The effects of Sida rhombifoia L. on benign prostatic hyperplasia in testosterone propionate-induced animal model and its active constituents

Benign prostatic hyperplasia (BPH) is a pathologic process that is more likely to develop after middle age [1]. More than 50% of men aged over 60s have BPH and 15 to 30% of those affected suffer lower urinary tract symptoms, such as, urinary retention, bladder infection, bladder calculi, or renal failure [2],[3]. BPH is known to depend on androgens [4], especially dihydrotestosterone (DHT), which is the predominant hormone in immature, mature, and hypertrophic prostate glands. DHT is synthesized from testosterone by two isoenzymes of 5α-reductase, that is, types 1 and 2 [5], and type 2 5α-reductase (5AR) is found predominantly in prostate. An excessive accumulation of DHT leads to hyperproliferation of stromal and epithelial cells of the prostate gland which results in prostate size increase. Therefore, the inhibition of the enzyme, 5AR and thus normal masculinization appears to be one of the sensitive targets for the treatment of benign prostatic hyperplasia. During the search for active natural resources to treat or improve the symptoms of BPH, it was found that the extract of Sida rhombifolia L. showed the potent inhibitory effects on 5AR2 enzyme activity. This study aimed to investigate the beneficial effects of S. rhombifolia extract on testosterone propionate-induced benign prostatic hyperplasia (BPH) in rats. The administration of ethanolic extract of S. rhombifolia (100 mg/kg body weight, p.o.) for 6 weeks markedly attenuated prostate enlargement and reduced serum and prostate levels of DHT and 5AR in testosterone propionate-treated rats. The expressions of androgen receptor, prostate specific antigen (PSA), and proliferating cell nuclear antigen (PCNA) in the prostate tissues were remarkably suppressed in the extract-treated rats. Through activity-guided isolation, the compounds belong to terpenoid have been successfully isolated from the extract of S. rhombifolia. The structures of the isolated compounds were elucidated by extensive 1D and 2D spectroscopic methods including 1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC and NOESY. These findings regarding the effects of S. rhombifolia extract on of rats with testosterone-induced prostate hyperplasia suggest that the extract of S. rhombifolia and its active constituents may be useful for the treatment of prostate hyperplasia.

• References

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