Phytochemical Investigation and Antimicrobial Activity Evaluation Of Roots Of Rumex Abyssinicus

Abstract

The genus Rumex species belongs to the family Polygonaceae that contains a large number of chemically complex bioactive compounds such as anthraquinones, flavonoids, terpenes, steroids, leucoanthocyanidins and phenolic acids. The roots of Rumex abyssinicus is used traditionally for treating different diseases such as hepatitis, hemorrhoids, gonorrhea, typhus and wound. Therefore, this study was undertaken to identify bioactive secondary metabolites from the roots of Rumex abyssinicus and evaluation of its antimicrobial activities. With this regard, the air-dried, powdered root of R. abyssinicus was subjected to sequential extraction with petroleum ether, chloroform, acetone and methanol by maceration. Each of the extracts was filtered and concentrated using rotary evaporator, separately. Meanwhile, the crude extracts were kept in desiccator until dry for the next step. Then, the antimicrobial activities of crude extracts were tested against four bacterial strains (S. aureus, E. coli, P. aeruginosa and K. pneumoniae) and two fungal strains (C. albicans and S. Cervecia). Among the various root extracts of R. abyssinicus, the acetone crude extracts demonstrated the best zone of inhibition and subjected to column chromatography over silica gel eluted with petroleum ether containing increasing amount of the polarity of ethyl acetate, which resulted with the identification of chrysophanol and emodin. The structures of isolated compounds were elucidated using 1D and 2D NMR spectroscopic methods. The isolated compounds were also evaluated against microbial strains and indicate good inhibition zone against S. aureus (23.0±0.1) K. pneumoniae (22.5±0.4) and C. albicans (20.0±0.4 for compound-1 and 22.0±0.7 for compound-2)