Radix Scutellaria is widely applied to the treatment of diabetes mellitus in China.
Its main bioactive constituents contain baicalin, wogonoside, oroxyloside, and their
aglycones. To investigate the effect of type 2 diabetes mellitus on both pharmacokinetics
and tissue distribution of these flavonoid compounds, the six flavonoids in plasma
and tissues from the normal and type 2 diabetic rats after oral administration of
Radix Scutellaria extract were simultaneously measured by ultra-performance liquid
chromatog-raphy-tandem mass spectrometry (UPLC-MS/MS) method. The results showed that
baicalin, wogonoside, and oroxyloside had higher C max and AUC values ( P < 0.05)
in type 2 diabetic rats than that in normal rats and the tissue-distribution behaviors
of the six flavonoid compounds in hearts, livers, spleens, lungs, kidneys, brains,
pancreas, fat and muscle of the type 2 diabetic rats showed obviously differences
from the normal rats ( P < 0.05). In conclusion, the differences in the pharmacokinetics
of oroxyloside and tissue distribution of the six flavanoids in Radix Scutellaria
extract between diabetic and normal rats were found for the first time. The results
from the present study provided a crucial basis for a better understanding of in
vivo anti-diabetic mechanism of action of the six flavonoids from Radix Scutellaria
.