A path from synthesis to emergency use authorization of molnupiravir as a COVID-19 therapy.

Coronaviruses are a group of enveloped viruses with non-segmented, single-stranded, and positive-sense RNA genomes. It belongs to the 'Coronaviridae family', responsible for various diseases, including the common cold, SARS, and MERS. The COVID-19 pandemic, which began in March 2020, has affected 209 countries, infected over a million people, and claimed over 50,000 lives. Significant efforts have been made by repurposing several approved drugs including antiviral, to combat the COVID-19 pandemic. Molnupiravir is found to be the first orally acting efficacious drug to treat COVID-19 cases. It was approved for medical use in the UK in November 2021 and other countries, including USFDA, which granted approval an emergency use authorization (EUA) for treating adults with mild to moderate COVID-19 patients. Considering the importance of molnupiravir, the present review deals with its various synthetic strategies, pharmacokinetics, bio-efficacy, toxicity, and safety profiles. The comprehensive information along with critical analysis will be very handy for a wide range of audience including medicinal chemists in the arena of antiviral drug discovery especially anti-viral drugs against any variant of COVID-19.

EIDD-1931 Treatment Tweaks CYP3A4 and CYP2C8 in Arthritic Rats to Expedite Drug Interaction: Implication in Oral Therapy of Molnupiravir.

EIDD-1931 is the active form of molnupiravir, an orally effective drug approved by the United States Food and Drug Administration (USFDA) against COVID-19. Pharmacokinetic alteration can cause untoward drug interaction (drug-drug/disease-drug), but hardly any information is known about this recently approved drug. Therefore, we first investigated the impact of the arthritis state on the oral pharmacokinetics of EIDD-1931 using a widely accepted complete Freund's adjuvant (CFA)-induced rat model of rheumatoid arthritis (RA) after ascertaining the disease occurrence by paw swelling measurement and X-ray examination. Comparative oral pharmacokinetic assessment of EIDD-1931 (normal state vs arthritis state) showed that overall plasma exposure was augmented (1.7-fold) with reduced clearance (0.54-fold), suggesting its likelihood of dose adjustment in arthritis conditions. In order to elucidate the effect of EIDD-1931 treatment at a therapeutic regime (normal state vs arthritis state) on USFDA-recommended panel of cytochrome P450 (CYP) enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) for drug interaction using the same disease model, we monitored protein and mRNA expressions (rat homologs) in liver tissue by western blotting (WB) and real time-polymerase chain reaction (RT-PCR), respectively. Results reveal that EIDD-1931 treatment could strongly influence CYP3A4 and CYP2C8 among experimental proteins/mRNAs. Although CYP2C8 regulation upon EIDD-1931 treatment resembles similar behavior under the arthritis state, results dictate a potentially reverse phenomenon for CYP3A4. Moreover, the lack of any CYP inhibitory effect by EIDD-1931 in human/rat liver microsomes (HLM/RLM) helps to ascertain EIDD-1931 treatment-mediated disease-drug interaction and the possibility of drug-drug interaction with disease-modifying antirheumatic drugs (DMARDs) upon coadministration. As elevated proinflammatory cytokine levels are prevalent in RA and nuclear factor-kappa B (NF-kB) and nuclear receptors control CYP expressions, further studies should focus on understanding the regulation of affected CYPs to subside unexpected drug interaction.

Sila-CBD Derivatives as Inhibitors of Heme-Induced NLRP3 Inflammasome: Application in Hemolytic Diseases.

Synthesis and biological evaluation of silicon-incorporated phytocannabinoids with improved pharmacological properties toward inflammatory diseases are described. The synthesized sila-analogues 15a, 15b, and 15c displayed potent inhibition of pro-inflammatory cytokines, including IL-1ß, TNF-α, and IL-6 at 10 µM. Further, the release of heme during the lysis of red blood cells in hemolytic diseases is one of the major reasons for inflammation associated with the pathophysiology of these diseases. Due to scanty literature related to inhibitors of heme-mediated induction of the NLRP3 inflammasome, we decided to test these compounds against it. Compounds 15a and 15c significantly inhibited the heme-mediated induction of the NLRP3 inflammasome at a concentration of 0.1 µM. Interestingly, the sila-CBD derivatives also showed higher metabolic stability in contrast to their carbon analogues. Anti-NLRP3 inflammasome activity of compounds 15a and 15c were further validated in vivo against heme-mediated peritoneal inflammation. The anti-inflammatory activity of these compounds could be useful in treating diseases such as sickle cell anemia and thalassemia involving the hemolysis-mediated activation of the NLRP3 inflammasome.

Impact of Disease States on the Oral Pharmacokinetics of EIDD-1931 (an Active Form of Molnupiravir) in Rats for Implication in the Dose Adjustment.

