Fermentation filtrates of Rubus coreanus relax the corpus cavernosum and increase sperm count and motility

We investigated the effects of fermentation filtrates from Rubus coreanus on the function of the male reproductive system. We performed an ex vivo study to determine if the candidate compounds relax isolated New Zealand white rabbit corpus cavernosum, which were precontracted by phenylephrine (5 x 10(-5) M). The results reveal that the filtrates of the reddish-purple (FRRC) and green (FGRC) R. coreanus exerted concentration-dependent relaxing effects, leading to median effective concentrations of 4.53 mg/mL and >10 mg/mL, respectively. For the in vivo study, male ICR mice were orally administered FRRC or FGRC (100 or 500 mg/kg) for 28 days, and the reproductive organ weights, serum testosterone level, cauda epididymal sperm counts, and motility were analyzed. Both the FRRC and FGRC had no significant effect on the reproductive organ weights; however, FRRC (100 or 500 mg/kg) enhanced testosterone levels and especially sperm counts at the higher dose (500 mg/kg). In comparison, FGRC increased hormone levels and sperm counts at a relatively low dose (100 mg/kg). In summary, it is proposed that the crude fermentation filtrates of ripe R. coreanus have positive effects on the function of the male reproductive system by triggering a penile erection, enhancing serum testosterone levels, and increasing epididymal sperm counts.