Evaluation of Antioxidant Activity of Trigonella foenum-graecum Using Several In Vitro Assays

Abstract

The present study has been designed to examine the antioxidant activity of the methanol extracts of Trigonella foenum-graecum. Antioxidant activity was determined by using 1, 1-diphenyl-2-picrylhydrazyl (DPPH)radical scavenging and ferric reducing power assays. In addition, % yield, total phenolic and total flavonoid contents were also determined. Total phenolic contents were expressed as gallic acid equivalent (GAE) while total flavonoids contents were expressed as quercetin equivalent (QE) of the methanol extracts of Trigonella foenum-graecum. Total phenolic contents of the methanol extract of Trigonella foenum-graecum were found 226.66 ± 5.23 μg GAE/mg of the dried extract. On the other hand, the total flavonoid contents in the methanol extract was 237.6667 ± 6.21 μg QE/mg of the dried extract. The methanol extract of Trigonella foenum-graecum displayed very strong antioxidant activity by scavenging DPPH free radical with an IC50 value of 281.875 ± 7.32 μg/ml compared to the positive control ascorbic acid of which IC50 value is129.7143 ± 3.95 μg/ml. On the other hand, Trigonella foenum-graceum methanolic extract also showed strong ferric reducing power compared with the ascorbic Acid. Moreover, the total antioxidant capacity of the methabnol extract of Trigonella foenum-graceum was found to be 188.57 ± 6.47 μg AAE/mg of the dried extract. From the above results, it can be concluded that the methanol extract of Trigonella foenum-graceum has very strong antioxidant potential which might be associated with the high level of phenolic and flavonoids type compounds present in the extract. Therefore, Trigonella foenum-graceum could be used as a source of naturally occurring potent antioxidants that might ameliorate oxidative stress and related disorders. However, this plant needs further investigation in order to find out the responsible chemical compounds associated with the antioxidant activity of Trigonella foenum-graceum.