COMPARATIVE STUDY OF THE EFFECTS OF CRASEONYCTERIS THONGLONGYAI COMPOST AND CHEMICAL FERTILIZER ON SOME ANTIOXIDANT CONSTITUENTS IN THE LEAF OF CERATOTHECA SESAMOIDES (FALSE SESAME)

Application of manure to enrich the nutrient contents of soil is a common practice by vegetable growers as it improves the soil fertility and plant yield. Thus, farmers are engaged in application of different types of organic and chemical fertilizers. The objective of this study is to evaluate the effects of Craseonycteris thonglongyai compost (organic manure) and chemical fertilizer on the concentrations of some antioxidants(β-carotene, carotenoids, tocopherol, chlorophyll, lycopene and ascorbic acid) in Ceratotheca sesamoides in a pot experiment. The leaves of C. sesamoides were harvested at market maturity and subjected to standard analytical procedures. The concentrations of β-carotene, tocopherol, chlorophyll, lycopene and carotenoids were determined by spectrophotometric method while titrimetric method was used to evaluate ascorbic acid content in the samples. The results showed that the concentration of lycopene in the leaves of C. sesamoides increased significantly (p < 0.05) with the application of both C. thonglongyai compost and chemical fertilizer, however, the concentration of the compound was significantly (p < 0.05) higher in the vegetable cultivated with C. thonglongyai compost compared to chemical fertilizer. Application of chemical fertilizer significantly (p < 0.05) decreased the β-carotene and ascorbic acid contents in C. sesamoides whereas; C. thonglongyai compost significantly (p < 0.05) elevated their concentrations in the leaves of the vegetable. While application of chemical fertilizer had no significant (p > 0.05) effect on the concentrations of chlorophyll, carotenoid and tocopherol in the vegetable, the concentrations of these parameters increased significantly (p < 0.05) with application of C. thonglongyai compost. The results suggest that application C. thonglongyai compost increased the concentrations of the antioxidants in C. sesamoides compared chemical fertilizer. Thus C. thonglongyai compost is a better fertilizer in the improvement of the antioxidant contents in C. sesamoides than chemical fertilizer.