Eleazu et al 2017 The role of dietary polyphenols in the management of erectile dysfunctionMechanisms of action
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Eleazu et al 2017 The role of dietary polyphenols in the management of erectile dysfunctionMechanisms of action


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Biomedicine & Pharmacotherapy 88 (2017) 644\u2013652
Review
The role of dietary polyphenols in the management of erectile
dysfunction\u2013Mechanisms of action
Chinedum Eleazua,*, Nwite Obianujua, Kate Eleazub, Winner Kaluc
a Federal University, Ndufu-Alike, Ikwo, Ebonyi State, Nigeria
b Ebonyi State University, Abakaliki, Ebonyi State, Nigeria
cMichael Okpara University of Agriculture, Umudike, Abia State, Nigeria
A R T I C L E I N F O
Article history:
Received 5 January 2017
Received in revised form 20 January 2017
Accepted 20 January 2017
Keywords:
Erectile dysfunction
Polyphenols
Nutrition
Antioxidants
Nutraceuticals
A B S T R A C T
The incidence of erectile dysfunction (ED) is on the increase and it is estimated that it will affect about
322 million men globally by the year 2025 if adequate measures are not taken to curb it. Natural
polyphenols in plant based diets have gained public interest in recent times due to their roles in the
prevention of various disease that implicate free radicals/reactive oxygen species and recently on ED.
However, the role of polyphenols in the management of ED has not been explored due perhaps to limited
data available. Hence this study which reviewed the role of dietary polyphenols in the management of ED
and their mechanisms of action. Literature search was carried out in several electronic data bases such as
Pubmed, Google Scholar, Medline, Agora and Hinari from1972 to 2016 to identify the current status of
knowledge on the role of polyphenols in the management of erectile dysfunction. Progress made so far in
this direction suggests inhibition of arginase, acetylcholinesterase, angiotensin converting enzyme, rho-
kinase II; activation of endothelial and neuronal NO synthase; decreased synthesis of luteinizing
hormone and testosterone reduction; activation of silent information regulator 2-related enzymes
(sirtuin1) as well as free radical/reactive oxygen species inhibition as the mechanisms through which the
polyphenols identified in this review exert beneficial roles in the management of ED.
© 2017 Elsevier Masson SAS. All rights reserved.
Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 645
1.1. Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
2. Overview of polyphenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
2.1. Classification of polyphenols and their dietary sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
2.2. Pharmacokinetics of polyphenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
2.3. Metabolism and absorption of polyphenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
2.4. Bioavailability of polyphenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647
2.5. Excretion/elimination of polyphenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647
2.6. Polyphenols and oxidative stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 647
3. Biochemistry of penile erection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 648
3.1. Etiology of erectile dysfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
3.2. Erectile dysfunction and oxidative stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
4. Management of erectile dysfunction with dietary polyphenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
5. Effect of polyphenols on the efficacy of other medicines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
Available online at
ScienceDirect
www.sciencedirect.com
* Corresponding author.
E-mail address: eleazon@yahoo.com (C. Eleazu).
http://dx.doi.org/10.1016/j.biopha.2017.01.125
0753-3322/© 2017 Elsevier Masson SAS. All rights reserved.
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mailto:eleazon@yahoo.com
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C. Eleazu et al. / Biomedicine & Pharmacotherapy 88 (2017) 644\u2013652 645
1. Introduction
Erectile dysfunction (ED) is defined as the inability to achieve or
maintain an erection sufficient for satisfactory sexual performance
[1]. Erectile dysfunction has been reported to affect more than 150
million males throughout the world [2] and it has been estimated
that it will affect about 322 million men globally by the year 2025
[3] if adequate measures are not taken to curb it.
Although phosphodiestrase 5-inhibitors such as: sildenafil,
tadalafil and vardenafil have been useful in the treatment of ED, the
Fig. 1. Chemical structures o
Source: [24]
adverse side-effects associated with their usage, their costs as well
as drug interactions underscores the need for alternative measures
[2].
The process of penile erection is multifactorial as it depends on
a balance between psychological, hormonal, neurological, vascular,
and cavernosal factors. Therefore, an alteration in any one or a
combination of these factors may lead to ED [4].
Despite the multifactorial nature of ED, there are indications
that reactive oxygen species (ROS)/free radicals may be connected
to it. It has been suggested that accumulation of endogenous nitric
f different polyphenols.
646 C. Eleazu et al. / Biomedicine & Pharmacotherapy 88 (2017) 644\u2013652
oxide synthase (NOS) (the enzyme that catalyzes the synthesis of
nitric oxide (NO) from the endothelial cells)) inhibitors in the
ischaemic penile corpus cavernosum may be involved in erectile
tissue dysfunction and structural damage [5\u20138]. This accumulation
could lead to oxidative stress caused by malfunction of antioxidant
enzymes and excessive production of free radicals/ROS such as
superoxide anion radical (O2\ufffd), hydrogen peroxide (H2O2) and
hydroxyl radical (OH\ufffd) [9,10]. In addition, studies have also shown
that non-phagocyte NADPH oxidase is the major producer of ROS in
the vascular endothelium [11].
Oxygen-free radicals in NO-rich tissues tend to combine to form
peroxynitrite (O¼NOO)), a highly cytotoxic product of O2\ufffd and
nitric oxide (NO) radical reaction [11\u201313].
Accumulation of these