Chemical composition, antioxidant, and enzyme inhibitory properties of Rauwolfia vomitoria extract.

OBJECTIVES: Rauwolfia vomitoria is one ethno-botanicals in Nigeria used by traditional health practitioners in managing several human diseases. However, necessary information regarding its effect on enzymes implicated in the development and progression of erectile dysfunction is missing in the literature. Thus, this study investigated the antioxidant property and impact of Rauwolfia vomitoria extract on erectile dysfunction-related enzymes in vitro. METHODS: High performance liquid chromatography was used to identify and quantify Rauwolfia vomitoria's phenolic components. Then, utilizing common antioxidant assays, the extract's antioxidant properties were evaluated and finally the effect of the extract on some enzymes (AChE, arginase and ACE) implicated in erectile dysfunction was investigated in vitro. RESULTS: The results showed that the extract inhibited AChE (IC50=388.72 µg/mL), arginase (IC50=40.06 µg/mL) and ACE (IC50=108.64 µg/mL) activities. In addition, phenolic rich extract of Rauvolfia vomitoria scavenged radicals and chelated Fe2+ in concentration dependent manner. Furthermore, rutin, chlorogenic acid, gallic acid, and kaempferol were found in large quantities by HPLC analysis. CONCLUSIONS: Therefore, one of the potential reasons driving Rauwolfia vomitoria's use in folk medicine for the treatment of erectile dysfunction could be its antioxidant and inhibitory activities on several enzymes linked to erectile dysfunction in vitro.

Antioxidant-rich Terminalia catappa fruit exerts antihypertensive effect via modulation of angiotensin-1-converting enzyme activity and H2S/NO/cGMP signalling pathway in Wistar rats.

INTRODUCTION: The present study aimed at investigating the effect of Terminalia catappa fruits on blood pressure, NO/cGMP signalling pathway, angiotensin-1-converting enzyme and arginase activity, and oxidative stress biomarkers in L-NAME-induced hypertensive rats. MATERIALS AND METHODS: Forty-two Wistar rats were divided into seven groups. Hypertension was induced via oral administration of 40 mg/kg of L-NAME for 21 days. Thereafter, the hypertensive rats were treated with Terminalia catappa fruit-supplemented diet and sildenafil citrate for 21 days. The blood pressure was measured and cardiac homogenate was prepared for biochemical analyses. RESULTS: The results showed that L-NAME caused a significant (p < 0.05) increase in systolic and diastolic blood pressure, and heart rate as well as ACE, arginase and PDE-5 activity, with a simultaneous decrease in NO and H2S levels as well as increased oxidative stress biomarkers. However, treatment with Terminalia catappa fruits-supplemented diets and sildenafil citrate lowered blood pressure and modulated ACE, arginase, and PDE-5 activity, improved NO and H2S levels, as well as antioxidant status. CONCLUSION: Findings presented in this study provide useful information on the antihypertensive property of Terminalia catappa fruits, alongside some possible mechanisms. Hence, Terminalia catappa fruits could be considered a dietary regimen and functional food in alleviating hypertension.

Glycemic indices and effect of bitter leaf (Vernonia amygdalina) flavored non-alcoholic wheat beer (NAWB) on key carbohydrate metabolizing enzymes in high fat diet fed (HFD)/STZ-induced diabetic Wistar rats.

