Ex vivo and In vivo Antioxidant Related Effects of Zingiber officinale Roscoe (Ginger) Extracts in Humans

Abstract

Aims: To investigate antioxidant related effects of Zingiber officinale Roscoe (ginger) in humans. Study Design: Venous blood from healthy volunteers was used to conduct ex vivo experiments. For in vivo study, nine healthy volunteers, each received orally 250 ml of aqueous extract of ginger daily for 5 days. Venous bloods were taken before and  one hour after the first dose of aqueous extract (sample I and II respectively) and then one day after the last dose of day five (i.e. day 6, sample III). The first blood taken before the first dose (i.e. sample I), served as control for the next samples of II and III. Methodology: The following assays were performed: Erythrocyte reduced glutathione (GSH), Malonyldialdehyde (MDA), Protein carbonyl (PC), superoxide dismutase (SOD), Percentage hemolysis, serum total antioxidant status (TAS) and selected biochemical tests. Results: Pre-incubation of erythrocytes ex vivo with methanolic extract of ginger then exposed to H₂O₂ decreased significantly MDA production (i.e. anti-lipid-peroxidant), PC production (i.e. anti-protein-oxidant) and oxidant hemolysis (i.e. anti-hemolytic) in a concentration dependent manner. Ginger extract had no effect on GSH of ex vivo incubated erythrocytes. Oral administration of aqueous extracts of ginger to healthy volunteers, for 5 days, increased significantly serum TAS (from 1.08 to 1.24 mmol/l = 15% increase), erythrocyte GSH (from 0.74 to 1.53 mg/g Hb = 107% increase) and SOD (from 1005.4 to 1374.5 U/gHb = 37% increase), decreased significantly erythrocyte MDA (from 23.7 to 15.5 nmol//g Hb = 35% decrease), and also caused a significant small decrease within the reference range in serum potassium (K) (from  4.3 to 4.0 mmol/L), and serum urea nitrogen (BUN) (from 17.9 to 13.5 mg/dL) and an increase in serum creatinine phosphokinase (CPK) (from 63.1 to 82.7 U/L), with no effect on other serum biochemical tests for kidney, liver, cardiac and pancrease, compared to 0 time administration. Conclusion: The study indicates that ginger can improve the base line of the defense mechanisms against possible oxidative stress and possibly inhibit pathological conditions related to oxidative stress.