Selected Bioactive Components in Fluted Pumpkin (Telfairia occidentalis) and Amaranth (Amaranthus caudatus) Leaves

Abstract

Aims: This study was carried out to assess the contents of total phenolics, flavonoids, condensed tannins, saponins and alkaloids in Telfairia occidentalis and Amaranthus caudatus leaves. Study Design: The experiment employed a 2×2×5 factorial design. Place and Duration of Study: Food Chemistry/Biochemistry Laboratory, Department of Food Science and Technology, Federal University of Technology, Akure, Nigeria, between November 2010 and June 2011. Methodology: The leaves were sun dried and milled into flour using a laboratory blender. The flour samples were separately soaked in ethanol and distilled water, filtered and rotary evaporated to obtain the respective aqueous (AECT) and ethanolic (EECT) concentrates. The concentrates were used for the determination of the above-mentioned phytochemicals and also for the assessment of free radical scavenging capacity using α,α-diphenyl-β-picrylhydrazyl (DPPH). Results: The results obtained clearly showed that using ethanol as a solvent to extract the bioactive components was more efficient than using distilled water, especially for total phenolic and flavonoid contents of the leaf extracts. The contents of total phenolics, flavonoids, saponins and alkaloids were higher in Amaranthus caudatus leaf extract than in Telfairia occidentalis leaf extract; whereas the content of condensed tannins was higher in T. occidentalis leaf extract than in A. caudatus leaf extract. The free radical scavenging capacity of Telfairia occidentalis leaf extract was higher than that of Amaranthus caudatus leaf extract at both 0.3 and 0.6µl concentration of the extract. At 0.3µl concentration of the extract, the free radical scavenging capacity of T. occidentalis leaf extract ranged from 81% to 89% while that of A. caudatusleaf extract ranged from 67% to 74%. Conclusion: The leaves contain substantial concentrations of the assayed phytochemicals. T. occidentalisleaves had higher free radical scavenging capacity than A. caudatus leaves.