Heteropogon contortus (L.) belongs to the family Poaceae, which is known to have bioactivities like anti-inflammatory, antioxidant, membrane and mast cell stabilization, antimicrobial and many more. The aim of the present study is to explore occurrence of phytochemicals and antioxidant activity by using the whole plant (including leaf, stem, and root) crude extract in three different solvents (methanol, hydroethanol, and aqueous). Using standard methods, presence of various bioactive compounds was determined. Quantitative evaluation of total phenol, flavonoid and tannin content were done by using the spectrophotometric techniques. For antioxidant property analysis, in-vitro techniques like ferric reducing antioxidant potential (FRAP) assay, diphenyl1-2-picrylhydrazyl (DPPH) and metal chelation assay were used. In plant extract preparation, the green colour extract of methanol with solid consistency observed to have highest % yield of 4.46 %, followed by hydroethanolic (3.86 %), and aqueous extract (2.95 %). Various phytocompounds (e.g., alkaloids, steroids, phenols, flavonoids, glycosides, carbohydrates, and resins) were observed in higher concentration in methanol, hydroethanol, and aqueous extract. Out of all extracts, the methanol extract observed to have highest flavonoid (30.07 ± 0.09 mg Quercetin equivalent (QE)/g), phenol (34.12 ± 0.028 mg of the Gallic acid equivalent (GAE)/g), and tannin (26.61 ± 0.008 mg of the Tannic acid equivalent (TAE)/g) content. In DPPH and metal chelation assay, the effective inhibitor was the methanol extract (42.94 ± 0.0061 µg/ml, 100.57 ± 0.085 µg/ml) in order of potency inhibitory concentration (IC50) while the FRAP value was observed maximum in the hydroethanol extract (258.41 ± 0.0085 mg/g). Thus, overall investigation of the plant extracts shows that the occurrence of variety of phytochemicals having antioxidant properties makes the plant a promising candidate for usage in the traditional medicine.
