Parquetina nigrescens and Spondias mombin protects against neurochemical alterations in the scopolamine model of cognitive dysfunction.

Natural plants which are effective in Alzheimer's disease (AD) management are of pharmacological importance, though there is little or no scientific proof for most of their claims. This study sought to evaluate the effect of Hog plum (Spondias mombin) and Ogbo (Parquetina nigrescens) leaves extracts on antioxidant levels and activities of key enzymes linked to cognitive function in scopolamine-induced cognitive dysfunctioned rats. Rats were pretreated with S. mombin (SM) and P. nigrescens (PN) leaves extracts (50 and 100 mg/kg), donepezil (5 mg/kg) for 2 weeks via oral administration before induction of memory impairment via single i.p. administration of scopolamine (3 mg/kg body weight). Experimental rats were subjected to behavioral tests to check for cognitive performance before experiment termination. The activities of hippocampal key enzymes linked to cognitive function were determined. Results showed that pretreatment with SM and PN prevented the cognitive impairment induced by scopolamine. Furthermore, increased cholinesterases, adenosine deaminase (ADA), ATP hydrolysis, monoamine oxidase (MAO), and arginase activities induced by scopolamine were significantly reduced in rats treated with SM and PN leaves extract. Additionally, elevated malondialdehyde (MDA) and reactive oxygen species (ROS) levels observed in scopolamine-induced rats were reduced significantly in SM- and PN- pretreated rats. Decreased AMP hydrolysis, and nitric oxide and antioxidant level induced by scopolamine were prevented in pretreated rats. This study concluded that SM and PN leave extract effectiveness in cognitive management may be due to their high antioxidant activities and neuromodulatory effects on key enzymes linked to AD. PRACTICAL APPLICATIONS: The use of natural products in the treatment and management of neurodegenerative diseases in Africa is becoming pertinent as the continent is blessed with medicinal plants while the price of synthetic drugs has been observed to be an economic burden on the continent. Parquetina nigrescens and Spondias mombin are examples of such medicinal plants that have been explored in folklore for the management of neurodegenerative diseases but there is a dearth of scientific validation for their use while there is no present data to evaluate possible mechanisms of action employed by these medicinal plants to mediate the therapeutic potential observed in folklore. Therefore, the present study seeks to validate the therapeutic use of P. nigrescens and S. mombin as observed in folklore as well as explore the possible mechanism of actions the plants may employ in mediating the proposed therapeutic potentials in neurodegenerative disease conditions while considering its toxicological effects in experimental animals.

Grapefruit peel extract mitigates paroxetine-induced erectile dysfunction in rats through stimulation of erectile response, antioxidant status, and inhibition of key enzymes related with impaired penile erection.

Despite the antidepressant potency of paroxetine, its side effect of erectile dysfunction is burdensome. Grapefruit peels (GFPs) are underutilized cultivar wastes with wide range of therapeutic potentials which have been attributed to their antioxidant behavior and phenolic contents' abilities to effectively inhibit enzymatic activities and manage endothelial dysfunction in cardiovascular disorders. This study aims to investigate the erectogenic potentials of GFP extract in a rat model of paroxetine-induced ED. Experimental rats were sectioned into five groups: [1: control; 2: paroxetine (10 mg/kg); 3: paroxetine + sildenafil (5 mg/kg); 4: paroxetine + GFP (50 mg/kg); 5: paroxetine + GFP (100 mg/kg)] and treated for 28 days. Sexual behavior of rats was assessed and effect of GFP on ecto-5' nucleotidases, phosphodiesterase-5, and adenosine deaminase (ADA) activities was determined in rats' penile tissues. The levels of malondialdehyde, nitric oxide (NO) as well as superoxide dismutase (SOD) and catalase activities were also determined. HPLC-DAD analysis showed the presence of naringin, rutin, caffeic acid, quercitrin, quercetin, and kaempferol glycoside. Oral administration of paroxetine reduced erectile response as revealed by their low intromission and mounting numbers as well as high intromission and mounting latencies. Paroxetine caused a significant elevation of ADA and phosphodiesterase-5 activities and malondialdehyde levels with drastic reduction in levels of NO, SOD, and catalase activities in rats' penile tissues. However, GFP extract reversed PDE-5, ADA, and antioxidant activities to normal levels, raised the concentration of NO. These results suggest the erectogenic effects and protective potentials of GFP extract against paroxetine-induced erectile dysfunction. PRACTICAL APPLICATION: Grapefruit peels are an environmental menace in many countries and this study showed that the peels can be used in the prevention / management of erectile dysfunction. The therapeutic potentials of the peels are due to the presence of bioactive compounds such as flavonoids and phenolic acids. Therefore, exploring the erectogenic potentials of the peels will translate to conversion of the wastes to therapeutic products.