In a bid to make the use of functional food easier in the management and prevention of diseases, product development and fortification from/with functional foods have become the recent focus of research. This study, therefore, sought to exploit the recent trend in the brewing industry on the production of non-alcoholic beers by investigating the possibility of having a non-alcoholic beer flavored with bitter leaf, a known plant widely reported to have a strong hypoglycemic effect, as against the traditional use of hops, and the effect of the produced beer on the glycemic indices and various diabetic biochemical parameters that serve as biomarkers for type-2 diabetes (T2D). The glycemic indices, as well as the inhibitory potentials of bitter leaf-flavored Non-alcoholic wheat beer (NAWB) in ratios of 100%HP, 100%BL, 75:25BL, 50:50BL, and 25:75BL, on enzymes linked to a high-fat diet/streptozocin (HFD/STZ)-induced T2D albino Wistar rats were investigated. There were no significant difference (p > .05) between the starch (1.72-1.77 mg/100 mL), amylose (0.22-0.24 mg/100 mL), and amylopectin (1.49-1.53 mg/100 mL) contents of the various samples. The Glycemic Index (GI) of the samples ranged from 36 to 73 with 75:25Bl and 50:50BL have the lowest (36) values. The samples reduced blood glucose levels and inhibited pancreatic α-amylase, lipase, and intestinal α-glucosidase activity. The inhibitory potentials of these beer samples on α-amylase and α-glucosidase as well as their ability to reduce blood glucose levels in diabetic rats thus making the bitter leaf flavored NAWB a suitable healthy beverage for better glycemic control in diabetics. PRACTICAL APPLICATIONS: This study revealed the potential of producing non-alcoholic wheat beer flavored with bitter leaves as a possible substitute for hops. The potential inherent in bitter leaf in the management of type 2 diabetes can thus be made available through a far-reaching beverage medium such as non-alcoholic beer to help in the treatment/management of T2D. The results of this research could be an eye-opener to the possible utilization of bitter leaf and by extension other plants that have been reported in the management of T2D. The use of the bitter leaf as a substitute for hops in the production of non-alcoholic beer in the brewing industry could help in a health-oriented campaign for safe drinks that could be helpful in the control of blood glucose levels of diabetic patients.

Nutraceutical potential of almond fruits in managing diabetes-related erectile dysfunction: Effect on Nrf-2 level and smooth muscle/collagen ratio.

Oxidative stress is one of the major crosstalk between diabetes and erectile dysfunction. Tropical almond is a natural antioxidant that works in a way to neutralize the effect of reactive oxygen species in disease management. This study therefore aimed to evaluate the effects of tropical almond on the nuclear factor erythroid-2-related factor-2 (nrf-2) level and smooth muscle/collagen ratio, as well as other biochemical indices in the penile tissue of diabetic rats. Six non-diabetic male rats (control) and 36 diabetic male rats were divided into six groups (n = 6). The diabetic male rats were placed on almond-supplemented diets except for the diabetic control group. Thereafter, the rats were sacrificed penile tissues were excised for nrf-2, smooth muscle/collagen ratio, and other biochemical analyses. The results revealed a significant (p < 0.05) decrease in nrf-2 level, smooth muscle/collagen ratio, and total thiol level, with a concomitant increase in acetylcholinesterase activity in comparison to the control group. Interestingly, therapy with diets high in almond fruits significantly enhances the nrf-2 level, smooth muscle/collagen ratio, and total thiol level in comparison with the untreated diabetic group. In addition, dietary inclusion of almond fruits significantly reduced acetylcholinesterase activity in diabetic male rats. Therefore, the preventive management with almond fruits could be beneficial in combating erectile dysfunction associated with diabetes. The activities of almond fruits reported in this study could be due to their antioxidant property and the inherent phytoconstituents (amino acids, phenolic compounds, and flavonoids).

Almond and date fruits enhance antioxidant status and have erectogenic effect: Evidence from in vitro and in vivo studies.

This study was designed to investigate the efficacies of almond and date fruits on redox imbalance and enzymes relevant to the pathogenesis of erectile dysfunction. The total polyphenol contents, ferric reducing antioxidant power, and vitamin C content were determined spectrophotometrically. Phenolic and amino acid compositions were quantified using HPLC; meanwhile, the antioxidant activities were determined using DPPH, ABTS, FRAP, and metal chelation. Also, the effect of almond and date extract on advanced glycated end-products (AGEs) formation, arginase, and phosphodiesterase-5 activities was evaluated in vitro. Thereafter, the influence of almond and date supplemented diets on copulatory behaviors in normal rats was assessed, followed by arginase and phosphodiesterase-5 activities determination in vivo. The results revealed that date and almond extracts exerted antioxidant properties, prevented AGEs formation in vitro, and inhibited arginase and phosphodiesterase-5 activities in vitro and in vivo. Besides, almond and date supplemented diets significantly enhance sexual behaviors in normal rats when compared with the control. Among the active compounds identified were gallic acid, ellagic acid, quercetin, and rutin. All the 20 basic amino acids were identified. Given the aforementioned, date and almond could represent a reliable source of functional foods highly rich in compounds with antioxidant activity, and arginase and PDE-5 inhibitory properties. PRACTICAL APPLICATIONS: Fruits are essential part of the human diet that furnish the body with important nutrients. Despite the crucial roles of fruits in human diets, some fruits like almond and date are underutilized among Nigerians. However, we characterized the important compounds present in these fruits and how their presence contributes to the biological activities of the fruits. Finally, we relate the chemical composition and the observed biological activities to the overall health and wellness of the consumers.

