Vernonia Amygdalina Del. stimulated glucose uptake in brain tissues enhances antioxidative activities; and modulates functional chemistry and dysregulated metabolic pathways

Vanillin improves glucose homeostasis and modulates metabolic activities linked to type 2 diabetes in fructose-streptozotocin induced diabetic rats

OBJECTIVE

This study investigated the antidiabetic effect of vanillin using in vitro, in silico, and in vivo experimental models.

METHODOLOGY

Type 2 diabetes (T2D) was induced in male Sprague-Dawley (SD) rats using fructose-streptozotocin (STZ), then orally administered low (150 mg/kg bodyweight) or high (300 mg/kg bodyweight) dose of vanillin for 5 weeks intervention period.

RESULTS

Vanillin suppressed the levels of blood glucose, serum cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-c), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, urea, uric acid, when elevated serum insulin, HDL-cholesterol, and concomitantly improved pancreatic β-cell function, glucose tolerance, and pancreatic morphology. It also elevated both serum and pancreatic tissue GSH level, SOD and catalase activities, and hepatic glycogen level, while depleting malondialdehyde level, α-amylase, lipase, acetylcholinesterase, ATPase, ENTPDase and 5'-nucleotidase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, and glycogen phosphorylase activities.

CONCLUSIONS

The results indicate the potent antidiabetic effect of vanillin against T2D and its associated complications.

Impact of Preparative Isolation of C-Glycosylflavones Derived from Dianthus superbus on In Vitro Glucose Metabolism

Dianthus superbus L. has been extensively studied for its potential medicinal properties in traditional Chinese medicine and is often consumed as a tea by traditional folk. It has the potential to be exploited in the treatment of inflammation, immunological disorders, and diabetic nephropathy. Based on previous studies, this study continued the separation of another subfraction of Dianthus superbus and established reversed-phase/reversed-phase and reversed-phase/hydrophilic (RPLC) two-dimensional (2D) high-performance liquid chromatography (HPLC) modes, quickly separating two C-glycosylflavones, among which 2″-O-rhamnosyllutonarin was a new compound and isomer with 6‴-O-rhamnosyllutonarin. This is the first study to investigate the effects of 2″-O-rhamnosyllutonarin and 6‴-O-rhamnosyllutonarin on cellular glucose metabolism in vitro. First, molecular docking was used to examine the effects of 2″-O-rhamnosyllutonarin and 6″-O-rhamnosyllutonarin on AKT and AMPK; these two compounds exhibited relatively high activity. Following this, based on the HepG2 cell model of insulin resistance, it was proved that both of the 2″-O-rhamnosyllutonarin and 6‴-O-rhamnosyllutonarin demonstrated substantial efficacy in ameliorating insulin resistance and were found to be non-toxic. Simultaneously, it is expected that the methods developed in this study will provide a basis for future studies concerning the separation and pharmacological effects of C-glycosyl flavonoids.

Therapeutic Benefit of Vernonia amygdalina in the Treatment of Diabetes and Its Associated Complications in Preclinical Studies

Diabetes mellitus (DM), a complex heterogeneous metabolic disorder characterized by a defect in the function of insulin, is on the rapid rise globally. Sustained hyperglycemia which is a major sign of DM is linked to the generation of reactive oxygen species which promotes adverse complications of the disorder. Traditional herbal treatment of DM is a common practice in Africa and other tropical parts of the world. Vernonia amygdalina (VA), one of the highly researched species in the Asteraceae family, has proven to possess potent antidiabetic properties. Several phytochemicals identified in multiple extracts from VA are purported to be responsible for the antidiabetic potential of the plant. In this review, we discuss the therapeutic potential of VA in diabetes and its associated complications. We appraise the current evidence and further suggest potential areas that could be effectively exploited in future VA research on diabetes.

Nutraceutical management of metabolic syndrome as a palliative and a therapeutic to coronavirus disease (COVID) crisis

The global market for medicinal plants and herbs is on the increase due to their desirability, efficacy, and less adverse effects as complementary and alternative medications to the orthodox pharmaceuticals, perhaps due to their natural components and qualities. Metabolic syndromes are managed with changes in diet, exercise, lifestyle modifications and the use of pharmacological agents. Plants are now known to have potent antioxidant and cholinergic activities which are relevant to the management of several metabolic syndromes, which are unfortunately, co-morbidity factors in the coronavirus disease crisis. This review will focus on the biological activities of some plant products used as complementary and alternative medicines in the management of metabolic syndromes, and on their reported antiviral, antithrombotic, angiotensin-converting enzyme inhibitory properties, which are integral to their usage in the management of viral infections and may give an avenue for prophylactic and therapeutics especially in the absence of vaccines/formulated antiviral therapies.

