Introduction
Erectile dysfunction (ED) remains one of the most distressing complications of diabetes mellitus (DM), affecting not only physiological health but also the quality of life, self-esteem, and interpersonal relationships. The global rise in diabetes prevalence has inevitably led to an increase in diabetes-related sexual dysfunction, which is often resistant to conventional pharmacological interventions. While phosphodiesterase type 5 inhibitors such as sildenafil citrate have proven effective, their benefits are not universal, and they do not address the underlying oxidative and structural changes that contribute to ED in diabetic individuals.
In this context, there has been growing interest in plant-based therapies—especially those with long-standing ethnomedicinal use. One such plant is Dracaena arborea, a tall tree native to West Africa, traditionally reputed for its aphrodisiac properties. Indigenous healers have long combined its root extracts with palm wine to enhance male sexual performance. The current experimental work investigates the pharmacological validity of these claims, evaluating the impact of aqueous and ethanolic extracts of D. arborea root bark on sexual behavior in male rats with streptozotocin-induced type 1 diabetes.
Diabetes Mellitus and Erectile Dysfunction: The Pathophysiological Link
Diabetes mellitus is characterized by chronic hyperglycemia resulting from impaired insulin secretion, insulin action, or both. Sustained hyperglycemia triggers oxidative stress, leading to neuropathy, endothelial dysfunction, and structural changes in cavernosal smooth muscle. Advanced glycation end-products (AGEs) and oxygen-derived free radicals further disrupt nitric oxide synthesis and impair vasodilation, creating a physiological environment hostile to erectile function.
In diabetic males, ED often results from a combination of:
- Peripheral neuropathy impairing sensory and motor nerve signaling.
- Endothelial dysfunction reducing nitric oxide-mediated smooth muscle relaxation.
- Structural degeneration of penile tissue, including loss of smooth muscle fibers.
- Hormonal dysregulation, particularly reduced testosterone levels.
These pathophysiological alterations are often more severe in type 1 diabetes, where hyperglycemia tends to be more persistent and less amenable to lifestyle correction. Notably, in the streptozotocin rat model, erectile and nitrergic dysfunctions emerge within four weeks, making it a suitable experimental framework for studying therapeutic interventions.
The Rationale for Using Dracaena arborea
The choice of D. arborea for this study is anchored in both ethnobotanical evidence and preliminary laboratory findings. Previous pilot research indicated that ethanolic extracts of D. arborea significantly enhanced copulatory activity in normal and androgen-deprived rats via dopaminergic and/or cholinergic pathways. The plant’s phytochemical profile—rich in phenols, flavonoids, saponins, and sterols—suggests potential antioxidant, androgenic, and smooth muscle relaxant properties, all of which could theoretically counteract diabetic ED.
Study Design and Experimental Approach
Animal Model
The study utilized adult male Wistar rats, pre-trained for sexual activity to ensure baseline copulatory competence. Diabetes was induced via intraperitoneal injection of streptozotocin (50 mg/kg), followed by four weeks of hyperglycemia stabilization. Only rats with fasting blood glucose exceeding 200 mg/dL were included.
Treatment Groups
The 48 rats were assigned to eight groups:
- Control – Healthy rats, distilled water.
- Diabetic Control – Diabetic rats, distilled water.
- Sildenafil Citrate – 1.44 mg/kg.
- TMAO – 20 mg/kg, an antioxidant chemical chaperone.
5–6. Aqueous Extract – D. arborea at 100 mg/kg and 500 mg/kg.
7–8. Ethanol Extract – D. arborea at 100 mg/kg and 500 mg/kg.
Treatments were administered orally for four weeks.
Behavioral Assessment
Sexual performance was evaluated weekly in controlled mating trials with hormonally primed receptive females. Parameters measured included:
- Mount Latency (ML) – Time until first mount.
- Mount Frequency (MF) – Number of mounts before ejaculation.
- Intromission Latency (IL) – Time until first intromission.
- Intromission Frequency (IF) – Number of intromissions before ejaculation.
