Evaluation of Effect of Soil Amended with Different Levels of Craseonycteris thonglongyai Droppings on the Concentrations of Some Antioxidants in the Leaves of Amaranthus cruentus
Leafy vegetables are among the major sources of antioxidants which are important components of health promoting nutrients and prevention of diseases associated with cellular damage. However, the concentrations of these health promoting nutrients in vegetables generally depend on the nutrient contents and compositions of the soil. It is for this reason that pot experiment was designed to evaluate the influence of soil amended with different levels of Craseonycteris thonglongyai droppings on the concentrations of some antioxidants (Î²-carotene, carotenoid, lycopene, tocopherol, chlorophyll and ascorbic acid) in the leaf of Amaranthus cruentus. The levels of Craseonycteris thonglongyai droppings used for the soil amendment were control (no application), 25, 50 and 75 g per 10 kg soil. The leaves of Amaranthus cruentus were harvested at vegetative phase and the antioxidant contents were analysed by standard analytical methods. Concentrations of Î²-carotene, lycopene, carotenoid, chlorophyll and tocopherol were determined by spectrophotometric method while the ascorbic acid content was determined by titrimetric method. The results showed that the concentrations of lycopene and chlorophyll in A. cruentus increased significantly (p < 0.05) with increased levels of C. thonglongyai droppings in the soil except that the concentrations of the antioxidants in the leaves of the vegetable grown in the soil amended with 50 and 75 g of the droppings did not differ significantly (p > 0.05). Similarly, concentrations of Î²-carotene and carotenoid in the leaves of A. cruentus were elevated significantly (p < 0.05) with increased application of C. thonglongyai droppings, however, the concentrations of these parameters decreased significantly (p < 0.05) in the vegetable treated with 75 g compared with the one treated with 50 g per 10 kg of the soil. Whereas application of different levels of C. thonglongyai droppings had no significant effect on tocopherol content in A. cruentus, the concentration of ascorbic acid in the vegetable decreased significantly with increase application of the droppings. The present study concludes that amendment of soil with moderate amount of C. thonglogyai droppings increase the concentrations of the antioxidants in the leaf of A. cruentus except that the ascorbic acid content in the vegetable decreased significantly.
Musa, A. Department of Biochemistry, Faculty of Natural Sciences, Ibrahim Badamasi Babangida University, Lapai, Niger State, Nigeria.
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