Kolaviron modulates dysregulated metabolism in oxidative pancreatic injury and inhibits intestinal glucose absorption with concomitant stimulation of muscle glucose uptake

This present study investigated the antioxidative and antidiabetic properties of kolaviron by analysing its inhibitory effect on key metabolic activities linked to T2D, in vitro and ex vivo. Kolaviron significantly inhibited α-glucosidase and α-amylase activities, and intestinal glucose absorption dose-dependently, while promoting muscle glucose uptake. Induction of oxidative pancreatic injury significantly depleted glutathione level, superoxide dismutase, catalase, and ATPase activities, while elevating malondialdehyde and nitric oxide levels, acetylcholinesterase and chymotrypsin activities. These levels and activities were significantly reversed in tissues treated with kolaviron. Kolaviron depleted oxidative-induced metabolites, with concomitant restoration of oxidative-depleted metabolites. It also inactivated oxidative-induced ascorbate and aldarate metabolism, pentose and glucuronate interconversions, fructose and mannose metabolism, amino sugar and nucleotide sugar metabolism, and arginine and proline metabolism, while reactivating selenocompound metabolism. These results depict the antidiabetic properties of kolaviron as indicated by its ability to attenuate oxidative-induced enzyme activities and dysregulated metabolisms, and modulated the enzyme activities linked to hyperglycaemia.

The levels of nitrite, nitrate and lipid peroxidation in diabetic mouse brain: the effect of melatonin and pentoxifylline

OBJECTIVE

This study investigated the relationship between diabetes (DM) and nitrite, nitrate and MDA levels and effect of melatonin and pentoxifylline.

METHODS

Sixty mice were randomly divided into four groups. Control: no action; Diabetes group (DM): after fasting-blood-glucose (FBG) was measured, 150 mg/kg alloxane was applied intraperitoneally three-times every other day; Diabetes + Melatonin (DM + MLT) and Diabetes + Pentoxifylline groups (DM + PTX): following the same procedures with DM, 10 mg/kg melatonin and 50 mg/kg pentoxifylline were administered subcutaneously six days, respectively. Following FBG analysis, brain tissues were taken under the anaesthesia. Nitrite, nitrate and MDA levels were measured.

RESULTS

In the all groups with alloxane, FBG were higher than in before application (p < .05). Also, FBG, nitrite, nitrate and MDA levels in the DM + MLT and DM + PTX groups were lower than in the DM (p < .05).

CONCLUSIONS

Nitrite and nitrate may be related to etiopathogenesis of DM, and pentoxifylline and especially melatonin relatively decrease nitrite, nitrate and lipid peroxidation.

Harpephyllum caffrum fruit (wild plum) facilitates glucose uptake and modulates metabolic activities linked to neurodegeneration in isolated rat brain: An in vitro and in silico approach

Alteration in brain glucose metabolism due to glucose uptake reduction has been described in the onset of certain neurodegenerative disorders. This study determined Harpephyllum caffrum fruit's potential ability to improve glucose uptake and its modulatory effects on intrinsic antioxidant, glucogenic, cholinergic, and nucleotide-hydrolyzing enzyme activities in isolated rat brain. Consequently, the bioactive compounds of the fruits were identified with LC-MS. The fruit significantly improved brain glucose uptake following coincubation with glucose and brain tissue. The fruit extract also elevated GSH level, SOD, catalase, glycogen phosphorylase, and ENTPDase activities while simultaneously suppressing NO and malonaldehyde levels and fructose-1,6-bisphosphatase, ATPase, acetylcholinesterase and butyrylcholinesterase activities. LC-MS analysis revealed S-methylcysteine sulfoxide, dihydroquercetin, 3,4-dimethyl-2,5-bis(3,4,5-trimethoxyphenyl) tetrahydrofuran (MTHF), nobiletin, puerarin, quercetin 3-rutinoside, 8-D-glucosyl-4',5,7-trihydroxyflavone, asperulosidic acid, 1,2,4,6-tetragalloylglucose, and phellamurin. This study suggests the neuroprotective effects of H. caffrum fruit due to its ability to enhance glucose uptake, attenuate glucose-induced oxidative stress while modulating glucogenic, cholinergic, and nucleotide-hydrolyzing enzyme activities in normal brain tissues. PRACTICAL APPLICATIONS: Available scientific evidence describes oxidative stress as one of the physiological processes contributing to aging-associated neurodegeneration in humans. In this regard, commonly consumed natural products from plants have attracted much interest due to their ability to mitigate redox imbalance-related pathologies that affect various organs in the body such as the brain. Harpephyllum caffrum or bush mango is an evergreen plant native to the South African vegetation. The fruit from the plant is consumed locally as food or specifically for improving the nutritional quality of meals as deserts or condiments. While previous findings described the high antioxidant properties of the fruits, this study reported possible mechanisms via which the plant may exhibit ameliorative effects against oxidative stress-related neurological disorders in the brain. Hence, findings from the current work present another justification for the significance of fruits as a safer nutraceutical alternative for therapy in neurological disease management.

