Antioxidant profiling of indigenous oat cultivars with special reference to avenanthramides

Zia, M. A.; Pasha, I.; Zhu, M. J.; Manzoor, M. S.; Shehzad, A.

Antioxidant profiling of indigenous oat cultivars with special reference to avenanthramides

2020

Zia, M. A. | Pasha, I. | Zhu, M. J. | Manzoor, M. S. | Shehzad, A.

Oat (Avena sativa) of the South Asian region, particularly Pakistan, remains neglected for decades. Oat is unique in terms of the presence of exceptional polyphenolic compounds known as avenanthramides (AVAs). AVAs have therapeutic effects and behave as antioxidative, anti-proliferative, and vasodilatory agents. The present work was designed to explore the nutritional and antioxidant aspects of oat, especially of their phenolic content, including AVAs. Three cultivars of oat (S-2000, S-2011, and L-632) were examined for their proximate composition and mineral profile. Conventional solvents (acetone, ethanol, and methanol) and supercritical carbon dioxide (SC-CO₂) were used for polyphenol extraction. Extracts were spectrophotometrically analysed for their phytochemical profile and antioxidant activity. Vital avenanthramides (AVA-A, AVA-B, and AVA-C) were quantified through HPLC/UV-Vis detector. The data reported highest total phenolic content (222.72 mg GAE/100 g) and total flavonoid content (137.13 mg QE/100 g) in S-2011 with maximum antioxidant activity (1,1-diphenyl-2-picrylhydrazyl IC₅₀ = 12.38 mg/ml and ferric reducing antioxidant power = 39.98 µmol/g). This highest antioxidant potential was examined in supercritical extract while methanol evaluated the best among conventional solvents. Best extractions were further analysed with HPLC for the quantification of AVAs. SC-CO₂ extraction recorded maximum concentrations of AVA-A (137.84 µg/g), AVA-B (105.10 µg/g), and AVA-C (119.86 µg/g) in S-2011 cultivar. In conclusion, oat is the rich source of antioxidants with the presence of exceptional AVAs.

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