Taxifolin suppresses rat and human testicular androgen biosynthetic enzymes.

Taxifolin is a flavonoid. It has been used as a chemopreventive agent and supplement. It may have some beneficial effects to treat prostate cancer by suppressing androgen production in Leydig cells. The objective of the present study was to study the effects of taxifolin on androgen production of rat Leydig cells isolated from immature testis and some rat and human testosterone biosynthetic enzyme activities. Rat Leydig cells were incubated with 100µM taxifolin without (basal) or with 10ng/ml luteinizing hormone (LH), 10mM 8-bromoadenosine 3',5'-cyclic monophosphate (8BR), and steroid enzyme substrates (20µM): 22R-hydroxychloesterol, pregnenolone, progesterone, and androstenedione. The medium concentrations of 5α-androstane-3α, 17ß-diol (DIOL) and testosterone were measured. Taxifolin significantly suppressed basal, LH-stimulated, 8BR-stimulated, pregnenolone-mediated, and progesterone-mediated androgen production by Leydig cells. Further study demonstrated that taxifolin inhibited rat 3ß-hydroxysteroid dehydrogenase and 17α-hydroxylase/17, 20-lyase with IC50 values of 14.55±0.013 and 16.75±0.011µM, respectively. Taxifolin also inhibited these two enzyme activities in human testis with IC50 value of about 100µM. Taxifolin was a competitive inhibitor for these two enzymes when steroid substrates were used. In conclusion, taxifolin may have benefits for the treatment of prostate cancer.

[Clinical efficacy of vardenafil on ED patients with kidney-yang or -yin deficiency or liver-qi stasis].

OBJECTIVE: To study the clinical efficacy of vardenafil on erectile dysfunction (ED) patients with kidney-yang deficiency, kidney-yin deficiency or liver-qi stasis. METHODS: Based on the syndromes of Traditional Chinese Medicine, 124 ED patients were divided into Groups A (kidney-yang deficiency, n=44), B (kidney-yin deficiency, n=41) and C (liver-qi stasis, n = 39). All the patients were treated with vardenafil at 5 mg daily for 8 weeks, and the therapeutic effects were evaluated by comparing the scores on IIEF-5 and Erection Quality Scale (EQS) before and after the treatment. RESULTS: After vardenafil treatment, the IIEF-5 and EQS scores of the ED patients were markedly increased, with statistically significant differences among the three groups (P < 0.01). The success rate of sexual intercourse was significantly improved in Groups A, B (P < 0.01) and C (P < 0.05). And the hardness of penile erection was enhanced by 81.82%, 73.17% and 43.59% respectively in the three groups of patients. CONCLUSION: Vardenafil is more effective for ED patients with kidney-yang or kidney-yin deficiency than for those with liver-qi stasis.