Polyphenolic Fractions from Three Millet Types (Fonio,Finger millet,and Pearl millet): their Characterization and Biological Importance

BackgroundAs antioxidant-rich plant foods, cereals can impede lipid and starch breakdown in the human body, are germane to diabetes management.ObjectiveWe aim to identify newer sources of phytochemicals and health-promoting constituents desirable antidiabetic and antioxidant properties.MethodsThree millet types i.e. fonio (Digitaria exilis), finger millet (Eleusine coracana), and pearl millet (Pennisetum glaucum) available locally were investigated for antioxidant ability employing these assays i.e. DPPH, ABTS, H₂O₂, antidiabetic ability employing these assays i.e. α-amylase, α-glucosidase and inhibitory property on glycosylation formation. Preliminary characterization tools were employed i.e. UV-Visible spectroscopy (UV–visible) and Fourier-Transform Infrared Spectroscopy (FTIR) for the polyphenolic confirmation.ResultsThe absorbance intensity range 325–425 nm confirmed that polyphenolics are present in the three millet types; most of the biological results showed the activities are dose-dependent. Fonio millet extract revealed the highest activity against hemoglobin glycosylation (29.469 ± 0.399%) which compared favorably with the standard (acarbose) (29.354 ± 1.607%). Fonio millet extract also showed the best antioxidant activity (significantly higher% inhibition value = 47.909 ± 3.472) and the pearl millet revealed the least antioxidant activity (significantly lower% inhibition value = 44.910 ± 3.597) both at a concentration of 500 mg·ml^?1, though all the millet extracts showed activity towards this assay better than the standard (19.883 ± 2.485%). Fonio millet extract displayed a significantly higher percentage inhibition of α-amylase and glucosidase (43.729 ± 0.410% and 55.835 ± 2.198%) than finger millet (39.002 ± 1.604%; 43.971 ± 5.849%) and pearl millet (33.223 ± 2.708%; 30.845 ± 2.841%), respectively.ConclusionThe polyphenolic extracts from these millet types have therapeutic potentials, which may play significant roles in type 2 diabetes prevention and management, and hence these millets, especially fonio and finger millet, have the potential to be utilized as functional foods.