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Powerful protective effects of gallic acid and tea
polyphenols on human hepatocytes injury induced by hydrogen
peroxide or carbon tetrachloride in vitro
Tiejing Li, Xin Zhang and
Xinhuai Zhao*
Key Laboratory
of Dairy Science, Ministry of Education,
Northeast Agricultural University, 150030
Harbin,
People’s Republic of China.
*Corresponding
author.
E-mail:
zhaoxh@mail.neau.edu.cn.
Tel: +86 451 5519 1813.
Fax: +86 451 5519 0340.
Accepted 9 December, 2009 |
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Gallic
acid and tea polyphenols are found
in tea
and considered as natural antioxidants. In this study, the
cytoprotective
effects
of
gallic
acid and tea polyphenols against
human
hepatocytes
(HL - 7702 cell line)
oxidative
injury
induced by
hydrogen peroxide (H2O2) or carbon tetrachloride
(CCl4) were evaluated in vitro, with
a-tocopherol
as standard antioxidant. Some biochemical assays were carried out to
determine the cytoprotective effects of gallic acid and tea polyphenols
on the
hepatocytes
subjected to oxidative injury, including
cell
viability,
the
content of reduced glutathione
in cells, lactate dehydrogenase
leakage
into culture medium
and the
formation
of
malondialdehyde
in the cells.
Statistical results showed that pretreatment
of
the
cultured cells
with
gallic
acid, tea polyphenols or
a-tocopherol
at concentrations of 5, 10, 20 mg/l
for 30 min before oxidative injury of the cells could provide
cytoprotective effect to the cells to improve
cell viability,
increase
the
content of
reduced
glutathione
in cells,
reduce
lactate
dehydrogenase
leakage
into culture medium and decrease
the formation of
malondialdehyde
in the cells. It was shown that gallic acid and tea polyphenols
displayed stronger cytoprotective effect against oxidative injury of the
hepatocytes
than
a-tocopherol
at same addition level and gallic acid was the most powerful compound.
Key
words:
Gallic
acid, tea polyphenols,
hepatocytes,
oxidative
injury,
hydrogen peroxide, carbon tetrachloride. |
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