Antimicrobial phenolic secondary metabolites from the flowers of <i>Narcissus tazetta</i> L.

Abstract

Bioassay-guided fractionation of the ethyl acetate antimicrobial fraction from the hydroalcoholic extract of the fresh <i>Narcissus tazetta</i> L. flowers afforded a new antimicrobial compound, tazettin (<b>1</b>), along with 3-caffeoylquinic acid methyl ester (<b>2</b>), methyl-3,4-dihydroxybenzoate (<b>3</b>), and syringic acid (<b>4</b>). The compounds were assigned by NMR and (+)-HRESIMS analyses. Antimicrobial assays revealed that <b>1</b> potently inhibited <i>Staphylococcus aureus</i> (18 mm, MIC = 14.9 µM) and <i>Candida albicans</i> (16 mm, MIC = 29.8 µM. Compound <b>2</b> exhibited similar potency against <i>S. aureus</i> (16 mm, MIC = 10.8 µM) and <i>C. albicans</i> (18 mm, MIC = 10.8 µM), with moderate <i>Escherichia coli</i> inhibition (11 mm, MIC = 21.7 µM). Compound <b>3</b> displayed moderate effects on <i>S. aureus</i> (14 mm, MIC = 40 µM) and <i>C. albicans</i> (16 mm, MIC = 40 µM). Syringic acid (<b>4</b>) was least active against the three microbes (10-15 mm, MIC = 80.8 µM). Overall, <b>1-3</b> selectively targeted <i>S. aureus</i> and <i>C. albicans</i>, highlighting <i>N. tazetta</i> metabolites as promising antimicrobial leads.