Effect of post-harvest drying period on the chemical composition of Zingiber zerumbet Sm. Rhizomes essential oil and its biological activities

Abstract

Zingiber zerumbet Sm. (Family: Zingiberaceae) is an important perennial medicinal oil-bearing herb that is native to the Southeast Asia. This study examines the impact of different durations of post-harvest shade drying (ranging from 1 to 12 months) on essential oil yield and chemical composition of Z. zerumbet, in comparison to the freshly collected oil sample. This study explores how post-harvest shade drying impact the composition and longevity of Z. zerumbet rhizomes as well as its antimicrobial, antibiofilm activity. The oils were analyzed for their chemical composition analysis using a gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The post-harvest periods of drying (1-12 months) were discovered to enhance the concentration of marker constituents in the oil. The primary constituent, Zerumbone, was detected in concentrations ranging from 69.38 ± 5.63% to a maximum of 80.19 ± 1.53% as the drying duration of the rhizome was extended. The output of the essential oil was not significantly affected by drying times; however, it did have a noticeable impact on the proportions of monoterpenes. Both disc diffusion and broth microdilution assay were used in freshly collected Z. zerumbet oil for its antimicrobial potential against S. aureus, L. monocytogens, S. hominis, Salmonella enterica serovar Typhimurium, P. aeruginosa, S. intermedius, E. coli, and C. albicans. For the first time, the oil reported to exhibit antibiofilm activity against S. aureus which was validated using fluorescence microscopy, and effectively disrupts the biofilm by 47.38% revealing that essential oil was able to disintegrate the clusters of the pathogen. Z. zerumbet rhizome oil is effective to reduce food-borne microorganisms. Therefore, its essential oil, a natural source of bioactive zerumbone, may improve flavor, aroma, and preservation.

Keywords: Antibiofilm activity; Fluorescence microscopy; Post-harvest shade-drying; Zerumbone; Zingiber zerumbet.

Fig. 1

Gas chromatogram of the rhizome essential oil Zingiber zerumbet

Fig. 2

Compositional variation in major components of Z. zerumbet rhizome EOs of post-harvest shade drying experiment for different time period (1 to 12 M showed storage from 01 to 12 month)

Fig. 3

Dendrogram representing the similarity relation of the essential oil composition collected in different post-harvest storage periods

Fig. 4

Pearson’s correlation coefficient representation between essential oil constituents with post-harvest storage periods. The blue color represents the positive correlation and red color represent the negative correlation. The size of the dots represents the extent of correlation

Fig. 5

Graphical representation of the antibiofilm activity of the Z. zerumbet rhizome EO against S. aureus

Fig. 6

Fluorescence microscopic analysis of the Z. zerumbet rhizome EO against S. aureus at: a control, b 1/8 MIC, c 1/6 MIC, d ¼ MIC, e ½ MIC, f MIC