The acaricidal activities of an active constituent derived from Ostericum koreanum roots and its derivatives were determined using fumigant and direct-contact toxicity bioassays against Dermatophagoides farinae and Dermatophagoides pteronyssinus. This was compared with that of a commercial acaricide (benzyl benzoate). In the fumigant toxicity bioassay, 4-chloro-6-isopropyl-3-methylphenol (0.29 μg/cm2) was 37.17 times more effective than benzyl benzoate (10.78 μg/cm2) against D. farinae, followed by 6-fluoro-3-methylphenol (0.57 μg/cm2), 3-methylphenol (0.63 μg/cm2), 4-chloro-3-methylphenol (0.75 μg/cm2), and 4-isopropyl-3-methylphenol (0.78 μg/cm 2). In the direct-contact toxicity bioassay, 4-chloro-6-isopropyl-3- methylphenol (0.21 μg/cm2) was 36.81 times more toxic than benzyl benzoate (7.73 μg/cm2) against D. farinae, followed by 6-fluoro-3-methylphenol (0.40 μg/cm2), 3-methylphenol (0.41 μg/cm2), 4-isopropyl-3-methylphenol (0.56 μg/cm2), and 4-chloro-3-methylphenol (0.60 μg/cm2). The acaricidal effects of 3-methyphenol derivatives against D. pteronyssinus were similar to those against D. farinae. In structure-activity relationships, acaricidal activities could be related to the introduction of chloro, fluoro, and isopropyl functional groups onto the 3-methylphenol skeleton. These results indicate that naturally occurring 3-methylphenol and its derivatives are potential house dust mite control agents.
- acaricidal activity
- Dermatophagoides farinae
- Dermatophagoides pteronyssinus
- Ostericum koreanum
- structure-activity relationships
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)