Plantain peels restore sexual performance, hormonal imbalance, and modulate nitric oxide production and key enzymes of penile function in paroxetine-sexually impaired male rats

This study focused on the effect of unripe (UPP) and ripe (RPP) plantain peels' extracts (200 and 400 mg/kg) on sexual behavior, hormonal profiles [testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH)], and enzymes [acetylcholinesterase (AChE), phosphodiesterase-5' (PDE-5), arginase, angiotensin-I converting enzyme (ACE), ecto-5'neucleotidase, and adenosine deaminase (ADA)] in paroxetine (PAR)-induced penile dysfunction rats. From the result, arginase, PDE-5', ACE, ecto-5'-nucleotidase ADA, and AChE activities, sexual activities, hormonal profile, and NO level were reduced, while thiobarbituric acid reactive species (TBARS) level increased (p < .05) relative to normal control rats. However, treatment with UPP and URP reduced the activities of these enzymes, decreased TBARS levels, and increased hormones, and penile NO levels in PAR-induced rats. Thus, the use of UPP and RPP could be channeled towards the improvement of sexual performance in erectile dysfunction (ED) disorder. PRACTICAL APPLICATIONS: Plantain fruits are a tropical staple food crop commonly consumed at various stages of ripeness and cooking methods. However, its peels are regarded as a waste product with reported cases of environmental menace. Interestingly, plantain peel is being used as a major raw material for industrial applications in the agro-based industries and in folklore for the treatment of many human ailments due to its rich phytochemicals such as polyphenols, carotenoids, alkaloids, etc., which have been reported. A prelude study has also indicated its usefulness in ED management, but further pharmacological investigations are needed to proffer information on its effect in ED management and its anti-androgenic activity in male Wistar rats. The information from this study could be of pharmaceutical importance in designing natural remedies capable of improving penile rigidity, hormone profiles, and alteration of enzymes linked with ED.

Effects of dietary inclusion of Bambara groundnut and sweet orange peels on streptozotocin/HFD type-2 induced diabetes mellitus complications and related biochemical parameters

The effects of dietary inclusion of Bambara groundnut and sweet orange peels composite bread on low-dose streptozotocin and high-fat diet (HFD)-induced type-2 diabetes mellitus (T2D) complications was evaluated in the present study. Male experimental rats-induced T2D were administered with acarbose (standard) and fed with Bambara groundnut and sweet orange peels composite bread for a period of 14 days while monitoring their blood glucose levels. More so, the activities of angiotensin-I-converting enzyme (ACE), serum aspartate aminotransferase, alkaline phosphatase, and alanine aminotransferase activities, as well as nitric oxide (NO), reactive oxygen species (ROS), albumin, total bilirubin, creatinine, urea, and uric acid serum concentrations were assayed for. Diabetic untreated rats showed disorders in ACE, AST, ALT, and ALP activities, and NO, ROS, glucose, albumin, bilirubin, creatinine, urea, uric acid levels, as well as lipid profiles. Interestingly, these disorders were significantly ameliorated in composite bread diet-fed rats in comparison to the diabetic untreated rats. Meanwhile, the presence of polyphenols in the Bambara groundnut and sweet orange peels composite bread diet could have aided the amelioration of these metabolic disorders after the 14th day of administration. Finally, it was proposed that the ability of Bambara groundnut-wheat and sweet orange peel composite bread to treat T2D and its complications makes it a more successful therapy than medications that just target one of the diseased states. PRACTICAL APPLICATIONS: Diabetes mellitus is a global and chronic disease that presently affects 536.6 million people alongside 1.5 million deaths directly attributed to it yearly. Several drug and medicinal agents have been employed for the management of diabetes but those drugs are mostly limited to the management of diabetes while the associated complications are most untreated, while drugs that can manage diabetes and its related complications mostly come at high prices. Therefore, there is an urgent need to evaluate legumes, such as Bambara groundnut, with proven therapeutic potential in the management of diabetes and its complications. However, the Bambara groundnut takes a long period to prepare for a meal, therefore including it in a ready-to-eat product will not only improve its acceptability but also add to economic improvement. Furthermore, adding a waste product, sweet orange peels, will both add flavor and source of additional antioxidant attributes.

