Abstract:

Chemical constituents from the Bai ethnomedicinal plant Pararuellia delavayana and their antimicrobial activity were investigated. The isolation and purification were performed using various column chromatographic techniques, including silica gel column chromatography, D101 macroporous resin column chromatography, Sephadex LH-20 column chromatography, and high-performance liquid chromatography (HPLC). The structures of the isolated compounds were elucidated based on comprehensive analysis of their physicochemical properties, 1D, 2D NMR spectra, and mass spectrometry data. The antimicrobial activities of all isolates were evaluated using the microbroth dilution method. Eleven compounds were isolated from the ethyl acetate fraction of a 70% acetone extract of the dried whole plant, and identified as benzyl-(5-O-syringoyl-β-D-apiofuranosyl)-(1→2)-β-D-glucopyranoside (1), (6R, 9R)-3-oxo-α-ionol-9-O-β-D-glucopyranoside (2), byzantionoside B (3), linarionoside B (4), (-)-syringaresinol-4-O-β-D-glucopyranoside (5), (-)-syringaresinol-4-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (6), (+)-lyonirenisol-3α-O-β-D-glucopyranoside (7), luteolin (8), apigenin (9), tilianin (10), and β-sitosterol (11). Compound 1 was a new benzyl alcohol glycoside, named pararuellioside A. All compounds were reported from P. delavayana for the first time. According to in vitro antimicrobial assay, compound 8 exhibited significant activity against Staphylococcus epidermidis with a minimum inhibitory concentration (MIC) value of 50 μg/mL.

Key words: Bai ethnomedicinal plant, Pararuellia delavayana; chemical constituents, antimicrobial activity, pararuellioside A