The Leaf Essential Oils of <i>Syzygium oblatum</i> and <i>Syzygium abortivum</i>: Chemical Composition, Antimicrobial Activity, and Molecular Docking Study

Background and Objectives Syzygium (the family Myrtaceae) is a well-known genus in the field of food chemistry and medicinal purposes. The current study aims to provide a chemical analysis of essential oils from the fresh leaves of two Vietnamese Syzygium species Syzygium oblatum (Roxb.) Wall. ex Steudel and S. abortivum (Gagnep.) Merr. &amp; L.M.Perry. Methods Chemical compounds in essential oils were identified using GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analysis. The broth microdilution method was used for the antimicrobial assay. Docking stimulation aided experimental results. Results ( E)-Caryophyllene (27.89%), α-selinene (18.34%), β-selinene (17.48%), and α-pinene (5.20%) were identified to be the main compounds in S. oblatum leaf essential oil, whereas the leaf essential oil of S. abortivum was dominated by ( E)-caryophyllene (19.56%), δ-cadinene (11.03%), germacrene D (10.34%), and γ-muurolene (5.50%). It noted that both studied oil samples with the MIC/IC 50 values of 8-32 µg/mL/4.56-10.37 µg/mL were comparable to the standard drugs in antimicrobial experiments against the Gram-positive bacteria Bacillus cereus and Enterococcus faecalis, and yeast Candida albicans. Molecular docking results showed that the main compound ( E)-caryophyllene primarily formed hydrophobic interactions with the microbial proteins C. albicans N-myristoyl transferase B. cereus patB1, and E. faecalis carbamate kinase with the binding affinities of −6.969, −6.342, and −5.530 kcal/mol, respectively Conclusion It is advised to isolate the main chemicals and conduct in vivo antibacterial experiments for both essential oils and their main compounds.