The Different Composition of Coumarins and Antibacterial Activity of Phlojodicarpus Sibiricus and Phlojodicarpus Villosus Root Extracts

Phlojodicarpus sibiricus, a valuable endangered medicinal plant, is a source of angular pyranocoumarins used in pharmacology. Due to limited resource availability, other pyranocoumarin sources are needed. In the present research, the chemical composition of a closely related species, Phlojodicarpus villosus, was studied, along with P. sibiricus. High-performance liquid chromatography and mass-spectrometric analyses, followed by antibacterial activity studies of root extracts from both species, were performed. P. sibiricus and P. villosus differed significantly in coumarin composition. Pyranocoumarins predominated in P. sibiricus, while furanocoumarins predominated in P. villosus. Osthenol, the precursor of angular pyrano- and furanocoumarins, was detected in both P. sibiricus and P. villosus. Angular forms of coumarins were detected in both species according to the mass-spectrometric behavior of the reference. Thus, P. villosus cannot be an additional source of pyranocoumarins because their content in the plant is critically low. At the same time, the plant contained large amounts of hydroxycoumarins and furanocoumarins. The extracts exhibited moderate antibacterial activity against five standard strains. The P. villosus extract additionally suppressed the growth of the Gram-negative bacterium E. coli. Thus, both Phlojodicarpus species are promising for further investigation in the field of pharmaceuticals as producers of different coumarins.