Nanoemulsions of sage tea and cumin essential oils against Tribolium castaneum: In vivo and in silico insights

Nanoemulsions protect the essential oils from degradation, increase their half-life, and reduce volatility through controlled release, enhancing their effectiveness for field applications. This study investigates the potential of nanoemulsions (SEO-N and CEO-N) derived from sage tea (Salvia officinalis) and cumin (Cuminum cyminum) essential oils (SEO and CEO) as eco-friendly insecticides. The main constituents of SEO were identified as β-thujone (23.76 %), eucalyptol (12.09 %), and caryophyllene (7.54 %), while CEO primarily contained cuminaldehyde (46.25 %), cymene (15.01 %), and terpinen-7-al (12.11 %) using GC-MS analysis. SEO-N and CEO-N were prepared (formulation of 4 % EO, 3 % Tween 80, 3 % ethanol, and 90 % water) using ultrasonic homogenization. The resulting nanoemulsions exhibited mean particle sizes of 137.9 nm and 97.02 nm, polydispersity index values of 0.232 and 0.127, and ζ-potentials of −11.5 and −12.3, respectively. In insecticidal tests, 500 ppm treatments of SEO and SEO-N resulted in 36.67 % and 30 % mortality, while CEO and CEO-N achieved 100 % and 73 % mortality in Tribolium castaneum after 7 days. Notably, 1000 ppm of all treatments resulted in 100 % mortality. Viridiflorol, caryophyllene oxide, and thujyl alcohol isomer in the SEO and tetracyclo[10.4.0.0(2,11).0(3,8)]hexadeca-3(8),4,6,9-tetraene-2-carbonitrile, 1-methyl-14,16-dimethylmethano, and 4-isopropylphenylacetic acid in the CEO showed higher activity against T. castaneum proteins (PDB IDs: 5YJ9, 6V3T, and 7LT2) than other molecules. The study demonstrates that SEO-N and CEO-N have insecticidal activity under laboratory conditions. In silico findings suggest their role in disrupting insect protein functions. Therefore, these formulations could serve as plant-based insecticidal agent for sustainable pest control and crop protection strategies, pending further validation through field studies.