Antioxidant compounds, antioxidant activities, and mineral contents among underutilized vegetables

ABSTRACT

Natural sources may be a method to introduce antioxidants in the human diet. Portulaca oleracea L., Peperomia pellucida L., and Trianthema portulacastrum L are underutilized leafy vegetables. The plants may be sources for total phenolic (TPC), total flavonoid (TFC), total carotenoid (TCC), and β-carotene but information is lacking. Antioxidant activity, ferric reducing antioxidant power (FRAP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH), and macro- and microminerals contents were investigated in P. oleracea, P. pellucida and T. portulacastrum. Trianthema portulacastrum had the highest TPC (1.34 ± 0.13 mg∙g⁻¹), TFC (0.58 ± 0.08 mg∙g⁻¹), TCC (0.14 ± 0.01 mg∙g⁻¹), and β-carotene (0.94 ± 0.18 mg∙g⁻¹) values. The antioxidant activity and FRAP assay were highest in P. oleracea (0.91 ± 0.09 mg∙g⁻¹); the DPPH assay for P. pellucida was highest (IC₅₀ = 7 µg∙mL⁻¹). The amount of K was highest in P. oleracea (55.470 ± 0.481 g∙kg⁻¹). The amount of Mn was highest in P. pellucida (0.251 ± 0.002 g∙kg⁻¹). The individual underutilized vegetables may be able to supply some antioxidant compounds and mineral contents for the human diet.

KEYWORDS:

• Peperomia pellucida
• portulaca oleracea
• trianthema portulacastrum
• carotenoid
• dpph assay
• flavonoid
• frap assay
• phenolic

Acknowledgments

The authors acknowledge the Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin, Besut campus, Besut 22200, Malaysia, for providing research facilities and financial support, and the Faculty of Agriculture, Universiti Putra Malaysia, Serdang 43400, Malaysia, and Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, Sabah 90503, Malaysia, for technical support.

Disclosure statement

The authors declare there are no conflicts of interest regarding the publication of this article.