In silico screening of chalcone derivatives as potential inhibitors of dihydrofolate reductase: Assessment using molecular docking, paired potential and molecular hydrophobic potential studies

FolE gene expression for folic acid productivity from optimized and characterized probiotic Lactobacillus delbrueckii

BACKGROUND

Lactobacillus delbrueckii was one of the most common milk lactic acid bacterial strains (LAB) which characterized as probiotic with many health influencing properties.

RESULTS

Among seven isolates, KH1 isolate was the best producer of folic acid with 100 µg/ml after 48 h of incubation; FolE gene expression after 24 h of incubation was in the highest value in case of KH1 with three folds. Lactose was the best carbon source for this KH1, besides the best next isolates KH80 and KH98. The selected three LAB isolates were identified through 16S rDNA as Lactobacillus delbrueckii. These three isolates have high tolerance against acidic pH 2-3; they give 45, 10, and 22 CFUs at pH 3, besides 9, 6, and 4 CFUs at pH2, respectively. They also have resistance against elevated bile salt range 0.1-0.4%. KH1 recorded 99% scavenging against 97.3% 1000 µg/ml ascorbic acid. Docking study exhibits the binding mode of folic acid which exhibited an energy binding of - 8.65 kcal/mol against DHFR. Folic acid formed four Pi-alkyl, Pi-Pi, and Pi-sigma interactions with Ala9, Ile7, Phe34, and Ile60. Additionally, folic acid interacted with Glu30 and Asn64 by three hydrogen bonds with 1.77, 1.76, and 1.96 Å.

CONCLUSION

LAB isolates have probiotic properties, antioxidant activity, and desired organic natural source for folic acid supplementation that improve hemoglobin that indicated by docking study interaction.

Identification and validation of the mode of action of the chalcone anti-mycobacterial compounds

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Chalcone 1a inhibits the growth of Mycobacterium bovis BCG (MIC 6.25 µg.ml⁻¹).

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Chalcone 1a directly targets InhA.

Objectives

The search for new TB drugs has become one of the great challenges for modern medicinal chemistry. An improvement in the outcomes of TB chemotherapy can be achieved by the development of new, shorter, cheap, safe and effective anti-TB regimens.

Methods

Chalcones (1a-1o) were synthesized and evaluated for their antimycobacterial activity against Mycobacterium bovis BCG using growth inhibition assays. Compound 1a was selected as a ‘hit’ compound. The mode of action of compound 1a, was identified by mycolic acid methyl esters (MAMEs) and fatty acid methyl esters (FAMEs) analysis using thin layer chromatography. Dose dependent experiments were conducted by over-expressing components of FAS-II in M. bovis BCG to confirm the target. Ligand binding using intrinsic tryptophan assay and molecular docking were used to further validate the target.

Results

MAMEs and FAMEs analysis showed dose-dependent reduction of MAMEs with the overall abundance of FAMEs suggesting that compound 1a targets mycolic acid biosynthesis. Direct binding of 1a to InhA was observed using an intrinsic tryptophan fluorescence binding assay, and a 2-fold IC₅₀ shift was observed with an InhA overexpressing strain confirming InhA as the cellular target.

Conclusion

The chalcone 1a exhibits potent antimycobacterial activity, displays a good safety profile and is a direct inhibitor of InhA, a key component in mycolic acid synthesis, validating this series for further anti-TB drug development.

Dietary flavonoids inhibit the glycation of lens proteins: implications in the management of diabetic cataract

The intervention of functional foods as complementary therapeutic approach for the amelioration of diabetes and sugar induced cataractogenesis is more appreciated over the present day chemotherapy agents owing to their nontoxic and increased bioavailability concerns. Dietary flavonoids, a class of bioactive phytochemicals is known to have wide range of biological activities against variety of human ailments. In the present study, we demonstrate anti-cataract effect of eight dietary flavonoids in sugar induced lens organ culture study. We present data on processes like inhibition of glycation-induced lens cloudiness, lens protein aggregation, glycation reaction and advanced glycation end products formation that can act as biochemical markers for this disease. The selected flavonoids were also tested for their aldose reductase (AR) inhibition (experimental and in silico). The molecular dynamics simulation results shed light on mechanistic details of flavonoid induced AR inhibition. The outcome of the present study clearly focuses the significance of kaempferol, taxifolin and quercetin as potential candidates for controlling diabetic cataract.

Synthesis and in silico investigation of thiazoles bearing pyrazoles derivatives as anti-inflammatory agents

Searching novel, safe and effective anti-inflammatory agents has remained an evolving research enquiry in the mainstream of inflammatory disorders. In the present investigation series of thiazoles bearing pyrazole as a possible pharmacophore were synthesized and assessed for their anti inflammatory activity using in vitro and in vivo methods. In order to decipher the possible anti-inflammatory mechanism of action of the synthesized compounds, cyclooxygenase I and II (COX-I and COX-II) inhibition assays were also carried out. The results obtained clearly focus the significance of compounds 5d, 5h and 5i as selective COX-II inhibitors. Moreover, compound 5h was also identified as a lead molecule for inhibition of the carrageenin induced rat paw edema in animal model studies. Molecular docking results revealed significant interactions of the test compounds with the active site of COX-II, which perhaps can be explored for design and development of novel COX-II selective anti-inflammatory agents.

Flavonoids as a scaffold for development of novel anti-angiogenic agents: An experimental and computational enquiry

Relationship between structural diversity and biological activities of flavonoids has remained an important discourse in the mainstream of flavonoid research. In the current study anti-angiogenic, cytotoxic, antioxidant and cyclooxygenase (COX) inhibitory activities of diverse class of flavonoids including hydroxyl and methoxy substituted flavones, flavonones and flavonols have been evaluated in the light of developing flavonoids as a potential scaffold for designing novel anti-antiangiogenic agents. We demonstrate anti-angiogenic potential of flavonoids using in vivo chorioallantoic membrane model (CAM) and further elaborate the possible structural reasoning behind observed anti-angiogenic effect using in silico methods. Additionally, we report antioxidant potential and kinetics of free radical scavenging activity using DPPH and SOR scavenging assays. Current study indicates that selected flavonoids possess considerable COX inhibition potential. Furthermore, we describe cytotoxicity of flavonoids against selected cancer cell lines using MTT cell viability assay. Structural analysis of in silico docking poses and predicted binding free energy values are not only in accordance with the experimental anti-angiogenic CAM values from this study but also are in agreement with the previously reported literature on crystallographic data concerning EGFR and VEGFR inhibition.