Polyphenolics-rich Psithum guajava budding leaf extract can reverse diabetes-induced functional impairment of cavernosal smooth muscle relaxation in rats

Diabetes Mellitus (DM) related Advanced Glycation End products (AGEs) are considered to induce functional impairment of cavernosal smooth muscle relaxation and cause Erectile Dysfunction (ED). We used rats to examine the in vitro effects of Psidium guajava L. (Myrtaceae) budding leaf extract (PE) on pharmacological relaxation of corpus cavernosum smooth muscle strips obtained from diabetic rats. After 8 weeks, the mean glycosylated haemoglobin (HbA1c), serum cholesterol and triglyceride concentrations were significantly higher in the non-PB diabetic than in the age-matched control animals. Interestingly, in diabetic animals fed PE, serum cholesterol and triglyceride levels were significantly lower than in their peers given a standard diet. The administration of PE to diabetic animals for 8 weeks reversed the expected impaired relaxation response and nitric oxide production in cavernosal smooth muscle exposed to acetylcholine or electrical field stimulation. The administration of PE to rats with 8 weeks of uncontrolled diabetes reverses DM-induced harmful effects on vascular smooth muscle.