A local Nigerian plant could provide the source of a novel drug for
alcohol induced kidney damage and diabetes.
NIGERIAN researchers have isolated a local plant, Abrus precatorious, which
seed extract has some anti-diabetic properties similar to that of a
conventional diabetic drug and could protect the kidney against alcohol-induced
damage.
The researchers from the department of human anatomy, Faculty of Basic
Medical Sciences, Niger Delta University, Bayelsa State; and the Department of
Anatomical Pathology, University of Port-Harcourt Teaching Hospital
Port-Harcourt, Rivers State, concluded: “The results of this study strongly
indicate that the aqueous extract of the seed of Abrus precatorius has
protective effect on alcohol-induced renal injury and that this effect is
related to the attenuation of alcohol- mediated lipid peroxidation of renal
parenchymal cells.
Lipid peroxidation refers to the oxidative degradation of lipids. It is the
process in which free radicals “steal” electrons from the lipids in cell
membranes, resulting in cell damage.
Parenchymal cells are the main functional cells of an organ or tissue - as
distinguished from non-parenchymal cells (frequently referred to as stromal
cells) that provide supporting structural elements such as cells forming the
connective tissue, blood vessels, and nerves.
The study was published in European Journal of Scientific Research.
Commonly called jequirity (from a Brazilian name); crab’s eyes (the seeds);
bird’s eye (the seeds); prayer beads (the seeds); lucky bean (the seeds);
Indian liquorice, or wild liquorice (the root), Abrus precatorious belongs to
the family Leguminosae-Papilionoideae. In Nigeria, it is omisinmisin in
Yoruba, and empo in Esan.
Previous studies have shown that the leaf extract of Abrus precatorius could
be applied on the eyes for cataract and chewed for asthma.
According to The useful plants of west tropical Africa, Vol. 3, Abrus
precatorious is a twining herbaceous, sub-woody, lianous plant with stems up to
1?5 cm diameter; of thickets, clearings, secondary jungle of all types and
galleried forest in slightly damp sites, throughout the region from Senegal to
Nigeria and Fernando Po.
The study investigated the renal protective activities of the seed extract
of Abrus precatorius following alcohol induced renal damage in adult male
Sprague dawley wister rats. Experimental rats were divided into six groups of
five rats per group. Renal damage was induced with alcohol (1.6g/kg) orally.
The treated group received the crude extract (200mg/kg) orally in addition to
alcohol for six weeks, with normal feeds and water ad libitum (water as
desired). Histological studies, biochemical indicators of renal function and
thiobarbituric acid-reactive substances, as markers of lipid peroxidation, were
thereafter determined.
Thiobarbituric Acid Reactive Substances (TBARS) is a well-established method
for screening and monitoring lipid peroxidation.
The researchers wrote: “Oral administration of alcohol caused significant
elevation of serum potassium and sodium levels as well as creatinine and
malondialdehyde levels. There were structural alterations in renal tubules,
glomerular infiltration by chronic inflammatory cells.
“Concurrent administration of same doses of alcohol and seed extract of
Abrus precatorius resulted in a suppression of alcohol-induced renal injury.
Measurement of malondialdehyde level indicated that this effect is related to
the attenuation of alcohol-induced lipid peroxidation by the seed extract. We
conclude that the seed extract of abrus precatorius could protect the kidney
against alcohol-induced parenchymal injury.”
Creatinine is a chemical waste molecule that is generated from muscle
metabolism. Creatinine is produced from creatine, a molecule of major
importance for energy production in muscles. Approximately two per cent of the
body’s creatine is converted to creatinine every day.
. Creatinine is transported through the bloodstream to the kidneys. The
kidneys filter out most of the creatinine and dispose of it in the urine.
Although it is a waste, creatinine serves a vital diagnostic function. Creatinine
has been found to be a fairly reliable indicator of kidney function. As the
kidneys become impaired the creatinine will rise. Abnormally high levels of
creatinine thus warn of possible malfunction or failure of the kidneys,
sometimes even before a patient reports any symptoms. It is for this reason
that standard blood and urine tests routinely check the amount of creatinine in
the blood.
