Phenolic constituents from the roots of Rumex hydrolapathum Huds (Polygonaceae) and their antimicrobial activity

Background: Rumex hydrolapathum Huds (Polygonaceae) is an evergreen shrub found in Africa, Europe, North America, and South Asia. It is used in the folk medicine in Cameroon for the treatment of typhoid and blood purification. Many other Rumex species are known for their use in the fight againt microbial infections. The present work was designed to investigate the phytochemical constituents of the ethyl acetate extract from the roots of R. hydrolapathum and their antimicrobial activities against pathogenic phenotypes. Methodology: Repeated silica gel and Sephadex LH-20 column chromatography were used for the isolation and purification of chemical compounds. Their structures were elucidated using spectroscopic (NMR) and spectrometry analyses in comparison with published data. The antimicrobial activities of the crude extract and the isolated compounds were evaluated using the broth microdilution method. Results: Six known phenolic compounds namely chrysophanol, physcion, emodin, chrysophanein, nepodin, and 2,5-dimethyl-7-hydroxychromone were isolated from the ethyl acetate extract from the roots of R. hydrolapathum. These compounds and the crude extract showed low to moderate antimicrobial activities against a panel of yeast and of gram-positive and gram-negative bacteria, depending on the microorganisms. Conclusion: The results obtained from this work may contribute in supporting the Rumex genus as a potential source of phenolic compounds which are well known for their various biological activities.
Keywords: Rumex hydrolapathum; Polygonaceae; phenolic compounds; antimicrobial activities.