Hydrocarbon stapled temporin-L analogue as potential antibacterial and antiendotoxin agents with enhanced protease stability.

Antimicrobial resistance (AMR) is a serious global concern and a huge burden on the healthcare system. Antimicrobial peptides (AMPs) are considered as a solution of AMR due to their membrane-lytic and intracellular mode of action and therefore resistance development against AMPs is less frequent. One such AMPs, temporin-L (TL) is a 13-mer peptide reported as a potent and broad-spectrum antibacterial agent with significant immunomodulatory activity. However, TL is toxic to human erythrocytes at their antibacterial concentrations and therefore various analogues were synthesized with potent antimicrobial activity and lower hemolytic activity. In this work, we have selected a non-toxic engineered analogue of TL (eTL) and performed hydrocarbon stapling of amino acid residues at i to i + 4 positions at different part of sequence. The synthesized peptides were investigated against both the gram-positive and gram-negative bacteria as well as methicillin resistant S. aureus, its MIC was measured in the concentrations range of 0.9-15.2 µM. All analogues were found equal or better antibacterial as compared to parent peptide. Interestingly one analogue eTL [5-9] was found to be non-cytotoxic and stable in presence of the human serum. Mode of action studies revealed membrane depolarizing and disruptive mode of action with live MRSA. Further in vivo studies of antimicrobial against MRSA infection and anti-endotoxin activities in mice model revealed potential activity of the stapled peptide analogue. Overall, this reports on stapled analogue of the AMPs highlights an important strategy for the development of new antibacterial therapeutics against AMR.

Significant Advancement in Various Synthetic Strategies and Pharmacotherapy of Piperine Derivatives: A Review.

BACKGROUND: Piperine is a natural compound found in black pepper that has been traditionally used for various therapeutic purposes. In the ayurvedic system of medication there is a lot of evidence which shows that the piperine is widely used for different therapeutic purpose. In recent years, there has been an increasing interest in the pharmacological and therapeutic potential of piperine and its derivatives in modern medicine. In order to increase the bioavailability and therapeutic effectiveness of piperine and its analogs, researchers have been looking at various extraction methods and synthesis approaches. Many studies have been conducted in this area because of the promise of piperine as a natural substitute for synthetic medications. OBJECTIVES: The objective of this review article is to provide an up-to-date analysis of the literature on the synthesis of piperine analogs, including their extraction techniques and various biological activities such as antihypertensive, antidiabetic, insecticidal, antimicrobial, and antibiotic effects. Additionally, the review aims to discuss the potential of piperine in modern medicine, given its traditional use in various medicinal systems such as Ayurveda, Siddha, and Unani. The article also provides a comprehensive analysis of the plant from which piperine is derived. CONCLUSION: This review article provides a thorough examination of piperine and the source plant. The best extraction technique for the extraction of piperine and the synthesis of its analogs with various biological activities, including antihypertensive, antidiabetic, insecticidal, antibacterial, and antibiotic properties, are covered in the article. This review aims to provide an updated analysis of the literature on the synthesis of piperine analogs.

Global uses of traditional herbs for hepatic diseases and other pharmacological actions: A comprehensive review.

Hepatocellular carcinoma (HCC) is the 7th most common cancer and the 3rd leading cause of cancer-related death worldwide. It is resistant to the majority of chemotherapeutics and has a dismal prognosis. Hepatocellular carcinoma is a prevalent complication of chronic liver disease (CLD) in India. Primary liver cancer is the 6th most common cancer worldwide and the 4th most prevalent cause of cancer-related death. In 2018, it affected 841,000 people and caused 782,000 deaths around the world. Thus, research into the tumor cycle and its prevention through suitable herbal (Unani/Ayurvedic) medication is critical for reducing the impact of primary liver cancer. Treatment options for end-stage liver cancer are limited, necessitating costly liver transplantation, which is unavailable in most countries. Here, we present the results of a comprehensive literature survey to determine the benefits of using various herbs with liver protective and antioxidant properties. This information will be useful to researchers working on liver carcinoma and free radical scavenging, both of which are important in curbing potential carcinogens.

