[Interaction of nourishing and tonifying blood effects of the combination of Angelicae sinensis Radix and Astragali Radix studied by response surface method].

The combination of Angelicae sinensis Radix (Danggui, DG) and Astragali Radix (Huangqi, HQ) is a popular herb pair commonly used in clinic for the treatment of blood deficiency syndrome in China. The aim of this paper is to study the interaction of DG and HQ nourishing and tonifying blood effects by response surface method. The blood deficiency mice were induced by injecting N-acetylphenylhydrazine (sc) and cyclophosphamide (ip). The blood deficiency mice were administrated intragastrically with DG-HQ extracts (0:1, 1: 5, 2:5, 2:3, 1:1, 3:2, 5:2, 5:1, 1:0). The changes of the peripheral blood indexes and organ indexes were observed. The indexes were integrated by comprehensive index method; the interactions of DG and HQ were analyzed by the response surface diagram established with Matlab software. The results showed that DG and HQ at most of their combination ratios had synergic effect. Within the range of 1:5 - 5:1, all of the extracts of DG-HQ showed synergic effect, and among which, high-doses had better effects than low-doses. The highest value (-1) of the synergic effect was showed when DG was 10 - 40 g at the same time of HQ as 90 -180 g, and DG was 50 - 100 g at the same time of HQ as 20 - 100 g. DG-HQ at all combination dosages within Chinese Pharmacopeia (DG: 6 - 12 g, HQ: 9 - 30 g) had certain synergic effect, and Danggui Buxue Decoction (DG: 6 g, HQ: 30 g) also was at this range. The results provided scientific basis to the clinical application of DG and HQ. And the response surface method was firstly applied to quantitatively evaluate the bio-activity change of herb combination, which provided a novel way for modern basic research on the interaction of herbs.