| Objective:(1) The extraction, content determination, comparison of various kinds of dietary fiber (derived from wild rice, corn, apple and celery) and flavonoid (from wild rice and corn) were studied to investigate the basis of how to these biological effects occur.(2) The influences, which different sources of extracted dietary fiber and flavonoid had, on the content of triglyceride (TG), malondialdehyde (MDA) and superoxide dismutase (SOD) were researched in oleic acid-induced HepG2non-alcoholic fatty liver cytoplasm, to explore the different effects of these dietary fiber and flavonoid on the non-alcoholic fatty liver cell.(3) The effects of Peroxisome Proliferator-Activated Receptor-a (PPAR-a) and Camitine acyl Transferase-1A (CPT-1A) were detected in non-alcoholic fatty liver cell at mRNA level to study the mechanism, which indicated how to these different kinds of dietary fiber and flavonoid influence non-alcoholic fatty liver.Methods:(1) Using enzyme-chemical methods to extract dietary fiber from wild rice and corn, while the dietary fiber of apple and celery were obtained by chemical methods. The content of dietary fiber was measured according to the GB method. The flavonoid of wild rice and corn were extracted by extraction-reflux method and their content were determined by colorimetry.(2) Vitro non-alcoholic fatty liver model was established by oleic acid-induced HepG2cell. The concentration of oleic acid used was determined by MTT, oil red O staining and the detection of cytoplasm TG content.(3) After the steatosis of HepG2cell induced by oleic acid, adding different dietary fiber (extracted from wild rice, corn, celery and apple) and flavonoid (extracted from wild rice and corn), the changes of cytoplasm TG, MDA, SOD content were observed. Also the expressions of intracellular PPAR-a and CPT-1A mRNA were assayed. Results:(1) The total dietary fiber (TDF) content of wild rice was7.242g/100g, the corn TDF content was9.13g/100g, compared with rice, both were higher. In the pretreated apple powder TDF content accounted for13.52%, while the TDF content accounted for38.6%in the pretreated celery powder. The content of flavonoid in wild rice was3.674g/100g, significantly higher than the corn.(2)0.5mM oleic acid led to intracellular TG significant increase and lipid droplet visible accumulation, furthermore, it had no significant influence on cell viability, these mentioned above showed that0.5mM was the best concentration to induce steatosis.(3)100μg/ml dietary fiber from wild rice and corn could reduce the content of TG and MDA, increasing SOD content in HepG2non-alcoholic fatty liver cytoplasm, this showed these dietary fiber had a certain improvement on non-alcoholic fatty liver. The role of celery dietary fiber was less, the role of apple dietary fiber was not obvious.100μg/ml flavonoid from wild rice and corn could also reduce the TG content in the model.(4) Compared with non-alcoholic fatty liver model group, the intracellular expressions of PPAR-α and CPT-1A mRNA concerning the dietary fiber treatment of wild rice, corn, celery and the flavonoid treatment of wild rice and corn were significantly higher (P＜0.05), while the expressions increased slightly but not statistically significant (P＞0.05) in apple dietary fiber treatment.Conclusion:(1) HepG2cell, incubated with0.5mM oleic acid for24hours, induced steatosis and formed non-alcoholic fatty liver model.(2) Dietary fiber and flavonoid from wild rice and corn could have a certain good value on non-alcoholic fatty liver cell, probably by activation of PPAR-a, which promoted the expression of CPT1A, increasing fatty acid breakdown, and led to body fat reduction and slowing down the formation of fatty liver.(3) Dietary fiber extracted from celery could also improve non-alcoholic fatty liver steatosis, but the role of dietary fiber of apple was not obvious. The reasons may be that dietary fiber extracted from various food sources had different soluble and insoluble dietary fiber composition, besides phytochemicals combined with dietary fiber were different, which led to different roles. |
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