Investigations on the Endemic Species Taraxacum mirabile Wagenitz: HPLC–MS and GC–MS Studies, Evaluation of Antioxidant, Anti-Inflammatory, and Antimicrobial Properties, and Isolation of Several Phenolic Compounds

In this study, the aim was to investigate the chemical content and in vitro antioxidant, antimicrobial, and anti-inflammatory activities of petroleum ether (PE), dichloromethane (DCM), ethyl acetate (EA), and n-butanol (n-BuOH) fractions obtained from ethanol extracts of the aerial parts and roots of the endemic <i>Taraxacum mirabile</i> Wagenitz. This plant is found in the Aksaray-Eskil region and has not been studied in phytochemical studies before. In this context, the chemical content of the aerial parts and root PE fractions was analyzed by GC-MS analysis in terms of terpenes and steroid substances. The composition of phenolic compounds in the aerial parts and root DCM and EA fractions was determined by HPLC-MS analysis. Apigenin, luteolin, and caffeic acid were isolated from the EA fraction of aerial parts. The total amounts of phenolic substances and the DPPH, ABTS, and FRAP antioxidant activities of PE, DCM, EA, and n-BuOH fractions were investigated, and it was found that the fractions had the ability to scavenge DPPH^• and ABTS^•+ radicals, as well as to reduce Fe (III) to Fe (II); however, all of the fractions were significantly less effective (<i>p</i> < 0.05) than the reference antioxidant quercetin. Considering that antioxidants can also exert an anti-inflammatory effect, these fractions were evaluated for their ability to inhibit cyclooxygenases (COX-1 and COX-2), the key enzymes of arachidonic acid metabolism that lead to the production of important mediators of inflammation. It was observed that fractions had the ability to inhibit both enzymes, suggesting their possible beneficial effects against inflammation. However, no extract had greater inhibitory activity than the positive control, indomethacin. The antimicrobial activity was determined against different bacterial and fungal strains. It was observed that the aerial parts and root n-BuOH and EA fractions showed weak antibacterial effects. No antifungal activity has been detected against <i>Candida</i> sp.