Inhibition of gastric H+, K+-ATPase and Helicobacter pylori growth by phenolic antioxidants of Zingiber officinale.

Ulcer is a common global problem characterized by acute gastric irritability, bleeding, etc. due to either increased gastric cell proton potassium ATPase activity (PPA) or perturbation of mucosal defence. Helicobacter pylori has been identified as a major ulcerogen in addition to oxidative stress and nonsteroidal anti-inflammatory drugs. In this paper, we report ginger-free phenolic (GRFP) and ginger hydrolysed phenolic (GRHP) fractions of ginger (Zingiber officinale) as potent inhibitors of PPA and H. pylori growth. GRFP and GRHP inhibited PPA at an IC(50) of 2.9 +/- 0.18 and 1.5 +/- 0.12 microg/mL, exhibiting six- to eight-fold better potency over lansoprazole. GRFP is constituted by syringic (38%), gallic (18%) and cinnamic (14%) acids and GRHP by cinnamic (48%), p-coumaric (34%) and caffeic (6%) acids as major phenolic acids. GRFP and GRHP further exhibited free radical scavenging (IC(50) 1.7 +/- 0.07 and 2.5 +/- 0.16), inhibition of lipid peroxidation (IC(50) 3.6 +/- 0.21 and 5.2 +/- 0.46), DNA protection (80% at 4 microg) and reducing power abilities (80-338 U/g) indicating strong antioxidative properties. GRFP and GRHP may thus be potential in-expensive multistep blockers against ulcer.