Effects of Dietary Polyphenols on Vasculogenic Erectile Dysfunction: A Systematic Review of Pre-Clinical Studies

Erectile dysfunction (ED) is a medical condition characterized by the inability to achieve or maintain a satisfactory erection, primarily treated with oral phosphodiesterase type 5 inhibitors. Treatment effectiveness is diminished in severe vasculogenic ED, particularly in patients with diabetes mellitus, highlighting the need for exploring alternative/complementary interventions. Among them, dietary phenolic compounds are known for their antioxidant and anti-inflammatory properties. This systematic review focuses on catechin (EGCG), quercetin, resveratrol, and curcumin and their influence on the pathophysiology of ED. Following PRISMA 2020 guidelines (PROSPERO registration number CRD42023402016) searches across PubMed, Scopus, and Web of Science until October 2024 were conducted using relevant keywords. Inclusion criteria required original articles in English, while in silico studies, review articles, editorials, and original studies lacking essential polyphenol administration information were excluded. After an initial search that located 409, 445, and 285 publications in each database respectively, rigorous screening resulted in 26 publications comprising animal, ex vivo, and in vitro studies. Their quality was assessed using GRADE and SYRCLE ROB tools, revealing an overall "medium-high" or "high quality." These polyphenols consistently demonstrated improvements in erectile function, encompassing behavioral, functional, molecular, and hormonal aspects. However, limitations were identified, such as the predominant reliance on animal models and in vitro trials, which may not precisely reflect human physiological responses. Further clinical investigations are needed to ascertain data translational potential, standardize dosages, and establish safe and effective prescription recommendations. Prioritizing clinical trials is essential for validating the widespread applicability and efficacy of polyphenols in managing ED.