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 :

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.