Purpose: To investigate the anti-hyperglycaemic activity of methanol extract of
Tribulus terrestris
L.
Zygophyllaceae in glucose-loaded normal rabbits.
Methods: The animals were randomly assigned to 4 groups (n = 5) and treated with a single oral dose.
Group 1 served as normal control group and received distilled water; group 2 served as hyperglycaemic
control; group 3 was treated with glibenclamide (5 mg/kg, aqueous suspension) and served as
reference standard; group 4 received methanol extract of
Tribulus terrestris L. (250 mg/kg). Groups 3
and 4 were orally treated with glucose (5 g/kg) after 1 h of drug and extract administration, respectively.
Fasting blood glucose (FBG) was determined prior to (0 h) and at 30 min, 1, 2 and 3 h after dosing for
acute toxicity study.
Results: On comparing within groups, a single dose of the methanol extract of
Tribulus terrestris L.
lowered FBG to levels comparable to that of glibenclamide (36 vs. 55 %), and reaching the initial level
(0 h) at 2 h. FBG were significantly (p < 0.05) lowered at 2 and 3 h in both glibenclamide (45.5 and 56.9
%) and extract (45.7 and 52.7 %) groups as compared with their respective glucose levels at 0.5 h. On
the other hand, on comparing between groups, both glibenclamide and methanol extract significantly (p
< 0.05, p < 0.001) lowered the rise in blood glucose at 1 h (33.9 and 22.5 %), 2 h (62.8 and 59.16 %),
and 3 h (64.6 and 57.1 %) with respect to the hyperglycaemic control group.
Conclusion: The methanol extract of the aerial parts of
Tribulus terrestris L. possesses potential antihyperglycaemic
activity in glucose-loaded normal rabbits. Further studies on various organic solvents
fractions and isolated compounds from this plant are required.
