TLC-bioautography identification and GC-MS analysis of antimicrobial and antioxidant active compounds in Musa × paradisiaca L. fruit pulp essential oil

Introduction: The absence of microbial growth and resistance to oxidative deterioration in fruits of Musa × paradisiaca L. (bananas) is an indication of the presence of antimicrobial and antioxidant metabolites.

Objective: In order to investigate the secondary metabolomic spectrum as well as the active antimicrobial and antioxidants present in essential oils (EOs) from fruits of different geographical areas of M. × paradisiaca, gas chromatography-mass spectroscopy (GC-MS) principal component data correlation analysis is complemented with antimicrobial assays and phytochemical and bioautographic antioxidant fingerprints with thin layer chromatography (TLC).

Methodology: An EO was obtained by steam distillation and subjected to GC-MS and TLC for metabolomic profiling from fruit pulp. The antimicrobial potential was tested in both Escherichia coli as a gram negative and Bacillus subtilis as a gram positive microbe. Potential antioxidant metabolites were identified through TLC-bioautography and GC-MS analysis of active zones.

Results: A maximum of 0.56% v/w EO was isolated from fruit pulps of M. × paradisiaca. Minimum inhibitory concentrations (MICs) against B. subtillis and E. coli were 0.25 and 0.35 μg/mL, respectively. Thus, 56 metabolites were identified through GC-MS. The major abundant antimicrobial metabolites found in EOs are α-thujene, γ-terpinene, α- and β-pinene, sabinene, β-myrcene, limonene, α-capaene, caryophyllene and (Z,E)-α farnesene. Aceteugenol, palmitic acid, stearic acid, palmitin, and stearin were identified as antioxidant metabolites. Principal component analysis of metabolite data reveals correlations and a clear separation based on metabolites obtained from various areas.

Conclusion: The data generated using metabolic profiling and cluster analysis helped to identify antimicrobial and antioxidant compounds in M. × paradisiaca.