Can gallic acid potentiate the antihyperglycemic effect of acarbose and metformin? Evidence from streptozotocin-induced diabetic rat model

This study investigated the influence of dietary phenolic acid- Gallic acid (GA) on the antihyperglycemic properties of acarbose (ACA) and metformin (MET). Streptozotocin-induced diabetic rats were treated (p.o) with ACA, MET, GA and their combinations for 14 days. The effects of the treatments on blood glucose and insulin levels, pancreas α-amylase and intestinal α-glucosidase activities, as well as thiobarbituric acid reactive species (TBARS), thiol and reactive oxygen species (ROS) levels, including antioxidant enzyme activities were investigated. A significant increase in blood glucose, insulin, ROS and TBARS levels, and impaired antioxidant status, as well as elevation in the activities of α-amylase and α-glucosidase observed in diabetic rats were ameliorated in the treatment groups. Hpwever, GA had varying effects on the antidiabetic properties of the drugs. Nevertheless, GA showed more potentiating effects on the antidiabetic effect of MET and these effects were better observed at the lower dose of GA.

Berberine modulates crucial erectogenic biomolecules and alters histological architecture in penile tissues of diabetic rats

Berberine is an isoquinoline alkaloid, found in several plants. Diabetes induces erectile dysfunction (ED) via reduction in some hormones and enzymes implicated in sexual function. This study aimed to investigate the role of berberine on crucial biomolecules linked to penile function in diabetic rats. Sixty-three (63) adult male rats were used and distributed into nine groups (each = 7). Group I-IV normal rats administered with citrate buffer (pH 4.5), sildenafil citrate (SD, 5.0 mg/kg), 50 and 100 mg/kg of berberine, respectively, via oral gavage. Rats in groups V-IX were diabetic rat with ED treated with buffer, SD, 50 and 100 mg/kg of berberine, and acarbose (25 mg/kg ACA) respectively. The result revealed that histological architecture in penile tissues were altered in diabetic groups treated with berberine, sildenafil citrate and acarbose when compared to the diabetic control group. Treatment with berberine, increased testosterone, luteinizing hormone and follicle-stimulating hormone in diabetic rat with ED. Also, reduced prolactin level and acetylcholinesterase, angiotensin-1 converting enzyme, adenosine deaminase and arginase activities were observed in berberine treated diabetic rat with ED. Molecular docking analysis revealed that berberine had strong binding affinities for these enzymes. Thus, berberine could represent a potential therapeutic agent for diabetes-induced ED.

Evaluation of different almond (Terminalia catappa) extracts against oxidative stress induced by cyclosporine in brain and liver of rats

OBJECTIVES

This study was designed to evaluate the ameliorative effect of almond (Terminalia catappa) leaf (ALE) and stem bark (ABE) extracts on the enzyme activities and oxidative stress markers in the brain and liver tissues of cyclosporine-A (CsA) stressed male albino rats.

METHODS

Eighty-eight adult male rats weighing between 200 and 220 g were randomly distributed to into 11 groups (n=8) and different doses (100 and 200 mg/kg bwt.) of ALE and ABE were administered through oral gavages to the normal rats and 50 mg/kg/bwt/day CsA-stressed, while normal control rats was given a saline solution (p.o), and the treatment lasted for 14 days. Blood plasma, liver and brain tissues were prepared for biochemical analysis.

RESULTS

Neuronal [acetylcholinesterase (AChE) and butrylcholinesterase (BChE) and arginase] enzyme activities and thiobarbituric acid reactive species (TBARS) level, plasma aspartate transferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities, liver non-protein thiol (NPSH) level were analyzed. The results revealed that, the administration of CsA induced a significant increase in neuronal AChE, BChE, arginase, TBARS level, but decreased nitric oxide (NO) level. CsA also increased ALT, AST, and ALP activities in the blood plasma of CsA stress rats compared to normal control, but were significantly reversed respectively (p<0.001) upon treatment with the ALE and ABE dose-dependently.

