Dihydroquercetin improves rotenone-induced Parkinsonism by regulating NF-κB-mediated inflammation pathway in rats.

This study examined the effect of dihydroquercetin (DHQ), also knofigurewn as taxifolin, on rotenone-induced Parkinsonism in rats. Male Wistar rats were administered 1.5 mg/kg rotenone for 10 days and subsequently treated with 0.25-1.0 mg/kg DHQ for 3 days followed by the assessment of parkinsonian symptoms. Brain striatal redox stress and neurochemical dysfunction markers were assessed spectrophotometrically. Histopathological evaluation of the striatum was done by hematoxylin and eosin staining technique. The expression of genes involved in the activation of NF-κB signaling pathway (IL-1ß, TNF-α, NF-κB and IκKB), and the p53 gene in the striatum were determined by RT-qPCR. DHQ attenuated parkinsonian symptoms as well as striatal redox stress, neurochemical dysfunction, and histological alterations occasioned by rotenone toxicity. Importantly, DHQ significantly suppressed the rotenone-induced upregulation of IL-1ß, NF-κB, and IκKB expression (p < 0.05) in the striatum of parkinsonian rats. DHQ demonstrated notable neurotherapeutic potential against rotenone-induced Parkinsonism in rats by improving parkinsonian symptoms (bradykinesia, catalepsy, postural instability, impaired locomotor behavior, and tremor) and neurochemical dysfunctions via modulation of genes involved in the activation of the canonical pathway of NF-κB-mediated inflammation.

Identification of lead compounds from large natural product library targeting 3C-like protease of SARS-CoV-2 using E-pharmacophore modelling, QSAR and molecular dynamics simulation.

COVID-19 is a novel disease caused by SARS-CoV-2 and has made a catastrophic impact on the global economy. As it is, there is no officially FDA approved drug to alleviate the negative impact of SARS-CoV-2 on human health. Numerous drug targets for neutralizing coronavirus infection have been identified, among them is 3-chymotrypsin-like-protease (3CLpro), a viral protease responsible for the viral replication is chosen for this study. This study aimed at finding novel inhibitors of SARS-CoV-2 3C-like protease from the natural library using computational approaches. A total of 69,000 compounds from natural product library were screened to match a minimum of 3 features from the five sites e-pharmacophore model. Compounds with fitness score of 1.00 and above were consequently filtered by executing molecular docking studies via Glide docking algorithm. Qikprop also predicted the compounds drug-likeness and pharmacokinetic features; besides, the QSAR model built from KPLS analysis with radial as binary fingerprint was used to predict the compounds inhibition properties against SARS-CoV-2 3C-like protease. Fifty ns molecular dynamics (MD) simulation was carried out using GROMACS software to understand the dynamics of binding. Nine (9) lead compounds from the natural products library were discovered; seven among them were found to be more potent than lopinavir based on energies of binding. STOCK1N-98687 with docking score of -9.295 kcal/mol had considerable predicted bioactivity (4.427 µM) against SARS-CoV-2 3C-like protease and satisfactory drug-like features than the experimental drug lopinavir. Post-docking analysis by MM-GBSA confirmed the stability of STOCK1N-98687 bound 3CLpro crystal structure. MD simulation of STOCKIN-98687 with 3CLpro at 50 ns showed high stability and low fluctuation of the complex. This study revealed compound STOCK1N-98687 as potential 3CLpro inhibitor; therefore, a wet experiment is worth exploring to confirm the therapeutic potential of STOCK1N-98687 as an antiviral agent.

Identification of Main Protease of Coronavirus SARS-CoV-2 (Mpro) Inhibitors from Melissa officinalis.

BACKGROUND: The recent outbreak of Coronavirus SARS-CoV-2 (Covid-19), which has rapidly spread around the world in about three months with tens of thousands of deaths recorded so far is a global concern. An urgent need for potential therapeutic intervention is of necessity. Mpro is an attractive druggable target for the development of anti-COVID-19 drug development. METHODS: Compounds previously characterized by Melissa officinalis were queried against the main protease of coronavirus SARS-CoV-2 using a computational approach. RESULTS: Melitric acid A and salvanolic acid A had higher affinity than lopinavir and ivermectin using both AutodockVina and XP docking algorithms. The computational approach was employed in the generation of the QSAR model using automated QSAR, and in the docking of ligands from Melissa officinalis with SARS-CoV-2 Mpro inhibitors. The best model obtained was KPLS_Radial_ 28 (R2 = 0.8548 and Q2=0.6474, which was used in predicting the bioactivity of the lead compounds. Molecular mechanics based MM-GBSA confirmed salvanolic acid A as the compound with the highest free energy and predicted bioactivity of 4.777; it interacted with His-41 of the catalytic dyad (Cys145-His41) of SARS-CoV-2 main protease (Mpro), as this may hinder the cutting of inactive viral protein into active ones capable of replication. CONCLUSION: Salvanolic acid A can be further evaluated as a potential Mpro inhibitor.

Ameliorative effect of quercetin, catechin, and taxifolin on rotenone-induced testicular and splenic weight gain and oxidative stress in rats.

Background The physiological functions of the testis and spleen can be affected through several cellular and molecular mechanisms such as the generation of reactive oxygen species (ROS) that causes oxidative stress. This study aimed at investigating the protective effect of catechin, quercetin, and taxifolin in rotenone-induced testicular and splenetic toxicity. Methods Male Wistar rats were administered with 1.5 mg/kg rotenone (s.c.) for 10 days followed by post-treatment with catechin (5, 10, or 20 mg/kg), quercetin (5, 10, or 20 mg/kg), and taxifolin (0.25, 0.5, or 1.0 mg/kg) for 3 days (s.c.), followed by estimation of biochemical markers of oxidative stress, inflammatory activities, and tissue damage in testes and spleen. Results Exposure of rats to rotenone caused reduced body weight gain, increased organ weight, decreased glutathione level and activities of glutathione transferase and superoxide dismutase, enhanced lipid peroxidation, and increased activities of prooxidant/proinflammatory enzymes and lactate dehydrogenase, which were mitigated by post-treatment with flavonoids. In general, quercetin and taxifolin showed better activity than catechin. Conclusions Catechin, quercetin, and taxifolin ameliorated rotenone-induced weight disturbances and oxidative damage in rats, indicating their potential relevance in toxicant and pesticide-induced tissue injury.