A bioassay for mosquito repellency against Aedes aegypti: method validation and bioactivities of DEET analogues.
OBJECTIVE
Vector-borne diseases are still a major mortality factor in Africa and South-east Asia and effective mosquito repellents are therefore needed. An efficient and safe in-vitro assay system using artificial blood and skin substitute could facilitate the development of novel repellents, as most assays currently rely on human subjects or vertebrate whole blood. Moreover, examining the skin permeation profiles could provide safer mosquito repellents. The new assay system could serve as an initial system for testing new repellent candidates upon validation with DEET and its analogues.


METHODS
N,N-Diethyl-meta-toluamide (DEET) and five analogues were synthesised and used to validate a novel in-vitro bioassay using artificial blood and collagen membrane. Repellency against Aedes aegypti was correlated with lipophilicity and skin permeation.


RESULTS
The new in-vitro assay showed good reproducibility (interday relative standard deviation <10% at high concentrations). Four of the five DEET analogues showed repellency similar or superior to that of DEET. Repellency correlated linearly with lipophilicity but stronger repellents tended to permeate skin better.


CONCLUSIONS
The new in-vitro assay using blood substitute and collagen membrane significantly simplifies screening of possible mosquito repellents. Lipophilicity as well as skin permeation profiles should be considered before testing of compounds that are candidates for mosquito repellents.
Jahn
Alexander
A
Department of Biotechnology & Department of Biomedical Laboratory Science, Dongseo University, Busan, South Korea.
Kim
Seok Yong
SY
Choi
Joon-Ho
JH
Kim
Dae-Duk
DD
Ahn
Young-Joon
YJ
Yong
Chul Soon
CS
Kim
Jung Sun
JS
D000330:Aedes; D000818:Animals; D001681:Biological Assay / Q000379:methods*; D001802:Blood Substitutes / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D003671:DEET / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology*; D005260:Female; D007302:Insect Repellents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D009032:Mosquito Control / Q000379:methods; D015203:Reproducibility of Results; D012869:Skin Absorption
D001802:Blood Substitutes; D007302:Insect Repellents; D003671:DEET; D003094:Collagen