Inhibitory effect of Taraxacum officinale   L (Compositae) aqueous root extract on spermatogenesis

Purpose: To investigate if T. officinale root aqueous extract has anti-spermatogenic activity similar to that of the whole plant which was shown previously to inhibit spermatogenesis.
Methods: T. officinale aqueous extract was prepared by soaking 100 g of dried materials in 1 L distilled water for two days at 45 ^oC. Fifty adult male rats were divided into five groups and treated for 60 days. Four groups were gavaged with the whole plant or root aqueous extract in low or high doses. The male rat rats were allowed to mate with female rats. The control group received distilled water. Sperm count, motility and morphology as well as chromatin integrity were evaluated.
Results: Serum testosterone level, sperm parameters, pregnancy rate and average number of fetuses per pregnant females decreased significantly in the treated groups compared to control and in the root-receiving rats compared to the whole plant-receiving rats. Female rats which were mated with high dose root-receiving males did not deliver fetuses. Cross sections of seminiferous tubules of T. officinale-treated rats showed lesions and disorganized germinal epithelium. Late spermatogenesis maturation arrest (spermatid stage) was observed in all of the treated groups except the high dose root-receiving group which showed early maturation arrest (spermatocyte stage). In addition, the mRNA level of two spermatogonial stem cell markers responsible for self-renewal and proliferation of spermatogonia increased in high dose-receiving rats.
Conclusion: T. officinale root aqueous extract has inhibitory effects on spermatogenesis. Further studies are required to identify specific ingredient(s) in T. officinale that may be useful as male contraceptive(s).

Keywords
Taraxacum officinale; Dandelion; GDNF family receptor alpha 1; Macrophage Colony-Stimulating Factor; Promyelocytic Leukaemia Zinc-Finger; Testosterone; Sperm count