Composition and Antimicrobial Activity of Ginger (Zingiber officinale Roscoe)

Zingiber officinale Roscoe has been widely used for hundreds of years, whether for its analgesic, antipyretic, or antimicrobial potential. The aim of this study was to evaluate the composition and the ranges of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of aqueous rhizome and leaf extracts of Z. officinale and synergism of these extracts with antibiotics against six isolates of Staphylococcus spp. The chemical composition of the crude extract from the rhizome of Z. officinale cultivated in the region of Umuarama (Brazil) was analyzed by gas chromatography coupled with a mass spectrometer and detected Zingerone (47.65%), α-Zingiberene (14.92%), β-Sesquiphellandrene- (6.16%), α-Curcumene (4.49%), Methyl 10-trans, 12-cis-octadecadienoate (4.42) and Gingerol (4.37). Six samples of Staphylococcus spp. from Veterinary Students’ nasal swabs were collected for antimicrobial susceptibility tests. The antibacterial activities of the aqueous extracts of ginger rhizome and leaves were evaluated with broth microdilution, and then synergism of the rhizome extract with the antimicrobials was verified to calculate the fractional inhibitory concentration index (FICI). All the Staphylococcus spp. samples showed resistance to ampicillin and penicillin, 66.67% to erythromycin, and 33.33% to tetracycline. The MIC90% of each extract was estimated to be 235 mg/mL and 13.27 mg/mL for the leaf and rhizome, respectively. With the aqueous leaf extract, none of the samples presented MBC within the studied concentration range. On the other hand, the MBC obtained by the aqueous rhizome extract was 7.81 mg/mL for 50% of the samples. Calculation of the FICI showed that ½ MIC yielded the best result, with two synergistic relationships when combined with ampicillin. This research shows a potential use for the aqueous extract of ginger as an alternative or auxiliary therapy against resistant microorganisms