Volatile Metabolite Signatures of Amorphophallus prainii tubers and their Predicted Affinity for Insect Chemosensory Targets

Volatile metabolites play important roles in plant–insect interactions, yet the chemical composition and potential ecological relevance of tuber-derived volatiles in many Amorphophallus species remain poorly documented. This study aimed to characterize water-extractable volatile/derivatizable metabolites from Amorphophallus prainii tubers and to evaluate their possible relevance to insect chemoreception. Tubers were subjected to cold-water maceration (20–23 °C, 48 h) and hot-water extraction (100 °C, 4–6 h), followed by methoxyamination, MSTFA silylation, and GC–MS analysis. The metabolite profiles differed between extraction conditions, although both extracts were dominated by low-molecular-weight acids, ketones, furans, nitrogen-containing compounds, and phenols. Acetic acid was the principal component in both cold- and hot-water extracts (27.78% and 20.83% area, respectively). Hot-water extraction increased several ketone- and ester-type compounds, such as 1-propanol, 2,2-dimethyl-, acetate (11.55%) and 2-hydroxy-3-methyl-2-cyclopenten-1-one (5.85%). To explore their potential role as insect chemical cues, selected metabolites were evaluated through molecular docking against representative insect odorant-binding and chemosensory proteins (PDB: 2WC5, 1N8U, 4Z39, 1OOF, 3S0D). Several cyclopentenone-related ligands showed comparatively favorable predicted binding affinities, including 2-ethyl-3-methylcyclopent-2-en-1-one with −6.4 kcal mol⁻¹ against Bombyx mori OBP2 (2WC5). These findings indicate that A. prainii tubers contain chemically diverse metabolites and highlight cyclopentenone derivatives as priority candidates for future experimental validation in insect chemosensory and behavioural studies.