| This dissertation is composed of three chapters. The first chapter researched the antioxidant activity of Malus halliana Koehne and Chaenomeles speciosa. The second chapter studied the hepatoprotective effect of M. halliana and C. speciosa on acute liver injury induced by carbon tetrachloride in mice. The third chapter summarized the mechanism of chemical liver injury.Chapter I Antioxidant activity of Malus halliana Koehne and Chaenomeles speciosa in vitroThe chapter includes two parts. The first part,1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging,[2,2’-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid] diamonium salt (ABTS) radical scavenging and ferric reducing antioxidant power (FRAP) assay were used to evaluated the antioxidant activities of the different extracts of leaves from M. halliana. The results showed that the extracts of n-BuOH (MHLBU) and EtOAC (MHLEA) had antioxidant activity. MHLBU had the best DPPH radical scavenging (IC50=35.8μg·mL-1), which were weaker than that of the positive control BHT, BHA and PG (IC5o=23.01,9.33and4.04μg·mL-1).It also had the highest ferric reducing power (TEAC=869.73μmol/g), which were weaker than that of the positive control BHT, BHA and PG (TEAC=1387.73,6864and14122.67μmolTEg·-1). MHLEA had higher ABTS radical scavenging (IC50=3.5μg·mL-1) than that of the positive control BHT (ICso=4.39μg·mL-1), but which were weaker than that of the positive control PG and BHA (IC50=0.98and2.86μg·mL-1).The second part,[2,2’-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid] diamonium salt (ABTS) radical scavenging,1,1-diphenyl-2-picrylhydraz y1(DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assay were used to evaluated the extracts of C. speciosa leaves.The results showed that, in three extracts of C. Speciosa, CSLEA had the best Antioxidant activity (DPPH:IC50=40.8μg·mL-1, ABTS:IC50=7.1μg·mL-1, FRAP=1203.9μmol TE·g-1), but that were still inferior to the positive control BHT, BHA and PG.Chapter Ⅱ Hepatoprotective effect of Malus halliana Koehne and Chaenomeles speciosaThe chapter includes two parts. The first part discussed the hepatoprotective effect of M. halliana. The results showed that The level of GOT and GPT on serum significantly decreased of each dose group of MHLBU and MHLEA in mice compared with the model group, and did not show a dose-dependent manner. The level of GOT and GPT on serum significantly decreased in MHLBU (100mg·kg-1) and MHLEA (200mg·kg-1) group (P<0.05and P<0.01,respectively). Oral administration each dose of MHLBU and MHLEA could significantly decrease MDA and significantly increase SOD level in liver tissue compared with the model group,the level of MDA decreased significantly (P<0.001and P<0.01, respectively) of MHLBU (400mg·kg-1) and MHLEA (400mg·kg-1). The results also showed that each dose of MHLBU and MHLEA (200mg·kg-1) could signific SOD level in liver tissue (P<0.001), other treatment groups could significantly increase SOD level in liver tissue. The effect was better than the positive control except MHLBU (400mg·kg-1). The second part discussed the hepatoprotective effect of C. speciosa compared with the model group. The level of GOT and GPT on serum significantly decreased of each dose group of CSLBU and CSLEA in mice. The level of GOT and GPT on serum significantly decreased of CSLBU (600mg·kg-1) than other treatment groups (P<0.05and P<0.001). And the effect was better than the positive control. Oral administration each dose of CSLBU and CSLEA could significantly decrease MDA content in liver tissue (P<0.01and P<0.001, respectively) and that also very significantly increase SOD level in in liver homogenate of acute liver injury mice, the effect was better than the positive control. The results showed that the EtOAC and n-BuOH extract of M. halliana and C. speciosa were uesful to protect CCl4-induced liver injury and hepatoprotective mechanisms was related to improve the antioxidant capacity of liver cells.Chapter Ⅲ Research of progress of mechanism of chemical liver injuryThe mechanism of chemical liver injury research progress of free radical damage, plasma membrane damage, the change of ionic concentration, cholestasis, mitochondria damage and metabolic disorder were summarized. |
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