Computational drug discovery of potential phosphodiesterase inhibitors using in silico studies

Pterocarpus soyauxii (Fabaceae) aqueous extract to prevent neuropsychiatric disorders associated with menopause by triggering ROS-dependent oxidative damage and inhibiting acetylcholinesterase, GABA-transaminase, and monoamine oxidase A: In vitro, in vivo, and in silico approaches

Pterocarpus soyauxii (PS) is traditionally used in Cameroon medicine to alleviate postmenopausal symptoms. Previous research has shown that it has tissue-selective potential and estrogen-mimetic effects on vaginal atrophy. Phytoestrogens like 7-O-acetyl formononetin, khrinone A, and 3',5'-dimethoxy-4-stilbenol were found in its water extract by UHPLC, but there is no evidence of its effects on neurological disorders linked to post-menopause (ND-PO). The study aimed to investigate the phytochemical profile of PS aqueous extract, assess its neuroprotective potential in rats, and explore possible underlying pathways. We used colorimetric assays to study the phytochemical profile of PS extract. Effects of the extract on behavioral parameters, neuronal signaling, and integrity in an 84-day ovariectomized rat model. Molecular docking was performed to assess the ability of 7-O-acetyl formononetin, an isoflavone contained in PS, to cross the BBB and its binding affinity to the active sites of AChE, MAO-A, and GABA-T. Besides, the anti-AChE/BChE, antioxidant, and anti-inflammatory effects of PS were assessed by in vitro tests. PS aqueous extract contains polyphenols (656.58 ± 9.18 mgEAG/100gMS), flavonoids (201.25 ± 5.52 mgEQ/100gDW), and tannins (18.42 ± 1.25 mg/100gDW). It slows down anxiety, depressive disorders, cellular disorganization, and neuronal death in the hippocampus, dentate gyrus, and neocortex. In silico modeling was a powerful tool to assess the 7-O-acetylformononetin's ability to cross the BBB and strongly bind and inhibit AChE, MAO-A, and GABA-T. Thus, by combining GABAergic, cholinergic, and serotoninergic modulation, PS aqueous extract also possesses remarkable anti-AChE/BChE in vitro and induces antioxidant and anti-inflammatory potential in macrophages. Such estromimetics, antioxidant, anti-inflammatory, cholinergic, and monoaminergic modulators represent promising activities to develop neuroprotective drugs with optimal therapeutic profiles for menopausal women.

Chemical Composition, In Silico and In Vitro Antimutagenic Activities of Ethanolic and Aqueous Extracts of Tigernut (Cyperus esculentus)

Tigernut, also known as Cyperus esculentus, is said to be high in nutritional and medicinal value. The purpose of this study was to determine the C. esculentus’s antimutagenic activity. The ethanolic and aqueous extracts of the nut were analyzed for chemical constituents, antioxidants, ultraviolet-visible, and gas chromatography-mass spectrometry using standard procedures. The extracts contained a total of 17 major compounds that were docked against human RecQ-like protein 5 (RECQL5) helicase protein. The antimutagenic property of the ethanolic extract in vitro was assessed using the Allium cepa chromosome assay. Onion bulbs were pre-treated with 200 mg/kg of ethanolic extract of C. esculentus for 24 h and then, grown in NaN₃ (250 μg/L) for 24 h; onion bulbs were also first exposed to NaN₃ (250 μg/L) for 24 h before treatment with 100 mg/kg and 200 mg/kg of the ethanolic extract respectively. Standard methods were used to determine the mitotic index and chromosomal aberrations. Results revealed that C. esculentus ethanolic extract contained flavonoids (22.47 mg/g), tannins (0.08 mg/g), alkaloids (19.71 mg/g), glycosides, phenol, and tannin and showed high scavenging activity against 2,2-diphenyl-1-picrylhydrazyland H₂O₂. Docking with RECQL5 showed good binding energies (∆G>−7) of five compounds in C. esculentus ethanolic extract. The A. cepa assay results revealed a significant (P<0.05) reduction in chromosomal aberrations and a higher mitotic index in groups treated with the C. esculentus ethanolic extract. The antimutagenic activity of C. esculentus ethanolic extract was attributed to its high levels of phytosterols and phenolic compounds.

Hetero-Tricyclic Lead Scaffold as Novel PDE5A Inhibitor for Antihypertensive Activity: In Silico Docking Studies

Objective:

To screen the phytochemicals for phosphodiesterase 5A (PDE5A) inhibitory potential and identify lead scaffolds of antihypertensive phytochemicals using in silico docking studies.

Methods:

In this perspective, reported 269 antihypertensive phytochemicals were selected. Sildenafil, a PDE5A inhibitor was used as the standard. In silico docking study was carried out to screen and identify the inhibiting potential of the selected phytochemicals against PDE5A enzyme using vLife MDS 4.4 software.

Results:

Based on docking score, π-stacking, H-bond and ionic interactions, 237 out of 269 molecules were selected which have shown one or more interactions. Protein residue Gln817A was involved in H-boding whereas Val782A, Phe820A and Leu804A were involved in π-stacking interaction with ligand. The selected 237 phytochemicals were structurally diverse, therefore 82 out of 237 molecules with one or more tricycles were filtered out for further analysis. Amongst tricyclic molecules, 14 molecules containing nitrogen heteroatom were selected for lead scaffold identification which finally resulted in three different basic chemical backbones like pyridoindole, tetrahydro-pyridonaphthyridine and dihydro-pyridoquinazoline as lead scaffolds.

Conclusion:

In silico docking studies revealed that nitrogen-containing tetrahydro-pyridonaphthyridine and dihydro-pyridoquinazoline tricyclic lead scaffolds have emerged as novel PDE5A inhibitors for antihypertensive activity. The identified lead scaffolds may provide antihypertensive lead molecules after its optimization.