Current Enzyme Inhibition - Volume 19, Issue 1, 2023

Background: Benzofurans, interesting heterocyclic compounds, are available abundantly in nature and show a wider range of pharmacological activities. Moreover, in recent years this moiety has been found to have strong antituberculosis potential. Considering the importance of this moiety in the field of medicinal chemistry, we have synthesized a few benzofuran derivatives. Methods: These derivatives were also characterized by standard spectroscopic methods. Synthesized compounds were observed for their anti-tuberculosis activity using microplate Alamar Blue assay (MABA) assay and found to have a minimum of 100 (μg/mL) of minimum inhibitory concentration (MIC) values. Moreover, our molecular docking analyses depicted strong inhibitory potential against a popular TB target, Decaprenylphosphoryl-β-d-ribose 2′-epimerase (DprE1), a crucial enzyme for cell wall synthesis. Results: Compound 9e was found to have a strong binding energy score of -148.47 kcal/mol against the selected targets (PDB id: 6HEZ). Conclusion: All compounds were also found to possess drug-likeness characteristics when checked with Lipinski's filter.

Background: α-Amylase inhibitors are considered an important therapeutic target to control type 2 diabetes mellitus, reducing postprandial hyperglycemia. Medicinal plants are an important source with inhibitory activities of this enzyme but are little studied. Objective: The present study explored the α-amylase inhibition with extracts of 11 medicinal plants available in Saltillo, Mexico; the kinetic mechanism of inhibition of selected extracts and their phytochemical screening; evaluation of the toxicity of Bidens odorata extract in Artemia salina model, as well as estimation of its inhibitory effect under in vitro digestive tract conditions. Methods: The inhibitory assays were carried out spectrophotometrically with aqueous suspensions of the extracts obtained after evaporation of solvent from aqueous and ethanolic infusions. Results: Eleven plants showed an inhibitory effect of α-amylase above 10% of the initial activity at 666.7 ppm. Four plants were selected for kinetic assay due to the inhibitory effect near or higher than 20%. The IC50 for the aqueous suspension of the ethanolic extract of Bidens odorata was 851 ppm, similar to that detected with the drug acarbose. The inhibition mechanism for Bidens odorata, Cinchona succirub, and Opuntia ficus-indicata was competitive, and for Cnidoscolus chayamansa it was uncompetitive. All selected extracts presented flavonoids, the majority contained terpenoids, 3 contained tannins and phenols. The aqueous infusion of Bidens odorata - model of a functional drink showed no toxicity and was characterized by resistance for 60 min to the simulated stomach and intestinal conditions in vitro. Conclusion: The findings of this study revealed the species of medicinal plants, which were not previously considered as sources of α-amylase inhibitors, and their kinetic mechanisms of inhibition, which can be used for functional hypoglycemic food preparation.

