Hemisyntheses and In-silico Study of New Analogues of Carlina Oxide from Carthamus Caeruleus Roots

Abstract

Aim and objective: Nowadays, developing effective antibiotics for bacterial control has become difficult due to increased resistance to the available medicines in the market. Essential oils possess interesting biological properties as some of their components have very powerful antiviral and antibacterial properties. Carthamus caeruleus is a plant that has antibacterial and antioxidant activity due to the presence of an acetylenic compound, Carlina oxide. The aim of this work was to provide, for the first time, the chemical modifications to the structure of Carlina oxide and the insilico study of these analogues.

Materials and methods: The essential oil of Carthamus caeruleus was extracted by steam distillation in a Clevenger-type apparatus. Carlina oxide component was separated by column chromatography. Five new analogues were synthetized and identified by spectroscopic analyses (RMN, IR and SM). Molecular docking simulation study was performed using Molecular Operating Environment software (MOE) on three enzymes of bacterial origin (Streptococcus pyogenesis and Enterococcus faecalis).

Results: Five new compounds derived from Carlina oxide were synthesized (IM8-IM12), and their structures were characterized by infrared (IR), 1H and 13C nuclear magnetic resonance (NMR). The new synthesized compounds were evaluated as mSpeB, DHFR from Enterococcus faecalis and DNA gyrase inhibitors by a docking analysis using MOE. These results show interesting ligand interactions with the three enzymes, and the best result was attributed to the complexes formed with IM9, which had the lowest score.

Conclusion: In fact, these new compounds could lead to powerful approaches for the research and development of new antibiotics.

Keywords: Carlina oxide; DNA gyrase inhibitors.; Enterococcus faecalis; reductive amination. molecular docking; vilsmeier-haack reaction.