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.

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.

Shaddock (Citrus maxima) peels extract restores cognitive function, cholinergic and purinergic enzyme systems in scopolamine-induced amnesic rats.

This study investigated the effect of shaddock peels extract on cognitive function in scopolamine-induced amnesic rats. Wistar rats were pretreated with shaddock peels extract (50 and 100 mg/kg) and donepezil (5 mg/kg) for fourteen days via oral administration. Memory impairment was induced at the end of the treatment period via a single intraperitoneal administration of scopolamine (3 mg/kg). Thereafter, the animals were subjected to behavioral studies (Morris water maze and Y-maze tests). Finally, the rats were sacrificed and the hippocampus of the rat's brain was isolated for biochemical analyses. The results showed a significant decrease in memory and cognitive function as revealed by Morris water maze and Y-maze tests in scopolamine-induced rats which were reversed by shaddock peels extract. Also, there was a significant decrease in the activity of adenosine monophosphohydrolase (AMPase) with a simultaneous increase in activities of adenosine deaminase (ADA), adenosine triphosphate diphosphohydrolase (ATPdase), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in scopolamine-induced rats when compared with the control. Besides, a significant increase in malondialdehyde (MDA) and reactive oxygen species (ROS) levels were observed in scopolamine-induced rats. However, donepezil or shaddock peels extract (50 and 100 mg/kg) caused a significant inhibitory effect on AChE, and ADA activities when compared to scopolamine-induced rats. Rats treated with shaddock peels extract also showed a significant reduction in MDA and ROS levels compared to scopolamine-induced rats. Therefore, our findings showed that the cognitive-enhancing effects of shaddock peels extract could be due to antioxidant activities and modulation of some enzymes linked with cognitive dysfunction.

Effect of citrus peels-supplemented diet on longevity, memory index, redox status, cholinergic and monoaminergic enzymes in Drosophila melanogaster model.

This study sought to determine the life span promoting effecof orange (Citrus sinensis), tangerine (Citrus maxima) and grapefruit (Citrus paradisi) peels in Drosophila melanogaster model. Flies (both gender, 3 to 5 days old) were divided into seven (7) groups (n = 5) containing 40 flies each; group I (control) flies were fed with basal diet, II-VII were flies were fed with basal diet containing 0.1 and 1.0% of tangerine peel (TP), orange peel (CP), and grapefruit peel (GP) respectively, for 14 days. Locomotor performance and memory index were assessed via negative geotaxis and aversive phototaxis suppression assays, respectively. Thereafter, the fly homogenates were assayed for activities of acetylcholinesterase (AChE), monoamine oxidase (MAO) and antioxidant enzymes as well as other indices of their redox. The results revealed that the citrus peels significantly improved longevity, locomotor performance, memory index, antioxidant status, and modulate cholinesterase and monoamine oxidase enzyme activities in treated flies when compared to the control. The results obtained suggest that the citrus peels offer potentials as dietary supplement with life span promoting properties in D. melanogaster model which could as well serve as a functional food additives. PRACTICAL APPLICATIONS: Citrus peels, although often considered agro-wastes, are used as food supplements and food ingredents especially in production of candies, jams and custards. This study suggests the use of orange (Citrus sinensis), tangerine (Citrus maxima), and grapefruit (Citrus paradisi) peels as dietary supplements which offers potential life span promoting properties.

Anticholinesterase activity and antioxidant properties of Heinsia crinita and Pterocarpus soyauxii in Drosophila melanogaster model.