The pharmacokinetic alteration of an antimicrobial medication leading to sub-therapeutic plasma level can aid in the emergence of resistance, a global threat nowadays. In this context, molnupiravir (prodrug of EIDD-1931) is the most efficacious orally against corona virus disease (COVID-19). In addition to drug-drug interaction, the pharmacokinetics of a drug can significantly vary during any disease state, leading to disease-drug interaction. However, no information is available for such a recently approved drug. Therefore, we aimed to explore the oral pharmacokinetics of EIDD-1931 in seven chemically induced disease states individually compared to the normal state using various rat models. Induction of any disease situation was confirmed by the disease specific study(s) prior to pharmacokinetic investigations. Compared to the normal state, substantially lowered plasma exposure (0.47- and 0.63-fold) with notably enhanced clearance (2.00- and 1.56-fold) of EIDD-1931 was observed in rats of ethanol-induced gastric injury and carbon tetrachloride-induced liver injury states. Conversely, paclitaxel-induced neuropathic pain and cisplatin-induced kidney injury states exhibited opposite outcomes on oral exposure (1.43- and 1.50-fold) and clearance (0.69- and 0.65-fold) of EIDD-1931. Although the highest plasma concentration (2.26-fold) markedly augmented in the doxorubicin-induced cardiac injury state, streptozocin-induced diabetes and lipopolysaccharide-induced lung injury state did not substantially influence the pharmacokinetics of EIDD-1931. Exploring the possible phenomenon behind the reduced or boosted plasma exposure of EIDD-1931, results suggest the need for dose adjustment in respective diseased conditions in order to achieve desired efficacy during oral therapy of EIDD-1931.

Orally bioavailable styryl derivative of rohitukine-N-oxide inhibits CDK9/T1 and the growth of pancreatic cancer cells.

The chromone alkaloid is one of the classical pharmacophores for cyclin-dependent kinases (CDKs) and represents the first CDK inhibitor to reach clinical trials. Rohitukine (1), a chromone alkaloid isolated from Dysoxylum binectariferum inspired the discovery of several clinical candidates. The N-oxide derivative of rohitukine occurs naturally, with no reports on its biological activity. Herein, we report isolation, biological evaluation, and synthetic modification of rohitukine N-oxide for CDK9/T1 inhibition and antiproliferative activity in cancer cells. Rohitukine N-oxide (2) inhibits CDK9/T1 (IC50 7.6 µM) and shows antiproliferative activity in the colon and pancreatic cancer cells. The chloro-substituted styryl derivatives, 2b, and 2l, inhibit CDK9/T1 with IC50 values of 0.17 and 0.15 µM, respectively. These derivatives display cellular antiproliferative activity in HCT 116 (colon) and MIA PaCa-2 (pancreatic) cancer cells with GI50 values of 2.5-9.7 µM with excellent selectivity over HEK293 (embryonic kidney) cells. Both analogs induce cell death in MIA PaCa-2 cells via inducing intracellular ROS production, reducing mitochondrial membrane potential, and inducing apoptosis. These analogs are metabolically stable in liver microsomes and have a decent oral pharmacokinetics in BALB/c mice. The molecular modeling studies indicated their strong binding at the ATP-binding site of CDK7/H and CDK9/T1.

Ellagic Acid Exerts Dual Action to Curb the Pathophysiological Manifestations of Sickle Cell Disease and Attenuate the Hydroxyurea-Induced Myelosuppression in Berkeley Mice.

The use of adjuvant therapy is an attractive approach to manage sickle cell disease (SCD) symptomatically. The present study aimed to investigate the potential of ellagic acid as an adjuvant therapy with hydroxyurea (HU), a key drug for SCD with myelosuppressive toxic effects. A panel of experiments was performed using SCD patient's blood (ex vivo) and transgenic mice model of SCD (in vivo). Ellagic acid exhibited the following beneficial pharmacological actions: (a) potent anti-sickling, polymerization inhibitory, and inherent non-hemolytic activity; (b) pronounced action to abrogate HU-induced neutropenia and to improve key hematological parameters during SCD (RBC, Hb, platelet levels); (c) considerable action to foster vascular tone (L-proline); (d) marked attenuating effect against oxidative stress (nitrotyrosine, hypoxanthine, MDA, GSH); (e) substantial inhibitory role against inflammation (analgesic activity and regulation of hemin, TNF-α, IL-1ß, NF-κB/IκBα); (f) remarkable outcome of declining vaso-occlusive crisis (P-selectin, ERK1/2); (g) notable shielding deed against elevated biochemical marker for organ toxicity (creatinine); (h) noticeably prevented histopathological alterations of the spleen. Additionally, the pharmacokinetic study results of HU in the presence and absence of ellagic acid using a mouse model demonstrate that ellagic acid could be safely co-administered with HU. Overall findings suggest that ellagic acid is a promising candidate for adjuvant therapy in SCD based on its own significant ability against SCD and potentiating capability of HU action via targeting improvement at the various stages of pathophysiological complications during SCD and minimizing HU-induced toxicological manifestations.

