Molecular docking and quantum mechanical studies on biflavonoid structures as BACE-1 inhibitors

Chimgin from Ferula haussknechtii as AChE inhibitor and confirmation of the absolute configuration

Alzheimer's disease (AD) is the most common cause of dementia worldwide and is classified as a neurodegenerative disorder. From a drug design perspective, natural products (NPs) are more drug-like and are highly compatible with biological systems compared to most synthetic libraries. NPs provide a more efficient and cost-effective approach to new drug discovery. However, the complexity of NPs makes their identification a challenging task. Chimgin, a bicyclic monoterpene with three chiral centers, exhibits a wide range of biological activity. Despite this, the exact structure of chimgin has remained unclear until now. In this study, we quantified the amount of chimgin in Ferula haussknechtii using analytical Reversed-phase high-pressure liquid chromatography equipped with photodiode array detector (RP-HPLC-PDA). Furthermore, we determined the absolute configuration of chimgin through electronic circular dichroism (ECD) spectroscopy and time-dependent density functional theory (TDDFT) calculations. Finally, we evaluated its inhibitory effect on AChE through in vitro and in silico studies. The extraction process yielded an output of 2.82 ± 0.10% with an exact amount of 0.62 ± 0.04 mg of chimgin per 100 g of plant. Based on the results of ECD and TDDFT calculation, the absolute configuration of chimgin was determined to be 1S, 2S, 4S. Chimgin exhibited an inhibitory effect on AChE with an IC50 of 37.43 µM and its mechanism of action was found to be competitive. HighlightsChimgin was isolated from the roots of Ferula haussknechtii.The amount of chimgin in the plant was determined by RP-HPLC-PDA.Its absolute configuration of chimgin was determined using ECD.In vitro acetylcholinesterase activity of the chimgin was evaluated.The docking and molecular dynamic simulation of chimgin was done.

Design, synthesis and biological evaluation of non-glucosidal based 1,3,4-thiadiazoles as SGLT-2 inhibitors

AIM

Type-2 diabetes mellitus (T2DM) is a major metabolic disorder needing insulin-independent treatments; this study developed Schiff base 1,3,4-thiadiazole as Sodium Glucose Co-transporters 2 (SGLT2) inhibitors.

MATERIALS AND METHODS

The target compounds were synthesized followed by docking studies, in vitro and in vivo analysis.

RESULTS

In vitro assay revealed SSS 6 and SSS 2 exhibited high SGLT2 inhibition activity i.e. 78.57% ± 2.8 and 74.60% ± 1.12 compared to dapagliflozin (93.65% ± 4.48) at same dosage in enzyme inhibition assays. In vivo results reveals that SSS 2 significantly improved excretion of urinary glucose (854 ± 46.51 mg/body weight) as compared to dapagliflozin (775 ± 32.68 mg/body weight. SSS 6 and SSS 2 significantly decreased blood glucose levels (137 ± 4.89 mg/dL and 183 ± 15.07 mg/dL) relative to dapagliflozin (158 ± 15.9 mg/dL).

CONCLUSION

Compounds SSS 6 and SSS 2 emerge as a potential candidates for further investigation as SGLT2 inhibitors for treating T2DM.

Computer-assisted evaluation of plant-derived β-secretase inhibitors in Alzheimer’s disease

Background

Alzheimer’s disease (AD) is a progressive neurodegenerative age-related dementia that results in memory loss of elderly people. Many hypotheses have been formally articulated till now to decipher the pathogenesis of this disease. According to the compelling amyloidogenic hypothesis, β-secretase is a key regulatory enzyme in AD development and is therefore considered as one of the major targets for the development of drugs to treat AD. In this study, 40 plant-derived phytocompounds, proven to have β-secretase inhibitory activity in different laboratory experiments, were evaluated using computational approaches in order to identify the best possible β-secretase inhibitor(s).