Cannabis sativa L. (var. indica) Exhibits Hepatoprotective Effects by Modulating Hepatic Lipid Profile and Mitigating Gluconeogenesis and Cholinergic Dysfunction in Oxidative Hepatic Injury

Cannabis sativa L. is a crop utilized globally for recreational, therapeutic, and religious purposes. Although considered as an illicit drug in most countries, C. sativa until recently started gaining attention for its medicinal application. This study sought to investigate the hepatoprotective effect of C. sativa on iron-mediated oxidative hepatic injury. Hepatic injury was induced ex vivo by incubating hepatic tissues with Fe2+, which led to depleted levels of reduced glutathione, superoxide dismutase, catalase and ENTPDase activities, triglyceride, and high-density lipoprotein-cholesterol (HDL-C). Induction of hepatic injury also caused significant elevation of malondialdehyde, nitric oxide, cholesterol, and low-density lipoprotein-cholesterol (LDL-C) levels while concomitantly elevating the activities of ATPase, glycogen phosphorylase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, amylase, and lipase. Treatment with the hexane, dichloromethane (DCM), and ethanol extracts of C. sativa leaves significantly (p < 0.05) reversed these levels and activities to almost near normal. However, there was no significant effect on the HDL-C level. The extracts also improved the utilization of glucose in Chang liver cells. High-performance liquid chromatography (HPLC) analysis showed the presence of phenolics in all extracts, with the ethanol extract having the highest constituents. Cannabidiol (CBD) was identified in all the extracts, while Δ-9-tetrahydrocannabinol (Δ-9-THC) was identified in the hexane and DCM extracts only. Molecular docking studies revealed strong interactions between CBD and Δ-9-THC with the β2 adrenergic receptor of the adrenergic system. The results demonstrate the potential of C. sativa to protect against oxidative-mediated hepatic injury by stalling oxidative stress, gluconeogenesis, and hepatic lipid accumulation while modulating cholinergic and purinergic activities. These activities may be associated with the synergistic effect of the compounds identified and possible interactions with the adrenergic system.

Vanillin modulates activities linked to dysmetabolism in psoas muscle of diabetic rats

Skeletal muscles are important in glucose metabolism and are affected in type 2 diabetes (T2D) and its complications. This study investigated the effect of vanillin on redox imbalance, cholinergic and purinergic dysfunction, and glucose-lipid dysmetabolism in muscles of rats with T2D. Male albino rats (Sprague-Dawley strain) were fed 10% fructose ad libitum for 2 weeks before intraperitoneally injecting them with 40 mg/kg streptozotocin to induce T2D. Low (150 mg/kg bodyweight (BW)) and high (300 mg/kg BW) doses of vanillin were orally administered to diabetic rats. Untreated diabetic rats and normal rats made up the diabetic control (DC) and normal control (NC) groups, respectively. The standard antidiabetic drug was metformin. The rats were humanely put to sleep after 5 weeks of treatment and their psoas muscles were harvested. There was suppression in the levels of glutathione, activities of SOD, catalase, ENTPDase, 5'Nucleotidase and glycogen levels on T2D induction. This was accompanied by concomitantly elevated levels of malondialdehyde, serum creatine kinase-MB, nitric oxide, acetylcholinesterase, ATPase, amylase, lipase, glucose-6-phosphatase (G6Pase), fructose-1,6-biphophastase (FBPase) and glycogen phosphorylase activities. T2D induction further resulted in the inactivation of fatty acid biosynthesis, glycerolipid metabolism, fatty acid elongation in mitochondria and fatty acid metabolism pathways. There were close to normal and significant reversals in these activities and levels, with concomitant reactivation of the deactivated pathways following treatment with vanillin, which compared favorably with the standard drug (metformin). Vanillin also significantly increased muscle glucose uptake ex vivo. The results suggest the therapeutic effect of vanillin against muscle dysmetabolism in T2D as portrayed by its ability to mitigate redox imbalance, inflammation, cholinergic and purinergic dysfunctions, while modulating glucose-lipid metabolic switch and maintaining muscle histology.

