Formamidine-Based Thiuram Disulfides as Efficient Inhibitors of Acid Corrosion of Mild Steel: Electrochemical, Surface, and Density Functional Theory/Monte Carlo Simulation Studies.

Electrochemical, surface, and density functional theory (DFT)/Monte Carlo (MC) simulation studies were used in investigating the characteristics of N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-bis(2,6-dimethylphenyl)formimidamide) (DS1), N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-bis(2,6-diisopropylphenyl)formimidamide) (DS2), N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-dimesitylformimidamide) (DS3), and N,N'-(disulfanne-1,2-dicarbonothioyl)bis(N,N'-bis(2,6-dichlorophenyl)formimidamide) (DS4) as inhibitors of acid corrosion of mild steel. The inhibitors were found to effectively reduce the rates of steel dissolution at the anode as well as cathodic hydrogen evolution. The order of inhibition efficiencies of studied compounds is DS1 (PDP/LPR/EIS: 98.60/97.98/96.94%) > DS2 (PDP/LPR/EIS: 98.36/96.86/96.90%) > DS3 (PDP/LPR/EIS: 94.66/87.44/94.30%) > DS4 (PDP/LPR/EIS: 83.57/77.02/75.17%) at 1.00 mM, and the overall efficiencies appeared to depend on the molecular and electronic structures of the compounds. The compounds offered high resistance to charge transfer across the electrode/electrolyte system by forming adsorbed film whose resistance increased with an increase in concentration. Findings suggested that the adsorption process involved combined chemisorption and physisorption. DFT calculations and MC simulations provided theoretical justifications for the experimental results.

Eggplant (Solanum spp) supplemented fruits diet modulated the activities of ectonucleoside triphosphate diphosphohydrolase (ENTPdase), monoamine oxidase (MAO), and cholinesterases (AChE/BChE) in the brain of diabetic Wistar male rats.

Type 2 diabetes mellitus is associated with complications such as Alzheimer disease (AD). Tropical eggplant (Solanum gilo, Solanum kumba, and Solanum aethiopicum) fruits have been extensively used for the treatment of different ailments. This study assesses the effect of an eggplant supplemented-diet on purinergic, monoaminergic, and cholinergic enzyme systems in diabetic male rats, besides determining the presence of alkaloids using GC-MS chromatography. Results from this study show that eggplant fruit diet modulates the activities of the enzymes in purinergic, monoaminergic, and cholinergic enzyme systems associated with AD-like symptoms. Solanum kumba-supplemented diet significantly (p < 0.05) reduced enzyme activities better than S. gilo and S. aethiopicum, which could be due to its rich phytochemical constituents. In conclusion, eggplant fruits could serve as a holistic measure in the prevention of diabetes-related complications such as neurodegenerative disease. PRACTICAL APPLICATIONS: The therapeutic management of diabetes fails to holistically address inflammatory response which likely contributes to type 2 diabetes mellitus (T2DM) occurrence by causing insulin resistance; this, in turn, is intensified in the presence of hyperglycemia to promote long-term complications such as neurodegenerative disorders. The health benefit of a tropical eggplant fruit diet inform a nutritional and therapeutic approach for the prevention and treatment of T2DM and its associated complications such as neurodegenerative disorders has been proved. The eggplant fruit-supplemented diet, which is cost-effective with little or no side effect, could substantially increase the antioxidant status and also modulate the activities of neuronal enzymes in a diabetic model with dementia, as well as Alzheimer's-like symptoms. This study, therefore, revealed more of the benefits of tropical eggplant fruits vis-à-vis their management in hyperglycemia-mediated neurodegeneration.

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.

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.

Effect of cooking on glycemic index, antioxidant activities, α-amylase, and α-glucosidase inhibitory properties of two rice varieties.

This study was designed to investigate the influence of cooking on the glycemic index (GI), amylose, and amylopectin contents of two rice varieties. Two rice varieties (foreign long rice and ofada) were sourced for, divided into two, one portion cooked and the other used raw. The sugar, starch, amylose, and amylopectin contents as well as glycemic indices, antioxidant properties, and the ability of the rice to inhibit carbohydrate-hydrolyzing enzymes (α-amylase and α-glucosidase) were determined. In addition, polyphenol content was determined. The results revealed that cooking caused a significant increase in starch content of the rice varieties. In the same vein, cooking increases the amylopectin content but has no effect on the amylose content. In addition, cooking shows no effect on polyphenol content but significantly increases radical scavenging ability of rice varieties used in this study. Furthermore, cooking lower the α-amylase and α-glucosidase inhibitory properties of two rice varieties except for foreign rice. However, the inhibitory effect of both cooked and raw foreign and ofada rice on α-amylase and α-glucosidase coupled with their low GI may explain their important role in controlling blood glucose level.

In Vitro Studies on the Antioxidant Property and Inhibition of α-Amylase, α-Glucosidase, and Angiotensin I-Converting Enzyme by Polyphenol-Rich Extracts from Cocoa (Theobroma cacao) Bean.

Background. This study sought to investigate the antidiabetic and antihypertensive mechanisms of cocoa (Theobroma cacao) bean through inhibition of α-amylase, α-glucosidase, angiotensin-1 converting enzyme, and oxidative stress. Methodology. The total phenol and flavonoid contents of the water extractable phytochemicals from the powdered cocoa bean were determined and the effects of the extract on α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities were investigated in vitro. Furthermore, the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), 2,2..-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), hydroxyl (OH), and nitric oxide (NO)] scavenging ability and ferric reducing antioxidant property of the extract were assessed. Results. The results revealed that the extract inhibited α-amylase (1.81 ± 0.22 mg/mL), α-glucosidase (1.84 ± 0.17 mg/mL), and angiotensin-1 converting enzyme (0.674 ± 0.06 mg/mL [lungs], 1.006 ± 0.08 mg/mL [heart]) activities in a dose-dependent manner and also showed dose-dependent radicals [DPPH (16.94 ± 1.34 mg/mL), NO (6.98 ± 0.886 mg/mL), OH (3.72 ± 0.26 mg/mL), and ABTS (15.7 ± 1.06 mmol/TEAC·g] scavenging ability. Conclusion. The inhibition of α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities by the cocoa bean extract could be part of the possible mechanism by which the extract could manage and/or prevent type-2 diabetes and hypertension.