Antioxidant, antimutagenic and antigenotoxic effects of the acetone and methanol extracts from some legumes

Abstract

The objectives of this study were aimed to determine the total phenolic and flavonoid contents, antioxidant activities, antigenotoxicity and antimutagenicity of the extracts of legume seeds and seed coats of black bean, mung bean, peanut, red kidney bean and soybean. The total phenolic content assayed by the Folin–Ciocalteu method. The extract of raw red kidney bean seed exhibited the highest total phenolics (128.5 ± 11.7 mg GAE/g dry extract). After heat treatment (autoclaving), the legume seeds and seed coats extracts of peanut showed the highest total phenolics (131.2 ± 3.5 and 498.1 ± 21.8 mg GAE/g dry extract, respectively). High content of total flavonoid was found in raw seed of black bean (37.5 ± 1.0 mg CE/g dry extract) and raw seed coats of red kidney bean (328.2 ± 5.7 mg CE/g dry extract) and peanut (328.0 ± 12.9 mg CE/g dry extract). Total antioxidant activity measured using DPPH assay and ferric reducing antioxidant power (FRAP) assay. The legume seeds extract of black bean exhibited the highest DPPH scavenging effect and reducing power (FRAP value) with 95.2 ± 2.1% and 423.4 ± 1.7 µM/g dry extract, respectively in raw seeds and 86.1 ± 1.1% and 153.9 ± 1.5 µM/g dry extract, respectively in processed seeds. For raw seed coats, peanut extract displayed the highest scavenging effect with 92.3 ± 0.3% followed by red kidney bean (89.7 ± 0.3%) and black bean (87.1 ± 2.4%). The extracts of raw seed coats of peanut and red kidney bean had high FRAP value (2067.7 ± 112.5 and 2063.3 ± 58.6 µM/g dry extract, respectively), followed by processed black bean (1495.6 ± 59.4 µM/g dry extract). The seed coats extracts of black bean, peanut and red kidney bean had the highest phenolic content and antioxidant activity while soybean extract had the lowest. This study was also aimed to determine the antigenotoxicity and antimutagenicitiy of legumes extracts by single cell gel electrophoresis (comet) assay and somatic mutation and recombination test (SMART). Processed legume seed extracts of peanut and black bean exhibited the highest inhibition on DNA break induced by hydrogen peroxide (34.7% and 35.6%, repectively) in the Comet assay. Processed seed coats extracts of black bean, peanut and red kidney bean exhibited strong inhibition (63.3%, 63.2% and 61.8%, respectively). By using SMART, legume seeds of red kidney bean showed the highest antimutagenicity (57.2%), followed by peanut (54.0%) in the SMART. Seed coats extracts at the lowest concentration exhibited weak antimutagenic activity (6.2- 38.8%). Seed coats extract of red kidney bean showed the highest antimutagenicity (38.8%). However, at the higher concentrations, the seed coats extracts exhibited synergistic effect on the mutagenicity of urethane. The finding from this study suggested that the antimutagenic/co-mutagenic activity depends upon the levels of phenolics consumed.