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168 华 中 农 业 大 学 学 报 第 41 卷

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Protective mechanism of flavonoids extracts from
Pericarpium Citri Reticulatae‘Chachi’on t-BHP-induced

oxidative damage in HepG2 cells

TAO Yexing,YU Qian,LIU Ruiting,ZHANG Xiwen,WU Ting,PAN Siyi,XU Xiaoyun
College of Food Science and Technology/Key Laboratory of Environment Correlative
Dietology，Ministry of Education/Hubei Key Laboratory of Fruit & Vegetable Processing &
Quality Control，Huazhong Agricultural University，Wuhan 430070，China

Abstract The flavonoids extracts of Pericarpium Citri Reticulatae‘Chachi’（PCR-CF）were ex⁃
tracted and purified from fresh-dried tangerine peel and Pericarpium Citri Reticulatae‘Chachi’（PCR-C）
stored for 1 year and 10 years to study the effects of aging process on the antioxidant activities of Pericarpi⁃
um Citri Reticulatae‘Chachi’. The changes of contents of flavonoids were analyzed with HPLC. The anti⁃
oxidant activities of PCR-CF were evaluated by using tert-butyl hydroperoxide（t-BHP）-induced oxidative
damage in human hepatoma cells（HepG2 cells）as the model. The molecular mechanism of antioxidant ac⁃
tivity was further explored via real-time fluorescence quantitative PCR（qRT-PCR）and Western blot. The
results showed that the content of hesperidin fluctuated，but the overall trend was decreasing during the ag⁃
ing process of dried tangerine peel. The contents of polymethoxyflavonoids（PMFs） and total PMFs
showed an increasing trend，among which the content of PCR-C10F was the highest，and the content of to⁃
tal PMFs reached（98.66±0.56）mg/g. Moreover，PCR-CF from different storage years significantly in⁃
creased the levels of SOD and GSH and reduced the contents of MDA There was significant difference be⁃
tween different storage periods. The antioxidant activity of PCR-C10F was the strongest，in which the level
of SOD，GSH and MDA reached （139.38±17.38） U/mg，（117.81±3.22） μmol/g and （0.39±0.03）
nmol/mg，respectively. The results of correlation analyses showed that the accumulation of nobiletin was
the main active component of PCR-C10F to maintain redox balance. PCR-C10F significantly up-regulated
the mRNA expression levels of Nrf2（P<0.001）and increased the expression levels of Nrf2（P<0.05）in
nuclear protein. The mRNA（P<0.001）and protein（P<0.01）expression levels of antioxidant enzymes
were significantly activated，and the mRNA（P<0.001）and protein（P<0.05）expression levels of HO-1
was significantly decreased. It is indicated that the contents of PMFs in PCR-CF showed increasing trends
and the antioxidant activities enhanced during aging process. PCR-C10F can protect against oxidative stress
by regulating the Nrf2-ARE antioxidant signaling pathway. It will provide a theoretical basis for rational
storage and quality control of PCR-C.
Keywords Pericarpium Citri Reticulatae‘Chachi’；flavonoids；antioxidant activity；Nrf2-ARE path⁃

way

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