ARI Volume 1 Number 2.pdf - Zoology and Environmental Biology ...

AKAH, Peter et al. 92
Table 1: Effect of V. amygdalina aqueous leaf extract on blood glucose of diabetic rats
Groups Dose of
Blood glucose (mg %) at hr after treatment
extract
a
%
Reduction
after 8 hr
0 hr 2 hr 4 hr 8 hr 24 hr
Non-diabetic
DW
(control)
Non-diabetic
(2 ml/kg) 123.6±2.4 125.1±1.6 121.8±3.1 126.3±9.5 124.4±7.3 -2.0
(treated)
80 mg/kg
DW
125.4±5.0 114.5±4.4* 100.6±3.0* 81.3±6.1* 103.1±1.5* 35.6
Diabetic (control) (2 ml/kg) 298.7±6.5 278.1±5.0 281.5±3.2 311.6±7.2 326.5±4.2 -4.3
Diabetic(treated) 80 mg/kg 291.1±9.4 265.0±8.6* 209.5±4.1* 194.5±2.0* 231.6±5.1* 33.2
a
Values are means ± SEM, (n=10), *P < 0.05; DW = distilled water
Table 2: Effect of V. amygdalina aqueous leaf extract on serum triglyceride level of
diabetic rats
Groups Dose of
extract
Serum triglyceride (mg %) at hr after treatment a
%
Reduction
after 8 hr
0 hr 2 hr 4 hr 8 hr 24 hr
Non-diabetic
DW
(control)
Non-diabetic
(2 ml/kg) 193.6±2.4 192.8±4.1 195.1±10.6 193.2±7.7 191.4±2.1 0
(treated)
80 mg/kg
DW
192.5±5.1 161.4±4.5* 150.7±5.4* 136.4±2.5* 160.5±1.6* 29.1
Diabetic (control) (2 ml/kg) 386.9±6.5 407.1±10.2 404.8±5.2 381.7±4.2 403.8±17.8 1.3
Diabetic(treated) 80 mg/kg 355.5±6.0 333.5±5.3 188.3±4.2* 158.0±3.5* 231.6±5.7* 55.6
a
Values are means ± SEM; (n=10), *P < 0.05, DW = distilled water
DISCUSSION
The hypoglycaemic potentials of medicinal
plants have been documented (Akah et al.,
2002). The result of this study confirms our
earlier report (Akah and Okafor, 1992) on the
hypoglycaemic effect of the leaf extract of V.
amygdalina in rabbits. Although several
biologically active constituents were reported
present in the extract (Fafunso and Basir, 1977;
Akah and Okafor, 1992), it was not
demonstrated which of the groups of
phytochemical were responsible for the effect
and the mechanism of action. The prompt and
remarkable reduction in blood glucose in both
the fasting normal rats and alloxan diabetic rats
(with blood sugar levels comparable to total
pancreatomy) point to a mechanism of action
different from that of sulphonylureas, and
unrelated to insulin secretion from pancreatic βcells.
In diabetes, the causes and sites of
intervention in the biochemical process are
diverse (Larner 1985), and high serum total
triglyceride level has been implicated (Anaja
1995).
It is now widely believed that an
important signal for insulin secretion may be the
link between glucose and lipid metabolism; and
long-term exposure of islet cells to high levels of
fatty acids may result in β-cell dysfunction
(lipotoxicity), and diminished glucose-stimulated
insulin secretion (Krolewski et al., 1994, Haffner
et al., 1998). It has been established that
hyperlipidaemia does not only increase the risk
of ischaemic heart disease (IHD) in diabetic
patients, but also may impair glycaemic control,
accelerates the progression of renal insufficiency
and increases mortality (Akbar, 2001).
Moreover, an alarming proportion of diabetic
patients with dyslipidaemia is not aware of the
problem and only a small fraction receives lipidlowering
therapy (Isseb et al., 1996). Since
dyslipidaemia occurs in most diabetic patients
(Isseb et al., 1996), the utilization of lipidlowering
drugs is now advocated for diabetic
patients.
In the present study, V. amygdalina
leaf extract evinced a potent lowering of serum
triglyceride level in both normoglyceamic and
alloxan-induced diabetic rats. The effect on
blood glucose and serum triglyceride level
followed the same time course and peaked by
the 8 th hour. Adequate treatment of diabetes
dyslipidaemia through diet is critical in reducing
risk and complications, and the role of medicinal
plants in the treatment of diabetes is emerging.