Synthesis and SAR of Potential Anti-Cancer Agents of Quinoline Analogues: A Review.

Quinoline has recently become an important heterocyclic molecule due to its numerous industrial and synthetic organic chemistry applications. Quinoline derivatives have been used in clinical trials for a variety of medical conditions that causes cancer. The present literature study is composed of recent progress (mainly from 2010 to the present) in the production of novel quinoline derivatives as potential anti-cancer agents, as well as their structure-activity relationship, which will provide insight into the development of more active quinoline hybrids in the future. The present review comprises the synthetic protocols of biologically active Quinoline analogs with their structure-activity relationship studies as anti-cancer agents, which provide depth view of work done on quinoline derivatives to the medicinal chemist for future research.

Design, Synthesis, In Vivo, and In Silico Evaluation of Benzothiazoles Bearing a 1,3,4-Oxadiazole Moiety as New Antiepileptic Agents.

In the presented manuscript, a new series of 2-[4-methoxy-3-(5-substituted phenyl-[1,3,4]oxadiazol-2-ylmethoxy)-phenyl]-benzothiazoles (6a-n) have been synthesized and studied in vivo and in silico for their anticonvulsant potential. Maximum electroshocks (MES) and subcutaneous pentylenetetrazol (scPTZ) models have been used for in vivo anticonvulsant activity. Auto Dock 4.2 software was used for in silico studies, and the targeted protein was 5IOV.sThe antidepressant activity of selected compounds (most active) was determined as a reduction in locomotor activity through an actophotometer. In vivo and In silico studies proved that among all the synthesized compounds, 6f, 6h, 6j, and 6l were the most potent with no neurotoxicity as compared to conventional drugs (phenytoin and phenobarbital). The in silico studies also indicated about different binding interactions of synthetic compounds to localize the binding receptors. The most likely mode of action for these drugs, according to the docking analysis of active compounds with various targets, is their binding to the VGCC and NMDA receptors.

Recent Updates on Synthesis, Biological Activity, and Structure-activity Relationship of 1,3,4-Oxadiazole-quinoline Hybrids: A Review.

Due to their diverse applications in industrial and synthetic organic chemistry, quinoline and 1,3,4-oxadiazole have become important heterocyclic compounds. Quinoline and 1,3,4- oxadiazole compounds have been developed for various medical conditions such as anti-cancer, anti-bacterial, anti-fungal, antimalarial, antioxidants, anti-HIV, anticonvulsant, antiviral, etc. The current review includes synthetic protocols for biologically active 1,3,4-oxadiazole incorporating quinoline hybrids with their structure-activity relationship to explore work (Mainly from 2010 to 2021) based on 1,3,4-oxadiazole-quinoline hybrids to the medicinal chemist for further research in the development of the molecule.

Combinatorial delivery of Ribociclib and green tea extract mediated nanostructured lipid carrier for oral delivery for the treatment of breast cancer synchronising in silico, in vitro, and in vivo studies.

PURPOSE: The current research investigated the development and evaluation of dual drug-loaded nanostructure lipidic carriers (NLCs) of green tea extract and Ribociclib. METHOD: In silico study were performed to determine the effectiveness of combinational approach. The prepared NLCs were subjected to in vitro drug release, lipolysis, haemolysis and cell line studies to assess their in vivo prospect. RESULTS: In silico study was done to get docking score of EGCG (-8.98) close to Ribociclib (-10.78) in CDK-4 receptors. The prepared NLCs exhibited particle size (175.80 ± 3.51 nm); PDI (0.571 ± 0.012); and %EE [RBO (80.91 ± 1.66%) and GTE 75.98 ± 2.35%)] respectively. MCF-7 cell lines were used to evaluate the MTT assay, cellular uptake and antioxidant (ROS and SOD) of prepared NLCs. In vitro drug release showed the controlled release up to 72 h. In vitro lipolysis and in vitro haemolysis studies showed the availability of drugs at absorption sites and the greater in vivo prospects of NLCs respectively. Pharmacokinetic study revealed a 3.63-fold and 1.53-fold increment in RBO and GTE bioavailability in female Wistar rats respectively. CONCLUSION: The prominent potential of green tea extract and RBO-loaded NLCs in enhancing their therapeutic efficacy for better treatment of breast cancer.

