Phytochemical Profiles and Antioxidant Activity of Grasses Used in South African Traditional Medicine.

Grasses are a valuable group of monocotyledonous plants, used as nourishing foods and as remedies against diseases for both humans and livestock. Phytochemical profiles of 13 medicinal grasses were quantified, using spectrophotometric methods and ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS), while the antioxidant activity was done using DPPH and ferric-reducing-power assays. The phytochemical analysis included the total soluble phenolic content, flavonoids, proanthocyanidins, iridoids and phenolic acids. Among the 13 grasses, the root methanolic extracts of spp., and contained the highest concentrations of total soluble phenolics (27-31 mg GAE/g DW) and flavonoids (4-13 mg CE/g DW). Condensed tannins and total iridoid content were highest (2.3 mg CCE/g DW and 3.2 mg HE/g DW, respectively) in . The most common phenolic compounds in the grass species included -coumaric, ferulic, salicylic and vanillic acids. In the DPPH radical scavenging assay, the EC values ranged from 0.02 to 0.11 mg/mL for the different grasses. The best EC activity (lowest) was exhibited by roots (0.02 mg/mL) and inflorescences (0.04 mg/mL), spp. roots (0.04 mg/mL) and leaves (0.06 mg/mL). The highest ferric-reducing power was detected in the whole plant extract of (0.085 ± 0.45; r = 0.898). The observed antioxidant activity in the various parts of the grasses may be due to their rich pool of phytochemicals. Thus, some of these grasses provide a source of natural antioxidants and phytochemicals that can be explored for their therapeutic purposes.