α-Glucosidase and advanced glycation end products inhibition with Vernonia amygdalina root and leaf extracts: new data supporting the antidiabetic properties

OBJECTIVE

This study aims to investigate antidiabetic activity of several Vernonia amygdalina extracts to study their potential use in medicine.

METHODS

Aqueous and ethanol extracts were obtained by maceration and Soxhlet extraction from roots and leaves of V. amygdalina. The extracts were tested as inhibitors of α-glucosidase activity and of advanced glycation end products (AGEs) formation. Further, radical scavenging activity was examined detecting the oxygen radical absorbance capacity, while the potential cytotoxicity of extracts was estimated with MTT assay.

KEY FINDINGS

In aqueous and ethanol extracts, several polyphenolic compounds were identified; in detail, (-)-catechin and luteolin were found in leaf extracts, while caffeic acid, chlorogenic acid and the terpenoid vernodalol were recognized in root extracts. Regarding antidiabetic activity, the aqueous root extracts efficiently inhibited α-glucosidase activity in a concentration-dependent manner (IC50 = 5.6 µg/ml and 39.8 µg/ml, respectively of macerated and Soxhlet extracts), whereas those obtained from leaves exhibited lower potency. Furthermore, AGEs formation was reduced by all V. amygdalina extracts starting from 10 µg/ml.

CONCLUSIONS

The aqueous extracts of V. amygdalina roots obtained by maceration and Soxhlet extraction show remarkable anti-α-glucosidase activity, and all extracts have favourable antiglycation and antioxidant activities.

Vanillin exerts therapeutic effects against hyperglycemia-altered glucose metabolism and purinergic activities in testicular tissues of diabetic rats

Testicular dysfunctions leading to male infertility has been reported in type 2 diabetes (T2D), with glucose dysmetabolism, cholinergic and purinergic dysfunction being major contributors. In the present study, the effect of vanillin on glucose metabolism, purinergic and cholinergic dysfunctions were investigated in testicular tissues of T2D rats. Male Sprague-Dawley rats were divided into 6 groups containing 5 rats each. T2D was induced in rats by administering 10 % fructose ad libitum for 14 days followed by a single intraperitoneal injection (40 mg/kg body weight) of streptozotocin. T2D rats were orally administered with vanillin at 150 and 300 mg/kg body weight (bw). Diabetic control (DC) consisted of untreated diabetic rats, while normal control (NC) consisted of normal rats and they were administered with distilled water only. Metformin was used as the standard antidiabetic drug. After 5 weeks treatment, the rats were sacrificed, and the testes were harvested. Induction of T2D led to significantly depleted testicular levels of glutathione, glycogen content, superoxide dismutase and catalase enzyme activities, with concomitantly elevated levels of nitric oxide, malondialdehyde, acetylcholinesterase, glucose-6-phosphatase, fructose-1,6-biphophastase, glycogen phosphorylase, amylase and lipase activities. These activities and levels were significantly reversed to near normal in rats treated with both doses of vanillin as compared with metformin. These results, when taken together, suggest the therapeutic effect of vanillin against hyperglycemia-mediated metabolic dysfunctions in testes of T2D rats. This is depicted by the ability of the phenolic to attenuate oxidative imbalance, purinergic and cholinergic dysfunctions, while suppressing glucose dysmetabolism.

Caffeic Acid Protects against Iron-Induced Cardiotoxicity by Suppressing Angiotensin-Converting Enzyme Activity and Modulating Lipid Spectrum, Gluconeogenesis and Nucleotide Hydrolyzing Enzyme Activities

The protective effects of caffeic acid on angiotensin-converting enzyme (ACE) and purinergic enzyme activities, as well as gluconeogenesis was investigated in iron-induced cardiotoxicity. Cardiotoxicity was induced in heart tissues harvested from healthy male SD rats by 0.1 mM FeSO₄. Treatment was carried out by co-incubating hearts tissues with caffeic acid and 0.1 mM FeSO₄. Cardiotoxicity induction significantly (p < 0.05) depleted GSH level, SOD, catalase, and ENTPDase activities, with concomitant elevation of the levels of malondialdehyde (MDA), nitric oxide, ACE, ATPase, glycogen phosphorylase, glucose 6-phosphatase, fructose 6-biphsophatase, and lipase activities. There was significant (p < 0.05) reversion in these levels and activities on treatment with caffeic acid. Caffeic acid also caused depletion in cardiac levels of cholesterol, triglyceride, LDL-c, while elevating HDL-c level. Our results suggest the protective effect of caffeic acid against iron-mediated cardiotoxicity as indicated by its ability to suppress oxidative imbalance and ACE activity, while concomitantly modulating nucleotide hydrolysis and metabolic switch.