BACKGROUND: Plant alkaloids have become important sources of nutraceuticals owing to their pharmacological importance especially in the management of neurodegenerative diseases such as Alzheimer's disease. In assessing the therapeutic potentials of plant phytochemicals, the fruit fly (Drosophila melanogaster) has emerged as a very veritable tool and has been largely accepted as an alternative model in biomedical research. OBJECTIVES: In this study, alkaloid extracts from bush apple (Heinsia crinita (Afzel.) G. Taylor and padauk (Pterocarpus soyauxii Taub.) leaves were assessed on D. melanogaster exposed to aluminum toxicity. MATERIALS AND METHODS: Alkaloid extracts were prepared by solvent extraction method. Thereafter, the extracts were evaluated for their in vitro antioxidant properties, Fe2+-chelating abilities and inhibitory effects on drosophila acetylcholinesterase (AChE) activity. The samples were also characterized for their constituent alkaloids via HPLC. Thereafter, effective safe dose of the extracts were determined in D. melanogaster (Harwich strain). Subsequently, flies assaulted with AlCl3 were co-treated with the extracts (8.3 and 16.6 µg/g) for seven days, during which their survival rate was monitored. This was followed by assaying for the activities of AChE, antioxidant enzymes [superoxide dismutase (SOD), catalase and glutathione-S-transferase (GST)]. Also, the flies were assayed for levels of thiobarbituric acid reaction substance (TBARS) and reactive oxygen species (ROS). RESULTS: The results revealed that both extracts showed in vitro antioxidant properties with Padauk showing significantly higher antioxidant properties in vitro. However, there was no significant difference in their in vitro AChE inhibition. In vivo, Al-induced toxicity reduced survival rate, elevated AChE, SOD and GST activities, as well as TBARS and ROS levels which were ameliorated by the extracts. It was also revealed that piperine was predominant in PA, while 1-cyclohexen-1-yl-pyrrolidine was predominant in BA. CONCLUSION: Our data suggest that the protective abilities of these extracts against Al-induced toxicity can be primarily associated with their anticholinesterase and metal chelating abilities. Thus, these vegetables can be potential sources of nutraceuticals against aluminum toxicity and associated diseases.

Effect of dietary inclusion of almond fruit on sexual behavior, arginase activity, pro-inflammatory, and oxidative stress markers in diabetic male rats.

This study was designed to examine the effect of almond-included diets on sexual behavior, arginase activity, and pro-inflammatory markers in diabetic male rats. Forty-two male rats were divided into seven groups (n = 6). Diabetes was triggered via a single dose intraperitoneal injection of streptozotocin (50 mg/kg). Diabetes was confirmed 72 hr after STZ induction, and animals with blood glucose ≥ 250 mg/dl were considered diabetic and used for the experiment. The effects of almond-supplemented diets on glucose level, sexual function, NF-κB and TNF-α levels, arginase and purinergic enzyme activities, and levels of oxidative stress markers were assessed. A significant decrease in sexual activities with a simultaneous increase in pro-inflammatory markers, arginase and purinergic enzyme activities as well as TBARS and ROS levels was observed in diabetic rats. Interestingly, treatment with supplemented diets ameliorated the effects. Conclusively, intake of almonds could prevent the risk of erectile dysfunction in diabetic subjects. PRACTICAL APPLICATIONS: Intake of diets rich in fruits, nuts, and vegetables has been reported to reduce the risk of metabolic syndrome. Here, we investigate the effect of dietary inclusion of almond fruit on sexual behavior, arginase activity, oxidative stress, and pro-inflammatory markers in diabetic male rats. Interestingly, data generated from this work reveal that the supplemented diets enhanced sexual activities, and reduced oxidative stress and pro-inflammatory markers in diabetic male rats. Thus, consumption of almond (drupe and seed) could prevent/reduce the erectile dysfunction in individual with diabetes.

HPLC phenolic fingerprinting, antioxidant and anti-phosphodiesterase-5 properties of Rauwolfia vomitoria extract.

Background In Nigerian traditional medicine, Rauwolfia vomitoria has been reported to be useful in the management of various human diseases, but there is no relevant information to substantiate its involvement in managing diseases arising from vascular dysfunction and oxidative stress. However, this study sought to investigate the antioxidant property of R. vomitoria and its effect on phophodiesterase-5 activity in vitro. Methods The antioxidant property was assessed through ferric-reducing antioxidant power (FRAP), copper chelation, and ABTS radical-scavenging activity. In addition, the effect of R. vomitoria on phosphodiesterase-5 (PDE-5) activity was assessed in vitro. Furthermore, analysis of phenolic compounds present in R. vomitoria was carried out using high-performance liquid chromatography (HPLC). Results The findings in this study revealed that R. vomitoria inhibited PDE-5 in a dose-dependent manner (IC50 = 252.42 µg/mL). Furthermore, the antioxidant activity of R. vomitoria was established through FRAP (19.68 mg AAE/g), ABTS radical-scavenging ability (74.25 mmol TEAC/g), and Cu2+-chelating ability (IC50 = 0.13 mg/mL). Conclusions The antioxidant property of R. vomitoria and its inhibitory effect on PDE-5 could be useful in the management of diseases arising from vascular dysfunction and oxidative stress.