Synthesis, biological evaluation, and in silico studies of indole-tethered pyrazoline derivatives as anticancer agents targeting topoisomerase IIα.

We herein report a new series of indole-tethered pyrazoline derivatives as potent anticancer agents. A total of 12 compounds were designed and synthesized by conventional as well as microwave-irradiated synthesis methods. The latter method results in a significant reduction in the duration of reaction along with improved yields. All synthesized derivatives (7a-7l) were evaluated for their cytotoxic activity against A431, HeLa, and MDAMB-231 cell lines. Compounds 7a and 7b were found most potent in the series and demonstrated an IC50 value of 3.17 and 5.16 µM against the A431 cell line, respectively, compared to the standard drug doxorubicin. Compounds 7a and 7b significantly suppress colony formation, migration, and S phase cell cycle arrest of A431 cells. Furthermore, compound 7a regulated the expression of apoptotic proteins causing the downregulation of procaspase 3/9, antiapoptotic protein Bcl-xL, and upregulation of proapoptotic protein Bax in a dose-dependent manner. Topoisomerase enzyme inhibition assay confirmed that compounds 7a and 7b can significantly inhibit topoisomerase IIα. In vivo oral acute toxicity of compounds 7a and 7b revealed that both compounds are safe compared to doxorubicin; cardiomyopathy studies showed normal architecture of cardiomyocytes and myofibrils. In addition, molecular docking studies revealed the possible interaction of compounds 7a and 7b within the active binding site of the topoisomerase enzyme. The 100 ns molecular dynamic simulation of compounds 7a and 7b proved that both compounds validate all screening parameters.

Insight into the Isolation, Synthesis, and Structure-Activity Relationship of Piperine Derivatives for the Development of New Compounds: Recent Updates.

Currently, black pepper commands the leading position among all the spices as a spice of great commercial importance in all the world trade and finds its way into the dietary habits of millions of people worldwide. Black pepper is biologically known as Piper nigrum and contains piperine as the main active chemical constituent. This paper highlights various general methods for extracting piperine from the crude drug such as maceration extraction, hydrotropic extraction, accelerated solvent extraction, thin-layer chromatography, and extraction with ethanol & dichloromethane Ionic fluid-based ultrasonic-assisted extraction, etc. In this review, piperine and its analogs exhibit numerous pharmacological activities and synthetic schemes of insecticidal activity, anti-cancer activity, anti-inflammatory activity, anti-diabetic activity, anti-hyperlipidemic activity, antifungal activity, narcotic activity, etc. and its structure-activity relationship. The biochemistry of piperine has also been summarized in the presented article. This very exhaustive review details the complete information about piperine, its derivatives, and further processing. Furthermore, the current study summarises recent research that has linked piperine to its use as a treatment for a variety of ailments.

1,3,4-Oxadiazoles as Potential Pharmacophore for Cytotoxic Potentiality: A Comprehensive Review.

Cancer is a kind of human cell degenerative disease that has affected many people for several years. Cancer is caused due to the abnormal growth of cells in every particular part of the body. The 1,3,4-oxadiazole ring is found to be a binding moiety that has anticancer potential. Various works on the 1,3,4-oxadiazole moiety showing anticancer activity have been reported. The present analysis summarizes general synthetic methods for 1,3,4 oxadiazole. Different receptors on which these drug acts are discussed. This review also presents pharmacophore models for topoisomerase-I, histone deacetylase, and epidermal growth factor enzymes.

Roflumilast and tadalafil improve learning and memory deficits in intracerebroventricular Aß1-42 rat model of Alzheimer's disease through modulations of hippocampal cAMP/cGMP/BDNF signaling pathway.

