HPLC/ESI-MS Characterization of Phenolic Compounds from Cnicus benedictus L. Roots: A Study of Antioxidant, Antibacterial, Anti-Inflammatory, and Anti-Alzheimer's Activity.

The phenolic composition of Cnicus benedictus roots from four Algerian regions was investigated. Extractions were performed in both hydro-methanolic (30 : 70, v/v) and hydro-ethanolic (30 : 70, v/v) solvents. Their efficiency was determined in terms of the qualitative and quantitative composition in phenolic compounds by HPLC-LC/MS of the different extracts isolated from C. Benedictus roots. Cnicus benedictus roots extract have been characterized by high content of phenolic compounds, where the trans chalcone, 2,3-dihydro flavone, 3-hydroxy flavone and cinnamic acid constitute the major components, in addition to fourteen minor acidic compounds and flavonoids as rutin. The hydro-methanolic extract was the richest in phenolic compounds yield from C benedictus. On the other hand, hydro methanolic (30 : 70, v/v) and hydro ethanolic (30 : 70, v/v) extracts exhibited a high anti-inflammatory activity by in vitro 5-lipoxygenase inhibitory activity (IC50 : 6.05±94.16 µg/mL) as well as by in silico docking according two methods. Likewise, anti-Alzheimer activity of extracts was confirmed by this last technique taking into account the major compounds identified. Antibacterial tests revealed interesting results compared to amoxicillin for the different regions studied with a high content in trans chalcone and 3-hydroxy Flavone.

DFT study of the mechanisms of nonenzymatic DNA repair by phytophenolic antioxidants.

Reactive oxygen species (ROS) can oxidize and thus damage DNA. Exposure to high levels of ROS is therefore linked with the development of severe illnesses such as cancer, diabetes, and coronary heart disease. Effective treatments for these diseases are yet to be found, despite intensive research. However, it is known that the natural nonenzymatic repair of DNA damage using phytophenols occurs more rapidly than the corresponding enzymatic repair process. Carvacrol, thymol, thymohydroquinone, and p-cymene-2,3-diol are strong natural antioxidant phytophenols that are found in medicinal plants. Their antioxidant activities, which involve reacting with and eliminating ROS before they reach and damage DNA, were studied in this work. Homolytic and heterolytic antioxidant mechanisms that allow these phytophenol antioxidants to eliminate the ROS .OH and .O2- in both vacuum and water (physiological environment) were investigated using density functional theory (DFT). The results showed that the homolytic mechanism is preferred in vacuum, whereas the heterolytic mechanisms are more probable in polar environments. In addition, the electronic properties of these phytophenols were studied and correlated with their antioxidant activities. It appears that these phytophenols can be used as antioxidants in vitro and in vivo to protect living systems from dangerous ROS. Graphical abstract Antioxidant reaction of carvacrol with OH. and .O-2 radicals.