Unveiling chemical composition of peppermint oil and its bioactivities compared with (R)-(+)-limonene: antimicrobial, antibiofilm, and insecticidal perspectives.

BACKGROUND

Peppermint (Mentha piperita L.) essential oil (MPEO) is recognized for its broad-spectrum antimicrobial properties and potential applications in food preservation. This study aimed to determine whether the bioactivity of MPEO is attributable to (R)-(+)-limonene or whether the complete essential oil provides higher efficacy due to interactions among multiple constituents.

RESULTS

MPEO was characterized using GC-MS and evaluated for antimicrobial activity in vitro against Gram-positive and Gram-negative bacteria and yeasts, and in situ in the vapor phase on strawberries, plums, beetroot, and tomatoes. Antibiofilm activity against Salmonella enterica was assessed using crystal violet assay and MALDI-TOF MS, while insecticidal activity was tested against Callosobruchus maculatus and Megabruchidius dorsalis. GC-MS revealed a menthol chemotype dominated by menthol (54.2%), with isomenthone (8.4%), isomenthol acetate (5.7%), 1,8-cineole (5.7%), linalool (3.1%), β-caryophyllene (3.5%), limonene (2.7%), and α-pinene (1.5%). MPEO generally produced larger inhibition zones and lower minimum inhibitory concentration values than (R)-(+)-limonene, and stronger in situ growth suppression. Antibiofilm activity was demonstrated in both assays. In insecticidal tests, limonene was more effective than MPEO at 6.25-50%, while both treatments were nearly fully effective at 100%.

CONCLUSION

MPEO showed greater overall antimicrobial efficacy than (R)-(+)-limonene, supporting the importance of interactions among its constituents. Its combined antimicrobial, antibiofilm, and insecticidal activities indicate potential for use as a natural bio-preservative and in integrated pest management. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.