Organ-specific valorization of Mentha pulegium L.: Optimization of essential oil production and insecticidal, antimicrobial, and antioxidant activities

Efficient valorization of aromatic plant bioresources requires optimized extraction and an understanding of organ-specific chemical profiles. This study optimized the hydrodistillation of Mentha pulegium L. essential oils (EOs) using a 2⁴ full factorial design, identifying plant organ as the dominant factor influencing yield. A validated predictive model (R² = 0.98) established optimal conditions for leaf EO extraction (240 min, 90 °C, plant-to-water ratio of 0.25), with a predicted yield of 3.24%. GC–MS analysis confirmed a pulegone/menthone chemotype and revealed marked organ specificity: leaf EO was enriched in oxygenated monoterpenes (85.39%), primarily pulegone (50.31%) and menthone (26.92%), whereas stem EO contained lower levels (66.65%) and unique diterpenoids. Bioassays demonstrated superior multi-modal efficacy of leaf EO, including contact toxicity (LD₅₀ = 0.18 µL insect⁻¹), fumigant activity (LC₅₀ = 12.4 µL L⁻¹ air), and repellency (RD₅₀ = 0.08 µL cm⁻²), alongside strong antimicrobial and antioxidant activities. The results indicate leaf processing for the development of natural biopesticide and preservative products. • Factorial optimization (2⁴ design) improved M. pulegium EO yield to 3.24%. • Leaf EO richer in oxygenated monoterpenes (pulegone 50%, menthone 27%). • Strong contact, fumigant, and repellent activities vs. S. oryzae and T. castaneum . • Broad-spectrum antimicrobial and antioxidant efficacy. • Organ-specific processing enables sustainable biopesticide development.