Promotion of Mitochondrial Biogenesis via Activation of AMPK-PGC1ɑ Signaling Pathway by Ginger (Zingiber officinale Roscoe) Extract, and Its Major Active Component 6-Gingerol.

Abstract

Several studies indicated that ginger (Zingiber officinale Roscoe) enhances thermogenesis and/or energy expenditure with which to interpret the beneficial effects of ginger on metabolic disorders. It is well known that mitochondrial activity plays an essential role in these processes. Thus, this study aimed to investigate the effect of ginger extract (GE) and its major components, 6-gingerol and 6-shogaol, on mitochondrial biogenesis and the underlying molecular mechanisms. Our results showed that GE at dose of 2 g/kg promoted oxygen consumption and intrascapular temperature in mice. The mitochondrial DNA (mtDNA) copy number in muscle and liver increased. Expression levels of oxidative phosphorylation (OXPHOS) related proteins and AMP-activated protein kinase ɑ/proliferator-activated receptor gamma coactivator 1 ɑ (AMPK/PGC1ɑ) signaling related proteins in the muscle, liver, and brown adipose tissue (BAT) increased as well. In HepG2 cells, GE at concentration of 2.5 and 5 mg/mL increased mitochondrial mass and mtDNA copy number. GE promoted ATP production, the activities of mitochondrial respiratory chain complex I and IV, and expression levels of OXPHOS complex related proteins and AMPK/PGC1ɑ signaling related proteins. The antagonist of AMPK eliminated partly the effect of GE on mitochondrial biogenesis. 6-Gingerol increased mitochondrial mass, mtDNA copy number and ATP production, and the activities of mitochondrial respiratory chain complexes in HepG2 cells as well. However, both 6-gingerol at high concentration of 200 µM and 6-shogaol at 10 to 200 µM inhibited cell viability. In conclusion, GE promoted mitochondrial biogenesis and improved mitochondrial functions via activation of AMPK-PGC1ɑ signaling pathway, and 6-gingerol other than 6-shogaol, may be the main active component. PRACTICAL APPLICATION: Ginger (Zingiber officinale Roscoe) is a food seasoning and also used as a medical plant in alternative medicine throughout the world. Here, we demonstrated that ginger extract (GE) promoted mitochondrial biogenesis and mitochondrial function via activation of AMPK-PGC1ɑ signaling pathway both in mice and in HepG2 cells, and 6-gingerol may be its main active component. Ginger, with anticipated safety, is expected to be a long-term used dietary supplement and be developed into a new remedy for mitochondrial dysfunctional disorders.