Phenolic distribution, antioxidant activity, and enzyme inhibitory properties of eggplant (Solanum aethiopicum) cultivated in two different locations within Nigeria.

Solanum aethiopicum is commonly cultivated in Nigeria for its nutritional and medicinal properties. Although, information on the possible effect of location on the biological activities of S. aethiopicum has not been reported, however, present research work investigated the phenolic contents and distribution, antioxidative properties, and enzyme inhibitory activities of S. aethiopicum collected from two locations in Nigeria. HPLC phenolic profile, polyphenol contents, free radical scavenging activities, and inhibitory effect of eggplant extracts on carbohydrate metabolizing enzymes were carried out. Significant variations were observed in the phenolic profile, polyphenol contents, antioxidant activities, and enzymes inhibitory properties of the extracts from different locations. In most of the analyses carried out, extract of eggplant fruit collected from Uyo (UEF) showed higher activities than the one obtained from Ibadan (IEF). Thus, findings from this study revealed that geographical location may influence the phenolic contents, antioxidant, and enzymes inhibitory properties of eggplant fruits. PRACTICAL APPLICATIONS: The geographical location of a particular place determines the nature and biological activities of plants cultivated in the area. Hence, we presented the effect of location on the phenolic profile, antioxidant, and enzyme inhibitory properties of eggplant fruit (S. aethiopicum) cultivated in two different locations in Nigeria. However, data generated in this study showed the effect of location on phenolic composition and biological activities of eggplant fruit cultivated in Nigeria.

Orange peels modulate antioxidant markers and key enzymes relevant to erection in the penile tissue of paroxetine-treated rats.

In comparison to other antidepressant drugs, erectile dysfunction (ED) is more pronounced in paroxetine use. On the other hand, orange (Citrus sinensis) peels commonly consumed in various forms are used in folkloric medicine for ED management. Thus, this study evaluated the effect of orange peels infusion on sexual behaviour, nitric oxide (NO) level and some enzymes (arginase, phosphodiesterase-5 [PDE-5], acetylcholinesterase [AChE] and adenosine deaminase [ADA]) in paroxetine-treated rats. Erectile dysfunction was induced with paroxetine (10 mg/kg body weight). The animals were grouped into five (n = 6): normal rats; paroxetine-induced rats; paroxetine-induced rats treated with sildenafil citrate (5 mg/kg); paroxetine-induced rats treated with orange peels infusion (50 mg/kg); Paroxetine induced rats treated with orange peel infusions (100 mg/kg). The results revealed a significant decrease in sexual behaviour, NO level and the activities of antioxidant enzymes, while there was a significant increase in arginase, PDE-5, AChE and ADA activities in paroxetine-induced rats. However, orange peel infusions ameliorated erectile dysfunction in paroxetine-treated rats. This study showed some possible biochemical basis underlying the use of orange peels infusion in erectile dysfunction management.

Anogeissus leiocarpus attenuates paroxetine-induced erectile dysfunction in male rats via enhanced sexual behavior, nitric oxide level and antioxidant status.

Sexual dysfunction is a side effect of the antidepressant drug paroxetine. Anogeissus leiocarpus is a medicinal plant with a wide range of biological activities which include antioxidant and antiulcer properties. With these in mind, we investigated the effect of Anogeissus leiocarpus stem bark extract on paroxetine-induced sexual dysfunction in male Wistar rats. Forty-two adult male Wistar rats were divided into seven experimental groups: normal control, PAR (10 mg/kg), PAR + sildenafil (5 mg/kg), ALE (50 and 100 mg/kg) and PAR + ALE (50 and 100 mg/kg). The experiment lasted for 21 days, after which the rats were subjected to sexual behavioral test. Various biochemical assays (phosphodiesterase-5, arginase, acetylcholinesterase, nitric oxide and MDA) were carried out on the penile tissue homogenate. From our findings, paroxetine significantly altered sexual behavior in male rats and increased phosphodiesterase-5, arginase and acetylcholinesterase activities with a concomitant decrease in nitric oxide level. Furthermore, paroxetine altered antioxidant status which revealed by increased MDA level and reduced thiol level. However, treatment with Anogeissus leiocarpus stem bark extract reversed the altered sexual behavior in male rats and boosted antioxidant status. In addition, administration of Anogeissus leiocarpus stem bark extract resulted in a significant attenuation of phosphodiesterase-5, arginase and acetylcholinesterase activities in paroxetine-induced rats. In view of the aforementioned findings, Anogeissus leiocarpus could be considered a promising natural agent in erectile dysfunction management.

