International Journal of Applied Research on Medicinal Plants (ISSN: 2689-7377)

Article / research article

"Effect of Saw Palmetto Extract on Erectile Dysfunction and Libido in Patients with Lower Urinary Tract Symptoms Because of Benign Prostatic Obstruction"

Bojan Tršinar 1, Samo Kreft 2*

1University Medical Centre Ljubljana, Zaloška cesta 7, 1000 Ljubljana, Slovenia

2Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, 1000 Ljubljana, Slovenia

*Corresponding author: Samo Kreft, Faculty of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, 1000 Ljubljana, Slovenia. Tel: +386014769703; Fax: +386014258031; Email: samo.kreft@ffa.uni-lj.si

Received Date: 20 June, 2019; Accepted Date: 6 July, 2019; Published Date: 16 July, 2019 

Abstract

Background: Herbal medicinal products containing extracts of saw palmetto berries (Serenoa repens) are used for treatment of Lower Urinary Tract Symptoms (LUTS) because of Benign Prostatic Obstruction (BPO). Improvement of sexual dysfunctions was also shown.

Methods:  Here we performed a multicentric open label clinical study on 84 men to confirm its effects on LUTS/BPO on Slovenian population and this is only the second study investigating the effect on sexual dysfunctions.

Results: In 6 months of treatment the International prostate symptom score (IPSS) improved from 12.7 to 9.2 (p = 7.0×10-12) and the quality of life score improved from 2.4 to 1.7 (p = 9.2×10-4). Prostate-Specific Antigen (PSA) levels did not change. The proportion of patients with unsatisfactory libido reduced from 26.5 % to 13.2 % (p=0.036) during the therapy and a non-significant trend of reduction of erectile dysfunction was observed.

Conclusion: Our results are in agreement with the previous research on the efficacy of saw palmetto, but regarding the libido and erectile dysfunction, further controlled studies are needed.

Keywords: Berries; Erectile Dysfunction; Libido; Saw Palmetto (Serenoa Repens); Slovenian Population

List of Abbreviations

BPE       :               Benign Prostatic Enlargement;

BPH       :               Benign Prostatic Hyperplasia;

BPO       :               Benign Prostatic Obstruction;

ED          :               Erectile Dysfunction;

IPSS       :               International Prostate Symptom Score;

LUTS     :               Lower Urinary Tract Symptoms;

PSA        :               Prostate-Specific Antigen;

QoL       :               Quality of Life

Background

Extracts of saw palmetto berries (Serenoa repens) are used for treatment of mild to moderate LUTS/BPO, Erectile Dysfunctions, to improve testicular atrophy and sperm production, and as a genitourinary and sexual stimulant [1]. The plant is endemic to Florida and neighbouring regions in the south east of United States.

The prostate is positioned below the urinary bladder of man and surrounds the urethra [2]. In man after the age of 40, the prostatic tissue enlarges (Benign Prostatic Enlargement - BPE) because of Benign Prostatic Hyperplasia (BPH) which often causes Benign Prostatic Obstruction (BPO) [3]. It constricts the urethra and causes urgent and frequent urination, nocturia, incomplete bladder emptying and weak urine stream. This occurs in 30% of men in their 60s and 50% of men older than 80 [4].

In addition to obstructive and irritative symptoms, BPO also affects sexual functions [5]. Patients with LUTS/BPO are at 3.7-fold higher risk of developing erectile dysfunction, compared with patients without LUTS/BPO and the severity of the LUTS correlates with frequency and severity of erectile and ejaculatory dysfunctions [6]. The main medical treatments for LUTS/BPO are alpha blockers and 5-alpha-reductase-inhibitors. Both treatment options are effective on the LUTS/BPO; but they have further negative impact on sexual functions [7-8]. Sexual dysfunctions are the most often reported adverse events of 5-alpha-reductase-inhibitors [9].

More than 32 controlled clinical trials investigated efficacy of saw palmetto preparations for LUTS/BPO treatment [10-11]. In most cases, the tested products contained 320 mg lipophilic berry extract per day [12]. Compared with placebo, the studies demonstrate good efficacy of long-term saw palmetto use to treat LUTS/BPO symptoms; the results are similar to finasteride [13] and tamsulosin [14], but saw palmetto has a much better safety profile than these substances particularly in regards to sexual dysfunctions [10]. As modes of action, in vitro and in vivo inhibition of both isoforms of the 5-alphareductase [15-16] and anti-inflammatory activities [17-18] have been reported, as well as inhibition of autonomous receptors in the lower urinary tract [19]. It is very desirable to find a treatment that not only improves the symptoms of BPO but also has no negative or possibly even a beneficial impact on sexual dysfunctions [20]. A pilot clinical trial showed that a saw palmetto extract improved sexual dysfunctions in patients with mild to moderate BPO [21]. Here we performed a multicentric clinical study to confirm the results. There are more than 32 studies investigating the effects of saw palmetto on LUTS/BPO, but this is only the second study investigating its effect on sexual dysfunctions.

