The present study aims to investigate the effect of ethyl acetate fraction of roots
of Rubia cordifolia (RCEAF) on blood glucose level and glucose utilization study to find out the mechanism
of action of the extract. Recently we have reported hypoglycaemic effect of ethanolic
extract of roots of R. cordifolia L. (RCAE). RCEAF was fractionated from RCAE by column chromatography. Single dose
study of RCEAF (50,100 and 200mg/kg, p.o.) was carried out in i) normal fasted ii) oral glucose tolerance test (OGTT) iii)
alloxan (120mg/kg, s.c.)- induced diabetic rats. Repeated dose study of RCEAF (100
and 200mg/kg, p.o.) was carried out for two weeks. The blood glucose levels were estimated by glucose
oxidase- peroxidase reactive strips (One Touch, Johnson and Johnson, India). We found
that, oral pre-treatment with RCEAF induced a significant (P<0.05) decrease in blood
glucose level in i) normoglycaemic rats at 6h ii) OGTT at ½ h compared to control
glucose fed rats iii) alloxan- induced diabetic rats at 6h. After two weeks daily
administration of RCEAF, diabetic treated rats showed significant (P<0.05) reduction
in blood glucose level as compared to diabetic control rats. In vitro experiment showed that insulin (0.05 IU/mL) increased glucose utilization by an isolated
rat diaphragm. Alone RCEAF (25mg/mL) as well as combination of RCEAF (25mg/mL) and
insulin (0.05 IU/mL) showed a marked increase (P<0.05) of glucose uptake. This exhibited
the extra- pancreatic effect of the RCEAF. Further studies with estimation of insulin
and insulin receptor may give more insight into the mechanism of the antidiabetic
activity of the R. cordifolia.
