The induction of dominant lethal mutations upon chronic administration of khat (Catha edulis) in albino mice.

The mutagenicity of a methanolic extract of khat has been evaluated on male germ cells using the dominant lethal test in albino mice. An aqueous solution of khat extract was administered orally in doses of 50, 100 and 200 mg/kg body wt., respectively, to 3 different groups of male mice for a period of 6 weeks. At the end of treatment each male mouse was allowed to mate with 2 different groups of 3 females each, on 2 consecutive weeks. These females were necropsied on the 13th day of their presumptive mating, and the number of implants in each female and the ratio of live and dead embryos were determined. The results of this study showed that the treatment of male mice over a period of 6 weeks produced a dose-dependent reduction in the rate of fertility in the first week after mating, which was irreversible in the second week at the highest dose (200 mg/kg). Khat extract also induced post-implantation loss during the first week following treatment. However, a comparison of the results of the first and second weeks showed a reversible pattern of dominant lethality.