Effect of Methanol Extract of Duranta Erecta Leaves on the Oxidative Stress Status in Testosterone-Induced Benign Prostatic Hyperplasia in Albino Rats

Abstract

Benign prostatic hyperplasia (BPH) is a common urinary tract disorder reported among ageing men of which inflammation, oxidative stress, proliferative, and apoptotic changes play important roles. The present study was carried out to evaluate the antioxidant potential of methanol extract of Duranta erecta leaves in in vitro models and its effects on some biochemical parameters in testosterone-induced BPH in male albino rats. The extract was subjected to phytochemical screening, DPPH assay, ferric reducing antioxidant power assay, nitric oxide assay, and antioxidant vitamins and minerals analysis. Acute toxicity of the plant extract was determined using Lorke’s method. Benign prostatic hyperplasia was induced in adult male albino rats (203-305 g) by subcutaneous injection of testosterone propionate for 28 days. All the rats injected with testosterone propionate had a serum prostate specific antigen (PSA) level ≥ 1.70 ng/ml. At the end of treatment, rats were anesthetised and blood was collected via cardiac puncture to determine serum levels of PSA, testosterone, dihydrotestosterone and acid phosphatase. The prostate was weighed, assayed and histologically examined. The phytochemical screening of the extract indicated the presence of flavonoid (24.20 ± 0.14 mg QE/g), alkaloid (15.87 ± 1.71 mg/g), total phenol (12.73 ± 0.61 mg GAE/g), tannin (9.24 ± 0.03 mg TAE/g), terpenoid (8.90 ± 0.96 mg/g), steroid (2.65 ± 0.55 mg/g) and saponin (5.55 ± 0.76 mg/g). The results of all the in vitro antioxidant assays proved that the extract had an antioxidant potential in a concentration dependent manner. The antioxidant activity of the sample was compared to the ascorbic acid and gallic acid as standards. The antioxidant mineral composition of the extract revealed the presence of zinc (1.82 ± 0.03 mg/100g) and selenium (0.59 ± 0.04 mg/100g). The antioxidant vitamins composition of the extract showed lower concentrations of vitamin C (0.35 ± 0.01 mg/100g) and vitamin E (0.68 ± 0.07 mg/100g). The extract had an LD50 greater than 5000 mg/kg b.w and therefore was not acutely toxic for oral use. Duranta erecta extract significantly (p < 0.05) reduced testosterone-induced increase in prostate weight, prostatic index, serum testosterone, dihydrotestosterone, PSA and acid phosphatase relative to the untreated rats. Testosterone caused significant (p < 0.05) increase in malondialdehyde as well as reduction in glutathione, superoxide dismutase, catalase and glutathione peroxidase activities which were attenuated by the extract. The disruption of the prostate histoarchitecture by testosterone was also ameliorated by Duranta erecta extract. Methanol extract of Duranta erecta leaves showed antioxidant properties and reduced the effect of testosterone-induced BPH possibly through enhancement of antioxidant defense mechanisms and inhibition of inflammatory mediators. Thus, Duranta erecta could be a potential phytotherapeutic agent in the management of BPH in men.