Antioxidant potential of selected whole grain cereals consumed by Sri Lankans: a comparative in vitro study

Abstract

Whole grains of rice [improved: Bw 361 (red) and Bg 359 (white); traditional: Kalu Heeneti (red) and Suwadal (white)], corn, finger millet, wheat, barley and oat were used in this study. Ethanolic extracts (EEs) and methanolic extracts (MEs) of whole grain cereals were evaluated for total polyphenolic content (TPC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), DPPH and ABTS radical scavenging antioxidant properties (AP) in vitro (n=3 each). Results showed significant differences (p<0.05) between extracts and among cereals for investigated AP. In general, MEs of cereals showed significantly higher (p<0.05) activity compared to EEs of cereals. Among the studied cereals, finger millet exhibited the highest AP in both extracts for TPC, FRAP and ORAC while for DPPH and ABTS it's only in MEs. The mean TPC, FRAP and ORAC of MEs of finger millet were 708.45 ± 11.72 mg gallic acid equivalents (GAE), 1413.69 ± 1.61, 1240.45 ± 67.38 mg Trolox equivalents (TE) and 955.76 ± 2.03 mg TEjl00 g grain, respectively while for EEs it was 275.36 ± 4.26 mg GAE, 606.34 ± 5.00 mg TE and 1112.52 ± 24.38 TEjl00 g grain respectively. For DPPH and ABTS radical scavenging activities the IC50 values of MEs of finger millet were 49.42 ± 6.65 and 10.74 ± 0.44 IlgjmL respectively. Ofthe cereals analyzed the second highest AP was observed in traditional red rice variety, Kalu Heeneti (except for ORAC) for both extracts tested. Whole grains of wheat and oats had very low AP compared to finger millet and red rice varieties analyzed in the present study. It is concluded that finger millet possesses highest AP.

Anti-inflammatory and Antioxidant Properties of Finger Millet (Eleusine coracana (L.) Gaertn.) Varieties Cultivated in Sri Lanka

“…There were no significant differences (P ≥ 0:05) between the ORAC values of ethanolic and methanolic extracts in Ravi and Oshadha varieties. ORAC values of common cereals were reported in previous studies [30]. ORAC values of methanolic extracts of white and red rice varieties ranged from 150.61 to 439.64 mg trolox equivalents per 100 g of flour on a dry weight basis, while ORAC values of ethanolic extracts ranged from 108.32 to 272.08 mg trolox equivalents per 100 g of flour on a dry weight basis.…”

“…TPCs of common cereals were reported by Abeysekera et al [30]. According to their findings, TPCs of methanolic extracts of white and red rice varieties ranged from 29.34 to 139.79 mg GAEs per 100 g of flour on a dry weight basis, while TPCs of ethanolic extracts ranged from 59.78 to 113.56 mg GAEs per 100 g of flour on a dry weight basis.…”

Evaluation of the Toxicity of Secondary Metabolites in Aqueous Extracts of Ficus thonningii Blume in Wistar rats

“…Recent studies conducted in Sri Lanka scientifically proved that the rice varieties tested in the present study had high amounts of phenolic antioxidants, tocopherols and γ-oryzanols [8][9][10]17,34]. Therefore, presence of such compounds in brans of these rice varieties may be at least partly responsible for the observed physiological radical scavenging activities.…”

A Comparative Study on Potential Antioxidants and Antioxidant Activity in Raw and Cooked Selected Locally Grown Legumes in Sri Lanka

“…Zhao et al, 2014 reported that TPC of legumes extracts ranged 9.5 -47.6 mg (GAE) /g [10]. Further it was reported that the TPC of legumes were significantly higher than that corn, millets, wheat and rice [19] [26]. The data reported by , analyzing twenty one varieties of legumes, the TPC ranged from 0.57 -9.60 mg (GAE)/g were in the same range of our varieties [27].…”

“…The ground grain powder (2.5 g) and 20 times the sample weight of volume of 70% ethanol were shaken overnight at room temperature (25 ± 2°C). Extracts were then centrifuged at 3000 g for 15 min, supernatant filtered through syringe filters, evaporated under vacuum in a rotary evaporator and resulted solution was freeze dried at -40 0 C, 18 h, 0.1 mbar [19].…”