GC–MS analysis and anti–microbial activity of Prunella vulgaris L. extracts

Inhibitory effects of extracts from Prunella vulgaris on biofilm formation of Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a highly prevalent pathogen capable of strongly adhering to food processing equipment and the contact surfaces, where it forms resilient biofilms that are difficult to eliminate. Prunella vulgaris (P. vulgaris), a traditional Chinese herbal medicine, has demonstrated strong potential in inhibiting S. aureus biofilm formation. This study investigated the inhibitory mechanisms of P. vulgaris extracts against S. aureus growth and biofilm formation, evaluating the biofilm inhibitory concentration, bactericidal concentration and their effects on ica operon gene expression. The P. vulgaris extracts exhibited a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 1.25 mg/mL. At the MIC level, the extracts not only suppressed S. aureus growth and metabolic viability but also inhibited polysaccharide intercellular adhesion (PIA), prevented biofilm formation and disrupted mature biofilms. Furthermore, P. vulgaris extracts demonstrated concentration-dependent effects on extracellular polymeric substances (EPS) production: while 1/2 MIC concentrations stimulated EPS synthesis, double-MIC concentrations markedly suppressed it. Notably, the extracts consistently downregulated icaA and icaD expression at both MIC and 2 × MIC concentrations. Therefore, P. vulgaris exhibits significant potential against S. aureus-induced foodborne diseases, demonstrating promise as a novel antibacterial agent for future applications in both pharmaceutical development and food safety enhancement.

Characterization and identification of the wide-polarity multicomponents from Prunella vulgaris by offline two-dimensional liquid chromatography and hydrophilic interaction chromatography coupled to ion mobility-quadrupole time-of-flight mass spectrometry

Metabolites identification is crucial to develop functional foods or perform quality control. Prunella vulgaris (Xia-Ku-Cao) is a medicinal and edible plant used as the herbal medicine or main additive in functional beverage. However, current analytical strategies can only on-line characterize tens of compounds, restricted by insufficient chromatographic resolution and low coverage of the mass spectrometric scan methods. This work was designed to characterize the wide-polarity components from the ear of P. vulgaris. The total extract was fractionated by semi-preparative high-performance liquid chromatography into the retained medium-polarity fraction and unretained polar fraction, which were further analyzed by offline two-dimensional liquid chromatography (2D-LC) and hydrophilic interaction chromatography, respectively. Data-independent high-definition MSE of the Vion™ ion mobility time-of-flight mass spectrometer was utilized enabling the high-coverage acquisition of collision-induced dissociation-MS2 data. The offline 2D-LC, configuring the XBridge Amide and HSS T3 columns, gave high orthogonality (0.81) and effective peak capacity (1555). Automatic peak annotation facilitated by the UNIFI™ bioinformatics platform and comparison with 62 reference compounds achieved the efficient and more reliable structural elucidation. We could characterize 255 compounds from P. vulgaris, with numerous phenylpropanoid phenolic acids and triterpenoid O-glycosides newly reported. Especially, collision cross section (CCS) prediction and targeted isolation of three compounds assisted in the identification of 39 groups of isomers. Additionally, 17 hydrophilic compounds, involving oligosaccharides and organic acids, were characterized from the unretained polar fraction. Conclusively, the in-depth metabolites identification of P. vulgaris was accomplished, and the results can benefit the development and better quality control of this valuable plant.

Prunella vulgaris L.: An Updated Overview of Botany, Chemical Composition, Extraction Methods, and Biological Activities

Prunella vulgaris L. (PV) is a well-known renewable drug resource full of different groups of biologically active substances with a wide range of pharmacological actions and applications in medicine. In this review, we present an updated comprehensive overview of the botany, extracting methods, chemical composition, and pharmacological activity of different parts of PV extracts. As a result of this review, it was found that chemical composition of PV depends on various factors ranging from the part of the plant to the method of extraction. We also highlight extraction methods that have not been previously used for obtaining PV extracts and may have high scientific interest. With this review, we hope to guide present and future professionals and provide possible previously unexplored areas to find new solutions associated with PV plant.