CONCLUSIONS

The study revealed that ALE and ABE could prevent neuronal dysfunction and liver toxicity induced by CsA administration, however, higher dose (200 mg/kg) of the studied extracts appears to be more potent.

Effect of Plantain Bulb's Extract-Beverage Blend on Blood Glucose Levels, Antioxidant Status, and Carbohydrate Hydrolysing Enzymes in Streptozotocin-Induced Diabetic Rats

The pharmacological properties of various parts of plantain trees have directed its use in folkloric management of diabetes and other human ailments. However, little is known about plantain bulb extract (PBE) and their mechanisms of action. This study evaluated the effect of PBE-beverage blends (including 1% and 2 % cocoa powder) sweetened with honey on blood glucose levels, antioxidant status, and carbohydrate hydrolysing enzyme activities in streptozotocin (STZ)-induced diabetic rats. Animals were selected at random and distributed into 7 groups (n=7), as follows: normal control (NC), untreated diabetic rats, diabetic rats treated with acarbose (STZ-ACA), diabetic rats administered PBE (STZ- PBE), diabetic rats administered honey and PBE (STZ-HPBE), diabetic rats administered 1% cocoa powder-with HPBE blend (STZ-CHPBE-1), and diabetic rats administered 2% cocoa powder with HPBE blend (STZ-CHPBE-2). Compared with the controls, untreated diabetic rats exhibited increased blood glucose levels and hydrolysing enzyme activities, and significant decreases in the activities of antioxidant (catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase) enzyme and non-enzymatic (glutathione) antioxidants. However, changes in activities were comparatively reversed in all rats administered plantain bulb formulations. CHPBE-2 was slightly more effective than CHPBE-1. Overall, both blends could serve as nutraceutical and/or functional drinks in the management of diabetes.

Citrus spp. essential oils improve behavioral pattern, repressed cholinesterases and monoamine oxidase activities, and production of reactive species in fruit fly (Drosophila melanogaster) model of Alzheimer's Disease

Much emphasis has been placed on the biological activities of citrus peel's essential oils (CPEOs) against human ailments. This study investigated the effect of Citrus limon and Citrus reticulata peel's essential oils (EOs) on behavioral and neurochemical imbalance in transgenic and Harwish (Wild) fruit flies. Flies were divided into seven groups comprising of the control and those that were fed with 0.1, 0.5, and 1.0 µg/ml of the dietary inclusions of study CPEOs for 7 days. Thereafter, behavioral profile was examined using lethality response and negative geotaxis assays. Effect of the EOs on cholinesterase and monoamine oxidase (MAO) activities, and antioxidative parameters were determined. The result showed a significant improvement of behavioral pattern and biochemical parameters of the flies fed with studied CPEOs inclusive diets. Conclusively, both EOs exert neuroprotective capability by reducing cholinesterases and monoamine activities, and also prevent oxidative stress, which are implicated in neuronal dysfunction in humans. PRACTICAL APPLICATIONS: With the growing increase in the search for safer alternatives, having no side effects, for the management of neurodegenerative diseases, a large proportion of the populace is beginning to find solace in the use of natural products. Also, the wide array of similarities between the humans and the dipteran insects, fruit flies is a perfect organism for the study of neurodegenerative diseases. Therefore, this study presents the neuroprotective potentials of lemon and tangerine peels-derived EOs, and the possibility of their exploration as neuroactive agents and alternative in the management of Alzheimer's disease (AD).

Extracts from Almond (Terminalia catappa) leaf and stem bark mitigate the activities of crucial enzymes and oxidative stress associated with hypertension in cyclosporine A-stressed rats

