(urtica dioica)
Stinging nettle root is used for urination disorders associated with benign prostatic hyperplasia (BPH), including nocturia, frequency, dysuria, urinary retention, and irritable bladder.
Stinging nettle root is also used orally for joint ailments, as a diuretic, and an astringent. It is also used in conjunction with copious fluid intake in so-called "irrigation therapy" for urinary tract infections (UTI), urinary tract inflammation, and kidney stones (nephrolithiasis).
Stinging nettle root contains polysaccharides with immunomodulating and some anti-inflammatory effects. The root seems to have an antiproliferative effect on prostatic epithelial and stromal cells; and may also lessen the effects of androgenic hormones by competitively blocking access to human sex hormone binding globulin (SHBG).
Some researchers think that stinging nettle might be beneficial for allergic rhinitis due to quercetin content. Quercetin is thought to have anti-inflammatory and mast-cell stabilizing effects. It decreases histamine release from basophils and mast cells.
Preliminary research shows that an aqueous extract of stinging nettle leaves can decrease adenosine deaminase activity in prostate tissue from men with localized prostate cancer. Stinging nettle contains beta-sitosterol. Laboratory research suggests beta-sitosterol might have antiproliferative effects on the prostate, possibly by inhibiting growth factors.
A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: urticae radix.
Chrubasik JE, Roufogalis BD, Wagner H, Chrubasik S.
Department of Forensic Medicine, University of Freiburg, Albertstr. 9, 79104 Freiburg, Germany.
Nettle root is recommended for complaints associated with benign prostatic hyperplasia (BPH). We therefore conducted a comprehensive review of the literature to summarise the pharmacological and clinical effects of this plant material. Only a few components of the active principle have been identified and the mechanism of action is still unclear. It seems likely that sex hormone binding globulin (SHBG), aromatase, epidermal growth factor and prostate steroid membrane receptors are involved in the anti-prostatic effect, but less likely that 5alpha-reductase or androgen receptors are involved. Extract and a polysaccharide fraction were shown to exert anti-inflammatory activity. A proprietary methanolic nettle root extract and particular fractions inhibited cell proliferation. Isolated lectins (UDA) were shown to be promising immunomodulatory agents, having also anti-viral and fungistatic effects. However, despite these in vitro studies it is unclear whether the in-vitro or animal data are a surrogate for clinical effects. The clinical evidence of effectiveness for nettle root in the treatment of BPH is based on many open studies. A small number of randomised controlled studies indicate that a proprietary methanolic extract is effective in improving BPH complaints. However, the significance and magnitude of the effect remains to be established in further confirmatory studies before nettle root treatment may be accepted in the guidelines for BPH treatment. The risk for adverse events during nettle root treatment is very low, as is its toxicity. Pre-clinical safety data remain to be completed.
Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study.
Department of Urology, Urology Nephrology Research Center, Shaheed Beheshti University of Medical Sciences, Tehran, Iran.
PURPOSE: To determine the effects of therapy with Urtica dioica for symptomatic relief of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). MATERIAL AND METHODS: A 6-month, double-blind, placebo-controlled, randomized, partial crossover, comparative trial of Urtica dioica with placebo in 620 patients was conducted. Patients were evaluated using the International Prostate Symptom Score (IPSS), the maximum urinary flow rate (Qmax), postvoid residual urine volume (PVR), Serum Prostatic- Specific Antigen (PSA), testosterone levels, and prostate size. At the end of 6-month trial, unblinding revealed that patients who initially received the placebo were switched to Urtica dioica. Both groups continued the medication up to 18 months. RESULTS: 558 patients (90%) completed the study (287/305, 91% in the Urtica dioica group, and 271/315, 86% in the placebo group). By intention- to-treat analysis, at the end of 6-month trial, 232 (81%) of 287 patients in the Urtica dioica group reported improved LUTS compared with 43 (16%) of 271 patients in the placebo group (P < 0.001). Both IPSS and Qmax showed greater improvement with drug than with placebo. The IPSS went from 19.8 down to 11.8 with Urtica dioica and from 19.2 to 17.7 with placebo (P = 0.002). Peak flow rates improved by 3.4 mL/s for placebo recipients and by 8.2 mL/s for treated patients (P < 0.05). In Urtica dioica group, PVR decreased from an initial value of 73 to 36 mL (P < 0.05). No appreciable change was seen in the placebo group. Serum PSA and testosterone levels were unchanged in both groups. A modest decrease in prostate size as measured by transrectal ultrasonography (TRUS) was seen in Urtica dioica group (from 40.1 cc initially to 36.3 cc; P < 0.001). There was no change in the prostate volume at the end of study with placebo. At 18-month follow-up, only patients who continued therapy, had a favorable treatment variables value. No side effects were identified in either group. CONCLUSION: In the present study, Urtica dioica have beneficial effects in the treatment of symptomatic BPH. Further clinical trials should be conducted to confirm these results before concluding that Urtica dioica is effective.
Cardiovascular effects of Urtica dioica L. (Urticaceae) roots extracts: in vitro and in vivo pharmacological studies.
Testai L, Chericoni S, Calderone V, Nencioni G, Nieri P, Morelli I, Martinotti E.
Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy.
Urtica dioica (Urticaceae) is a plant principally used in the traditional medicine of oriental Marocco as antihypertensive remedy (J. Ethnopharmacol., 58 (1997), 45). The aim of this work was to evaluate a possible direct cardiovascular action of the plant and to investigate its mechanism of action. In aortic preparations with intact and functional endothelial layer, pre-contracted with KCl 20 mM or norepinephrine 3 microM, the crude aqueous and methanolic extracts of the plant roots, as well as purified fractions elicited a vasodilator action. Nevertheless, the vasodilator activity was not present in aortic rings without endothelial layer. In aortic rings with intact endothelial layer, the vasorelaxing effect was abolished by L-NAME, a NO-biosynthesis inhibitor, and ODQ, a guanylate cyclase inhibitor. Furthermore, potassium channel blockers (TEA, 4-aminopyridine, quinine, but not glybenclamide) antagonized the vasodilator action of the purified fraction F1W of U. dioica. The same fraction produced a marked decrease of inotropic activity, in spontaneously beating atria of guinea-pig, and a marked, but transient, hypotensive activity on the blood pressure of anaesthetized rats. It is concluded that U. dioica can produce hypotensive responses, through a vasorelaxing effect mediated by the release of endothelial nitric oxide and the opening of potassium channels, and through a negative inotropic action.