Antimicrobial Activity of Phenylpropanoyle from the Rhizome of Zingiber officinale Roscoe (Zingiberaceae)

Aim: This study was carried out to determine the phytochemical and the antimicrobial activities of Zingiber officinale (Zingiberaceae) Rhizome.

Methodology: The air-dried and powdered rhizome (1.0 kg) of Z. officinale was extracted with ethyl acetate (1.5 L) at room temperature for 72 h. After evaporation under reduced pressure, 46.5 g of crude extract was obtained. The CH2Cl2 extract was purified by column chromatography over silica gel 60 (230-400 mesh) and preparative TLC using a gradient system of hexane, ethyl acetate and MeOH.

Agar diffusion test plates with Escherichia coli CIP 548, Listeria monocytogenes CIP 82110, Enterococcus faecalis CIP 76117, Bacillus cereus CIP 6624, Staphylococcus aureus CIP 7625, Pseudomonas fluorescents CIP 6913, Bacillus substilis ATCC 6636, Candida lusitaniae ATCC 200950, Candida tropicalis ATCC 750, Cryptococcus neoformans CIP 95026, Aspergillus flavus, and Aspergillus parasiticus as test strains were performed.

Results: A new nonyl-3-phenylpropanoate (1), together with known compounds, 8-hepthyl-12- propyldecanol (2) were isolated from the ethyl acetate extract of the rhizome of Zingiber officinale. The structures of the two compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral data, chemical reactions, and comparison with previously known analogue.

The two compounds isolated from ethyl acetate extract showed antibacterial and antifungal activity and the Minimal Inhibitory Concentration (MIC) against the test fungi varied from 3.34 mM to 5.08 mM for compound 1 and from 3.81 mM to 5.08 mM for compound 2.

Conclusion: One new compound, nonyl-3-phenylpropanoate, isolated from ethyl acetate extract of Zingiber officinale rhizome exhibited antibacterial and antifungal activities.