Influence of malaria infection on peroxyl-radical trapping capacity in plasma from rural and urban Thai adults.

Measurement of peroxyl-radical trapping capacity (TRAP) were made in plasma from patients with malaria from a rural and an urban Thai community. The results were compared with those from control subjects living in the same areas and chosen to match the patients closely. Measurements were also made of various antioxidants including nutritional indices vitamin C and alpha-tocopherol and the non-nutritional indices urate and protein-sulphydryl. Parasite counts, temperature on examination and the duration of illness were recorded together with measurements of plasma caeruloplasmin (EC 1.16.3.1), retinol and malondialdehyde (MDA). In general, most measurements made in the villagers were lower than those in the comparable urban groups. The exceptions were caeruloplasmin and MDA when the latter was expressed as MDA:cholesterol ratio. TRAP values were extremely low in 50% of the villagers and 25% of the urban patients with malaria and these results correlated with retinol and vitamin C and inversely with malonaldehyde. The results suggested that low TRAP values are associated with lipid peroxidation and that vitamin C and possibly retinol may be destroyed by the oxidative conditions present in the plasma in this disease.