Effects of R-(+)- and S-(-)-limonene on the respiratory tract in mice

Tidsskriftartikel - 2000

Resume

The effects of airborne R-(+)- and S-(-)-limonene were studied in conscious BALB/c mice by continuous monitoring respiratory rate (f), tidal volume (VT) and mid-expiratory flow rate (VD) during an exposure period of 30 min. Both enantiomers decreased f from a trigeminal reflex, i.e., due to sensory irritation. The exposure concentration decreasing f by 50% (RD50) in the first 10 min of the exposure period was estimated to be 1076 ppm for R-(+)-limonene and 1467 ppm for S-(-)-limonene. Results for sensory irritation of R-(+)-limonene in BALB/c mice and humans are in close agreement. The reported sensory irritation threshold is above 80 ppm in humans while the no-observed-effect level was estimated to be 100 ppm in mice. The enantiomers were devoid of pulmonary irritation or general anesthetic effects with R-(+)-limonene =1599 ppm and S-(-)-limonene =2421 ppm. R-(+)-limonene did not influence VT below 629 ppm. S-(-)-imonene increased VT above 1900 ppm. Both enantiomers induced a mild bronchoconstrictive effect above 1000 ppm.

Reference

Larsen ST, Hougaard KS, Hammer M, Alarie Y, Wolkoff P, Clausen PA, Wilkins C, Nielsen GD. Effects of R-(+)- and S-(-)-limonene on the respiratory tract in mice. Hum Exp Toxicol 2000;19(8):457-466.
doi: 10.1191/096032700682694233

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