Combined effects of Stephania Radix and Astragali Radix in antihyperglycemic action of Boi-ogi-to (Fang-ji-huang-qi-tang) in streptozotocin-induced diabetic mice

粉防已を用いた防已黄耆湯(48-160mg/kg/day)は,防已を用いた防已黄耆湯と比較して,ストレプトゾトシン(STZ)-誘発糖尿病ddY マウスの高血糖値を有意に下降させた。防已黄者湯の血糖下降作用は,腹腔内投与と経口投与のいずれにも見られ,血中へのインスリン遊離促進作用と平行した。各構成生薬の単味およぴ混合物,方剤からの一味抜き方剤の血糖下降作用を防已黄耆湯の作用と比較した。防己黄耆湯から粉防已または黄耆を除くと,血糖下降作用は消失した。粉防已は単味で強力な血糖下降作用を示した。黄耆は,単味では作用を示さないが,粉防已の血糖下降作用を8倍も増強した。黄者は,粉防已のインスリン遊離促進作用も増強した。以上の結果から,粉防已を用いた防已黄青湯は,STZ-糖尿病態の高血糖値を改善し,その改善作用は,インスリン遊離促進作用に依存することを明らかにした。この防已黄耆湯の作用は,黄耆と粉防已の複合作用によって導かれると結論できた。

Kampo medicine, Boi-ogi-to (Fang-ji-huang-qi-tang: FJHQ) is composed of different crude drugs between Japan and China to be used clinically in the treatment of arthritis and edema. FJHQ consists of Sinomeni Caulis et Rhizoma (SCR), Astragali Radix (AR), Atractylodes Lanceae Rhizoma, Glycyrrhizae Radix, Zingiberis Rhizoma and Zizyphi Fructus in Japan. Stephania Radix (SR) is a component of FJHQ in China as a substitute for SCR. We have previously reported that FJHQ composed with SR [FJHQ(SR)] decreases high blood glucose levels in streptozotocin (STZ)-induced diabetic mice to a greater extent than FJHQ composed with SCR [FJHQ(SCR)] when they were intraperitoneally administered (Jpn. J. Oriental Med. 49, 607, 1999). The present study investigated roles of combined crude drugs in antihyperglycemic action of FJHQ(SR) in STZ-diabetic mice. FJHQ(SR) by oral administration also showed a significant drop in high blood glucose level and elevated blood immunoreactive insulin level of STZ-diabetic mice. The time course of the maximally elevating action of FJHQ(SR) on blood insulin level occurred earlier than that of antihyperglycemic action. FJHQ without SR and FJHQ without AR did not significantly affect the high blood glucose level, but, FJHQ without the other 4 individual crude drugs have similar actions as that of FJHQ(SR). SR directly decreased high blood glucose level and elevated blood insulin level in the diabetic mice. AR did not have direct effects but potentiated the action of SR on both blood glucose and insulin levels. These results demonstrate that AR and SR have a combined effect in the FJHQ(SR)-induced antihyperglycemic action and elevating action on blood insulin level in STZ-diabetic mice.