- Post-Ejaculatory Interval (PEI) – Recovery time before resuming copulation.
Key Findings
Glycemic Control
Notably, D. arborea did not significantly lower blood glucose levels, indicating that its prosexual effects were independent of glycemic regulation. This distinguishes it from some plant-based interventions that act primarily via antihyperglycemic pathways.
Sexual Performance
In untreated diabetic rats, sexual performance declined sharply:
- Reduced MF and IF.
- Prolonged ML, IL, and PEI.
- Near-complete loss of sexual activity in later ejaculatory series.
In contrast, sildenafil citrate, TMAO, and high-dose D. arborea extracts (aqueous 500 mg/kg, ethanol 100 mg/kg) significantly improved copulatory performance:
- MF and IF increased by ~88–90% in the first two weeks.
- ML and IL decreased by over 90% after four weeks.
- PEI shortened by ~65% in the most responsive groups.
The beneficial effects were most pronounced during the first three ejaculatory series, diminishing in later series—a phenomenon likely related to pharmacokinetic factors and fatigue in prolonged mating tests.
Mechanistic Insights
Antioxidant Activity
Phenols and flavonoids in D. arborea may mitigate oxidative stress in penile tissues, preserving endothelial nitric oxide synthase activity and smooth muscle responsiveness. This is particularly relevant in diabetic ED, where oxidative damage plays a central role.
Androgenic Potential
Sterols and saponins in D. arborea could act via androgenic pathways, enhancing testosterone production or mimicking androgen effects. Testosterone is pivotal for libido, erectile function, and overall sexual motivation.
Smooth Muscle Relaxation
Flavonoids are known to induce corpus cavernosum relaxation, improving arterial inflow and erection quality. This effect complements any androgenic activity, addressing both the vascular and hormonal dimensions of sexual function.
Comparison with Sildenafil and TMAO
While sildenafil remained the most potent agent in restoring sexual function, D. arborea extracts demonstrated efficacy comparable to TMAO, with the added advantage of multiple bioactive constituents. Unlike sildenafil, which targets phosphodiesterase-5 inhibition, D. arborea likely exerts a multifaceted effect—antioxidant, androgenic, and vasorelaxant—making it potentially valuable as an adjunctive therapy.
Clinical Relevance and Future Directions
Although these findings are based on an animal model, they have several implications:
- Adjunctive Role in Therapy – D. arborea could complement conventional drugs in diabetic men with partial response to PDE-5 inhibitors.
- Non-Glycemic Mechanism – Its effects are independent of blood sugar control, making it applicable even in patients with persistent hyperglycemia.
- Safety Profile – Traditional use and lack of major adverse effects in animal studies suggest good tolerability, but clinical trials are essential.
Future studies should explore:
- Long-term efficacy and safety in chronic diabetic models.
- Standardization of extract composition for consistent dosing.
- Potential synergistic effects with conventional ED medications.
- Clinical trials to validate efficacy in human subjects.
Conclusion
Dracaena arborea root extracts significantly improve sexual behavior in diabetic male rats without affecting blood glucose levels. The observed effects—shortened latencies, increased copulatory frequencies, and reduced recovery intervals—are likely mediated by the plant’s antioxidant, androgenic, and smooth muscle relaxant properties. While sildenafil remains superior in potency, D. arborea offers a promising natural alternative or adjunct for managing diabetic erectile dysfunction, especially in settings where access to pharmaceuticals is limited or where patients prefer herbal interventions.
FAQ
1. Does Dracaena arborea lower blood sugar in diabetics?
No. In this study, D. arborea did not significantly reduce blood glucose levels. Its sexual function benefits appear unrelated to glycemic control.
2. How does D. arborea improve erectile function?
The plant contains phenols, flavonoids, saponins, and sterols that may reduce oxidative stress, enhance testosterone activity, and relax penile smooth muscle, improving erectile quality and sexual motivation.
3. Can humans use D. arborea for erectile dysfunction?
While traditional use and animal studies are promising, human clinical trials are necessary to confirm efficacy, safety, and optimal dosing before routine use is recommended.
