A brief review of the biological potential of indole derivatives

Modulating the aggregation of human prion protein PrP106-126 by an indole-based cyclometallated palladium complex

The spontaneous aggregation of infectious or misfolded forms of prion protein is known to be responsible for neurotoxicity in brain cells, which ultimately leads to the progression of prion disorders. Bovine spongiform encephalopathy (BSE) in animals and Creutzfeldt-Jakob disease (CJD) in humans are glaring examples in this regard. Square-planar complexes with labile ligands and indole-based compounds are found to be efficiently inhibitory against protein aggregation. Herein, we report the synthesis of an indole-based cyclometallated palladium complex. The ligand and complex were characterized by various spectroscopic techniques such as UV-visible, NMR, IR, and HRMS. The molecular structure of the complex was confirmed by single-crystal X-ray crystallography. The interaction of the complex with PrP106-126 was studied using UV-visible spectroscopy, CD spectroscopy, MALDI-TOF MS, and molecular docking. The inhibition effects of the complex on the PrP106-126 aggregation, fibrillization and amyloid formation phenomena were analysed through the ThT assay, CD, TEM and AFM. The effect of the complex on the aggregation process of PrP106-126 was determined kinetically through the ThT assay. The complex presented high binding affinity with the peptide and influenced the peptide's conformation and aggregation in different modes of binding. Furthermore, the MTT assay on neuronal HT-22 cells showed considerable protective properties of the complex against PrP106-126-mediated cytotoxicity. These findings suggest that the compound influences peptide aggregation in different ways, and the anti-aggregation action is primarily associated with the metal's physicochemical properties and the reactivity rather than the ligand. As a result, we propose that this compound be investigated as a potential therapeutic molecule in metallopharmaceutical research to treat prion disease (PD).

NQNHC Ligand-Enabled Cu(I)-Catalyzed Double Hydroamination: A Regio- and Chemoselective Bicyclization of o-Amino 1,6-Diyne

In this work, we have developed an efficient method for the intramolecular double hydroamination of aniline by employing o-amino 1,6-diyne as a potential starting material. This protocol enables easy access to bioactive motif 3,4-dihydro-1H-[1,4]oxazino[4,3-a]indole through an intramolecular cascade bicyclization and concomitant isomerization pathway in one pot. This transformation has been effectively achieved by utilizing a stereoelectronically tuned, π-accepting NHC-supported copper(I) system. During ligand optimization trials, naphthoquinone-annulated N-heterocyclic carbene, Nq(IDipp) [1,3-bis(2,6-diisopropylphenyl)-4,5-naphthoquino-imidazolidene]-supported copper(I) complexes of the type Nq(IDipp)CuX (X = Cl or I) were synthesized and fully characterized using various spectroscopic techniques. For this conversion, NHC plays a crucial role in providing the optimum electron density around the metal center. It is a highly regio- and chemoselective transformation with a high atom economy and uses cheap, environmentally benign copper-based catalysts. Furthermore, a plausible mechanism has been proposed on the basis of experimental observations and literature support.

Anticancer perspectives of monocarbonyl analogs of curcumin: A decade (2014-2024) review

Monocarbonyl analogs of curcumin (MACs) represent structurally modified versions of curcumin. The existing literature indicates that MACs exhibit enhanced anticancer properties compared with curcumin. Numerous research articles in recent years have emphasized the significance of MACs as effective anticancer agents. This review focuses on the latest advances in the anticancer potential of MACs, from 2014 to 2024, including discussions on their mechanism of action, structure-activity relationship (SAR), and in silico molecular docking studies.