Malondialdehyde level is the end product of lipid peroxidation and is used
as a marker of free radical-induced tissue damage.
Glomerular filtration rate (GFR) is a test used to check how well the
kidneys are working. Specifically, it estimates how much blood passes through
the tiny filters in the kidneys, called glomeruli, each minute.
The researchers said the finding is supportive evidence that the seed
extract of Abrus precatorius has protective effect against alcohol induced
renal injury and that this effect may be related to a reduction in
alcohol-induced lipid peroxidation. ß
The active metabolites in the seed of Abrus precatorius include abrin, abrus
agglutinin, glycyrrhizin gallic acid, trigonelline, precatorine and lipolytic
enzymes. Glucine, Coumestrans, resin asparagines and sterols, among others,
have also been demonstrated. Gallic acid, glycyrrhizin and trigonelline are
potent antioxidants. These metabolites may account for the ability of the seed
extract of Abrus precatorius to attenuate alcohol induced lipid peroxidation of
renal cell membrane vivo.
The seed extract of Abrus precatorius have also been shown to possess other
pharmacologic properties. It was shown to have anti-fertility effect.
Researchers have also demonstrated ureterotonic effect and antidiarrhoeal
effect. More recently, Adelowotan et al. demonstrated antimicrobial activities
with the aqueous extract of the seed of Abrus precatorius.
The researchers added: “Although Abrus precatorius has been shown to be
stable in the gastrointestinal tract, the presence of toxic lectins in its seed
limits its pharmacologic utility. Abrin and Abrin agglutinin are type IV
ribosome inactivating proteins that inhibit protein synthesis in eukaryotes and
induce apoptosis.
“Concurrent administration of vitamin E, a potent antioxidant, with alcohol
and Abrus precatorius seed extract did not produce enhanced antioxidant effect
in this study. This can be explained by the diversity of the mechanisms by
which antioxidants restrict lipid peroxidation by free radicals. Denisov and
Azatyam explained that the co-administration of two inhibitors of free radicals
to an oxidized hydrocarbon or other substances may exhibit a net additive,
synergistic or antagonistic effect. It is not unlikely therefore that a net
antagonistic effect was the outcome following concurrent administration of the
seed extract of Abrus precatorius, alcohol and vitamin E.”
Another study published in Journal of Applied Sciences and Environmental
Management has shown that the chloroform – methanol extract of Abrus
precatorius seed has some anti-diabetic properties similar to that of
chlopropamide (a conventional diabetic drug).
The researchers from the Departments of Biochemistry, University
of Port Harcourt, Rivers State,
and University of Nigeria, Nsukka, Enugu State,
studied the anti-diabetic effect of chloroform – methanol extract of Abrus
precatorious seed, in alloxan diabetic rabbits.
The effect was compared to that of chlorpropamide – a known anti-diabetic
drug in the class of sulphonylurea and a control group that received normal
saline instead of the extract. Normal blood glucose levels drawn before the
alloxan injection were 127.80 ± 2.55, 114.30 ± 4.17 and 123.60 ± 1.47 mg/100ml
for chloroform – methanol, chlorpropamide and control respectively. When 50mg /
kg body weight of chloroform – methanol, chlorpropamide and 5ml of normal
saline for control were given orally, blood glucose levels decreased in
chloroform – methanol and chlorpropamide groups of alloxan diabetic rabbits but
not in control.
The percentage reduction of blood glucose of chlorpropamide was 13.8, 32.3,
60.3, 53.5, 46.8, 46.3 and 46.2 after 05, 10, 20, 30, 40, 60 and 68 hours of
oral administration respectively, while that of chloroform – methanol extract
was 42.9, 58.7, 67.4, 69.1, 67.9, 56.6 and 51.8 per cent respectively. The peak
percentage reduction was 69.1 per cent after 30 hours and 61.3 per cent after
20 hours, for chloroform – methanol extract and chlorpropamide respectively.
The researchers concluded: “This study therefore has shown that the
chloroform – methanol extract of Abrus precatorius seed has some anti-diabetic
properties similar to that of chlopropamide. This is shown in their similar
percentage reduction in blood glucose level.”
