Repellent activity and application of plant essential oils against cat flea (Ctenocephalides felis)
Date Issued
2012
Date
2012
Author(s)
Su, Li-Chung
Abstract
Flea bites not only cause nuisance to humans and pets but also transmit diseases such as plague. Insect repellent is commonly recommended for personal protection in areas where fleas are present. Although synthetic repellents remain prevailing on the market, the development of plant material as flea repellents is increasingly important when considering human health and environmental safety. This study therefore aims to study the activity of numerous plant-based flea repellents by using an improved technique that speeds up the screen of repellents. Two pieces of long-stripped filter paper with the same size (0.7 by 9 cm) were impregnated with test compound and vehicle, respectively. After drying, the two filter papers were glued along the long side and inserted into the glass test tube (1.4 cm diameter, 25 cm long) where harbor 30 non-blood-fed cat fleas (Ctenocephalides felis). The distribution of cat fleas in each side of the filter paper was recorded after 30 min for the indication of repellency. The results showed that leaf essential oil of Cinnamomum osmophloeum (cinnamaldehyde type) exhibits 97.5%, 97.7% and 73.3% repellent activity against cat fleas when the concentration is 2%, 1% and 0.5%, respectively. Also, the trans-cinnamaldehyde, a main component of leaf essential oil of Cinnamomum osmophloeum, displays 97.6% repellent activity when the concentration is 2%. The heartwood essential oil of Taiwania cryptomerioides exhibits 89.6% repellent activity against cat fleas when the concentration is 2%. The leaf essential oil of Plectranthus amboinicus exhibits 83.8% repellent activity against cat fleas when the concentration is 2%, and the main component of which, thymol, displays 90.6% repellent activity against cat fleas when concentration is 0.5%. Particularly, the repellent activity of 2% trans-cinnamaldehyde remains its repellency property (up to 95.3%) even after 8 hours. Furthermore, the fed cat fleas were highly repelled by 0.5% of thymol and 2% of trans-cinnamaldehyde. The repellent test of diblock-encapsulated main components revealed that the repellent activity of diblock solution of 2% trans-cinnamaldehyde against adult cat fleas is higher and more stable than thymol. Moreover, the diblock solution of 2% trans-cinnamaldehyde exhibits better and longer repellent activity than un-encapsulated 2% trans-cinnamaldehyde.
Subjects
cat flea
repellent
plant essential oil
Cinnamomum osmophloeum
Taiwania cryptomerioides
Plectranthus amboinicus
trans-cinnamaldehyde
thymol
SDGs
Type
thesis
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