdomen was quickly opened to expose the liver. The liver was then dissected; blot dry weighed using the Metttler Toledo weighing balance and quickly homogenated with 10% normal saline for biochemical assay.
Biochemical assay: The measurement of enzyme activity was done using
the spectrophotometer. ALT and AST activity were determined by the method of
Reitman and Frankel (1957).
Statistical analysis: The results were expressed as Mean±SD. The student t-test was used for the evaluation of statistical significance. The results were judged significant if p<0.05.
RESULTS AND DISCUSSION
Traditional medicine is known to be popular in sub-Saharan Africa, where over
80% have reported its utilization. It is claimed to be easily accessible, affordable,
available and acceptable (Sato, 2012).
The reasons for the continued dependence of Africans on traditional medicine
range from their belief systems to the relatively high cost and limited access
to Western medicine (Busia, 2005).
Piliostigma thonningii has been known to be of diverse application in
economic and ethnomedical purposes in Africa (Igoli et
al., 2005; Togola et al., 2005). The leaves,
roots and twig of Piliostigma thonningii have been useful for the treatment
of fever, wound infection, jaundice, chicken pox, respiratory ailments, diarrhea,
tooth ache and chronic ulcer.
Piliostigma thonningii has been used for different and several medicinal
purposes and its aqueous leaf extract likely contains antilipidaemic and anticholesterolaemic
substance (s) which may be useful in the prophylactic and curative management
of lipid peroxidation, high blood pressure and cardiovascular disorders (Ighodaro
and Omole, 2012).
The results from this study revealed that the activities of aspartate aminotransferase
in serum, showed a significant increase (34.20±12.9*) at (p<0.05)
upon chronic consumption of ethanolic extract of P. thonningii when compared
with that of the control B (18.02±1.54). The result also showed that
the liver AST was significantly increased (32.75±5.89*) when compared
to that of the control B (17.01±1.81) at (p<0.05). The implication
of this result is that chronic consumption of P. thonningii is injurious
to the liver. This is corroborated by the increase in the serum level of the
enzyme activity. Though AST is principally to assay for the kidney and the heart
activity. This increase in AST in serum may be connected with kidney and heart
tissue damage, one may not conclude that since that analysis was not done but
it is a possibility.
The results from the study also revealed that there was a significant increase
in the activity of alanine aminotransferase in the liver (17.01±5.86*)
when compared with that of the control B (5.1±1.11) at (p<0.05). There
was a corresponding increase in serum activity of the enzyme ALT (13.65±3.79*)
when compared with that of the control B (9.4±1.98) at (p<0.05). The
implication of this result is that the liver may have suffered injury hence
the leakage of the enzyme in the serum. These findings are in agreement with
Giboney (2005). He stated that ALT and AST are two of
the most reliable markers of hepatocellular injury or necrosis and that their
levels can be elevated in a variety of hepatic disorders. ALT and AST are considered
to be two of the most important test to detect the liver injury.
Although, ALT is more specific than AST, sometimes AST is compared directly
to ALT and the ratio is calculated. The ratio may be used to distinguish between
the different causes of liver damage. ALT and AST are associated with inflammation
of the and/or injury to the liver cell, a condition known as hepatocellular
liver injury. Damage to the liver typically results in a leak of AST and ALT
into the blood stream which was shown in Table 1, 2.
However, the causes of elevated enzyme activity of ALT can be further narrowed
down by measuring other enzyme activities.
| Table 1: |
Activities of Aspartate Aminotransferase in serum and liver
of Rattus novergicus after chronic consumption of ethanolic extract
of Piliostigma thonningii |
 |
| Values are Mean±SD, n = 6, * represent significant
differences of test groups in comparison with respective controls at p<0.05 |
| Table 2: |
Activities of Alanine Aminotransferase in serum and liver
of Rattus novergicus after chronic consumption of ethanolic extract
of Piliostigma thonningii |
 |
| Values are Mean±SD, n = 6, * represent significant
differences of test groups in comparison with respective controls at p<0.05 |
For instance, elevated ALT activity due to liver-cell damage can be distinguished
from urinary duct problems by measuring alkaline phosphatase. Also myopathy-related
ALT levels can be ruled out by measuring Creatine kinase enzymes.
CONCLUSION
This research has shown that chronic consumption of P. thonningii may cause liver injury thereby, increasing the liver enzyme activity (17.01±5.86*). The implication of this result is that excessive consumption of the extract of P. thonningii has a toxicity potential on the liver and possibly other organs and tissues in the system more so when there is no proper dosage formula for herbal medicine which is the danger of the use of herbal medicine in the treatment of diseases. However, if the extracts are taken in the right proportion, it would serve its medicinal purpose otherwise the individual being given such extracts Excessively, would end up having his/her liver and other tissues of the body destroyed.
ACKNOWLEDGMENT
We are grateful to Dr. A.B. Bamidele of the Department of Pharmacognocy, Faculty of Pharmacy, University of Benin and Mr. Kweki, Rume Godfrey of the Medical Biochemistry Department, Delta State University, Abraka-Nigeria for their technical assistance in carrying out this study.
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