Methods

The study was approved by the Medical Ethics Committee of the Republic of Slovenia (No. 16-234/3). 84 men with LUTS / BPO aged between 45 and 84 years of age (average 62.3 ± 9.2 years), were enrolled in this prospective, open, multicentric clinical trial. They were in good general health and they signed an informed consent to voluntary participate in the trial. The patients were enrolled by 19 physicians at the primary level.

The study did not include patients who have had surgery on the urinary bladder, prostate or pelvis, irradiation for pelvis, proven neurogenic bladder, stenosis of the bladder neck or urethra, stones in the bladder or urethra, recurrent urinary tract infections, cancer of the bladder and prostate, severe hepatic or renal insufficiency, diabetes mellitus, clinically significant cardiovascular or cerebrovascular disease, nervous system diseases, known intolerance to Saw Palmetto, therapy with inhibitors of 5-alpha reductase, blockers of alpha adrenergic receptors or phosphodiesterase 5-inhibitors. The study also did not include patients who have not been able to understand the research.

Upon entering the study all patients were clinical examined, digital rectal examination of the prostate was performed, they filled in the questionnaires for International Prostate Symptom Score (IPSS) and Quality of Life (QoL), gave the blood for total PSA analyses. Patients were also asked about a possible Erectile Dysfunction (ED) and libido. All patients then began treatment with the medicinal product Prostasan (Bioforce, Swizerland), 1 capsule per day containing 320 mg of the soft extract of saw palmetto berries (Serenoa repens) (W. Bartram) Small (synonym Sabal serrulata) (Michx.Schult.). The product was purchased on Slovenian market. Drug to extract ratio was; DER 9-12:1, extraction solvent 96% V/V ethanol. 1capsule per day was taken during or after a meal for 6 months. The data was collected at first (baseline) examination (at the start of treatment) and at second and third examination after 3 and 6 months of treatment. Patients came to second and third examination after 3 and 6 months of treatment. The same parameters were monitored as at the beginning of treatment. In addition, we collected the opinion of patients and their doctors about the efficacy and safety of the treatment, and recorded possible side effects. For statistical analysis, t-test and chi-square test were used.

Results

The study included 84 patients with LUTS/BPO, treated by 19 participating physicians (Figure 1).

The average age was 62.3 ± 9.2 years.

Treatment was prematurely terminated by 7 patients: one stopped treatment due to undesirable events (nausea), 3 patients were excluded due to exclusion criteria (lung cancer, stenosis of the bladder and alpha blocker therapy), and 3 patients left the study for unknown reason.

After 3 and 6 months of treatment the improvement of IPSS and the quality of life was statistically significant (Table 1 and Table 2). The values of total PSA levels after 3 and 6 months of treatment did not change significantly. The “difference in average” (Table 1) and the “average difference” (Table 2) are not exactly the same, since only the patients completing the therapy (3 months or 6 months respectively) are taken into account in Table 2, and all available data is considered in Table 1.

In 6 months of therapy, the proportion of patients with unsatisfactory libido significantly reduced (Table 3) from 26.5% to 13.2% (p=0.036). The trend of improvement was seen already in 3 months when 18.1% of patients had unsatisfactory libido. There was only a non-significant (p = 0.102) trend of reduction of erectile dysfunction from 36.9%, to 25.7% and to 28.9% at baseline, and after 3 and 6 months of therapy, respectively. Erectile dysfunction was strongly connected to IPSS (p = 0.004), and weakly with the quality of life (p = 0.08). Libido was not connected to any of those parameters (p > 0.25).

The vast majority of patients were satisfied with the therapy (Table 4) and they assessed the efficacy as good or moderate (Table 5). The physicians’ assessments of effectiveness were very similar (Table 5). They strongly correlated to patient’s assessments both at 3 months (Spearman Correlation = 0.776, p= 1.1×10-17) and at 6 months (Spearman Correlation = 0.735, p= 4.1×10-15).  Both patients and physicians assessed the safety of the therapy as good in average in more than 95% of cases (Table 4).

After the 3 month of therapy the patients were asked how quickly the effect of the therapy appeared. In average it appeared after 4.5 weeks (median: 3 weeks, modus: 4 weeks). The 6 patients reported that the effect did not appear yet after 3 months.

Two undesirable effects were reported after 3 months of therapy (moderate nausea and light polyuria). No undesirable effect was reported after 6 months of therapy.

Discussion

The interest for the treatment with natural medicines worldwide is constantly increasing. It is estimated that 30-50% of urological patients in the United States use herbal preparations [22].

In this prospective, open, multicentric clinical trial we confirmed in population of Slovenian man, that the herbal medicinal product containing 320 mg of the extract of saw palmetto berries is efficient in reducing LUTS/BPO. The patients were enrolled by family doctors, making study design closer to the real life situation in comparison to most other studies on palmetto which were conducted by urologists. Another advantage of this study is that the therapy lasted for 6 months, compared to 2 or 3 months in most previous studies; which proves the long term safety of palmetto. As in previous reports we found significant improvement of IPSS and Quality of life, but not in the concentration of total PSA [13,14,13,24]. Furthermore we confirmed that the product is well tolerated and safe with only mild and infrequent undesirable effects. Libido was significantly improved, and for erectile dysfunction we observed a trend of improvement. This support previous study were also erectile function and ejaculatory function significantly improved [21]. On the other hand, non-herbal LUTS/BPO therapies (e.g. 5-alpha-reductase inhibitors) are known to cause Erectile Dysfunction and decreased libido. The weakness of this study is, that the erectile dysfunction was assessed only as present/not present, and there was no control group therefore we cannot exclude the influence of placebo effect.

