Antibacterial constituents from roots of Zanthoxylum nitidum / 中草药

ABSTRACT

Objective: To isolate and identify the antibacterial constituents from the roots of Zanthoxylum nitidum. Methods: Bioassay-guided fractionation led to the isolation of compounds from the roots of Z. nitidum by using various chromatographic techniques such as silica gel, alumina, preparative TLC, and HPLC, and their chemical structures were then elucidated on the basis of spectroscopic data, including NMR, MS analysis, and their physicochemical properties. Results: Eleven compounds were isolated from the bioactive extracts in the roots of Z. nitidum and then were identified as skimmianine (1), oxychelerythrine (2), 8-methoxy-dihydrochelerythrine (3), β-sitosterol (4), L-sesamin (5), 8-methoxy-9-demethoxyldihydrochelerythrine (6), 4-hydroxy-N- methylproline (7), liriodenine (8), avicine (9), nitidine (10), and isobutyl benzoate (11), respectively. Compounds 1, 3, 6, 8, and 10 showed the potential inhibition on Staphylococcus aureus. Compound 8 showed the most potential inhibitory activity with MIC value of 31.3 μg/mL; Further studies demonstrated that compound 8 inhibited the clinical multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) activity with MIC value of 93.8 μg/mL, significantly. Conclusion: A series of bioactive alkaloids with the anti-staphylococcal activities were identified from the roots of Z. nitidum. Compounds 7, 9, and 11 are obtained from this plant for the first time, and the potential anti-staphylococcal activity of compound 8 against MRSA has been demonstrated, which has provided the chemical template as a new anti-bacterial agent against clinical multidrug-resistant MRSA infection.