Bioactive Components in Black Currant Fruit, Red Perilla (Shiso) Leaf, and Chinese Sweet Tea That Enhance Testosterone Production in Leydig Cells and Their Combined Effect in Male Mice

Testosterone is a steroid hormone that regulates diverse biological events. Several foods affect testosterone levels in the body, but little is known about the individual components that increase testosterone levels. In this study, black currant (Ribes nigrum) fruit, red perilla (shiso, Perilla frutescens) leaf, and Chinese sweet tea (Rubus suavissimus) enhanced testosterone production in testicular Leydig cells. Delphinidin-3-rutinoside (D3R), rosmarinic acid (RA), and myo-inositol (MI) were identified as bioactive components. Mechanistic analyses suggested that Star plays a role in the bioactivity of D3R and RA, and that the bioactivity of MI is related to Cyp19a1 downregulation. Supplementing the diet with a mixture of black currant fruit extract, red perilla leaf extract, and MI increased serum testosterone levels in male C57BL6/J mice, accompanied by an increased level of Star protein in the testis. These findings add to our knowledge about foods and their components that modulate testosterone levels.