Sirtuins are a family of proteins with enzymatic activity. There are seven mammalian sirtuins (SIRT1-SIRT7) that are found in different cellular compartments. They are a part of crucial cellular pathways and are regulated by many factors, such as chemicals, environmental stress, and phytochemicals. Several in vitro and in vivo studies have presented their involvement in anti-inflammatory, antioxidant, and antiapoptotic processes. Recent findings imply that phytochemicals such as resveratrol, curcumin, quercetin, fisetin, berberine, and kaempferol may regulate the activity of sirtuins. Resveratrol mainly activates SIRT1 and indirectly activates AMPK. Curcumin influences mainly SIRT1 and SIRT3, but its activity is broad, and many pathways in different cells are affected. Quercetin mainly modulates SIRT1, which triggers antioxidant and antiapoptotic responses. Fisetin, through SIRT1 regulation, modifies lipid metabolism and anti-inflammatory processes. Berberine has a wide spectrum of effects and a significant impact on SIRT1 signaling pathways. Finally, kaempferol triggers anti-inflammatory and antioxidant effects through SIRT1 induction. This review aims to summarize recent findings on the properties of phytochemicals in the modulation of sirtuin activity, with a particular focus on biochemical aspects.

Quercetin is a naturally occurring flavonoid of plant origin. This naturally occurring polyphenolic compound is generally known for its antioxidant and anti-inflammatory properties and has been reported to be a factor in improving the antioxidant defense system, lipid metabolism, and reducing the incidence of cardiovascular and inflammatory diseases. In this article, we will take a closer look at quercetin—what it is, what properties it has, what health benefits it can bring, and in which products it can be found. Thanks to its wide spectrum of action, quercetin is gaining popularity as an ingredient in dietary supplements, as well as an element of a healthy diet supporting overall health.

The benefits of physical activity and sports are widely known and proved to be crucial for overall health and well-being. In this research, the authors decided to measure the impact of endurance training in a professional male rowing team on the serum concentration levels of testosterone, estradiol, sex hormone binding globulin (SHBG) and nitric oxide (NO) and apolipoprotein A1 (Apo-A1). Proper levels of the serum concentration are necessary in order to maintain physical effectiveness. Authors analyzed the data and reviewed the former conterminous articles to find the possible mechanisms leading to changes of serum concentration of certain hormones and molecules. The direct effect of physical activity was a decrease in testosterone serum concentration (from 7.12 ± 0.4 to 6.59 ± 0.35 (ng/mL)), sex hormone binding globulin serum concentration (from 39.50 ± 2.48 to 34.27 ± 2.33 (nmol/L)), nitric oxide serum concentration (from 440.21 ± 88.64 to 432 ± 91.89 (ng/mL)), increase in estradiol serum concentration (from 78.2 ± 11.21 to 83.01 ± 13.21 (pg/mL)) and no significant increase in Apo-A1 serum concentration (from 2.63 ± 0.2 to 2.69 ± 0.21 (mg/mL)). Low testosterone concentration in OTS may be a consequence of increased conversion to estradiol, because gonadotropic stimulation is maintained. Apo-A1 serum concentration was measured due to a strong connection with testosterone level and its possible impact of decreasing cardiovascular risk.