A garlic extract protects from ultraviolet B (280-320 nm) radiation-induced suppression of contact hypersensitivity.
Lyophilized aged garlic extract has been incorporated at concentrations of 0.1%, 1% and 4% by weight into semipurified powdered diets and fed to hairless mice. Under moderate UVB exposure conditions resulting in 58% suppression of the systemic contact hypersensitivity response in control-fed mice, a dose-responsive protection was observed in the garlic-fed mice; contact hypersensitivity in the UVB-exposed mice fed 4% garlic extract was suppressed by only 19%. If the UVB exposure was replaced by topical application of one of a series of lotions containing increasing concentrations of cis-urocanic acid, a dose-responsive suppression of contact hypersensitivity was demonstrated in control-fed mice (urocanic acid at 25, 50, 100 and 200 micrograms per mouse resulting in 22-46% suppression). Mice fed a diet containing 1% aged garlic extract were partially protected from cis-urocanic acid-induced suppression of contact hypersensitivity, with greater protection from the lower concentrations of urocanic acid. Mice fed a diet containing 4% aged garlic extract were protected from all concentrations of urocanic acid. The results indicate that aged garlic extract contains ingredient(s) that protect from UVB-induced suppression of contact hypersensitivity and suggest that the mechanism of protection is by antagonism of the cis-urocanic acid mediation of this form of immunosuppression.
Reeve
V E
VE
Department of Veterinary Pathology, University of Sydney, New South Wales, Australia.
Bosnic
M
M
Rozinova
E
E
Boehm-Wilcox
C
C
D000284:Administration, Oral; D000287:Administration, Topical; D000818:Animals; D003877:Dermatitis, Contact / Q000188:drug therapy*; D005260:Female; D005612:Freeze Drying; D005737:Garlic; D007111:Immunity, Cellular / Q000187:drug effects*; D051379:Mice; D008812:Mice, Hairless; D009824:Ointments / Q000627:therapeutic use; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays; D014560:Urocanic Acid / Q000627:therapeutic use
D009824:Ointments; D010936:Plant Extracts; D011837:Radiation-Protective Agents; D014560:Urocanic Acid