Modulatory Effects of Alkaloid Extract from Gongronema latifolium (Utazi) and Lasianthera africana (Editan) on Activities of Enzymes Relevant to Neurodegeneration.

Most alkaloids are produced by plants as a defense mechanism against herbivores. Since alkaloids are known to possess pharmacological effects, this study sought to investigate the in vitro modulatory effect of alkaloid obtained from two commonly consumed vegetables in southern Nigeria, Lasianthera africana (editan) and Gongronema latifolium (utazi), on some enzyme activities relevant to neurodegeneration. Effects of the alkaloids on cholinesterases (acetylcholinesterase [AChE] and butyrylcholinesterase [BChE]) and monoamine oxidase (MAO) activities were determined in vitro. In addition, Fe2+ chelating ability as well as radical-scavenging abilities were determined. Alkaloid profile was also determined using gas chromatography coupled with flame ionization detector (GC-FID). The results revealed that the alkaloids inhibited AChE, BChE, and MAO activities in a concentration-dependent manner, such that the alkaloid from G. latifolium showed higher enzyme inhibition (AChE [IC50 = 87.39 µg/ml], BChE [IC50 = 118.65 µg/ml], and MAO [IC50 = 61.37 µg/ml]) than L. africana (AChE = 115.60 µg/ml; BChE = 169.48 µg/ml; MAO = 73.72 µg/ml). In addition, GC-FID analysis revealed abundance of choline in both extracts. Gongronema latifolium and Lasianthera africana alkaloid extracts inhibit enzymes (acetylcholinesterase, butyrylcholinesterase, and monoamine oxidase) implicated in neurodegenerative diseases. Hence, these vegetables could offer dietary supplement in the management of neurodegenerative diseases.

Modulatory effect of some citrus (Citrus limon, Citrus reticulata, Citrus maxima) peels on monoamine oxidase, phosphodiesterase-5 and angiotensin-1 converting enzyme activities in rat heart homogenate.

Background Citrus peels have been reported useful in folk medicine for the management of cardiovascular diseases, but there is dearth of information on the possible mechanisms for their therapeutic action. The aim of this study was to investigate the effect of methanolic extracts from some citrus [lime (Citrus limon), tangerine (Citrus reticulata), shaddock (Citrus maxima)] peels on some enzymes relevant to the management of cardiovascular diseases [monoamine oxidase (MAO), phosphodiesterase-5 (PDE-5) and angiotensin-1-converting enzyme (ACE)]. Methods Effect of methanolic extracts of lime, tangerine and shaddock peels on MAO, PDE-5 and ACE were carried out using standard methods. In addition, the ability of the extracts to prevent oxidative damage in rat heart homogenates was also investigated. Finally, the total polyphenol content of extracts was determined. Results The results revealed that methanolic extracts of lime, tangerine and shaddock peels inhibited MAO, PDE-5, ACE and pro-oxidants induced lipid peroxidation in rat heart homogenate in a concentration-dependent manner. Conclusions Findings in this study revealed citrus peel methanolic extracts as natural inhibitor of enzymes (MAO, PDE-5 and ACE) implicated in cardiovascular diseases. Therefore, citrus peels could help in the management of cardiovascular diseases possibly through inhibition of these enzymes.

In vitro anticholinesterase, antimonoamine oxidase and antioxidant properties of alkaloid extracts from kola nuts (Cola acuminata and Cola nitida).

