Isolation of an antimicrobial compound from Impatiens balsamina L. using bioassay-guided fractionation.

X Yang, D K Summerhurst, S F Koval, C Ficker, M L Smith, M A Bernards

Index: Phytother Res. 15(8) , 676-80, (2001)

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Abstract

By using brine shrimp (Artemia salina) lethality test-guided fractionation, a single bioactive compound (LC(50)=26 ppm) was isolated from the 95% ethanol extract of the dried aerial parts of Impatiens balsamina L. and subsequently identified as 2-methoxy-1,4-naphthoquinone (MNQ). The structure of MNQ was confirmed by UV, FT-IR, MS, and 1-and 2-D NMR spectroscopy. The antimicrobial activity of MNQ was evaluated using 12 bacterial and eight fungal strains. Five gram-positive and two gram-negative bacteria as well as all eight fungi (including multi-drug resistant strains) tested were highly sensitive to MNQ. A tea prepared according to traditional methods was found to contain sufficient MNQ to account for its antimicrobial properties.Copyright 2001 John Wiley & Sons, Ltd.