We investigated the effect of extracts from the leaf (ALE) and stem bark (ABE) of Almond tree on activities of some crucial enzymes [angiotensin-1 converting enzyme (ACE), arginase, acetylcholinesterase (AChE), phosphodiesterase-5 (PDE-5), adenosine deaminase (ADA), superoxide dismutase (SOD), catalase], and thiobarbituric acid reactive species (TBARS) associated with hypertension in normal adult male Wistar albino rats and Cyclosporine A (CsA)-stressed rats. The result revealed that CsA-stressed rats treated with captopril and extracts (ALE and ABE) had lowered ACE, arginase, AChE, PDE-5, ADA activities, and TBARS level, coupled with improved SOD and catalase activities compared with untreated CsA-stressed rats, which had reversed these biochemicals compared to normal rats. This suggests that the extracts could be explored to suppress hypertension and other cardiac injury known with CsA treatment; the potentials that could be linked with the constituent polyphenols. However, further studies including blood pressure should be determined to ascertain this claim. PRACTICAL APPLICATIONS: Drug-induced cardiotoxicity, hypertension, and organ damage are among the most common side effects of pharmaceutics. Therefore, it becomes imperative to find natural, effective, and alternative therapy with little or no side effect to combat drug toxicity. The use of Almond (leaf and stem bark) in folklore for the treatment/management of hypertension and other heart-related diseases without full scientific basis is on the increase. Hence, this study provides some biochemical evidences on the effect of Almond leaf and stem back extracts on crucial enzymes and oxidative stress markers involve in the incidence of hypertension in the course of Cyclosporine A administration. The findings of this study indicated that the studied plant materials could be promoted as nutraceutical agents to neutralize drug-induced cardiac injury and hypertension.

Editan (Lasianthera africana) leaf-inclusive diets modulate some neuronal enzyme activities and antioxidant status of cyclophosphamide-treated Wistar rats

The effect of Editan (Lasianthera africana) leaf inclusive diet (ELD) on neuronal cholinesterases (ChE), ecto-5'-nucleotidase, and endogenous antioxidant indices [superoxide dismutase (SOD), catalase (CAT), glutathione (GSH)] in cyclophosphamide (CYP)-administered albino rats were investigated. Thirty male albino Wistar rats were dissevered appropriately (n = 6). Group I-normal control rats (NC), II-untreated CYP-administered rats, III-CYP-administered rats pre-treated with donepezil (DON), group IV-CYP-administered rats fed ELD, and V-normal rats fed with ELD for 21 days. Results obtained revealed that CYP-administered rats significantly (p < .05) had elevated activities of ChE, ecto-5'-nucleotidase and thiobarbituric acid reactive species (TBARS), and concomitantly decreased in the antioxidant indices. However, pre-treatment with either DON or ELD reversed these effects, thereby eliciting a therapeutic effect which could be linked to the rich polyphenol and alkaloid constituents in the studied leaf, and could be responsible for the potential ethnopharmacological actions of the ELD in the management neurodegeneration. PRACTICAL APPLICATIONS: Currently, the use of plant-food to control diseased conditions due to their phytochemicals has been explored, most especially, the indigenous edible vegetables from the Southwestern part of Nigeria. "Editan" leafy vegetable scientifically known as Lasianthera africana is commonly used in soups preparation and in folklore for the management of some human ailments. Editan leaf is a rich source of alkaloid and phenolic compounds, which could be used to treat and or manage neurological diseases. This study, therefore, unravels the fact that the studied leafy vegetable possesses therapeutic potentials toward the management of neurological disorders.

Hypoglycemic effect of biscuits produced from flour blends of three medicinal foods on high-fat diet-streptozotocin-induced diabetic rats

The study evaluated the hypoglycemic effect of biscuits produced from flour blends of three medicinal foods (Unripe plantain fruits, Moringa seed, and pigeon pea) on high-fat diet (HFD)/streptozotocin (STZ)-induced (HFD/STZ) diabetic rats. The formulated biscuits were produced at different proportion of the flour blends and fed to HFD-STZ-induced diabetic rats for 14 days. The result showed that the formulated biscuits caused a significant increase in pancreas, liver, and kidney antioxidant molecules, decreased the production of thiobarbituric reactive acid species (TBARS) in pancreas, liver, and kidney homogenates, and reduced pancreatic α-amylase and intestinal α-glucosidase activities as against untreated diabetic rats. In conclusion, the use of formulated biscuits from the blends of flours from unripe plantain, Moringa seed, and pigeon pea could serve as functional food toward the treatment/management of diabetes and its possible complications such as diabetes-induced liver and kidney damage. PRACTICAL APPLICATIONS: The drug use in the management of diabetes such as acarbose have been reported to have side effects, while diet therapy is gaining much interest in the management of diabetes. Hence, there is a need for diets base therapy that will not only cure diabetes, but also combat its complications. In sight of this, unripe plantain, Moringa seed, and pigeon pea flours were blended and used to produce functional biscuits for diabetic rats. The biscuit could be produced on the large scale under hygienic and regulated condition.

