In Vitro Assay For The Anti-Diabetic Effect Of Ocimum Canum And Other Medicinal Plants

ABSTRACT

The major objective of this work was to establish an in

vitro assay system for evaluating Ocimum canum, an antidiabetic

plants, using insulin release from isolated

pancreatic p-islet cells of rats. An in vivo assay was

carried out to confirm the previous work by Hogarh (1996)

indicating the anti-diabetic activity of 0. canum. The

effect of the aqueous extract of fresh leaves of 0. canum on

lipid profile of genetically diabetic mice and their lean

littermates was also evaluated.

In vivo, the aqueous extract of fresh leaves of 0. canum

reduced fasting blood glucose levels and body weight of

genetically diabetic mice and their non-diabetic lean

littermates confirming Hogarh’s result. The extract lowered

serum total cholesterol and LDL-cholesterol levels and

raised HDL-cholesterol levels of the experimental animals,

but did not affect their triacylglycerol levels. However,

aqueous extract from dried leaves lowered, fasting blood

glucose levels but not body weight.

The anti-diabetic property of "mirabetic" a plant

preparation used for the management of diabetes mellitus was

also evaluated in vivo using STZ-induced diabetic mice and

their non-diabetic lean littermates. The "mirabetic"

extract did not prevent the rise in plasma glucose levels in

STZ-induced diabetic mice. In addition, the extract did not

lower plasma glucose concentrations of the littermates at

the end of the period, and did not affect the body weight of

the littermates either.

From In vitro experiments, the freeze dried extracts of

fresh leaves of 0. canum significantly, enhanced insulin

release from pancreatic p-islet cells. The effect was

concentration-dependent up to a concentration of 0.03 mg/ml

and thereafter decreased. The in vitro system established

with 0. canum was used to evaluate "mirabetic" and Desmodium

adscendens, a non anti-diabetic medicinal plant.

"Mirabetic" signifi-cantly enhanced insulin release while

D. adscendens decreased insulin release, with higher

concentrations completely inhibiting insulin release.

The results indicate that glucose-induced insulin release

which is the mode of action of 0. canum, could be used

effectively as an in vitro assay system to evaluate other

anti-diabetic plants.