Abstract:

Objective: To investigate the mitochondrial protection activity and underlying mechanism of total flavonoids from Vaccinium vitis-idaea (VTF). Methods: Freeze-dried V. vitis-idaea fruits were extracted by continuous reflux with 60% ethanol followed by purification with macroporous resin to prepare VTF. Total flavonoids were determined by AlCl3 colorimetry. Lipid peroxidation of liver and brain mitochondria was induced by Fe2+/VC in vitro. Thiobarbituric acid
(TBA) colorimetry was used to measure malondialdehyde (MDA) content. Mitochondrial permeability transition (MPT) of rat liver was induced by Ca2+ overload in vitro and measured by spectrophotometric method. The scavenging activities of VTF against superoxide anion (O2 －•) and hydroxyl (•OH) free radicals, which were produced by reduced nicotinamideadenine dinucleotide (NADH)/N-methylphenazonium methyl sulfate (PMS) and hydrogen peroxide (H2O2)/Fe2+ system, respectively, measured by NBT reduction and Fenton reaction colorimetry, respectively. The Na2S2O3 titration method was used to measure the scavenging activities of VTF against H2O2. The effect of VTF on Fe2+ chelation and reducing power was also examined. Results: The extraction yield of flavonoids from freeze-dried V. vitis-idaea fruits was 5.1%, and the content of VTF was 72.3%. VTF could inhibit mitochondrial MDA production and scavenge O2 －•, •OH and H2O2 significantly in a dose-dependent manner, respectively. It could increase Fe2+ chelation and reducing power in some degree and protect mitochondria from permeability transition. Conclusion: The protective effect of VTF on mitochondrial injury is ascribed to antioxidation, scavenging reactive oxygen species (ROS) and inhibiting MPT, which may be the underlying mechanism of mitochondrial protection by VTF.

Key words: Vaccinium vitis-idaea, total flavonoids, mitochondrial protection, reactive oxygen species, mitochondrial permeability transition