Effectiveness of Silymarin, Sulforaphane, Lycopene, Green Tea, Tryptophan, Glutathione and Escin on Human Health: Results of a Narrative Review

Background: Recently, the role of nutraceutical compounds in the prevention of human diseases has been rapidly increasing. Here, we aim to evaluate the beneficial effect of dietary supplementation with seven active principles, i.e., lycopene, sulforaphane, silymarin, glutathione, escin, tryptophan, and green tea catechins, on human health. Methods: An extensive search of PubMed and Medline database was performed with the following keywords: “silymarin”, “sulforaphane”, “lycopene”, “green tea catechins”, “tryptophan”, “glutathione” and “escin” accompanied by the keywords “supplement”, “supplementation”, and “nutraceutics”. All preclinical and clinical trials were considered for this review. Results: One hundred and eighteen full-text articles were eligible for inclusion in this review. The papers examined presented considerable variability due to the wide heterogeneity of dosages administered, population involved, and outcomes pursued. Conclusion: Nutritional supplementation with lycopene, sulforaphane, silymarin, glutathione, escin, tryptophan, and green tea catechins appears to exert a wide range of benefits on human health, ranging from mood and cognition to cardiovascular health, fertility, metabolism, antioxidant, and anti-inflammatory capabilities, as well as potential anticancer effects. Further studies are required to better define the potential synergic effect, optimal dosage, mechanism of action, and tolerability profiles of these substances.