Ayurveda-based phytochemical composition attenuates lung inflammation and precipitates pharmacokinetic interaction with favipiravir: an in vivo investigation using disease-state of acute lung injury.

Acute respiratory distress syndrome (ARDS) is a critical form of acute lung injury (ALI). Here, we investigated the effect of a defined combination of ten pure phytochemicals in equal proportions of weight (NPM) from plants, recommended by Ayurveda for any protective action against lipopolysaccharide (LPS)-induced ALI. Results indicate that NPM markedly improved protein and neutrophil contents, myeloperoxidase and hydroxyproline levels, oxidative stress markers (glutathione and malonaldehyde), inflammatory cytokines, and genes (IL-6, TNF-α, TGF-ß, and NF-κB/IκBα) in BALF/lung tissue. The histopathological examination of the lung revealed the shielding effect of NPM against ALI. NPM exhibited a protective effect on the lung by reducing oxidative stress and inhibiting inflammation. A substantial drop in favipiravir's oral exposure was observed in ALI-state compared to normal-state, but oral exposure upon NPM treatment in ALI-state followed similar behaviour of favipiravir alike normal-state without NPM treatment. Overall, results offer potential insight into Ayurvedic recommendations for immunity boosting during ALI situations.

Ameliorating effect of rutin against diclofenac-induced cardiac injury in rats with underlying function of FABP3, MYL3, and ANP.

Diclofenac is a widely prescribed anti-inflammatory drug having cardiovascular complications as one of the main liabilities that restrict its therapeutic use. We aimed to investigate for any role of rutin against diclofenac-induced cardiac injury with underlying mechanisms as there is no such precedent to date. The effect of rutin (10 and 20 mg/kg) was evaluated upon concomitant oral administration for fifteen days with diclofenac (10 mg/kg). Rutin significantly attenuated diclofenac-induced alterations in the serum cardiac markers (LDH, CK-MB, and SGOT), serum cytokine levels (TNF-α and IL-6), and oxidative stress markers (MDA and GSH) in the cardiac tissue. Histopathological examination and Scanning Electron Microscopy (SEM) findings displayed a marked effect of rutin to prevent diclofenac-mediated cardiac injury. Altered protein expression of myocardial injury markers (cTnT, FABP3, and ANP) and apoptotic markers (Bcl-2 and Caspase-3) in the cardiac tissue upon diclofenac treatment was considerably shielded by rutin treatment. MYL3 was unaffected due to diclofenac or rutin treatment. Rutin also significantly improved diclofenac-induced gastrointestinal and hepatic alterations based on the observed ameliorative effects in key mediators, oxidative stress markers, histopathology examination, and SEM findings. Overall results suggest that rutin can protect the diclofenac-induced cardiac injury by lowering oxidative stress, inhibiting inflammation, and reducing apoptosis. Further research work directs toward the development of phytotherapeutics for cardioprotection.

Glabridin Plays Dual Action to Augment the Efficacy and Attenuate the Hepatotoxicity of Methotrexate in Arthritic Rats.

Glabridin is chemically an isoflavane class of natural phenols and is found mainly in the roots of Glycyrrhiza glabra. It has several beneficial pharmacological actions for the management of inflammatory disorders as well as can counteract drug-induced toxic effects. On the other hand, methotrexate (MTX) is the first-line disease-modifying antirheumatic drug for the treatment of rheumatoid arthritis. However, its treatment is associated with major side effects like hepatotoxicity. In the quest to explore a suitable combination therapy that can improve the efficacy and reduce the hepatotoxicity of MTX, we hypothesized that glabridin might serve the purpose for which there is no literature precedent to date. We explored the antiarthritic efficacy of MTX in the presence or the absence of glabridin using Mycobacterium-induced arthritic model in rats. The results of reduction in paw swelling, inhibition of serum cytokines (TNF-α, IL-6, and IL-1ß), and improvement in the bone joints from radiological and histopathological findings suggest that glabridin can substantially augment the antiarthritic efficacy of MTX. Further, results of concomitant glabridin treatment with MTX in the experimental time frame demonstrate that glabridin could considerably prevent the MTX-induced hepatic alteration in serum biochemical markers (SGPT and SGOT) and oxidative stress markers (malondialdehyde (MDA) and glutathione reduced (GSH)). Moreover, glabridin showed a marked effect in impeding the regulation of NF-κB/IκBα and Nrf2/Keap1 pathways in the hepatic tissues. The results of simultaneous administration of glabridin with MTX in the rat model indicate that glabridin had no pronounced effect of causing severe alteration in the pharmacokinetic behavior of MTX. In summary, glabridin can significantly potentiate the antiarthritic efficacy of MTX and can also minimize its hepatotoxicity via the inhibition of inflammation and oxidative stress. Further research should be performed to develop glabridin as a phytotherapeutics for the improved efficacy and better tolerability of MTX at the reduced dose level of MTX.