Conclusions

In this study we confirmed that the saw palmetto extract improves the BPH symptoms: International Prostate Symptom Score (IPSS) and the quality of life. We also showed the improvement of libido during the therapy. For the effect on erectile dysfunction and libido further studies are needed before the final conclusions will be made.

Declarations

Ethics approval and consent to participate

The study was approved by the Medical Ethics Committee of the Republic of Slovenia (No. 16-234/3). The participants signed an informed consent to voluntary participate in the trial.

Consent for Publication

All authors approved the publication of this manuscript

Availability of Data and Materials

The original data is available upon request.

Competing Interests

None of the authors have any competing interests in the manuscript.

Funding

The research was founded by the institutions where the authors are affiliated

Authors' Contributions

Both authors equally contributed to the design of the study. BT organised the enrolment of the patients and physician’s examinations. SK made statistical analysis. Both authors wrote the article.

Acknowledgements

The authors are grateful to the institutions where they are affiliated.


Figure 1: Flowchart of the clinical trial.

 

IPSS

 QoL

Total PSA

Baseline

average

12.67

2.39

1.575

SD

5.06

1.22

1.164

min

4

0

0.090

max

27

6

6.600

After 3 month therapy

average

10.27

2.04

1.468

SD

5.02

1.15

0.892

min

2

0

0.120

max

30

6

4.300

After 6 month therapy

average

9.19

1.75

1.673

SD

5.44

1.16

1.493

min

1

0

0.180

max

28

6

7.270

Difference in average between baseline and 3 month of therapy

-2.41

-0.35

-0.107

Difference in average between baseline and  6 month of therapy

-3.49

-0.65

0.098

Table 1: IPSS, QoL and total PSA at baseline and after 3 and 6 months of therapy. Negative values represent lowering (improvement) of signs and symptoms. SD = standard deviation.


 

 

IPSS

QoL

Total PSA

After 3-month therapy

 

average difference

-2.60

-0.34

-0.118

 

SD

3.23

0.98

0.365

 

Min

-16

-3

-1.370

 

Max

6

3

0.600

 

p (t-test)

5.1×10-10

5.1×10-3

0.062

After 6 month therapy

average difference

-3.64

-0.58

-0.018

SD

3.81

1.37

0.972

Min

-12

-4

-1.250

Max

8

5

5.150

p (t-test)

7.0×10-12

9.2×10-4

0.91

Table 2: The difference in IPSS, QoL and total PSA from baseline to 3 and 6 months.


 

 

Erectile dysfunction

Libido

 

 

present

absent

unsatisfactory

satisfactory

Baseline

number of patients

31

53

22

61

%

36.9

63.1

26.5

73.5

 

After 3 month of therapy

number of patients

26

75

15

68

%

25.7

74.3

18.1

81.9

p (chi-square test)

0.102

0.191

After 6 month of therapy

number of patients

22

54

10

66

%

28.9

71.1

13.2

86.8

p (chi-square test)

0.285

0.036

Table 3: Erectile dysfunction and satisfaction by the libido at baseline and after therapy.


 

 

After 3 month of therapy

After 6 month of therapy

 

 

Number of patients

%

Number of patients

%

Satisfaction

yes

74

90.3

70

91.0

no

8

9.7

7

9.0

Patient assessment of safety

bad

2

2.4

1

1.3

moderate

1

1.2

4

5.3

good

79

96.3

71

93.4

Physicians’ assessment of safety

bad

1

1.2

0

0.0

moderate

1

1.2

4

5.1

good

79

97.5

74

94.9

Table 4: Satisfaction, patient’s assessment of effectiveness and safety and physician’s assessment of effectiveness and safety.


ssessment after 3 months

Physicians’ assessment of effectiveness

good

modarate

bad

Total

Patient assessment of effectiveness

good

39

2

1

42

51.%

moderate

4

26

1

31

37.8%

bad

1

4

4

9

11.0%

Total

44

32

6

82

100.0%

53.7%

39.0%

7.3%

100.0%

 

Assessment after 6 months

Physicians’ assessment of effectiveness

good

modarate

bad

Total

Patient assessment of effectiveness

good

46

6

0

52

68.4%

moderate

4

13

1

18

23.7%

bad

0

3

3

6

7.9%

Total

50

22

4

76

100 %

65.8%

28.9%

5.3%

100%

 

Table 5: Correlation of patient’s and physician’s assessment of effectiveness after 3 and 6 months.

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Citation: Kreft S, Tršinar B (2019) Effect of Saw Palmetto Extract on Erectile Dysfunction and Libido in Patients with Lower Urinary Tract Symptoms Because of Benign Prostatic Obstruction. Int J Appl Res Med Plants 2: 110. DOI: 10.29011/IJARMP-110.100110

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