Tetrahydrocannabinol-Rich Extracts From Cannabis Sativa L. Improve Glucose Consumption and Modulate Metabolic Complications Linked to Neurodegenerative Diseases in Isolated Rat Brains

Reduced brain glucose consumption arising from impaired glucose uptake and utilization has been linked to the pathogenesis and complications of neurodegenerative diseases. The ability of Cannabis sativa L. tetrahydrocannabinol (THC)-rich extracts to stimulate brain glucose uptake and utilization as well as its modulatory effect on gluconeogenesis, antioxidative, purinergic and cholinergic activities were investigated in isolated rats’ brains. C. sativa leaves were sequentially extracted to yield the hexane and dichloromethane extracts. The extracts were incubated at 37°C with freshly harvested brains in the presence of glucose for 2 h. The control consisted of incubation without the extracts, while brains without the extracts and glucose served as the normal control. Metformin was used as the standard drug. C. sativa extracts caused a significant (p < 0.05) increase in brain glucose uptake, with concomitant elevation of glutathione level, superoxide dismutase, catalase, and ecto-nucleoside triphosphate diphosphohydrolase activities compared to the controls. Incubation with C. sativa extracts also led to depletion in malondialdehyde and nitric oxide levels, acetylcholinesterase, butyrylcholinesterase, glucose 6-phosphatase and fructose-1,6-biphosphatase activities. GC-MS analysis of the extracts revealed the presence of THC. In silico analysis predicted THC to be permeable across the blood-brain-barrier. THC was also predicted to have an oral LD₅₀ and toxicity class values of 482 mg/kg and 4 respectively. These results indicate that C. sativa improves glucose consumption with concomitant suppression of oxidative stress and cholinergic dysfunction, and modulation of purinergic and gluconeogenic activities in brain tissues

Phytochemical constituents of sterol-rich fraction from Allium cepa L. and its cytotoxic effect on human embryonic kidney (HEK293) cells

The present study investigates the cytotoxic effect of the chemical fractions of Allium cepa (yellow variety) on Human Embryonic Kidney (HEK293) cells. Allium cepa was blended into paste and macerated in distilled water before subjecting to liquid-liquid fractionation, yielding the dichloromethane, ethyl acetate (EtOAc), butanol, and aqueous fractions. Their cytotoxicity on HEK293 cells were evaluated via MTT assay. The cytotoxic fraction (EtOAc) was further evaluated for its oxidative, pro-inflammatory, and apoptotic effects on the cells. The incubation of cells with EtOAc led to depleted level of GSH, SOD, and catalase activities, and elevated levels of malondialdehyde, nitric oxide, and myeloperoxidase as well as apoptotic activities. GC-MS analysis of EtOAc revealed allyl ionone, pentadecanoic acid, and phytol acetate as the predominant fatty acids, while ergost-7-en-3β-ol, campesterol, cycloartenol-3β acetate, sitosterol, and fucosterol as the predominant sterols. These results portray the cytotoxic effect of the EtOAc fraction of A. cepa on HEK293 cells. PRACTICAL APPLICATIONS: There have been increasing concerns in the toxicity and safety of foods. Allium cepa (onions) is among the common globally grown and consumed plant food. This study investigated its cytotoxic effect on normal Human Embryonic Kidney (HEK293) Cells. Although only the ethyl acetate fraction was cytotoxic against the cell line, it, however, portrays a need for caution in its usage.

Casein micelles from bovine Milk exerts Neuroprotection by stalling metabolic complications linked to oxidative brain injury

Caseins are the most abundant milk proteins in mammalian species and are assembled in supra-macromolecular structures called micelles. In this study, the microstructural properties, particle size, and elemental composition of isolated casein from bovine milk and its therapeutic effect on oxidative and cholinergic activities linked to dementia in oxidative brain injury were investigated. SEM analysis of the isolated casein micelles from skimmed fresh bovine milk revealed spherical colloid aggregates, while TEM analysis revealed dispersed spherical particles with a mean size of 63.15 ± 4.77 nm. SEM-EDX analysis revealed clusters of carbon, oxygen, sulfur, copper, sodium, magnesium, potassium, iron, and selenium. Treatment of oxidative brain injury with the isolated casein micelles led to elevated levels of GSH, SOD, catalase, ENTPDase, 5'NTPase activities, while concomitantly suppressing MDA, cholesterol, HDL-c levels, acetylcholinesterase and lipase activities. Treatment with the isolated casein micelles led to complete depletion of oxidative generated lipid metabolites, while deactivating oxidative-activated lipid metabolic pathways. These results indicate the microstructural properties, particle size, elemental composition, and antioxidant neuroprotective effect of casein micelles from bovine milk. Thus, demonstrating the nutraceutical properties of milk in the management of oxidative induced cognitive impairment.