Backgound: Alzheimer’s disease (AD) is a progressive and fatal neurodegenerative disease, clinically characterized by memory and cognitive dysfunction. AD affects about 35 million people worldwide today and is estimated to nearly double every 20 years. Cnidoscolus aconitifolius (Miller) I.M. Johnston has been reported in Nigerian ethnomedicine as a memory enhancer. There is a lack of scientific evidence to justify the claims. Moreover, there are no effective neurotherapeutic agents available for the treatment of AD; hence the need arises to search for new and more effective agents. Objective: This study aims to evaluate and identify potential molecules with anti-Alzheimer’s and antioxidant potentials from Cnidoscolus aconitifolius leaves. Methods: The air-dried leaves of Cnidoscolus aconitifolius (Miller) I.M. Johnston (PCG/UNN/0267) were extracted using the successive extraction procedure based on increasing the polarity of the eluent in the ascending order of n-hexane, ethyl acetate, and methanol. Phytochemical screening was carried out on the extracts using standard procedures. Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities were done according to Ellman’s method. Eserine was used as standard. Antioxidant potentials were evaluated using standard in vitro chemical analyses. A GC-MS (QP2010SE, SHIDMAZU JAPAN) analysis was done to identify bioactive compounds from the most active fraction. Statistical analyses were performed using one-way ANOVA followed by Dunnett’s Multiple Comparison test at α0.05. Results: Phytochemical analysis revealed the presence of tannins, resins, saponins, flavonoids, phenols, carbohydrates, alkaloids, and terpenoids. Ethyl acetate fraction demonstrated the highest acetylcholinesterase and butyrylcholinesterase inhibitory activity at 1 mg/mL with IC50 values of 0.288 ± 0.00 mg/mL (82.9% inhibition) and 0.440±0.02 mg/mL ((75.4% inhibition), respectively, compared to eserine (IC50=0.050 ± 0.01 mg/mL) for AChE and (IC50=0.049 ± 0.00 mg/mL) for BuChE. Metal (ferrous ion) chelating activity was also high in the ethyl acetate fraction with IC50 value of 0.160 ± 0.00 mg/mL compared to EDTA (IC50 = 0.085 ± 0.00 mg/mL) at 1 mg/mL. Hydroxyl radical scavenging activity was higher in the ethyl acetate fraction (IC50 = 0.352 ± 0.01 mg/mL) when compared to BHT (IC50 = 0.074 ± 0.00 mg/mL) at 1 mg/mL. The pro-anthocyanidin content was also higher in ethyl acetate (6.94 ± 0.16 mg cyanidin/g of sample) compared to other fractions. GC-MS analysis of the most active fraction (ethyl acetate) revealed a total of 56 compounds. The major compounds revealed were: n-Hexadecanoic acid (Area % of 13.45%; Retention time of 14.863), Phytol (Area % of 5.13%; Retention time of 15.864), Octadecanoic acid (Area % of 4.86%; Retention time of 16.211), 9, 12, 15-Octadecatrienoic acid (Z,Z,Z) (Area % of 26.85%; Retention time of 16.09), Squalene (% Area of 2.65%; Retention time of 20.94) and alpha-Tocopheryl acetate (% Area of 1.71%; Retention time of 23.40). Conclusion: C. aconitifolius has the potential to inhibit cholinesterase enzymes involved in the pathology of Alzheimer’s disease. The molecules identified could serve as potential drug leads in managing Alzheimer’s disease.

Background: Aromatase is a catalytic enzyme involved in the biosynthesis of estrogen from androgen. It catalyzes the last rate-limiting/crucial critical step in estrogen biosynthesis. Following the success of the aromatase inhibitor, researchers are working on developing a small physiologically active molecule with fewer side effects and improved tolerance. Objectives: Inhibition of the aromatase enzyme, which plays a major role in the rate-limiting phase, is one strategy to prevent estrogen synthesis. After knowing the importance of nitrogen atom containing moieties in the treatment of breast cancer, we have designed some N-(4-(1H-benzo[d]imidazol-2- yl)phenyl)arylamine derivatives through in silico screening such as ADMET analysis and molecular docking studies. From the present investigation, we aimed for the synthesis and biological evaluation of the most potent derivatives obtained in this study. Methods: The selected derivatives were synthesized and confirmed by spectral analysis (FTIR, 1H NMR, and Mass). Cytotoxic activity of the compounds was evaluated by colorimetric MTT assay on MDA-MB-231 (breast adenocarcinoma), MCF-7(breast adenocarcinoma), A549 (lung adenocarcinoma) NCI-H23 (Lung carcinoma) and A-498 (Renal carcinoma) cell line using Doxorubicin hydrochloride as a positive control. Results: From the present investigation, we have concluded that compound 10 [N-(4-(1Hbenzo[ d]imidazol-2-yl)phenyl)-1H-benzo[d]imidazol-5-amine) is most potent and exhibited -9.5 kcal/mol binding affinity. It has formed conventional hydrogen bonds with ALA306 and THR310. It displayed most promising activity with GI50 values 0.796 ± 0.06 μM, 0.695 ± 0.05 μM, 1.14 ± 0.06 μM, 2.15 ± 0.04 μM, and 0.987 ± 0.07 μM against MDAMB-231, MCF-7, A-549, NCI-H23, and A- 498, respectively when compared with Doxorubicin (0.306 ± 0.04 μM, 0.270 ± 0.02 μM, 0.297 ± 0.04 μM, 0.305 ± 0.04 μM, and 0.345 ± 0.09 μM). Conclusion: From the present investigation, it is concluded that the designed molecules had the potential to be developed as broad-spectrum anticancer agents.

