Pharmacological Study Of Berberine With Mitochondria As The Target

Various activities and targets have been found in the pharmacological researches of berberine(BBR).Among these studies,regulation of glucose and lipid metabolism and targeting mitochondria activity are promising area.To vertify the role of mitochondria as a target of BBR,and to discover the mechanism and consequence of BBR targeting mitochondria,this research exploited the relationship between targeting mitochondrial activity and the glucose-lowering & anti-tumor effect of BBR.As the foundation,we checked the relevance between regulating mitochondrial activity and glucose-lowering and anti-cancer effect of BBR.First,mice were administrated with 5-15mg/kg BBR(i.p.),and the results showed that BBR lowered body temperature,decreased energy charge in muscle,kidney and heart,and enlongated the viability in confined space.These results indicated that BBR suppressed energy metabolism in vivo.Second,HepG2 cells were administrated with 0.25-1.0?g/ml BBR,and the results showed that BBR stimulated glycolysis and lactate production,decreased ATP level,increased NADH level,suppressed TCA cycle enzymes mRNA expression.These results indicated that glycolysis-stimulating activity is relevant to the mitochondrial-suppressing activity of BBR.Third,a diabetic mice model was made by streptozotocin and high-fat food administration,and mice were oral administrated with 50-200mg/kg BBR for 4 weeks.The results showed that BBR showed moderate improvement on glucose and lipid disorder.And BBR increased energy chanrge and upregulated glycolytic and TCA cycle enzymes mRNA expression.Besides that,BBR regulated mtDNA copy number and mitochondrial fusion factors Opa1,Mfn1/2 mRNA expression in a hormestic manner,which maybe one of the machinism by which BBR regulated glucose and lipid metabolism.Fourth,HepG2 xenograft model mice were oral administrated with 50,400mg/kg BBR for 4 weeks.The results showed that BBR suppressed tumor growth,reduced tumor energy charge,decreased mtDNA copy number and TCA cycle enzymes mRNA expression.These results suggested that the anti-tumor activity of BBR is related to the mitochondrial-suppressing activity of BBR.All of these results vertified the relevance between regulating mitochondrial activity and glucose-lowering and anti-cancer effect of BBR.To further determine whether BBR inhibited tumor cell proliferation via reducing mitochondrial activity,a cell proliferation suppression and rescue experiment was designed.In the experiment,AKB(?-ketobutyrate)only served as exogenous electron receptor in cell and received electrons from NADH in the lactic dehydrogenase and other dehydrogenase catalyzed reaction,and help to regenerate NAD+,which partly substitite for the oxidation respiratory chain function.The results showed that high dose of BBR damaged mitochondrial structure and function and inhibited tumor cell proliferation in vitro.And AKB partedly rescued cell proliferation,but did not protect mitochondria.Cell proliferation inhibition is achived by interacting with all the target of BBR in cell,however,the rescuing effect of AKB only stand for part of the mitochondrial function.Thus,this study suggested that BBR inhibited tumor cell proliferation mainly via reducing mitochondrial activity.In summary,this study suggested that the glucose-lowering activity and the anti-cancer activity of BBR were related to the regulation of mitochondrial activity by BBR.And suppressing mitochondrial activity by BBR played an important role in the anti-tumor effect of BBR.This study provided new knowledge about the pharmacological activity of BBR with mitochondria as the target.