Analysis of rutin, β‐carotene, and lutein content and evaluation of antioxidant activities of six edible leaves on free radicals and reactive oxygen species

The antioxidant potency of soluble and bound phenolic extracts of freeze-dried six leafy vegetables was investigated using in vitro systems; singlet oxygen scavenging, hydroxyl radical scavenging, nitric oxide radical scavenging, and ABTS radicals assays. Further rutin, lutein, and β-carotene content of leaves were analysed. The results revealed that both soluble and bound phenolic extracts have exhibited antioxidant potential toward free radicals and reactive oxygen species concerned. However, soluble extracts showed a higher content of phenolics and flavonoids than the bound counterpart. The highest rutin, lutein, and β-carotene contents were observed in the leaves of Cassia auriculata, and the leaves of Passiflora edulis showed the highest vitamin C content. Positive associations between phenolics and antioxidant activities except for singlet oxygen radical scavenging ability were observed. Among the leafy types studied, C. auriculata have shown to possess more antioxidant bioactives such as β-carotene, lutein, and rutin and antioxidant activities. Practical applications This paper will give information about major bioactive compounds such as β-carotenoids, rutin, and lutein and antioxidant activity in selected green leafy vegetables due to cooking treatments. This is important for the public those concern about the healthy diet in the view of selecting leafy vegetables to combat many oxidative stress-related chronic diseases.