Assessing the antioxidant characteristics and polyphenol content of Tribulus terrestris microwave-assisted fruit extract

Abstract

Tribulus terrestris have been traditionally used as folk medicine owing to its rich source of polyphenolic compounds. The aim of the present study was to assess the antioxidant potential by performing quantification of polyphenolic compounds present in Tribulus terrestris fruit through HPLC analysis. Various extracts of Tribulus terrestris fruit were prepared through microwave-assisted extraction (MAE) carried out at three different time intervals of 1, 3, and 5 minutes respectively. The extracts were then subjected to antioxidant characterization. The results showed maximum values of TPC, TFC, DPPH, FRAP, and ABTS assay for the extract prepared at 3 minutes as 54.86±0.51mg GA/g, 544.33±4.50mg QE/g, 87.67±0.57%, 1051.67±3.21mM Fe⁺²/g, and 86.34±2.08% respectively. However, the minimum values of TPC, TFC, DPPH, FRAP, and ABTS were observed for the extract prepared at 1 minute heating time as 39.27±0.36mg GA/g, 282.66±3.51mg QE/g, 60.33±1.15%, 756.34±4.50mM Fe⁺²/g, and 66.33±1.52% respectively. Quantification of major polyphenolic compounds in microwave-assisted Tribulus Terrestris fruit extract was performed through HPLC analysis. The results of the analysis detected twenty-four polyphenolic compounds. The maximum concentration was detected for naringin i.e., 4694.18 mg/100g of dried extract among flavonoids, while the maximum phenolic acid was found to be salicylic acid i.e., 728.41 mg/100g of dried extract. The present study concluded that Tribulus terrestris fruit is a good source of natural antioxidants and various polyphenols