Comparative evaluation of phytochemical content, antioxidant capacities and overall antioxidant potential of select culinary microgreens

Abstract

A central field of research in recent times is the control of oxidative stress with the help of natural antioxidants. Green leafy vegetables are an important source of antioxidants in the diet. Microgreens, a novel form of leafy vegetables, are gaining popularity as a culinary ingredient. In this study, phytochemicals such as ascorbic acid (AsA), lutein (Lut), chlorophyll (Chl), total phenolics (TP) and total flavonoids (TF) with antioxidant functions were quantified in ten culinary microgreens. The antioxidant capacities of methanolic extracts of these microgreens were also determined using assays targeting different antioxidant mechanisms: DPPH and ABTS radical scavenging assays, FRAP and inhibition of linoleic acid peroxidation (ILAP). The study reports for the first time an overall assessment of the antioxidant potential of microgreens evaluated using the overall phytochemical composite index (OPCI) and antioxidant potential composite index (APCI). Roselle microgreens had the highest AsA, TP and TF content, and DPPH RSA and ILAP activities. Roselle and fennel microgreens recorded high OPCI and APCI. These indices were higher or comparable to the values obtained for spinach mature leaves. Correlation analysis revealed a significant contribution of TP and TF to radical scavenging activities, OPCI, and APCI. Thus, microgreens rich in antioxidant components could be used as a promising health-promoting culinary ingredient. • First report of overall antioxidant potential in ten tropical season specialty microgreens. • Roselle and fennel microgreens had high overall phytochemical composite index and antioxidant potency composite index. • Higher or comparable antioxidant indices obtained in microgreens than mature spinach leaves.