Evaluation of Antihyperglycemic and Hypoglycemic Activities of the Aqueous Leaf Extract of Rubus Erlangeri Engl (Rosacea) in Mice
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Date
2019-10
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Publisher
Addis Abeba University
Abstract
Diabetes mellitus is one of the most common non-communicable disorder in the world. It occurs
as a result of either the pancreas not producing enough insulin or the cells of the body not
responding properly to the insulin which is produced. Management of diabetes mellitus with
currently available modern medicines is costly and chances of side effects are high. These calls for
investigations of new and better compounds with least side effects. The experimental plant, Rubus
erlangeri is among Rubus species, which are used for management of diabetes mellitus in many
countries but its effect is not yet experimentally validated. Therefore, the aim of the present study
was to investigate the antidiabetic effects of this plant both in vitro and in vivo and find out the
relevance of the plant in controlling blood sugar. The in vitro study was assessed using a 3, 5Dinitrosalicylic
acid method for α-amylase inhibition activity and DPPH assay method for
antioxidant activity. The in vivo study on the other hand was carried out in normoglycemic, glucose
loaded hyperglycemic and streptozotocin (200 mg/kg) induced diabetic mice. Blood glucose level
was then determined using glucometer. In all in vivo models, the test groups received various (100,
200 and 400 mg/kg) doses of the Rubus erlangeri aqueous leaf extract whereas the positive
controls received glibenclamide (5 mg/kg) and the negative control as well as the normal control
groups received distilled water (10 mL/Kg). The in vitro results demonstrated that this plant has
an IC50 of 7.34±0.02 µg/ml for DPPH scavenging activity and 4.90±0.44 µg/ml in α-amylase
inhibition activity. In both cases, Rubus erlangeri showed comparable effect with the standard
drugs (ascorbic acid and acarbose). In the in vivo study, the extract significantly reduced blood
glucose level with 100 mg/kg at 60 min (p<0.05) as well as with 200 mg/kg and 400 mg/kg at the
1
st
and 2
I | P a g e
nd
h (p<0.01) following loading of 2.5 g/kg of glucose. It did not, however, produced
significant reduction of glucose level in normal mice compared to the control group. Rubus
erlangeri also produced significant reduction in blood level in streptozotocin-induced diabetic
mice. In the single dose study, the aqueous leaf extract lowered blood glucose level with 200 mg/kg
and 400 mg/kg at the 3
rd
and 4
th
h (p<0.05). Moreover, blood glucose level was reduced with daily
administrations of the extract. The reduction in fasting blood glucose level was significant with
lower dose (p<0.01) middle and higher dose of the extract at the 2
II | P a g e
nd
week (p<0.001) and with all
doses of extract at 3
rd
week (p<0.01). In addition, the extract produced less body weight reduction
after diabetic induction when it was compared with negative control group. This study revealed
that the aqueous leaf extract of Rubus erlanger has blood glucose lowering effect with low risk of
hypoglycemia.
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Keywords
Diabetes Mellitus, Rubus erlangeri, in vitro, in vivo, Streptozotocin