Isolation and antibacterial activities of phloroglucinol derivatives from Dryopteris crassirhizoma / 中草药

ABSTRACT

Objective To isolate the phloroglucinol derivatives in Dryopteris crassirhizoma and to discuss its antibacterial activity. Methods The phloroglucinol derivatives were isolated and purified by column chromatography on silica gel, Sephadex LH-20, semi preparative liquid phase, and recrystallization. Structures were proved by physicochemical properties and spectral methods (MS, 1H-NMR, 13C-NMR). The antibacterial activities against fungi and bacteria were tested by CLSI M38-A2 and M07-A9. Results 10 derivatives were obtained from ethanol extracts of D. crassirhizoma, and were identified as 1-butyrylphloroglucinol (1), 1-methyl-3-butyrylphloroglucinol (2), 2-acetyl-4-butyrylphloroglucinol (3), 1-methyl-3-acetyl-5-butyrylphloroglucinol (4), flavaspidic acid PB (5), norflavaspidic acid AB (6), flavaspidic acid AA (7), filixic acid ABA (8), flavaspidic acid AB (9), and filixic acid ABP (10). The antibacterial activity of compound 8 against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) was similar to cefoxitin (positive control), and the MIC of compound 8 was 2.5 μg/mL. Conclusion Compounds 1-4, new compounds, are isolated from D. crassirhizoma. Compound 8 has both antibacterial activities against fungi and bacteria.