Gonadal efficacy of Thymus quinquecostatus Celakovski: Regulation of testosterone levels in aging mouse models

Late-onset hypogonadism (LOH) is an age-related disease in men characterized by decreased testosterone levels with symptoms such as decreased libido, erectile dysfunction, and depression. Thymus quinquecostatus Celakovski (TQC) is a plant used as a volatile oil in traditional medicine, and its bioactive compounds have anti-inflammatory potential. Based on this knowledge, the present study aimed to investigate the effects of TQC extract (TE) on LOH in TM3 Leydig cells and in an in vivo aging mouse model. The aqueous extract of T. quinquecostatus Celakovski (12.5, 25, and 50 µg/mL concentrations) was used to measure parameters such as cell viability, testosterone level, body weight, and gene expression, via in vivo studies. Interestingly, TE increased testosterone levels in TM3 cells in a dose-dependent manner without affecting cell viability. Furthermore, TE significantly increased the expression of genes involved in the cytochrome P450 family (Cyp11a1, Cyp17a1, Cyp19a1, and Srd5a2), which regulate testosterone biosynthesis. In aging mouse models, TE increased testosterone levels without affecting body weight and testicular tissue weight tissue of an aging animal group. In addition, the high-dose TE-treated group (50 mg/kg) showed significantly increased expression of the cytochrome p450 enzymes, similar to the in vitro results. Furthermore, HPLC-MS analysis confirmed the presence of caffeic acid and rosmarinic acid as bioactive compounds in TE. Thus, the results obtained in the present study confirmed that TQC and its bioactive compounds can be used for LOH treatment to enhance testosterone production.