Analgesic Effects Of Total Flavone Of Rhododendron And Its Mechanism

Total flavone of rhododendron (TFR) is an active part extracted from the rhododendron. The major effective components in TFR are hyperin and quercetin etc. In this paper, analgesic effects of TFR and its mechanism were studied. The main results are as follows:1. TFR 100, 200 mg·kg^-1 ig remarkedly inhibited the pain of mice in the formalin test and reduced the number of the writhing in mice; 100,200 mg·kg^-1 TFR prolonged the latencies of paw-licking ; 100 mg·kg^-1 TFR inhibited tail-curling reaction in mice. These results suggested that TFR has marked analgesic effects.2. Icv TFR 5, 10 mg·kg^-1 remarkedly inhibited the writhing response induced by 0.6% acetic acid, and the max inhibitory rate is 52.1%. The result suggested that the central mechanism is at least partially involved in the analgesic effect of TFR.3. Ip EDTA 50 mg·kg^-1 or 100 mg·kg^-1 CaCl₂ did not influence the latencies of foot-licking on hot-plate tests in mice. However, the analgesic action of 200 mg·kg^-1 TFR in mice could be antagonized by CaCl₂ and enhanced by EDTA respectively. Icv 2mg·kg^-1 EDTA or 5mg·kg^-1 CaCl₂ has similar influence on analgesic effect of 200 mg·kg^-1 TFR. These results show that analgesic effects of TFR may be related to antagonizing of calcium ion.4. TFR 100 mg·kg^-1 ig significantly increased the mice serum NO contents, and 200 mg·kg^-1 TFR ig markedly increased the NO contents in mice cerebrum. TFR 50, 100, 200 mg·kg^-1 ig significantly reduced the contents of PGE₂ in mice cerebrum and 200 mg·kg^-1 TFR ig remarkably reduced the PGE2 contents in mice serum. However, ig TFR did not influence the contents of MDA in mice cerebrum and serum. These implied that analgesic mechanisms of TFR may be related to inhibiting PGE2 production and...