Ageratum conyzoides — more commonly known as goatweed— has long been used in Caribbean folk medicine for prostate and urinary issues. Its extract's therapeutic properties may come from chemical compounds such as fatty acids, flavonoids, lignans, sterols and terpenoids.
Based on this, researchers from the Queensland University of Technology, University of Sydney, Children's Hospital at Westmead, and Medlab Clinical conducted a double-blind RCT to determine the safety and efficacy of A. conyzoides against BPH.
The study involved 109 men, aged between 41 and 76, with medically diagnosed BPH. They were given either 250mg of A. conyzoides extract or a placebo every day for 12 weeks.
The primary outcome measures consisted of the International Prostate Symptom Score (IPSS), daily urinary frequency, and safety evaluations, while secondary outcome measures included testosterone, cortisol levels, prostate-specific antigen (PSA), blood glucose, and lipids.
The researchers observed a significant decrease in total IPSS score and both daytime and nighttime urinary frequency following A. conyzoides treatment.
Steroid hormones, PSA levels, blood glucose, and lipids, on the other hand, remained in the healthy reference range in both groups.
The A. conyzoides extract was also found to effectively inhibit in human prostate epithelial cells mRNA expression of dihydrotestosterone (DHT), which is often involved in prostate enlargement and prostate cancer risk.
The underlying mechanism might be similar to that of 5α-reductase inhibitors that help to manage BPH symptoms. However, the study said "it is not known which constituents are 5α-reductase inhibitors in the A. conyzoides extract".
It further stated that while the two main triggers of BPH are said to be ageing and high androgen levels, chronic inflammation might also play a part via repeated tissue damage that leads to cellular proliferation.
As such, the researchers said A. conyzoides likely reduces BPH symptoms through its anti-spasmotic and anti-inflammatory properties.
The researchers observed "no notable effects on haematological and biochemical parameters, lipids, or blood glucose levels at the administered dose of 250 mg/d of A. conyzoides extract over 12 weeks".
There were also no changes to the participants' sexual function, and all except two of them tolerated the A. conyzoides extract well; intake of the extract caused diarrhoea in the two affected subjects.
Despite this, the study also noted that "oral administration of the ethanol extract of A. conyzoides at a dose of 500 and 750 mg/kg has been shown to exhibit marked gastro-protection against gastric ulcers, suggesting that there may be gastrointestinal effects that require further investigation".
So long, symptoms
The researchers said the study's overall results suggest that A. conyziodes may be effective in reducing BPH symptoms in otherwise healthy men, partially by inhibiting 5α-reductase enzyme activity.
They concluded: "This A. conyzoides extract may be a promising safe and effective treatment for reducing symptoms of BPH, by mechanisms that may involve both androgen moderation and / or anti-inflammatory and antispasmotic actions in healthy middle-aged and older men.
"Further studies are required to verify long-term effects on hormone levels, PSA levels and anti-inflammatory markers."
"Ageratum conyzoides L. inhibits 5-alphareductase gene expression in human prostate cells and reduces symptoms of benign prostatic hypertrophy in otherwise healthy men in a double blind randomized placebo controlled clinical study"
Authors: Matthew Detering, et al.