Erythrocytes and their membranes are favorable models to study the relationship between diabetes and susceptibility of erythrocytes to oxidative stress damage. The recommendation for the use of fermented papaya preparation (FPP) as a functional food for dietary management of type 2 diabetes was evaluated by assessing its effect on the human antioxidant status and erythrocyte integrity on a multi-ethnical pre-diabetic population. The in vivo effect of FPP was compared with its in vitro free radical scavenging potentials. FPP exhibited potent in vitro free radical scavenging activities thought to be attributed to residual phenolic or flavonoid compounds. Low doses of FPP significantly reduced the susceptibility of human erythrocytes to undergo free radical-induced hemolysis. The intake of 6g FPP/day for a period of 14weeks was observed to significantly reduce the rate of hemolysis and accumulation of protein carbonyls in the blood plasma of pre-diabetics. That FPP consumption on a daily basis can strengthen the antioxidant defense system in vivo was clearly demonstrated by the marked increase of total antioxidant status in the FPP-supplemented pre-diabetics. That FPP maintains the integrity of erythrocytes could benefit the strategies to improve the quality of future blood products.
Trial registration: ClinicalTrials.gov NCT01248143.
Keywords: Antioxidant; Blood product preservation; Erythrocyte hemolysis; Fermented papaya preparation; Oxidative stress; Type 2 diabetes.
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