GNPS Untargeted GC-MS Metabolomic Analysis of Essential Oils From Duguetia lanceolata and Evaluation of Antimicrobial...

In this study, the chemical composition of essential oils (EOs) extracted from leaves of Duguetia lanceolata collected in different seasons (autumn and winter) was analyzed using a GNPS untargeted GC-MS metabolomic approach. EO from autumn leaves (EO-A) contained 80 metabolites (93.8%), with limonene (28.5%), (+)-β-pinene (15.0%), cyclocolorenone (12.8%), 6,9-guaiadiene (3.1%), and 4-carvomenthenol (3.1%) as major constituents. EO from winter leaves (EO-W) comprised 102 compounds (88.0%), dominated by β-bisabolene (16.4%), β-gurjunene (6.4%), β-caryophyllene (4.7%), cyclocolorenone (3.9%), and dihydrocarveol (3.3%). The antimicrobial activity of both EOs was evaluated in vitro using the disk diffusion method against gram-positive and gram-negative bacteria, as well as selected yeast strains. MIC values ranged from 0.016 to 0.270 µg·mL^{- 1}, with EO-A generally exhibiting lower MICs than EO-W. EO-A was active against Acinetobacter baumannii, Candida krusei, and Candida parapsilosis, whereas EO-W showed no activity against these strains. Complementary in silico analyses supported these findings: PASS predictions suggested potential antibacterial and antifungal activity for the major constituents, and molecular docking indicated favorable binding of limonene and β-bisabolene to DNA gyrase B (A. baumannii) and lanosterol 14α-demethylase (CYP51, C. albicans), providing a mechanistic rationale for the observed antimicrobial effects. These results highlight the importance of seasonal collection in optimizing the bioactive potential of D. lanceolata leaves.