Extracts and silver nanoparticles from different parts of Rheum ribes: Characterization, in vitro antibacterial, and antioxidant activities, and in silico molecular dynamics studies

Rheum ribes is a medicinal plant with antioxidant, antibacterial effects, which have been demonstrated in various studies. In this study, the biological activities (antioxidant and antimicrobial) and phytochemical contents (total phenolic content and phenolic substances content by LC-ESI-MS/MS) of the fruit and peel extracts obtained from R. ribes were determined. The antioxidant content (DPPH˙ and FRAP) and total phenolic content (FCR) of R. ribes were analyzed for the first time using a new potentiometric biosensor method. In addition, the characteristic properties (XRD, FT-IR, FE-SEM, FESEM-EDX, TEM, and UV-Vis) and antibacterial properties of silver nanoparticles (AgNPs) prepared by an environmentally friendly green synthesis method were investigated. In addition, the interactions of the main component (hesperidin) in the LC-ESI-MS/MS content analyses with the topoisomerase IV were calculated theoretically. While the antioxidant activity of the R. ribes peel extract was comparable to that of the fruit extract, it was higher for FRAP and DPPH˙ scavenging activity. R. ribes (fruit)-AgNPs were found to have high activity against the microorganisms. The MolDock scores of hesperidin and possible hesperidin-AgNP were calculated to be -111.83 and -171.08, respectively. Thus, hesperidin-AgNP complex was found to have higher inhibitory properties than hesperidin. In the 100-ns MD simulation, the RMSD values were constant at 10 nm and the MM/PBSA calculation resulted in a binding energy of -16.15 kcal/mol for hesperidin.