Chemo-Diversity of Antibacterial Anthraquinones from the Roots of Morinda morindoides

Background: Morinda morindoides (Baker) (Rubiaceae) is a medicinal plant with antimicrobial properties currently used in Côte d'Ivoire and other countries. These properties have been described but most of the studies are dealing with crude extracts. Objective: The chemical structures of the bioactive compounds extracted from Morinda morindoides roots have been characterized. Methods: The root extracts were analyzed by using HPLC. Fourteen fractions were detected among which 11 compounds have been structurally identified by using a combination of 1H-NMR and 13CNMR and LC-HRMS methodologies. Results: All these compounds belong to anthraquinone family. The antibacterial activity of the eleven compounds was tested against six strains of microorganisms with ofloxacin as standard (two Gram-negative bacteria, two Gram-positive bacteria and two yeasts). The Minimal Inhibitory Concentrations recorded, varies from 8 to 128 μg / ml. Staphylococcus aureus was the most susceptible organism. Conclusion: We highlight the chemo-diversity of the antibacterial anthraquinones in the roots of Morinda morindoides.