Catechol protects against iron-mediated oxidative brain injury by restoring antioxidative metabolic pathways; and modulation of purinergic and cholinergic enzymes activities

OBJECTIVES

This study was aimed at investigating neuroprotective effect of catechol on redox imbalance, cholinergic dysfunctions, nucleotide hydrolysing enzymes activities, and dysregulated metabolic pathways in iron-mediated oxidative brain injury.

METHODS

Oxidative injury was induced in brain tissues by incubating with 0.1 mm FeSO₄ and treated with different concentrations of catechol.

KEY FINDINGS

Catechol significantly elevated glutathione level, superoxide dismutase and catalase activities, while depleting malondialdehyde and nitric oxide levels. It also inhibited the activities of acetylcholinesterase, butyrylcholinesterase, and ATPase, with concomitant elevation of ENTPDase activity. GC-MS analysis revealed that treatment with catechol completely depleted oxidative-generated lipid metabolites. While LC-MS analysis revealed depletion of oxidative-generated metabolites in brain tissues treated with catechol, with concomitant restoration of oxidative-depleted metabolites. Catechol also led to reactivation of oxidative-inactivated taurine and hypotaurine, purine, glutathione, glycerophospholipid, nicotinate and nicotinamide, fructose and mannose, pyrimidine metabolisms and pentose phosphate pathways. Catechol was predicted in silico to be permeable across the blood-brain barrier with a predicted oral LD₅₀ value of 100 mg/kg and a toxicity class of 3.

CONCLUSION

These results suggest the neuroprotective effects of catechol in iron-mediated oxidative brain injury.

Caffeic acid improves glucose utilization and maintains tissue ultrastructural morphology while modulating metabolic activities implicated in neurodegenerative disorders in isolated rat brains

Impaired glucose utilization has been implicated in the pathophysiology of neurodegenerative diseases. The neuroprotective effect of caffeic acid (CA) was investigated in the isolated rat brain by determining its ability to promote glucose uptake, mitigate redox imbalance, modulate purinergic and cholinergic activities, elemental distribution, and maintain tissue morphology. Isolated rat brains were incubated for 2 hours with glucose, CA and glucose, and metformin and glucose. There was an increased glucose uptake, glutathione level, superoxide dismutase, and catalase activities in brain tissues incubated with CA compared to the controls. Incubation with CA also led to significantly decreased levels of malondialdehyde, nitric oxide, acetylcholinesterase, butyrylcholinesterase, and ATPase activities. Electron microscopy (scanning electron microscopy and transmission electron microscopy) analysis portrayed a maintenance of tissue ultrastructural morphology in 2CA-incubated tissues as indicated by the intact synaptic vesicles, blood vessels, dendritic and neuronal network, mitochondria, and presynaptic membrane. CA also restored altered elemental levels in brain tissues. These results indicate the stimulatory potential of CA on brain glucose utilization with simultaneous neuroprotective activities.

Neurotoxicity in pre-eclampsia involves oxidative injury, exacerbated cholinergic activity and impaired proteolytic and purinergic activities in cortex and cerebellum

Women with a history of pre-eclampsia (PE) tend to have a higher risk of developing cardiovascular and neurological diseases later in life. Imbalance in oxidative markers and purinergic enzymes have been implicated in the pathogenesis of neurological disease. This study investigated the effect of PE on oxidative imbalance, purinergic enzyme inhibitory activity, acetylcholinesterase and chymotrypsin activities in the brain of PE rat model at post-partum/post-natal day (PP/PND) 60. Pregnant rats divided into early-onset and late-onset groups were administered with Nω-nitro-l-arginine methyl through drinking water at gestational days 8-17. Rats were allowed free access to water throughout the pregnancy and allowed to deliver on their own. The mother and the pups were euthanized at PP and PND 60, respectively, the cortex and the cerebellum excised, homogenized and stored for analyses of the enzymes. Results showed an increase in nitric oxide and malondialdehyde with a concomitant decrease in reduced glutathione and superoxide dismutase, an indication of oxidative damage. Also, there was an increase in acetylcholinesterase activity with a decrease in chymotrypsin, adenylpyrophosphatase and ecto-nucleoside triphosphate diphosphohydrolase activities in both the cortex and the cerebellum of the mother and the pups at PND 60. These results indicate the involvement of oxidative stress, increased cholinergic activity and depleted proteolytic and purinergic activities in PE-induced neurotoxicity.

