Abstract
Berberine is a natural alkaloid that has antineoplastic effects. However, in hepatoma cells like HepG2, the expressions of uptake transporters are minimal but efflux transporters are relatively high. Hence, how berberine enters and reaches a cytocidal concentration remains to be elucidated. In the present study, we revealed the accumulation mechanism of berberine in HepG2 cells. Cell organelles were isolated based on differential centrifugation; berberine concentration was measured using a liquid chromatography-tandem mass chromatography method or flow cytometry. Subcellular distribution of berberine was observed using a laser scanning confocal microscopy. The results showed that berberine was concentration-, temperature-, and time-dependently taken up and accumulated in HepG2 cells. Membrane drug transporters and cell membrane potential had limited effects in berberine uptake. However, qualitative and quantitative studies showed that berberine was enriched in the mitochondria; inhibition of mitochondrial membrane potential (MMP) by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) significantly decreased the intracellular berberine by up to 70%. More importantly, MMP not only significantly enhanced berberine uptake driven by cell membrane potential (P<0.01) but also inhibited p-glycoprotein (P-gp)-mediated berberine efflux (P<0.01). In brief, our results for the first time showed that MMP played crucial roles in berberine accumulation in HepG2 cells.
Highlights
Berberine is a natural quaternary protoberberine alkaloid [1]
The bioavailability of oral berberine is as low as 0.36% [5], mainly because of its limited solubility [6], extensive first-pass metabolism [5], and efflux mediated by p-glycoprotein (P-gp) during intestinal absorption [7] and after hepatic distribution [8]
We found that carbonyl cyanide 3-chlorophenylhydrazone (CCCP) treatment disturbed membrane potential (MMP), which was indicated by decreased intracellular rhodamine 123 (Rho123) concentration (Figure 6)
Summary
Berberine is a natural quaternary protoberberine alkaloid [1]. It has various pharmacological effects including antimicrobial, antioxidant, anti-inflammatory, anti-cholesterol, and antidiabetic activities [2]. The bioavailability of oral berberine is as low as 0.36% [5], mainly because of its limited solubility [6], extensive first-pass metabolism [5], and efflux mediated by p-glycoprotein (P-gp) during intestinal absorption [7] and after hepatic distribution [8]. The addition of silymarin, which inhibits P-gp, is able to improve the therapeutic effects of oral berberine on lipid and glucose metabolism by improving its bioavailability [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
