[Comparison of active ingredients and protective effects of Dendrobium huoshanense of different growth years on acute liver injury].

The differences of the active ingredients in Dendrobium huoshanense of different growth years and their protective effects on acute liver injury were studied to provide evidence for optimizing harvest time. The contents of polysaccharides, total flavonoids and total alkaloids in D. huoshanense of different growth years were determined by UV spectrophotometry, and the contents of gigantol in D. huoshanense were determined by HPLC. C57 BL/6 mice were randomly divided into blank control group(saline), modeling group(saline), high-dose(7.5 g·kg~(-1)) and low-dose(1.25 g·kg~(-1)) groups of D. huoshanense of different growth years. Each group was intragastrically administered every day for 2 weeks. 500 mg·kg~(-1) paracetamol was injected intraperitoneally 2 h after last treatment except the control group. After 12 hours, the serum and liver tissues were collected to detect the activities of ALT and AST, and the levels of SOD and MDA. The hepatic histopathological examination was performed. The results showed that the chemical constituents of D. huo-shanense of different growth years were significantly different(P<0.05). The contents of polysaccharide and gigantol of D. huoshanense of 2 growth years were the highest. The contents of flavonoids and alkaloids of D. huoshanense of 3 growth years were the hig-hest, followed by the D. huoshanense of 2 growth years, and the lowest were that of 1 growth year. Compared with the modeling group, D. huoshanense of different growth years could decrease the activities of ALT and AST in serum. Meanwhile, the levels of MDA reduced significantly, while those of SOD increased markedly. Histopathological results suggested that all D. huoshanense samples were effective in the reduction of the necrosis of hepatocytes in different degrees. The results of the multi-component SPSS paired tests showed that polysaccharide and gigantol probably played a leading role in the liver protection effects, while D. huoshanense of 2 growth years showed the best efficacy. The optimal harvesting time of D. huoshanense is 2 growth years.