Kolaviron stimulates glucose uptake with concomitant modulation of metabolic activities implicated in neurodegeneration in isolated rat brain, without perturbation of tissue ultrastructural morphology

Reduced glucose uptake usually occurs in type 2 diabetes due to down-regulation of brain glucose transporters. The potential of kolaviron, a biflavonoid from Garcinia kola to stimulate glucose uptake and suppress glucose-induced oxidative toxicity were investigated in rat brain. Its molecular interactions with the target proteins were investigated in silico. Kolaviron was incubated with excised rat brain in the presence of glucose for 2 h, with metformin serving as a positive control. Kolaviron caused a significant (p < 0.05) increase in glucose uptake, glutathione level, superoxide dismutase, catalase, ATPase, ENTPDase and 5'-nucleotidase activities, while concomitantly depleting malondialdehyde level, acetylcholinesterase and butyrylcholinesterase activities compared to brains incubated with glucose only. Electron microscopy (SEM and TEM) analysis revealed kolaviron had little or no effect on the ultrastructural morphology of brain tissues as evidenced by the intact dendritic and neuronal network, blood vessels, mitochondria, synaptic vesicles, and pre-synaptic membrane. SEM-EDX analysis revealed a restorative effect of glucose-induced alteration in brain elemental concentrations, with total depletion of aluminum and zinc. MTT analysis revealed kolaviron had no cytotoxic effect on HT-22 cells. Molecular docking revealed a potent interaction between kolaviron and catalase at the SER114 and MET350 residues, with a binding energy of 12 kcal/mol. Taken together, these results portray the potential of kolaviron to stimulate glucose uptake while concomitantly coffering a neuroprotective effect.

Necrostatin-1 Mitigates Cognitive Dysfunction in Prediabetic Rats With No Alteration in Insulin Sensitivity

Previous studies showed that 12 weeks of high-fat diet (HFD) consumption caused not only prediabetes but also cognitive decline and brain pathologies. Recently, necrostatin-1 (nec-1), a necroptosis inhibitor, showed beneficial effects in brain against stroke. However, the comparative effects of nec-1 and metformin on cognition and brain pathologies in prediabetes have not been investigated. We hypothesized that nec-1 and metformin equally attenuated cognitive decline and brain pathologies in prediabetic rats. Rats (n = 32) were fed with either normal diet (ND) or HFD for 20 weeks. At week 13, ND-fed rats were given a vehicle (n = 8) and HFD-fed rats were randomly assigned into three subgroups (n = 8/subgroup) with vehicle, nec-1, or metformin for 8 weeks. Metabolic parameters, cognitive function, brain insulin receptor function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, Alzheimer protein, and cell death were determined. HFD-fed rats exhibited prediabetes, cognitive decline, and brain pathologies. Nec-1 and metformin equally improved cognitive function, synaptic plasticity, dendritic spine density, microglial morphology, and brain mitochondrial function and reduced hyperphosphorylated Tau and necroptosis in HFD-fed rats. Interestingly, metformin, but not nec-1, improved brain insulin sensitivity in those rats. In conclusion, necroptosis inhibition directly improved cognition in prediabetic rats without alteration in insulin sensitivity.

Vanillin and vanillic acid modulate antioxidant defense system via amelioration of metabolic complications linked to Fe2+-induced brain tissues damage

The therapeutic effect of phenolics on neurodegenerative diseases has been attributed to their potent antioxidant properties. In the present study, the neuroprotective activities of vanillin and vanillic acid were investigated in Fe²⁺- induced oxidative toxicity in brain tissues by investigating their therapeutic effects on oxidative imbalance, cholinergic and nucleotide-hydrolyzing enzymes activities, dysregulated metabolic pathways. Their cytotoxicity was investigated in hippocampal neuronal cell lines (HT22). The reduced glutathione level, SOD and catalase activities were ameliorated in tissues treated with the phenolics, with concomitant depletion of malondialdehyde and nitric oxide levels. They inhibited acetylcholinesterase and butyrylcholinesterase activities, while concomitantly elevated ATPase activity. Treatment with vanillin led to restoration of oxidative-depleted metabolites and reactivation of the pentose phosphate and purine metabolism pathways, with concomitant activation of pathways for histidine and selenoamino metabolisms. While vanillic acid restored and reactivated oxidative-depleted metabolites and pathways but did not activate any additional pathway. Both phenolics portrayed good binding affinity for catalase, with vanillic acid having the higher binding energy of -7.0 kcal/mol. Both phenolics were not cytotoxic on HT22 cells, and their toxicity class were predicted to be 4. Only vanillin was predicted to be permeable across the blood brain barrier (BBB). These results insinuate that vanillin and vanillic acid confer a neuroprotective effect on oxidative brain damage, when vanillin being the most potent.