Effect of sieving on nutritional value, glycemic index, and carbohydrate digestive enzymes activity of gruel made from maize and sorghum

Cereal gruels are an important staple food in humid part of Africa, and commonly used as weaning food for children and the convalescents. This study sought to evaluate the effect of sieving; an important step in production of gruel. The cereal were soaked with distilled water for 72 hr, rinsed, and wet-milled, thereafter, portioned into two (sieved and Unsieved), and freeze dried. The nutritional value, mineral content, glycemic index, and α-amylase and α-glucosidase inhibitory ability of cereal gruels were investigated. The results make known that Unsieved gruel had a higher (p > .05) nutritional value and mineral content than sieved gruel. The sieved gruel had higher free sugar and glycemic index than the Unsieved. Nonetheless, the gruel extract inhibited α-amylase and α-glucosidase activity judging by their IC₅₀ values in vitro. Based on the results of this study, it can be argued that unsieved gruels had better nutritional contents than sieved gruel. PRACTICAL APPLICATIONS: Cereal gruels are commonly used as weaning food for children and the convalescence, there are concerns about the nutritional value of the food over the time, and this had led to different ways of enhancing the nutritional value through fortification with other substance but the originality of the food is being eroded. However, exclusion of sieving in the processing step, improves the nutritional value of the gruel.

Moringa oleifera leaf and seed inclusive diets influenced the restoration of biochemicals associated with erectile dysfunction in the penile tissue of STZ-induced diabetic male rats treated with/without Acarbose drug

We aim to evaluate the effect of Moringa leaf (ML) and seed (MS) inclusive diets on critical biomarkers [acetylcholinesterase (AChE), monoamine oxidase (MAO), angiotensin-I converting enzyme (ACE), adenosine deiminase (ADA) and arginase activities, and thiobarbituric acid reactive species (TBARS) level] associated with erectile dysfunction (ED) in the penile tissue of diabetic male rats treated with/without Acarbose (ACA). About 60 mg/kg BW streptozotocin (STZ)-induced diabetic rats were fed with ML and MS inclusive diets and cotreated with ACA for 14 days. The result indicated that AChE, MAO, ADA, ACE, and arginase activities, as well as TBARS level were (p < .05) restored in the diabetic rats fed with ML/MS inclusive diets treated with/without ACA compared to the untreated diabetic rats. In conclusion, the combination therapy of ML/MS inclusive diets plus ACA could be explored toward the management of diabetic-induced ED. PRACTICAL APPLICATIONS: We discovered in this study, treatments of diabetic rats with ACA and co-fed with 2% and 4% of Moringa leaf and seed inclusive diets for 14 days, could be of great benefit toward the management of ED caused by diabetes, as evidenced by the expression of some ED-related biomarkers in the penile tissue of diabetes male rats, compared to that of ACA treated alone. Thus, it seems reasonable to explore the effect of food-drug interaction on the large-scale clinical trial to manage diabetes complications, such as the potential effect of Moringa leaf and seed inclusive diets co-administered with ACA for the holistic management of diabetes-induced erectile dysfunction (ED).