BACKGROUND: Alzheimer's disease (AD) is the most prevalent age-dependent neurodegenerative disease characterized by progressive impairment of memory and cognitive functions. Cyclic nucleotides like cAMP and cGMP are well-known to play an important role in learning and memory functions. Enhancement of cAMP and cGMP levels in the hippocampus by phosphodiesterase (PDE) inhibitors might be a novel therapeutic approach for AD. Thus, the present study was planned to explore the therapeutic potential of roflumilast (RFM) and tadalafil (TDF) phosphodiesterase inhibitors in intracerebroventricular (ICV) Aß1-42 induced AD in rats. METHODS: ICV Aß1-42 was administered in rats followed by treatment with RFM (0.05 mg/kg) and TDF (0.51 mg/kg) for 15 days. Novel object recognition (NOR), and Morris water maze (MWM) test were performed during the drug treatment schedule. On the day, 22 rats were sacrificed, and hippocampus was separated for biochemical, neuroinflammation, and histopathological analysis. RESULTS: Aß1-42 infused rats were induce behavioral impairment and increased AChE, BACE-1, Aß1-42, GSK-3ß, phosphorylated tau (p-Tau), pro-inflammatory cytokines (TNF-α, IL-1ß, and IL-6) levels, oxidative stress (increased MDA, Nitrite and decreased GSH), histopathological changes, and reduced cAMP, cGMP, and BDNF levels. RFM and TDF significantly attenuated Aß1-42 induced memory deficits and neuropathological alterations in the hippocampus. CONCLUSION: The outcomes of the current study indicate that RFM and TDF lead to memory enhancement through upregulation of cAMP/cGMP/BDNF pathway, thus they may have a therapeutic potential in cognitive deficits associated with AD.

Synthesis, anti-convulsant activity and molecular docking study of novel thiazole pyridazinone hybrid analogues.

Pyridazinone analogues have been known to be potential candidates for anticonvulsant agents. We have identified several pyridazinone-based anticonvulsant agents. As a continuation to our previous research, a series of hybrid pyridazinone-thiazole connected through amide linkage were designed and synthesized. Among these, compound SP-5F demonstrated significant anticonvulsant activity with median effective dose of 24.38 mg/kg (MES) and 88.23 mg/kg (scPTz). Results of GABA estimation showed a marked increase in the GABA level when compared with control. Molecular docking studies at the active site of GABA receptor, further confirmed the GABA modulatory effects of SP-5F.

Molecular interactions of vinclozolin metabolites with human estrogen receptors 1GWR-α and 1QKM and androgen receptor 2AM9-ß: Implication for endocrine disruption.

Background: Vinclozolin (VCZ) is a widely used antifungal agent with capability to enter into the human food chain. VCZ metabolizes into seven metabolites M1-M7. Several studies have shown its effects on reprotoxicity. However, there is limited information available on the interaction of VCZ metabolites with nuclear receptors. In silico studies aimed at identifying interaction of endocrine disruptor with nuclear receptors serve a prescreening framework in risk assessment.Methods: We studied interactive potential of VCZ and its metabolites with human estrogen (ER) and androgen receptor (AR) using molecular docking method. Binding potential of VCZ and its metabolites with estrogen receptors 1GWR-α, 1QKM and androgen receptor 2AM9-ß was checked by using Schrodinger Maestro 10.5. Estradiol (E2), a natural ligand of ER and AR was taken as a reference.Results: VCZ and its metabolites showed higher or similar binding efficiency on interaction with target proteins when compared with E2. VCZ and its metabolites also exhibited agonistic effect against 1GWR-α, 1QKM and 2AM9-ß with strong binding potential to them.Conclusion: Some VCZ metabolites such as M4 and M5 showed higher binding potencies with 1GWR-α, 1QKM and 2AM9-ß than E2. Toxicity data of VCZ is well endowed. However, endocrine disrupting potential of VCZ via nuclear receptor mediated pathway is less understood. This in silico study revealing that not only VCZ but its metabolites have potential to interact with 1GWR-α, 1QKM and 2AM9-ß offers a platform for further exploration of VCZ in this direction.

