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Investigation on the antimicrobial activities of gingers (Etlingera coccinea (Blume) S.Sakai & Nagam and Etlingera sessilanthera R.M.Sm.) endemic to Borneo

Daniel‐Jambun, D., Dwiyanto, J., Lim, Y.Y., Tan, J.B.L., Muhamad, A., Yap, S.W., Lee, S.M.
Journal of applied microbiology 2017 v.123 no.4 pp. 810-818
Bacillus cereus, Bacillus subtilis, Etlingera, Gram-positive bacteria, Staphylococcus aureus, anti-infective agents, antimicrobial properties, bacterial infections, ethyl acetate, hexane, leaves, methanol, methylene chloride, minimum inhibitory concentration, rhizomes, solvents, Borneo
AIMS: To investigate the antimicrobial properties of Etlingera coccinea and Etlingera sessilanthera and to isolate and identify the antimicrobial compounds. METHODS AND RESULTS: Extracts were obtained via sequential solvent extraction method using hexane, dichloromethane, ethyl acetate, methanol and water. Antimicrobial activity testing was done using broth microdilution assay against 17 strains of bacteria. The leaf hexane extract of E. coccinea and rhizome hexane extract of E. sessilanthera showed best antimicrobial activities, with minimum inhibitory concentration (MIC) values ranging from 0·016 to 1 mg ml⁻¹ against Gram‐positive bacteria. From these active extracts, two antimicrobials were isolated and identified as trans‐2‐dodecenal and 8(17),12‐labdadiene‐15,16‐dial with MIC values ranging from 4 to 8 μg ml⁻¹ against Bacillus cereus, Bacillus subtilis and Staphylococcus aureus. CONCLUSION: Etlingera coccinea and E. sessilanthera demonstrated good antimicrobial activities against clinically relevant bacteria strains. The antimicrobial compounds isolated showed low MIC values, hence suggesting their potential use as antimicrobial agents. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to identify the potent antimicrobials from these gingers. The antimicrobials isolated could potentially be developed further for use in treatment of bacterial infections. Also, this study warrants further research into other Etlingera species in search for more antimicrobial compounds.