EFFECTS OF ALMOND (Terminalia catappa L.) AND DATE (Phoenix dactylifera L. MILL) FRUITS SUPPLEMENTED DIETS ON ERECTILE DYSFUNCTION IN DIABETIC AND HYPERTENSIVE WISTAR RATS

Abstract

Several studies have reported that intake of diet rich in fruits, vegetables and nuts may improve sexual functions in subjects with metabolic syndrome. Thus, this study sought to investigate the effect of almond (Terminalia catappa) and date (Phoenix dactylifera) fruits supplemented diets on diabetes- and L-NAME-induced erectile dysfunction in experimental animals. Aqueous extracts of almond and date were prepared, and the total phenol and flavonoid contents were determined. Also determined were the antioxidant properties [2,2-diphenyl-1-picrylhydrazyl (DPPH), total antioxidant capacity (TAC), hydroxyl radical, Fe2+ chelation, and ferric reducing antioxidant power (FRAP)] and the effect of extracts on formation of advanced glycated end-products (AGEs) in vitro. The effects of the extracts on phosphodiesterase-5 (PDE-5), arginase, 5’-nucleotidase and adenosine deaminase (ADA) activities were determined in vitro. The phenolic and amino acids composition of the fruits were determined using high performance liquid chromatography (HPLC). Thereafter, the effect of dietary supplementation of almond (drupe and seed) and date on sexual behaviours, hormonal levels, inflammatory markers and other important biochemical parameters relevant to erectile dysfunction in normal, diabetic and hypertensive rats were assessed. The results revealed that almond drupe extract had the highest total phenolic (24.36 mgGAE/g) and flavonoid contents (16.26 mgQUE/g), while almond seed extract had the least total phenol (4.66 mgGAE/g) and flavonoid content (3.63 mgQUE/g). The aqueous extracts showed antioxidant properties and inhibited the activities of PDE-5, arginase, 5’-nucleotidase and adenosine deaminase in vitro. The HPLC analysis revealed the presence of all 20 amino acids and abundance of phenolic compounds such as gallic acid, chlorogenic acid, ellagic acid, rutin, isoquercitrin, quercetin and kaempferol. Furthermore, diabetes and hypertension caused a significant (p < 0.05) decrease in sexual behaviours (as revealed by decreased mounting and intromission frequencies, and increased mounting and intromission latencies), gasotransmitters (NO and H2S), antioxidant activities (thiols and nrf-2 levels) and hormones (testosterone, FSH and LH) levels, with concomitant increase in oxidative stress markers (ROS, AGEs and MDA), proinflammatory markers (NF-κB and TNF-α) and activities of some enzymes (PDE-5, arginase, ADA, acetylcholinesterase) implicated in erectile dysfunction. However, treatment with diets supplemented with almond (drupe and seed) and date significantly (p < 0.05) reversed these effects in diabetic and L-NAME induced rats. Findings in this study revealed that diets supplemented with almond and date modulate some important biomarkers relevant to erection in diabetic and hypertensive rats. Therefore, almond and date may represent a cheap and readily available functional foods and nutraceuticals in the management of erectile dysfunction associated with diabetes and hypertension.