Recent Progress of Benzimidazole Hybrids for Anticancer Potential.

This review presents the detailed account of factors leading to cancer and design strategy for the synthesis of benzimidazole derivatives as anticancer agents. The recent survey for cancer treatment in Cancer facts and figures 2017 American Chemical Society has shown progressive development in fighting cancer. Researchers all over the world in both developed and developing countries are in a continuous effort to tackle this serious concern. Benzimidazole and its derivatives showed a broad range of biological activities due to their resemblance with naturally occurring nitrogenous base i.e. purine. The review discussed benzimidazole derivatives showing anticancer properties through a different mechanism viz. intercalation, alkylating agents, topoisomerases, DHFR enzymes, and tubulin inhibitors. Benzimidazole derivatives act through a different mechanism and the substituents reported from the earlier and recent research articles are prerequisites for the synthesis of targeted based benzimidazole derivatives as anticancer agents. The review focuses on an easy comparison of the substituent essential for potency and selectivity through SAR presented in figures. This will further provide a better outlook or fulfills the challenges faced in the development of novel benzimidazole derivatives as anticancer.

Design and synthesis of cell selective α/ß-diastereomeric peptidomimetic with potent in vivo antibacterial activity against methicillin resistant S. Aureus.

Design of therapeutically viable antimicrobial peptides with cell selectivity against microorganisms is an important step towards the development of new antimicrobial agents. Here, we report four de novo designed, short amphipathic sequences based on a α-helical template comprising of Lys, Trp and Leu or their corresponding D-and/or ß-amino acids. Sequence A-12 was protease susceptible whereas its α/ß-diastereomeric analogue UNA-12 was resistant to trypsin and proteinase K up to 24 h. A-12 and UNA-12 exhibited broad-spectrum antibacterial activity (MIC: 2-32 µg/mL) against pathogens including methicillin resistant S. aureus (MRSA) and methicillin-resistant S. epidermidis (MRSE). Interestingly, A-12 was found to be most toxic (>50% haemolytic at 250 µg/mL) whereas UNA-12 was found to be non cytotoxic among the all analogues against hRBCs and human keratinocytes. Interaction studies with artificial membranes by tryptophan fluorescence and acrylamide quenching assay demonstrated A-12 interacted equally in bacterial as well as mammalian mimic membrane whereas UNA-12 was found to be more selective towards bacterial mimic membrane. Further microscopic tool has revealed membrane damaging ability of A-12 and UNA-12 with bactericidal mode of action against MRSA. Encouragingly, peptidomimetics analogue UNA-12 showed remarkable safety and efficacy against MRSA in in-vivo neutropenic mice thigh infection model. In summary, simultaneous replacement of the natural amino acids with D-/ß-congeners is a promising strategy for designing of potent, cell selective and protease stable peptide based antibiotics.

Design, Synthesis, and Pharmacological Screening of Pyridazinone Hybrids as Anticonvulsant Agents.

A series of new hybrid benzimidazole containing pyridazinones derivatives were designed and synthesized in accordance with the pharmacophoric requirements essential for the anticonvulsant activity. The synthesized compounds were evaluated for anticonvulsant activity on mice by the gold standard maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ)-induced seizure models. Among the compounds tested, SS-4F showed significant anticonvulsant activity in both the screens with ED50 values of 25.10 and 85.33 mg/kg in the MES and scPTZ screens, respectively. Compound SS-4F emerged as safer and effective anticonvulsant due to its several-fold higher protective indices. Further, the gamma-aminobutyric acid (GABA) estimation result showed a marked increase in the GABA level (1.7-fold) as compared to the control, which was further confirmed by good binding properties with the GABAA receptor.

Design, Synthesis, and Docking Study of Pyrimidine-Triazine Hybrids for GABA Estimation in Animal Epilepsy Models.

