Comparison of Different Extraction Procedures for Isolating Bacteriostatic and Anti-pseudorabies Virus Components from Rodgersia Sambucifolia (Hemsl)

Medicinal plants are considered a repository of bioactive ingredients. Rodgersia sambucifolia (Hemsl), a herbaceous perennial originating from East Asia, has demonstrated bacteriostatic and antiviral properties. The aim of this study was to identify an effective extraction procedure for isolating potential bacteriostatic and antiviral compounds from the plant. The crude extracts were obtained using ethanol, methanol or acetone, and stepwise extracted with ethyl acetate, n-butanol or water. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and diameters of the inhibition zone were evaluated for bacteriostatic efficacy. These tests were carried out with Enterococcus faecalis, Enterococcus faecium, Shigella dysenteriae, Streptococcus lactis, Staphylococcus aureus, and Streptococcus lactis. The antiviral activities of prevention, treatment, and neutralization, utilizing pseudorabies virus, were evaluated using swine testicular cell viability. The active ingredients from the best bioactivity extraction procedure were analyzed using liquid chromatography-mass spectrometry (LC-MS). When ranked highest to lowest, the bacteriostatic and antiviral effects were obtained in the order of the crude extracts prepared from ethanol, methanol, and acetone. Bacteriostatic and antiviral effects were highest in the stepwise extraction of ethyl acetate, followed by the extraction of n-butanol and water. The main compounds identified by LC-MS in the ethyl acetate phase in descending order of content were: bergenin, palmitic acid, baicalein, linoleic acid, chrysin, γ-linolenic acid, catechin gallate, catechin, ursolic acid, and baicalin. This study provides a research basis for the development of bacteriostatic and antiviral drugs from traditional Chinese herbal medicines.