Tissue and Growth Specific Chemical Profiles and Antimicrobial Activity of Libanotis buchtormensis (Fisch.) DC Extracts

Abstract

Libanotis buchtormensis (Fisch.) DC. is a traditional Chinese medicinal herb used for the treatment of rheumatism, articular pain, and symptoms of the common cold. To evaluate the possible medicinal value of the aerial parts of L. buchtormensis, the chemical composition and antibacterial activity were assessed on a tissue and growth specific basis. Results based on high performance liquid chromatography (HPLC) showed that the samples were divided into two main clusters, one associated with roots and the other associated with the aerial parts. Analysis of the bioactive chemical contents revealed that coumarin was the most abundant compound in leaves (0.53 to 0.82%), while osthole and isoimperatorin exhibited relatively high concentrations in roots. Two-year growth samples, which correspond with the harvest period of L. buchtormensis, contained the highest amounts of total coumarin, osthole, and isoimperatorin. Broth microdilution tests showed that Gram-positive bacterial strains (Staphylococcus aureus, S. epidermidis and Streptococcus agalactiae) were more sensitive to L. buchtormensis extracts than the Gram-negative bacterial strain (Escherichia coli). Staphylococcus aureus and S. epidermidis were more sensitive to the extracts, exhibiting significant correlation with osthole and isoimperatorin contents. Comparative analysis of the chemical profiles and antibacterial activity revealed significant differences between the root and the aerial parts, which implied that the clinical application of the aerial parts needed further study. In addition, the aerial parts could serve as a material source for osthole, having comparable content to that of the root.