Ethanol Extract of Lepidium meyenii Inhibits Phosphodiesterase-5 Activity and Ameliorates Biochemical Alterations in Paroxetine-induced Erectile Dysfunction in Rats

Abstract

Phosphodiesterase-5 (PDE-5) plays a crucial role in erectile function by regulating the degradation of cyclic guanosine monophosphate, and its overactivity is associated with erectile dysfunction (ED). ED, dyslipidemia, and cardiovascular diseases are interrelated conditions that frequently coexist in affected individuals. One plant that has been traditionally linked to ED management is Lepidium meyenii. Despite numerous claims of its efficacy, its inhibitory potential against PDE-5 and capacity to manage dyslipidemia—often present in ED and a precursor to cardiovascular diseases—remain unclear. In this study, the effect of ethanol extract of Lepidium meyenii roots on penile and cardiac PDE-5 activities, nitric oxide levels, testosterone concentration, and lipid profile was evaluated. ED was induced in rats by oral administration of paroxetine (10 mg/kg body weight) for 21 days prior to treatment with the plant extract. Forty-eight adult male rats were randomly assigned to six experimental groups: normal control; paroxetine (10 mg/kg); paroxetine + sildenafil (4 mg/kg); and paroxetine + Lepidium meyenii (25, 50, and 100 mg/kg). Treatment lasted for seven days following confirmation of ED, and relevant biochemical assays were conducted. The ethanol extract of Lepidium meyenii roots significantly inhibited penile and cardiac PDE-5 activities, elevated nitric oxide and testosterone concentrations, reduced cholesterol and triacylglycerol levels, and increased high-density lipoprotein concentrations. These results suggest that the ethanol extract of Lepidium meyenii roots may be effective in managing ED through PDE-5 inhibition and improvement of dyslipidemia, a key contributor to cardiovascular risk.