Results

Amentoflavone (IFD score: − 7.842 Kcal/mol), Bilobetin (IFD score: − 7.417 Kcal/mol), and Ellagic acid (IFD score: − 6.923 Kcal/mol) showed highest β-secretase inhibitory activities with high binding affinity among all the selected phytocompounds and interacted with key amino acids, i.e., Asp32, Tyr71, and Asp228 in the catalytic site of β-secretase. Moreover, these three molecules exhibited promising results in different drug potential assessment experiments and displayed signs of correlation with significant pharmacological and biological activities.

Conclusion

Amentoflavone, Biolbetin, and Ellagic acid could be investigated further in developing β-secretase-dependent drug for the effective treatment of AD. However, additional in vivo and in vitro experiments might be required to strengthen the findings of this experiment.

To be ionized or not to be ionized: the vital role of physicochemical properties of galbanic acid derivatives in AChE assay

Alzheimer's disease is a progressive neurodegenerative disorder and patients suffer from memory loss, a decline in language skill and impairment in other cognitive functions. In the cholinergic hypothesis, dysfunction of cholinergic neurons especially in the hippocampus and cerebral cortex contributes to cognitive decline in patients. So agents that enhance acetylcholine concentration could improve cognitive function. AChEIs are among the most studied anti-Alzheimer agents. Galbanic acid as a natural compound with a sesquiterpene coumarin scaffold is a weak inhibitor of AChE. In the present contribution, we discussed the impact of carboxylic group ionization on inhibitory effects. We performed in vitro and in silico studies on galbanic acid, methyl and ethyl galbanates as AChE inhibitors. The order of inhibitory effect on AChE was obtained as ethyl galbanate ∼ methyl galbanate > galbanic acid. Our study highlights the important role of the physicochemical properties of natural lead compounds in each specific assay.Communicated by Ramaswamy H. Sarma.

In silico Molecular Docking Study to Search New SGLT2 Inhibitor based on Dioxabicyclo[3.2.1] Octane Scaffold

Background:

Diabetes is a leading cause of high mortality rate in the world. Recently, SGLT2 inhibitors showed the promising result to treat diabetes and therefore several molecules are approved by the US FDA.

Objective:

SGLT2 inhibitors were designed based on dioxabicyclo[3.2.1] octane with the aim to search new lead molecule.

Methods:

The molecular structures were drawn in ChemBiodraw ultra and molecular docking study was performed by AutoDock Vina 1.5.6 software. The LogP and toxicity were predicted online using AlogP and Lazar in-silico respectively.

Results:

Among all the designed molecules, SK306 showed the maximum binding affinity against the 3dh4 SGLT2 protein of Vibrio parahaemolyticus. LogP values were also calculated in order to determine the lipophilic property of the best binding molecules which show LogP 2.82-3.79 in the range for good absorption and elimination, also predicted to be non-toxic.

Conclusion:

SGLT2 inhibitors were designed based on the dioxabicyclo [3.2.1] octane resulting in a new lead molecule with high binding affinity; also these molecules were predicted to be noncarcinogenic with low LogP.

Morelloflavone as a novel inhibitor of mitotic kinesin Eg5

Among 40 plant-derived biflavonoids with inhibitory potential against Eg5, morelloflavone from Garcinia dulcis leaves was selected for further testing based on in silico analysis of binding modes, molecular interactions, binding energies and functional groups that interact with Eg5. Computational models predicted that morelloflavone binds the putative allosteric pocket of Eg5, within the cavity surrounded by amino acid residues of Ile-136, Glu-116, Glu-118, Trp-127, Gly-117, Ala-133, Glu-215, Leu-214 and Tyr-211. Binding energy was -8.4 kcal/mol, with a single hydrogen bond formed between morelloflavone and Tyr-211. The binding configuration was comparable to that of a reference inhibitor, S-trityl-L-cysteine. Subsequent biochemical analysis in vitro confirmed that morelloflavone inhibited both the basal and microtubule-activated ATPase activity of Eg5 in a manner that does not compete with ATP binding. Morelloflavone also suppressed Eg5 gliding along microtubules. These results suggest that morelloflavone binds the allosteric binding site in Eg5 and thereby inhibits ATPase activity and motor function of Eg5.