Chrysophanol from the Roots of Kniphofia Insignis and Evaluation of Its Antibacterial Activities

Sequential extraction of the roots of Kniphofia insignis using cold maceration techniques and column chromatographic separation leads to the isolation of one monomeric anthraquinone, chrysophanol (1). The structure of the compound was established using spectroscopic analyses including NMR (1H and 13C-NMR, infrared) and comparison with reported literature. The in vitro antibacterial activities of the crude extracts and the isolated compounds were evaluated against four bacterial strains (S. aureus ATCC 25923, B. subtilis ATCC 6633, E. coli ATCC 35218, and P. aeruginosa ATCC 27853). Among them, the crude extract, acetone extract, has shown substantial antibacterial activity with the highest activity against E. coli (22.3 mm). However, compound 1 has a better zone of inhibition with 19.3 mm against P. aeruginosa.