Combination of chemical fingerprint and bioactivity evaluation to explore the antibacterial components of Salvia miltiorrhizae

The aim of this study was to explore the possible antibacterial components of Salvia miltiorrhizae on Pseudomonas aeruginosa using a combination of chemical fingerprint and bioactivity evaluation. The chemical fingerprints of 32 batches of S. miltiorrhizae samples from different sources were developed using high-performance liquid chromatography with diode array detection, and then were evaluated by similarity analysis and hierarchical clustering analysis. Anti-P. aeruginosa activity was determined by microcalorimetry. Some crucial thermokinetic parameters obtained from the heat-flow power-time curves of P. aeruginosa growth in the absence or presence of these S. miltiorrhizae samples were evaluated using principal component analysis. Thereafter, multiple linear regression analysis was used to analyze the fingerprint-activity relationship between the chemical fingerprints and anti-P. aeruginosa activity. This established the related equation between the inhibition ratio (I, %) of S. miltiorrhizae samples on P. aeruginosa and the peak areas of the common peaks. The results showed that the 32S. miltiorrhizae samples could be grouped into three clusters according to their chemical fingerprints and anti-P. aeruginosa activities. Protocatechualdehyde, salvianolic acid B, together with three unidentified compounds might be the major components that contributed largely to the antibacterial properties of S. miltiorrhizae and should be the focus of S. miltiorrhizae quality control. Thus, this study provided a preferred way for exploring the bioactive components of medicinal plants.