Antioxidants as supplements during drug-induced thrombocytopenia: a comparative analysis of Vanillic acid, L-carnitine and Caripill™

Drug-induced thrombocytopenia (DIT) is a disorder where platelet count declines as an adverse effect of therapeutic drugs. Plant extract of C. papaya Caripill™ is known to elevate platelet count under thrombocytopenic conditions. To evaluate the contribution of supplements with antioxidant potential to treat DIT, the comparative study of Caripill™, vanillic acid L-carnitine effect on platelet count and indices of oxidative stress in a model of rat thrombocytopenia induced through oral administration of hydroxyurea was performed. Wistar rats were grouped into four categories with five animals in each group: control (without any treatment); control + antioxidants; thrombocytopenia; thrombocytopenia + antioxidants. The above-mentioned antioxidants were supplemented orally at 50 mg/kg for 7 days. The level of lipid peroxidation products­, superoxides, protein carbonyls and sulfhydryls, SOD and CAT activity in isolated platelets as oxidative stress markers, and indices of platelets aggregation and ATP secretion as functional markers were used. Vanillic acid was shown to be beneficial, similar to Caripill™, during hydroxyurea-induced thrombocytopenia by maintaining platelet functions, enhancing both the antioxidant capacity of platelets and its number. L-carnitine efficiently up-regulated the enzymatic antioxidants, maintained platelet functions and protected lipids and proteins from oxidation in thrombocytopenic rats, however, it could not improve the platelet count. These findings open new avenues for employing the studied antioxidants as supplements for therapeutic purposes.