Phenolics in mulberry leaves protect Hep G2 cells against hyperglycemia‐induced oxidative damage

Abstract

Hyperglycemia is associated with increased risk of type 2 diabetes, partially due to increases in oxidative stress. Phenolics in mulberry leaves (MLP) may protect tissues from hyperglycemia‐induced oxidative damage. We examined the effect of MLP on hyperglycemia‐induced oxidative damage in hepatic HepG2 cells. HepG2 were treated with glucose (5.5 or 50 mM) with or without MLP at 10 or 100 μM GAE. Hyperglycemia‐induced oxidative damage in HepG2 was demonstrated by a 666% increase in O2.− production at 0.5 h, 400% increase in malondialdehyde (MDA) at 24 and 48 h, mitochondrial membrane hyperpolarization (MMHP) at 2 h followed by depolarization, and 474% increase in nucleus NFκB‐P65 at 4 h relative to the control cells (P ≤0.05). Both MLP doses inhibited hyperglycemia‐induced O2.− production by 40%. Hyperglycemia‐induced MDA production at 24 h was diminished by 34 and 54% by MLP at 10 and 100 μM, respectively. MLP treatment protected HepG2 cells from hyperglycemia‐induced MMHP in a dose‐dependent manner with the highest dose maintaining mitochondrial polarization status. MLP at 10 μM inhibited 35% hyperglycemia‐induced NFκB‐P65 translocation and at 100 μM completely prevented the NFκB activation. Our data show that MLP in vitro protects hepatoctyes from hyperglycemia‐induced oxidative damage.