Malanga (Xanthosoma sagittifolium) and Purslane (Portulaca oleracea) Leaves Reduce Oxidative Stress in Vitamin A-Deficient Rats

Abstract

Aim: This study examined the ability of tropical vegetables to reduce oxidative stress induced by vitamin A deficiency. Methods: Vitamin A-deficient male Wistar rats were divided into four groups which were treated for 30 days with different diets: AIN-93G vitamin A-deficient diet (DD), DD supplemented with pure β-carotene (β-D) and DD supplemented with malanga (Xanthosoma sagittifolium) (MD) or purslane (Portulaca oleracea) (PD) leaves as the only source of vitamin A. The thiobarbituric acid-reactive substances (TBARS), reduced (GSH) and oxidized (GSSG) glutathione, and antioxidant enzyme activities were determined in the heart and liver. Results: The rats fed β-D, MDand PD showed liver and heart TBARS concentrations lower than did DD rats. The liver GSH concentration of β-D, MD and PD rats was lower compared to DD rats. The heart GSSG concentration of the vegetable groups was significantly lower than in DD rats. Liver and heart catalase activities were not significantly different among the groups, nor was heart glutathione peroxidase (GPX) activity, however the β-D rats showed the highest liver GPX activity. There was no difference in liver glutathione-S-transferase level among the groups, while heart activity was higher in rats fed the vegetable leaves. Conclusion: This study evidences that the ingestion of purslane or malanga leaves may have a protective effect against oxidative stress caused by vitamin A deficiency.