Reduced testosterone production in TM3 Leydig cells treated with Aspalathus linearis (Rooibos) or Camellia sinensis (tea).

Flavonoids are major compounds of Aspalathus linearis and Camellia sinensis. They are classified as endocrine disruptors and some have been shown to inhibit testosterone production. TM3 Leydig cell cultures were treated with 250-5000 μg mL(-1) A. linearis (unfermented or fermented rooibos) or Camellia sinensis (green or black tea) for 24 h in the absence or presence of 6 mIU/200 μl human chorionic gonadotropin (hCG). Under nonstimulated conditions, all teas tend to decrease testosterone production (3.9-31.8%). However, under hCG-stimulation, a significant reduction in testosterone production was observed at all concentrations by both rooibos and tea (16.3-37.9%). MTT assay and phase contrast microscopy, revealed that at 250-1000 μg ml(-1) , both plants maintained the viability, proliferation and morphology of the cells, while 5000 μg ml(-1) was cytotoxic to the cells (P < 0.05). In conclusion, the results here demonstrate the anti-androgenic property of A. linearis and C. sinensis.