Effects Of Dihydromyricetin In Anti-inflammatory And Anti-allergic Activities

Ampelopsis grossedentata(Hand.-Mazz) W. T. Wang grows wildly in the south China. Healthy tea, which made from the stems and leaves, is used to treat common colds, pyretic fever, inflammation, pain-swelling of pharynx and larynx as well as jaundice hepatitis, with a long history of several hundred years among the people. Dihydromyricetin(DMY), the major flavone in Ampelopsis grossedentata, is one of the important active ingredients in Ampelopsis grossedentata. The anti-inflammatory activities and anti-allergy effects of DMY and its mechanism were studied in this thesis.DMY was examined for its action in anti-inflammatory and anti-allergic activities. Pharmacological experiments showed that DMY(500mg/kg, p.o., for 5d)significantly inhibited ear edema induced by croton oil in mice, and DMY(125,250,500mg/kg, p.o., for 7d)obviously lowerd the levels of ALT in plasma caused by P. acnes plus LPS in mice. Moreover, DMY(125,250,500mg/kg, p.o., for 7d) significantly suppressed ear edema and increment capillary permeability in the delayed hypersensitivity reaction induced by DNFB in mice.To investigate the mechanisms of DMY in anti-inflammatory and anti-allergic activities, the results showed that DMY(125,250,500 mg/kg, p.o., for 5d)obviously inhibited the release of LTB₄ and LTC₄ from neutrophils in mice caused by proteose peptone. DMY(0.01,0.1,1.0μmol/L)obviously suppressed the release of LTB₄ from neutrophils in rat caused by proteose peptone. And DMY(0.25,0.5,1.25,2.5,5×10³Î¼mol/L)significantly inhibited the release of histamine induced by compound 48/80 from peritoneal mast cells in rat. Moreover, DMY(2,4,8μmol/L)could significantly increase the ORAC activity, DMY(1.25,2.5,5,10,20×10³Î¼mol/L) had the capacity of scavenging free radicals in vitro.Our results indicate that DMY exerts significant anti-inflammatory activities and the modulatory effects on the immune functions, the mechanisms could be partly ascribed to its inhibitory effect on release of leukotrienes and histamine. Moreover, the mechanisms could be ascribed to its free radical scavenging activity, which implied that DMY would be a potential candidate for further investigation as a new botanical drug for human being.