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)
