关键词: 香芹酚, 纳米颗粒, 枇杷, 炭疽菌, 抑制作用

Abstract: Objective: To prepare casein (CS) nanoparticles (NPs) loaded with carvacrol (CL) for improved antifungal activity of CL. Methods: Carvacrol-loaded casein nanoparticles (CL-CS-NPs) were prepared through ultrasonic treatment. The difference in the CL retention rate of CL-CS-NPs, when incubated on solid culture medium, versus free CL and a physical mixture of casein and CL was detected by high performance liquid chromatography (HPLC). The in vitro growth inhibitory effects of free CL, casein + CL and CL-CS-NPs on Colletotrichum acutatum mycelium were evaluated as well as the inhibitory effects on Colletotrichum acutatum inoculated into loquat fruit (Eriobotrya japonica (Thunb.) Lindl. cv. Baisha). Results: Stable CL-CS-NPs (152.6 nm in diameter) could be prepared by adding CL (12 mg/mL) to casein solution (20 mg/mL) followed by ultrasonic treatment. The sustained release time of CL-CS-NPs was 4 days and 2 days longer than that of free CL group and casein + CL mixture group, respectively, indicating that nano-CL had an obvious sustained release effect, and CL-CS-NPs showed potential to prolong the time of action of CL on pathogens. The in vitro culture experiment showed that CL-CS-NPs completely inhibited Colletotrichum acutatum for 5 days, while casein + CL mixture and free CL were effective for 3 days. Loquats sprayed with CL-CS-NPs dispersion did not rot basically at 5 days after inoculation, and the average lesion diameter and disease incidence were only 1.5 mm and 10% at 7 days. Moreover, those treated with casein + CL mixture had relatively small lesions but a high disease incidence (80%) at 5 days, and seriously rotted with an average lesion diameter of up to 4.8 mm at 7 days. Conclusion: Spraying the CL-CS-NPs dispersion onto loquat fruit can have a significant inhibitory effect on anthracnose rot caused by Colletotrichum acutatum.

Key words: carvacrol, nanoparticles, loquat, anthracnose, inhibition effect