secoisolariciresinol-diglucoside and Prostatic-Hyperplasia

This exploratory study was designed to assess the effectiveness of a lignan-rich extract of flaxseed hulls (LinumLife EXTRA(®)) in alleviating symptoms in subjects with benign prostatic hyperplasia (BPH) compared with placebo. Two dosages of extract were compared against placebo in a double-blinded, randomized, parallel, multicenter study. Newly diagnosed cases of BPH in patients aged 45-75 years with an American Urological Association Symptom Index (AUASI) score of ≥13 were included. Study treatment consisted of 500 or 1000 mg of extract containing 100 mg (low-dose active [LDA] group, n=26) or 200 mg (high-dose active [HDA] group, n=26) of secoisolariciresinol diglucoside (SDG), respectively. The placebo (P) group (n=28) received matching maltodextrin capsules. Sixty subjects (LDA [n=19], HDA [n=20], and P [n=21]) completed the study as per the protocol requirements. Change in the AUASI score within a period of 8 weeks, from baseline to end of treatment, was assessed. Significant improvement of obstructive symptoms and management of irritable BPH symptoms was achieved in all groups after treatment. Due to a strong placebo effect, there was no statistical difference between the groups that were treated with flaxseed hull extract as compared with the placebo group. Treatment with flaxseed hull extract did not lead to adverse effects compared with placebo. Supplementation with flaxseed hull extract was found to be safe and well-tolerated and may have improved the quality of life of individuals with BPH. The significant placebo effect as well as the number of subjects per treatment group and the relative short duration of the study may explain the lack of statistical significance between groups.

Topics: Aged; Butylene Glycols; Double-Blind Method; Flax; Glucosides; Humans; India; Male; Middle Aged; Phytotherapy; Pilot Projects; Placebo Effect; Plant Extracts; Polysaccharides; Prostatic Hyperplasia; Quality of Life; Seeds; Treatment Outcome

A flaxseed lignan extract containing 33% secoisolariciresinol diglucoside (SDG) was evaluated for its ability to alleviate lower urinary tract symptoms (LUTS) in 87 subjects with benign prostatic hyperplasia (BPH). A randomized, double-blind, placebo-controlled clinical trial with repeated measurements was conducted over a 4-month period using treatment dosages of 0 (placebo), 300, or 600 mg/day SDG. After 4 months of treatment, 78 of the 87 subjects completed the study. For the 0, 300, and 600 mg/day SDG groups, respectively, the International Prostate Symptom Score (IPSS) decreased -3.67 +/- 1.56, -7.33 +/- 1.18, and -6.88 +/- 1.43 (mean +/- SE, P = .100, < .001, and < .001 compared to baseline), the Quality of Life score (QOL score) improved by -0.71 +/- 0.23, -1.48 +/- 0.24, and -1.75 +/- 0.25 (mean +/- SE, P = .163 and .012 compared to placebo and P = .103, < .001, and < .001 compared to baseline), and the number of subjects whose LUTS grade changed from "moderate/severe" to "mild" increased by three, six, and 10 (P = .188, .032, and .012 compared to baseline). Maximum urinary flows insignificantly increased 0.43 +/- 1.57, 1.86 +/- 1.08, and 2.7 +/- 1.93 mL/second (mean +/- SE, no statistical significance reached), and postvoiding urine volume decreased insignificantly by -29.4 +/- 20.46, -19.2 +/- 16.91, and -55.62 +/- 36.45 mL (mean +/- SE, no statistical significance reached). Plasma concentrations of secoisolariciresinol (SECO), enterodiol (ED), and enterolactone (EL) were significantly raised after the supplementation. The observed decreases in IPSS and QOL score were correlated with the concentrations of plasma total lignans, SECO, ED, and EL. In conclusion, dietary flaxseed lignan extract appreciably improves LUTS in BPH subjects, and the therapeutic efficacy appeared comparable to that of commonly used intervention agents of alpha1A-adrenoceptor blockers and 5alpha-reductase inhibitors.

Topics: Aged; Aged, 80 and over; Butylene Glycols; Diet; Double-Blind Method; Flax; Glucosides; Humans; Lignans; Male; Middle Aged; Phytotherapy; Placebos; Plant Extracts; Prostatic Hyperplasia; Quality of Life; Urinary Tract; Urination; Urine

Secoisolariciresinol diglucoside (SDG), a lignan extracted from flaxseed, has been shown to suppress benign prostatic hyperplasia (BPH). However, little is known about the mechanistic basis for its anti-BPH activity. The present study showed that enterolactone (ENL), the mammalian metabolite of SDG, shared the similar binding site of G1 on a new type of membranous estrogen receptor, G-protein-coupled estrogen eceptor 1 (GPER), by docking simulations method. ENL and G1 (the specific agonist of GPER) inhibited the proliferation of human prostate stromal cell line WPMY-1 as shown by MTT assay and arrested cell cycle at the G0/G1 phase, which was displayed by propidium iodide staining following flow cytometer examination. Silencing GPER by short interfering RNA attenuated the inhibitory effect of ENL on WPMY-1 cells. The therapeutic potential of SDG in the treatment of BPH was confirmed in a testosterone propionate-induced BPH rat model. SDG significantly reduced the enlargement of the rat prostate and the number of papillary projections of prostatic alveolus and thickness of the pseudostratified epithelial and stromal cells when comparing with the model group. Mechanistic studies showed that SDG and ENL increased the expression of GPER both in vitro and in vivo. Furthermore, ENL-induced cell cycle arrest may be mediated by the activation of GPER/ERK pathway and subsequent upregulation of p53 and p21 and downregulation of cyclin D1. This work, in tandem with previous studies, will enhance our knowledge regarding the mechanism(s) of dietary phytochemicals on BPH prevention and ultimately expand the scope of adopting alternative approaches in BPH treatment.

Topics: 4-Butyrolactone; Animals; Antineoplastic Agents, Phytogenic; Binding Sites; Butylene Glycols; Cell Line, Tumor; Cell Proliferation; Dietary Supplements; Flax; Gene Expression Regulation, Neoplastic; Glucosides; Glycosides; Humans; Lignans; Male; Models, Molecular; Molecular Docking Simulation; Neoplasm Proteins; Prostate; Prostatic Hyperplasia; Random Allocation; Rats; Rats, Wistar; Receptors, Estrogen; Receptors, G-Protein-Coupled; RNA Interference; Seeds