Buddleja saligna Willd (Loganiaceae) inhibits angiotensin-converting enzyme activity in oxidative cardiopathy with concomitant modulation of nucleotide hydrolyzing enzymatic activities and dysregulated lipid metabolic pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Buddleja saligna Willd (Loganiaceae), mostly indigenous to South Africa is traditionally used in the treatment cardio-dysfunctional related ailments amongst other diseases.

AIMS

The cardio-protective effect of B. saligna was investigated in ferric-induced oxidative cardiopathy.

METHODS

Hearts harvested from healthy male SD rats were incubated with 0.1 mM FeSO₄ to induce oxidative damage and co-incubated with B. saligna extract. Reaction mixtures without the extract served as negative control, while tissues without the extract or standard antioxidant (gallic acid) and pro-oxidant served as the normal control. The tissues were analyzed for levels of glutathione, malondialdehyde, and nitric oxide as well as cholinergic, angiotensin-converting enzyme (ACE), lipase, and purinergic enzymes activities, lipid profiles, fatty acid metabolic pathways and metabolites.

RESULTS

Induction of oxidative damage significantly (p < 0.05) depleted the levels of GSH, SOD, catalase, and ENTPDase activities, while concomitantly elevating the levels of MDA, NO, ACE, acetylcholinesterase, lipase and ATPase activities. These levels and activities were significantly reversed on treatment with B. saligna. Treatment with B. saligna also led to depletion of cardiac cholesterol and LDL-c levels, while elevating triglyceride and HDL-c level. It also depleted oxidative-induced lipid metabolites with concomitant generation of thirteen other metabolites. B. saligna also inactivated oxidative-induced pathways for beta oxidation of very long chain fatty acids, glycerolipid metabolism, and fatty acid elongation in mitochondria.

CONCLUSION

These results suggest that B. saligna protects against ferric-induced oxidative cardiopathy by mitigating oxidative stress, while concomitantly inhibiting ACE, acetylcholinesterase and lipase activities, and modulating lipid spectrum and dysregulated metabolic pathways.

Thymol polymeric nanoparticle synthesis and its effects on the toxicity of high glucose on OEC cells: involvement of growth factors and integrin-linked kinase

Background

Nowadays, the drug delivery system is important in the treatment of diseases.

Purpose

A polymeric nanoparticle modified by oleic acid (NPMO) as a Thymol (Thy) drug release system was synthesized from Thymbra spicata and its neurotrophic and angiogenic effects on rat’s olfactory ensheathing cells (OECs) in normal (NG) and high glucose (HG) conditions were studied.

Methods

The NPMO was characterized by using different spectroscopy methods, such as infrared, HNMR, CNMR, gel permeation chromatography, dynamic light scattering, and atomic force microscopy. Load and releasing were investigated by HPLC. The toxicity against OECs diet-induced by MTT assay. ROS and generation of nitric oxide (NO) were evaluated using dichloro-dihydro-fluorescein and Griess method, respectively. The expression of protein integrin-linked kinase (ILK), vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF) were evaluated by Western blotting.

Results

ThyNPMO is desirable for transferring drug as a carrier. The amount of Thy and extract (E) loaded on NPMO estimated at 43±2.5% and 41±1.8%, respectively. Then, 65% and 63% of the drug load were released, respectively. Thy, ThyNPMO, E, and ENPMO prevented HG-induced OECs cell death (EC50 33±1.5, 22±0.9, 35±1.8, and 25±1.1 μM, respectively). Incubation with Thy, ThyNPMO, E ,and ENPMO at high concentrations increased cell death with LC50 105±3.5, 82±2.8, 109±4.3, and 86±3.4 μM, respectively in HG states.

Conclusion

OECs were protected by ThyNPMO and ENPMO in protective concentrations by reducing the amount of ROS and NO, maintaining ILK, reducing VEGF, and increasing BDNF and NGF. The mentioned mechanisms were totally reversed at high concentrations.