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Tribolium castaneum is a challenging pest of stored products, causing significant economic losses. The present study explored the efficacy of Coridothymus capitatus essential oil and its primary constituent, carvacrol, as eco-friendly alternatives for managing this pest. To evaluate their insecticidal potential, repellency, fumigant toxicity, and antifeedant properties, progeny inhibition assays were performed. Carvacrol exhibited superior repellency compared to the essential oil, achieving a 92% repellency rate at 2 mg/cm2. Both compounds demonstrated significant fumigant toxicity against T. castaneum, with LC50 values of 168.47 and 106.5 μL/L for the essential oil and carvacrol, respectively, after 24 h. Carvacrol also outperformed the essential oil in antifeedant activity, inducing an 80.7% feeding deterrence at 1.17 mg/g. Moreover, both treatments effectively suppressed the development of the pest’s progeny. These results collectively underscore the potent insecticidal properties of C. capitatus essential oil and carvacrol, particularly carvacrol, as promising candidates for the sustainable management of T. castaneum in stored product protection.

Eimeria is among the most harmful parasites that affect domestic animals. The development resistance in Eimeria to the majority of regularly used anticoccidials necessitates development of an effective alternative strategy. This study was therefore aimed to investigate the therapeutic efficacy of essential oils combination, Pelargonium graveolens (geranium) with thymol (PGT) against Eimeria papillata murine model. Three doses of 50, 100, and 150 mg/kg were tested in Eimeria experimentally infected mice to determine the combination's highest effective dose. The results showed that the 150 mg/kg dose was the most effective, reducing the oocyst output by 56.92 % (P ≤ 0.001). This result has been associated with a 66.19 % (P ≤ 0.001) reduction in the jejunal developmental stages. The antioxidant effect of PGT decreased lipid peroxidation (P ≤ 0.05) and increasing reduced glutathione (GSH) (P ≤ 0.001). Moreover, PGT decreased the jejunum's apoptotic cell count (P ≤ 0.001). The in vitro results showed that PGT significantly inhibited oocysts sporulation and destructed 96.33 % of treated oocysts. In conclusion, PGT has therapeutic effect as an anticoccidial alternative to control murine eimeriosis.

Carvacrol is a monoterpenoid phenol found in many essential oils that has antibacterial, antifungal and antiparasitic activities. Drug loaded-invasome systems are used to deliver drugs utilizing nanoparticles to improve bioavailability, efficacy, and drug release duration. As a result, the present study developed carvacrol-loaded invasomes and evaluated their acaricidal effect against Rhipicephalus annulatus (cattle tick) and Rhipicephalus sanguineus (dog tick). Carvacrol loaded-invasome (CLI) was prepared and characterized using UV/Vis spectrophotometer, zeta potential measurements, Scanning Transmission Electron Microscopy (STEM), Fourier Transform Infrared (FT-IR) Spectroscopy, and Differential Scanning Calorimetry Analysis. CLI (5%) induced significant mortality (100%) in R. annulatus adult ticks with LC50 of 2.60%, whereas the LC50 of pure carvacrol was 4.30%. Carvacrol and CLI were shown to have a significant larvicidal action on both tick species, with LC50s of 0.24 and 0.21% against R. annulatus and 0.27 and 0.23% against R. sanguineus, respectively. Carvacrol and CLI (5%) induced significant repellent activities for 24 h against R. annulatus and R. sanguineus, as evidenced by the rod method and the petri-dish selective area choice method, respectively. High-performance liquid chromatography (HPLC) demonstrated that the CLI form had 3.86 times the permeability of pure carvacrol. Moreover, carvacrol and CLI inhibited acetylcholinesterase activity and decreased glutathione and malonedealdehyde levels in the treated ticks. In conclusion, invasomes significantly improved adulticidal and repellency activities of carvacrol against both tick species.