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 Cymbopogon spp., Cymbopogon nardus and Cenchrus ciliaris 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 Cymbopogon nardus. The most common phenolic compounds in the grass species included ρ-coumaric, ferulic, salicylic and vanillic acids. In the DPPH radical scavenging assay, the EC50 values ranged from 0.02 to 0.11 mg/mL for the different grasses. The best EC50 activity (lowest) was exhibited by Cymbopogon nardus roots (0.02 mg/mL) and inflorescences (0.04 mg/mL), Cymbopogon spp. roots (0.04 mg/mL) and Vetiveria zizanioides leaves (0.06 mg/mL). The highest ferric-reducing power was detected in the whole plant extract of Cynodon dactylon (0.085 ± 0.45; r2 = 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.

• Klíčová slova
• Poaceae, UHPLC, flavonoids, medicinal plants, phenolic acids, secondary metabolites,
• Publikační typ
• časopisecké články MeSH

Eucomis autumnalis (Mill.) Chitt. subspecies autumnalis is a popular African plant that is susceptible to population decline because the bulbs are widely utilized for diverse medicinal purposes. As a result, approaches to ensure the sustainability of the plants are essential. In the current study, the influence of smoke-water (SW) and karrikinolide (KAR1 isolated from SW extract) on the phytochemicals and antioxidant activity of in vitro and greenhouse-acclimatized Eucomis autumnalis subspecies autumnalis were evaluated. Leaf explants were cultured on Murashige and Skoog (MS) media supplemented with SW (1:500, 1:1000 and 1:1500 v/v dilutions) or KAR1 (10-7, 10-8 and 10-9 M) and grown for ten weeks. In vitro regenerants were subsequently acclimatized in the greenhouse for four months. Bioactive phytochemicals in different treatments were analyzed using ultra-high performance liquid chromatography (UHPLC-MS/MS), while antioxidant potential was evaluated using two chemical tests namely: DPPH and the β-carotene model. Smoke-water and KAR1 generally influenced the quantity and types of phytochemicals in in vitro regenerants and acclimatized plants. In addition to eucomic acid, 15 phenolic acids and flavonoids were quantified; however, some were specific to either the in vitro regenerants or greenhouse-acclimatized plants. The majority of the phenolic acids and flavonoids were generally higher in in vitro regenerants than in acclimatized plants. Evidence from the chemical tests indicated an increase in antioxidant activity of SW and KAR1-treated regenerants and acclimatized plants. Overall, these findings unravel the value of SW and KAR1 as potential elicitors for bioactive phytochemicals with therapeutic activity in plants facilitated via in vitro culture systems. In addition, it affords an efficient means to ensure the sustainability of the investigated plant. Nevertheless, further studies focusing on the use of other types of antioxidant test systems (including in vivo model) and the carry-over effect of the application of SW and KAR1 for a longer duration will be pertinent. In addition, the safety of the resultant plant extracts and their pharmacological efficacy in clinical relevance systems is required.

• Klíčová slova
• asparagaceae, conservation, eucomic acid, flavonoids, hydroxybenzoic acids, hydroxycinnamic acids, micropropagation, phenolic acids,
• Publikační typ
• časopisecké články MeSH