Abstract:

Excessive exposure to dietary lipids causes deranged homeostasis of cellular energy metabolism and oxidative
damage. Phlorizin is rich in phenolic hydroxyl groups which have been proved to play an antioxidant role in vivo and in vitro.
This study aimed to investigative the antioxidant activity of phlorizin in hamsters fed a high fat diet. Totally, 36 hamsters
were fed either control diet or one of the three experimental diets containing 3, 6, or 9 g/kg phlorizin for 6 weeks. Then
the enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), total antioxidant
capacity (T-AOC) and the content of malonaldehyde (MDA) in hamster serum, heart, kidney and liver were assayed.
Finally, the mRNA expression levels of antioxidant enzymes including SOD, GSH-Px, CAT, heme oxygenase-1 (HO-1)
and F-E2-related factor 2 (Nrf2) were detected by real-time PCR (RT-PCR). Antioxidant enzyme activity assays showed
that the activities of SOD, GSH-Px and CAT in serum, heart, kidney and liver were increased and the content of MDA was
significantly reduced by dietary phloridzin supplementation. RT-PCR results showed that the mRNA expression levels of
CuZn-SOD, Mn-SOD, GSH-Px, HO-1 and Nrf2 were significantly increased compared with those of the control group
(P ＜ 0.01), while CAT gene in 6 and 9 g/kg groups were significantly increased (P ＜ 0.01) compared with the control
group. Therefore, the protection of phloridzin against oxidative stress injury in hamsters fed a high fat diet may be mediated
through the induction of the expression of Nrf2 gene and the increases in the mRNA expression levels of SOD, GSH-Px,
CAT, and HO-1, which in turn increases the activities of antioxidant enzymes.

Key words: phlorizin, antioxidant, enzyme activity, gene expression