Background The development of cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors for management of neurodegenerative diseases such as Alzheimer's disease (AD) has come with their undesirable side effects. Hence, research for potent but natural ChE and MAO inhibitors with little or no side effects is essential. This study investigated the potentials of alkaloid extracts from two Cola species as nutraceuticals for prevention and management of AD. Methods Alkaloid extracts were obtained from two Cola species (Cola nitida [KN] and Cola acuminata [KA]) by solvent extraction method. The extracts were characterized for their alkaloid contents using gas chromatography (GC). The effects of the extracts on ChE and MAO activities were investigated in vitro. Also, the extracts' ability to inhibit Fe2+-induced lipid peroxidation in rat brain homogenate, scavenge DPPH and OH radicals, as well as chelate Fe2+ were determined. Results GC characterization revealed the presence of augustamine and undulatine as the predominant alkaloids in the extracts. There was no significant (P > 0.05) difference in the inhibitory effects of the extracts on ChE activities. However, KA extract exhibited significantly higher (P < 0.05) MAO inhibitory effect than KN. Also, KA extract inhibited Fe2+- induced malondialdehyde (MDA) production in rat brain homogenate more significantly than KN, while there was no significant difference in DPPH and OH radicals scavenging, as well as Fe2+-chelating abilities of the extracts. Conclusions Our findings revealed that KN and KA alkaloid extracts exhibited significant effect in vitro on biological pathways that may contribute to neuroprotection for the management of neurodegenerative diseases.

Phenolic-rich extracts of Eurycoma longifolia and Cylicodiscus gabunensis inhibit enzymes responsible for the development of erectile dysfunction and are antioxidants.

BACKGROUND: Herbs have been used from ages to manage male sexual dysfunction. Hence, this study sought to investigate the effects of Eurycoma longifolia (EL) and Cylicodiscus gabunensis (CG) stem bark extracts on some enzymes implicated in erectile dysfunction in vitro. METHODS: The extracts were prepared, and their effects on phosphodiesterase-5 (PDE-5), arginase, and angiotensin-1-converting enzyme (ACE) as well as pro-oxidant-induced lipid peroxidation were assessed. Furthermore, phenolic contents were determined, and their components were characterized and quantified using high-performance liquid chromatography with diode array detector (HPLC-DAD). RESULTS: The results revealed that the extracts inhibited PDE-5, arginase, and ACE in a concentration-dependent manner. However, IC50 values revealed that CG had higher inhibitory potential on PDE-5 (IC50=204.4 µg/mL), arginase (IC50=39.01 µg/mL), and ACE (IC50=48.81 µg/mL) than EL. In addition, the extracts inhibited pro-oxidant-induced lipid peroxidation in penile tissue homogenate. HPLC-DAD analysis showed that CG is richer in phenolic compounds than EL, and this could be responsible for higher biological activities observed in CG than EL. CONCLUSIONS: Hence, the observed antioxidant property and inhibitory action of CG and EL on enzymes relevant to erectile dysfunction in vitro could be part of possible mechanisms underlying their involvement in traditional medicine for the management of male sexual dysfunction.

Phenolic Constituents and Inhibitory Effects of Hibiscus sabdariffa L. (Sorrel) Calyx on Cholinergic, Monoaminergic, and Purinergic Enzyme Activities.

This study revealed the effect of phenolic extract from Hibiscus sabdariffa L. (sorrel) calyx on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO), and ecto-5' nucleotidase (E-NTDase) activities as well as pro-oxidant-induced oxidative damage in rat brain in vitro. Sorrel extract inhibited AChE (EC50 = 46.96 µg/mL), BChE (EC50 = 40.38 µg/mL), MAO (EC50 = 43.69 µg/mL), and E-NTDase (EC50 = 40.52 µg/mL) and stimulated Na+/K+-ATPase (EC50 = 22.01 µg/mL) activities. The phenolic extract also reduced Fe2+- (EC50 = 22.37 µg/mL) and sodium nitroprusside- (SNP-) (21.46 µg/mL) induced malondialdehyde (MDA) production in rat brain homogenates. Catechin (53.12 mg/g), chlorogenic (67.12 mg/g), rutin (16.25 mg/g), and caffeic acid (15.38 mg/g) were the most abundant phenolic compounds in the extract. The synergistic effects of the phenolic compounds may contribute to the enzyme inhibitory and stimulatory activities of the extract. Our findings suggest that sorrel extract shows promising potential for the treatment and/or management of some neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.