Curcumin Administration Mitigates Cyclophosphamide-Induced Oxidative Damage and Restores Alteration of Enzymes Associated with Cognitive Function in Rats' Brain

The use of chemotherapeutic drugs is associated with oxidative damage, cognitive dysfunction, and brain damage. This study sought to investigate the neuroprotective effect of curcumin against cognitive problems associated with treatment with cyclophosphamide via assessment of biomolecules associated with cognitive function in rats' brain homogenates. Rats were divided in to five groups: Control (vehicle), CUR (curcumin [20 mg/kg]), CPA (cyclophosphamide [150 mg/kg]), CUR1 + CPA (curcumin [20 mg/kg] and cyclophosphamide [150 mg/kg]), and CPA + CUR2 (cyclophosphamide [150 mg/kg] and curcumin [20 mg/kg]). After the treatment, cognitive behavior was assessed and enzymes [cholinesterases, purinergic enzymes, arginase, and angiotensin I-converting enzyme] associated with cognitive function were examined. Oxidative stress parameters [total thiol, non-protein thiol, malondialdehyde, and nitric oxide] including the expression of caspase-3 were also assessed in rats' brain. Our results showed that curcumin improved cognitive behavior, attenuated cholinergic deficit as revealed by the inhibition of cholinesterases, and improved purinergic signaling in cyclophosphamide-treated rats. Furthermore, curcumin reduced angiotensin-I-converting enzyme and arginase activities before and after treatment with cyclophosphamide. Curcumin also improved redox balance and showed protection against cyclophosphamide-induced oxidative damage to rats' brain via an increase in protein and non-protein thiols and nitric oxide levels as well as a significant reduction in malondialdehyde levels. Curcumin also prevented neuronal degeneration in different brain regions and reduced caspase-3 expression. Hence this study suggests that pre and post-treatment with curcumin improved neurobehavior, modulates some biomarkers associated with cognitive function and exhibit neuroprotection against cyclophosphamide-induced neurotoxicity in rats.

Modulatory effect of eugenol on arginase, nucleotidase, and adenosine deaminase activities of platelets in a carrageenan-induced arthritis rat model: A possible anti-arthritic mechanism of eugenol

This study investigated the effect of eugenol on arginase, nucleotidase and adenosine deaminase activities in platelets of carrageenan-induced arthritic rat model to explain a possible anti-arthritic mechanism of eugenol. Fifty adult female rats (140-250 g) were divided into ten (10) groups (n = 5). Group I received oral administration of corn oil, group II received 2.50 mg/kg of eugenol, group III and IV rats received oral administration of 5.0 and 10.0 mg/kg of eugenol respectively, group V received 0.20 mg/kg of dexamethasone orally, group VI rats was injected with 1% carrageenan (arthritic rats) and received saline solution orally (arthritic control rat group), group VII, VIII and IX: arthritic rats received 2.50, 5.0 or 10 mg/kg of eugenol orally respectively, group X: arthritic rats was administered with 0.20 mg/kg of dexamethasone orally. The animals were treated for 21 days, thereafter, tibiofemoral histological examination, thiobabituric acid reactive substances level, arginase, nucleoside triphosphate diphosphohydrolase, 5´-nucleotidase and adenosine deaminase activities were assessed. Tibiofemoral histological examination result showed that infiltration of inflammatory cells was significantly decreased with an increase in eugenol dose. Activities of arginase, adenosine triphosphate and adenosine monophosphate hydrolyses were significantly decreased while adenosine diphosphate hydrolysis and adenosine deaminase activities were significantly increased in arthritic rat groups administered with different doses of eugenol. Therefore, eugenol might be a natural complement and alternative promising anti-arthritic agent. These possible anti-arthritic mechanisms may be partly through the modulation of arginase and adenosine nucleotides hydrolyzing enzyme activities as well as the antioxidative action of eugenol.

Modulation of some markers of erectile dysfunction and malonaldehyde levels in isolated rat penile tissue with unripe and ripe plantain peels: identification of the constituents of the plants using HPLC

CONTEXT

Plantain fruit pulp has been used as a natural remedy to manage erectile dysfunction (ED) in traditional medicine. However, the potency of the peel has not been examined with respect to ED management.

OBJECTIVE

This study investigated and compared the inhibitory potential of unripe (UPP) and ripe (RPP) plantain peels on some enzymes associated with ED and Fe²⁺-induced oxidative stress in albino rat penile homogenate in vitro.

MATERIALS AND METHOD

Aqueous extract of the peels was prepared and the effect on phosphodiesterase-5 (PDE-5), arginase, acetylcholinesterase (AChE), angiotensin-I converting enzyme (ACE) and Fe²⁺-induced malonyladehyde in isolated albino rat penile homogenate were investigated. Phenolic constituents of the peels powder were characterized using high-performance liquid chromatography coupled with diode array detector (HPLC-DAD).