A series of new pyrimidine-triazine hybrids (4a-t) was designed and synthesized, from which potent anticonvulsant agents were identified. Most of the compounds exhibited promising anticonvulsant activity against the maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) tests, along with minimal motor impairment with higher safety compared to the standard drugs, phenytoin and carbamazepine. In the series, 5-(4-(4-fluorophenyl)-6-(4-hydroxyphenyl)-2-thioxo-5,6-dihydropyrimidin-1(2H)-yl)-1,2-dihydro-1,2,4-triazin-3(6H)-one (4o) and 5-(6-(4-hydroxy-3-methoxyphenyl)-4-(4-hydroxyphenyl)-2-thioxo-5,6-dihydropyrimidin-1(2H)-yl)-1,2-dihydro-1,2,4-triazin-3(6H)-one (4s) emerged as most potent anticonvulsant agents with median doses of 22.54 and 29.40 mg/kg (MES ED50 ), 285.02 and 293.42 mg/kg (scPTZ ED50 ), and 389.11 and 412.16 mg/kg (TD50 ), respectively. Docking studies were also performed for all synthesized compounds to get insight into the binding pattern toward the GABAA receptor as a possible mechanism of their anticonvulsant action, and in silico ADME studies were carried out to predict the safety and stability of the molecules. The increased GABA level in the experimental animals in the neurochemical estimation assay confirmed their GABAergic modulating activity. The most potent compounds were also evaluated for their neurotoxic and hepatotoxic effects. Fortunately, they did not show any sign of neurotoxicity or hepatotoxicity, suggesting that they have a broad spectrum of anticonvulsant activity with a large safety margin. Together, this research suggested that 4o and 4s may serve as leads in the discovery and development of new anticonvulsant drugs.

Design, Synthesis, and Biological Evaluation of 6-(2-Amino-substituted phenyl)-4-(substituted phenyl)-1,2,4-triazine-3,5(2H,4H)-dione Derivatives as Anticonvulsant Agents.

As per structural requirement essential for anticonvulsant activity, a series of new 6-(2-amino-substituted phenyl)-4-(substituted phenyl)-1,2,4-triazine-3,5-dione derivatives were designed and synthesized. All the synthesized title derivatives were assessed for in vivo anticonvulsant screening by the two most employed standard animal seizure models, maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ)-induced seizures, along with minimal motor impairment screening by rotarod test. Among all the synthesized compounds, the compound 4r showed excellent anticonvulsant activity with neither signs of neurotoxicity in the minimal motor impairment test nor signs of hepatotoxicity in the serum enzyme activity assay. The in silico studies of these title compounds were carried out for estimation of a pharmacophore pattern and the prediction of pharmacokinetic properties. To know the exact mechanism of our title compounds, a molecular docking study was carried out on the homology model of sodium ion (Na(+) ) channel and GABAA receptors. The results of the docking study as well as the in vitro study on both the receptors showed that our target compounds best act through the GABAA receptor rather than the Na(+) channel receptors. Additionally, GABA enzyme estimation was performed for further confirmation of the mechanism involved in its anticonvulsant activity. Conclusively, the compound 4r presents a novel scaffold in the search for safer and efficient anticonvulsants having neuroprotective as well as GABAergic effects.

Synthesis and evaluation of benzimidazole derivatives as selective COX-2 inhibitors.

A new series of 1-{(5-substituted-alkyl/aryl-1,3,4-oxadiazol-2-yl)methyl}-2-(piperidin-1-ylmethyl)-1Hbenzimidazoles (5a-5r) was synthesized and screened for their inhibitory activity against COX (1 and 2). In vivo antiinflammatory activity of potent compounds was done by carrageenan-induced rat paw edema model. In vitro anticancer activity of synthesized compounds was also performed at the National Cancer Institute (NCI) against NCI 60 cell lines panel. Out of the 18 compounds screened, 5h, 5i, 5j and 5l were found to be potent COX-2 inhibitors in the range of IC50 0.06-0.81 µM. In vivo anti-inflammatory screening results revealed that the compounds 5h and 5j manifested profound percent protection of 72.8 and 75.0%, respectively. Compound 5f exhibited moderate cytotoxicity with 58.79% growth inhibition against SNB-75 (CNS Cancer) cell lines and moderate activity against COX-2 (IC50 = 8.0 µM).