Abstract
There is considerable interest to enhance the nutritional quality of fresh produce especially vegetables. The effects of root treatment of spinach with commercial extracts of the brown macro alga, Ascophyllum nodosum (ANE) on antioxidant level of spinach were studied. At the concentration of 1.0 g/L, ANE treatment significantly increased the total phenolics and flavonoids content, total antioxidant activity (as measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity) and Fe2+ chelating ability in spinach leaves. The 1H NMR and LC-MS analyses of spinach extract suggests that the increased antioxidant activity is largely associated with flavonoids. The biological effect of ANE-enhanced polyphenols was tested using the Caenorhabditis elegans nematode model. The extracts from ANE-treated spinach significantly improved the survival of the animals under oxidative stress by 50% and high temperature stress by 61% as compared to the extracts from untreated plants (0% and 38%, respectively). Taken together, the results suggest that ANE stimulate flavonoid synthesis in spinach leaf thus enhancing its nutritional quality. Furthermore, the increased flavonoid content exerts beneficial effects in C. elegans against oxidative and heat stress.Article Outline
1. Introduction
2. Materials and methods
2.1. Chemicals, seeds and C. elegans
2.2. Plant culture and treatment
2.3. Preparation of spinach leaves and their extracts
2.4.Measurement of total phenolic content
2.5. DPPH radical scavenging assay
2.6. Ferrous ion chelating ability
2.7. Determination of ascorbic acid
2.8. Determination of flavonoid content
2.9. NMR spectroscopy analysis of spinach extracts
2.10. LC-MS analysis of spinach extracts
2.11. Effect of spinach extract on lifespan of C. elegans
2.12. Effect of spinach extract on oxidative and heat stresses of C. elegans
2.13. Statistical analysis
3. Results and discussion
3.1. Antioxidant content and the Fe2+ chelating ability of spinach
3.2. Effect of ANE treatment on flavonoid content of spinach leaves
3.3. Spinach extracts extend the lifespan of C. elegans
3.4. ANE-treated spinach imparts increased resistance to stresses of C. elegans
Acknowledgements
References