The Aphrodisiac and Androgenic Effects of Aqueous and Ethanol Extracts of Tribulus cistoides (Zygophyllaceae) on Nicotine-Induced Sexual Dysfunction in Male Wistar Rats.

Abstract

Male sexual dysfunction is a common condition, typically managed with phosphodiesterase Type 5 inhibitors and testosterone replacement therapy. However, these treatments often have undesirable side effects and are expensive, prompting interest in plant-based alternatives. This study investigated the aphrodisiac and androgenic potential of Tribulus cistoides (T. cistoides) in a nicotine-induced model of sexual dysfunction in male Wistar rats. A total of 45 male rats were divided into nine groups (n = 5 per group). Group 1 served as the normal control; Group 2 received nicotine only (1 mg/kg) to induce dysfunction; Group 3 received sildenafil citrate (5 mg/kg) as a positive control. Groups 4-6 were administered nicotine plus aqueous extracts of T. cistoides at doses of 50, 100, and 150 mg/kg, respectively. Groups 7-9 received nicotine plus ethanol extracts at the same doses. Sexual behavior was assessed on Days 1, 5, and 9, and animals were sacrificed on Day 10 for biochemical and histological analyses. Outcomes measured included reproductive organ weights, serum levels of testosterone, FSH, LH, oxidative stress markers, testicular protein content, and seminal vesicle fructose levels. Nicotine exposure impaired sexual behavior, as evidenced by increased mount latency and decreased mount frequency, intromission frequency, and penile licking. However, treatment with the plant extract effectively reversed these effects, restoring the sexual behavior parameters toward normal levels. Nicotine also significantly reduced testosterone levels (0.079 ± 0.006 ng/mL), while T. cistoides extracts markedly restored hormone levels to 1.002 ± 0.165 ng/mL (aqueous) and 0.865 ± 0.041 ng/mL (ethanol) and improved nitric oxide levels, and gonadotropin concentrations. Additionally, the extracts restored testicular oxidative balance and enhanced reproductive tissue biochemistry. These effects are likely mediated by bioactive phytochemicals such as saponins, alkaloids, and flavonoids, which may promote vasodilation, modulate hormone levels, and enhance nitric oxide production. Findings suggest that T. cistoides may offer a natural alternative for managing male sexual dysfunction with fewer side effects than conventional drugs.