Background: Gestational diabetes mellitus (GDM) is one of the prediabetes conditions in which high blood sugar levels and body weight increase during pregnancy. The underlying molecular and biochemical mechanisms of GDM have been poorly defined. Introduction: Aromatase enzyme activity is responsible for the conversion of androgens to estrogens and has a share in the regulation of body fat distribution and liver receptor homolog-1 (LRH- 1), which plays a critical role in cholesterol transport, acid homeostasis, and steroidogenesis in GDM patients. This study aims to determine the levels of aromatase enzyme and LRH-1 in GDM patients and to investigate the relationship between the levels of aromatase enzyme and LRH-1 and the levels of insulin, HbA 1c and total cholesterol. Methods: This prospective cross-sectional study was conducted over eleven months (September 2020 to July 2021). The study population was selected at Harran University Teaching and Research Hospital. The study included 32 GDM patients and 32 healthy pregnants. The automated assay measured serum fasting blood glucose, HbA1c, and insulin levels (AVIDA 1800 Chemistry System; Siemens). Aromatase enzyme activity and LRH-1 levels were determined by using a commercial enzyme-linked immunosorbent assay (ELISA) kit. Results: Aromatase activity decreased in GDM patients while LRH1 increased. Significant differences in means levels of fasting blood glucose (p = 0.11), insulin (p = 0.001) and HbA1c (p = 0.001) between the patients and control groups. There was a significant negative correlation between the levels of aromatase and insulin (r = -370, p = 0.037). In addition, a positive significant correlation coefficient (r = 0.645, p = 0.001) was found between HbA1c and total cholesterol among the patients' group. Conclusion: Our findings indicate that there is a negative relationship between aromatase activity and insulin levels. Aromatase and LRH 1 may play a role in the pathogenesis of GDM, and the use of LRH-1 agonists in treating the disease may be considered an alternative treatment in the future. However, additional studies are required to reveal the possible functions of these two proteins in GDM with their mechanisms.

Background: Breast cancer is currently the most diagnosed cancer worldwide. Neoplastic cells and components of the tumor microenvironment trigger enzymes and receptors to facilitate cancer advancement. Syringin, a natural phenylpropanoid glycoside, has been reported to possess anti-cancer activity and affinity with numerous druggable targets of breast carcinoma. Objectives: This work aims to evaluate the effects of syringin on the growth of breast cancer cells (MCF-7) and normal dermal fibroblast cells (HDFn) and its ability to inhibit the protein targets of breast cancer. Methods: Syringin was investigated on cell lines in vitro via MTT assay. Using non-cell-based activity assay kits, its influence on the activity of transforming growth factor-beta receptor type 1 (TGF-βR1), human epidermal growth factor receptor (HER2), epidermal growth factor receptor (EGFR), fibroblast growth factor receptor 4 (FGFR4), and matrix metalloproteinase-2 (MMP-2) was evaluated. Results: Syringin exhibited significant cytotoxicity against MCF-7 cells (IC50: 32.11 μM for 24 hours and 21.35 μM for 48 hours) and was non-toxic on healthy HDFn cells (IC50: >100 μM for 24 and 48 hours). It significantly suppressed the activity of cancer and angiogenesis regulating enzymes in vitro with commendable IC50 values on TGF-βR1 kinase (IC50: 6.48 μM), HER2 kinase (IC50: 7.18 μM), EGFR kinase (IC50: 12.38 μM), FGFR4 kinase (IC50: 16.03 μM), and MMP-2 (IC50: 16.07 μM). Conclusion: Findings showed the selective toxicity of syringin on breast cancer cells and its potential against pro-angiogenic enzymes. These discoveries strongly indicate the significance and therapeutic potential of syringin in targeted cancer therapy.

Background: Acute poisoning by Ethoprphos, an organophosphorus pesticide, leads to a veritable cholinergic syndrome whose diagnosis is based on the determination of cholinesterase activity. The treatment relies on the administration of atropine and pralidoxime to regenerate cholinesterases before their ageing. Case: We report a case of a two-year-old child, hospitalized for ethoprophos poisoning, with seizures associated with tight myosis, bronchial congestion, fever, and sialorrhea. The determination of butyrylcholinesterase and acetylcholinesterase showed low rates throughout the hospitalization. Knowing that pralidoxime was introduced from the 5th day of the poisoning, these rates could be explained by aging of cholinesterases. This phenomenon is well established for organophosphate pesticides (OPs) with methylated or ethyl alkyl groups in contrast to others that are much less documented such as dipropyled OPs such as ethoprophos. The recovery of the enzyme rates was very slow with good clinical improvement. Conclusion: Ethoprophos poisoning may cause a life-threatening prognosis with a possible phenomenon of cholinesterase aging in the absence of rapid management with administration of pralidoxime.