RESULT

Extract from UPP had higher PDE-5 (IC₅₀ = 3.10 μg/mL), arginase (IC₅₀ = 0.96 μg/mL), AChE (IC₅₀ = 6.30 μg/mL) and ACE (IC₅₀ = 0.41 μg/mL) inhibitory ability compared with RPP (PDE-5, IC₅₀ = 4.33 μg/mL; arginase, IC₅₀ = 1.34 μg/mL; AChE, IC₅₀ = 8.64 μg/mL; ACE, IC₅₀ = 0.63 μg/mL). The extract from UPP also had higher inhibition of Fe²⁺-induced lipid peroxidation. HPLC-DAD analysis revealed that gallic and caffeic acids, rutin, quercitrin and quercetin were abundant in UPP, while catechin, kaempferol, chlorogenic and ellagic acids were the dominant phenolic compounds in RPP.

DISCUSSION AND CONCLUSION

Inhibition of enzymes associated with ED and lipid peroxidation could be linked with the phenolic compounds. However, UPP appeared to be more potent.

Effect of caffeine, caffeic acid and their various combinations on enzymes of cholinergic, monoaminergic and purinergic systems critical to neurodegeneration in rat brain-In vitro

Caffeine and caffeic acid are two bioactive compounds that are present in plant foods and are major constituent of coffee, cocoa, tea, cola drinks and chocolate. Although not structurally related, caffeine and caffeic acid has been reported to elicit neuroprotective properties. However, their different proportional distribution in food sources and possible effect of such interactions are not often taken into consideration. Therefore, in this study, we investigated the effect of caffeine, caffeic acid and their various combinations on activities of some enzymes [acetylcholinesterase (AChE), monoamine oxidase (MAO) ecto-nucleoside triphosphate diphosphohydrolase (E-NTPase), ecto-5¹-nucleotidase (E-NTDase) and Na⁺/K⁺ ATPase relevant to neurodegeneration in vitro in rat brain. The stock concentration of caffeine and caffiec acid and their various proportional combinations were prepared and their interactions with the activities of these enzymes were assessed (in vitro) in different brain structures. The Fe²⁺ and Cu²⁺ chelating abilities of the samples were also investigated. The results revealed that caffeine, caffeic acid and their various combinations exhibited inhibitory effect on activities of AChE, MAO, E-NTPase and E-NTDase, but stimulatory effect on Na⁺/K⁺ ATPase activity. The combinations also exhibited Fe²⁺ and Cu²⁺ chelating abilities. Considering the various combinations, a higher caffeine to caffeic acid ratio produced significantly highest enzyme modulatory effects; these were significantly lower to the effect of caffeine alone but significantly higher than the effect of caffeic acid alone. These findings may provide new insight into the effect of proportional combination of these bioactive compounds as obtained in many foods especially with respect to their neuroprotective effects.

Polyphenolic compositions and in vitro angiotensin-I-converting enzyme inhibitory properties of common green leafy vegetables: A comparative study

This study compared the phenolic compositions of common green leafy vegetable extracts from Vernonia amygdalina (VA), Telfairia occidentalis (TO), Talinium triangulare (TT), and Amaranthus hybridus (AH) and their effects on the angiotensin-I-converting enzyme (ACE) and cisplatin-induced malonylaldehyde (MDA) production in an isolated rat kidney homogenate. HPLC confirmed the presence of phenolic compounds in the extracts. Furthermore, all extracts inhibited ACE activity dosedependently; however, the extract from VA exhibited the highest ACE activity while TT exhibited the least. Incubation of the kidney homogenate with 1mM cisplatin caused an increase in MDA production; however, all the extracts inhibited the level of MDA produced. Nevertheless, VA extract exhibited the highest inhibition. These activities of the vegetable extracts could be attributed to their phenolic compositions and may suggest some possible mechanism of the actions. However, VA appeared to be the most potent among the vegetables tested.