Impact of Spices on Micronutrients, Phenolic Compounds, in Vitro and in Vivo Antioxidant Potentialities in Eggplant Leaves Cooked with Water

Abstract

Eggplant leaves (<i>Solanum macrocarpon</i>) are rich in nutrients which are unfortunately lost during cooking. To reduce micronutrients losses and enhance antioxidant potentialities, they were cooked in water for 30 minutes with onion, ginger and Guinea pepper. The analyzes focused on the determination of vitamin C, β-carotene, phenolic compounds, free radical-scavenging and lipid peroxidation inhibitory activities. In Wistar rats, thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD) and glutathione peroxidase activities were also evaluated during 1 month. The results indicated that vitamin C remained low in eggplant leaves cooked with onion and spices. Cooked eggplant market leaves β-carotene content (187.11 μg/100 FM) increase from 447.43 μg/100 FM (with onion) to 905.44 μg/100 FM (with Guinea pepper). Ginger, Guinea pepper and onion improved eggplant field leaves free radical scavenging activities, which previous IC₅₀ value (12.00 µg/ml) became 0.67, 0.83 and 3.08 μg/ml respectively. TBARS rate increased only for rats which received eggplant market leaves cooked with onion from 0.02 to 0.03 nmol/ml. SOD activities increased during the firsts 2 weeks of experiment. Glutathione peroxidase activities is high in serum of rats which received eggplant field leaves cooked with onion (18.70 nmol/min/ml). Onion, ginger and Guinea pepper enhance eggplant antioxidant potentialities during cooking.