Evaluation of In vitro Antioxidant Potentials of Nymphaea lotus and Nymphaea pubescens Seed Oils

Abstract

Aim: The study is aimed at assessing the antioxidant potentials of Nymphaea lotus and Nymphaea pubescens seed oils. Study Design: It was designed to extract oil from the seeds and investigate their antioxidant properties to indicate their capabilities to improve oxidative stability. Place and Duration of Study: The research was conducted between August 2016 and January 2017 at Department of Biochemistry, Faculty of Basic Medical Sciences, Bayero University, Kano State-Nigeria. Methodology: 2, 2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging and reducing power assays were used to determine free radical scavenging activities and reducing power potential of Nymphaea lotus and Nymphaea pubescens seed oils. Results: From the DPPH radical scavenging assay, It shows that the IC50 value of the ascorbic acid (reference standard) was found to be higher (13.23± 0.16 μg/ml) compared to Nymphaea lotus seed oil (8.82 ± 0.82 μg/ml). The IC50 value of Nymphaea pubescens seed oil was also compared with the standard and was found to be (41.76 ± 0.98 μg/ml) higher than ascorbic acid (13.23± 0.16 μg/ml). The lower the IC50 value the higher the antioxidant activity of the oil. The order of the effectiveness of reducing capabilities of the oils was found to be N. lotus seed oil > ascorbic acid> N. pubescens seed oil. Gas chromatographic coupled mass spectroscopy analysis of the N. lotus seed oil showed that Dihydrocarveol (0.87%), Eicosane (1.10%), Lupeol (14.75%), Tetracosane (2.14%) and Viridiflorol (13.72%) were the major antioxidants compounds identified whereas Palmitic acid (23.57), Eicosane (7.65%), Oleic acid (37.85%), Tetracosane (3.10%) and Squalene (1.58%) were the major antioxidants detected in N. pubescens seed oil. Compared with standard (ascorbic acid), the results show that N. lotus seed oil possessed highest antioxidant potential. The higher antioxidant potential displayed by Nymphaea lotus seed oil could be attributed to the presence of these compounds that could act synergistically. Conclusion: Therefore, Nymphaea lotus seed oil and Nymphaea pubescens seed oil contains natural antioxidants that can improve oxidative stability.