Design and Characterization of a Generalist Biosensor for Indole Derivatives

Transcription factor (TF)-based biosensors are useful synthetic biology tools for applications in a variety of areas of biotechnology. A major challenge of biosensor circuits is the limited repertoire of identified and well-characterized TFs for applications of interest, in addition to the challenge of optimizing selected biosensors. In this work, we implement the IclR family repressor TF TtgV from Pseudomonas putida DOT-T1E as an indole-derivative biosensor in Escherichia coli. We optimize the genetic circuit utilizing different components, providing insights into biosensor design and expanding on previous studies investigating this TF. We discover novel physiologically relevant ligands of TtgV, such as skatole. The broad specificity of TtgV makes it a useful target for directed evolution and protein engineering toward desired specificity. TtgV, as an indole-derivative biosensor, is a promising genetic component for the detection of compounds with biological activities relevant to health and the gut microbiome.

Coumarin as an Elite Scaffold in Anti-Breast Cancer Drug Development: Design Strategies, Mechanistic Insights, and Structure-Activity Relationships

Breast cancer is the most common cancer among women. Currently, it poses a significant threat to the healthcare system due to the emerging resistance and toxicity of available drug candidates in clinical practice, thus generating an urgent need for the development of new potent and safer anti-breast cancer drug candidates. Coumarin (chromone-2-one) is an elite ring system widely distributed among natural products and possesses a broad range of pharmacological properties. The unique distribution and pharmacological efficacy of coumarins attract natural product hunters, resulting in the identification of numerous natural coumarins from different natural sources in the last three decades, especially those with anti-breast cancer properties. Inspired by this, numerous synthetic derivatives based on coumarins have been developed by medicinal chemists all around the globe, showing promising anti-breast cancer efficacy. This review is primarily focused on the development of coumarin-inspired anti-breast cancer agents in the last three decades, especially highlighting design strategies, mechanistic insights, and their structure-activity relationship. Natural coumarins having anti-breast cancer efficacy are also briefly highlighted. This review will act as a guideline for researchers and medicinal chemists in designing optimum coumarin-based potent and safer anti-breast cancer agents.

Indole as a Versatile Building Block in Cycloaddition Reactions: Synthesis of Diverse Heterocyclic Frameworks

Indole, a ubiquitous and structurally versatile aromatic compound, has emerged as a key player in the synthesis of diverse heterocyclic frameworks via cycloaddition reactions. These reactions are completely atom-economical and, hence, are considered as green reactions. This review article provides a comprehensive overview of the pivotal role played by indole in the construction of complex and biologically relevant heterocyclic compounds. Here we explore the chemistry of indole-based cycloadditions, highlighting their synthetic utility in accessing a wide array of heterocyclic architectures, including cyclohepta[b]indoles, tetrahydrocarbazoles, tetrahydroindolo[3,2-c]quinoline, and indolines, among others. Additionally, we discuss the mechanistic insights that underpin these transformations, emphasizing the strategic importance of indole as a building block. The content of this article will certainly encourage the readers to explore more work in this area.

"On-Water" accelerated dearomative cycloaddition via aquaphotocatalysis

Sulfur(VI) fluoride exchange (SuFEx) has emerged as an innovative click chemistry to harness the pivotal connectivity of sulfonyl fluorides. Synthesizing such alkylated S(VI) molecules through a straightforward process is of paramount importance, and their water-compatibility opens the door to a plethora of applications in biorelevant and materials chemistry. Prior aquatic endeavors have primarily focused on delivering catalysts involving ionic mechanisms, studies regarding visible-light photocatalytic transformation are unprecedented. Herein we report an on-water accelerated dearomative aquaphotocatalysis for heterocyclic alkyl SuFEx hubs. Notably, water exerts a pronounced accelerating effect on the [2 + 2] cycloaddition between (hetero)arylated ethenesulfonyl fluorides and inert heteroaromatics. This phenomenon is likely due to the high-pressure-like reactivity amplification at the water-oil interface. Conventional solvents proved totally ineffective, leading to the isomerization of the starting material.

Insight on novel oxindole conjugates adopting different anti-inflammatory investigations and quantitative evaluation

Background: A dual COX/5-LOX strategy was adopted to develop new oxindole derivatives with superior anti-inflammatory activity. Methods: Three series of oxindoles - esters 4a-p, 6a-l and imines 7a-o - were synthesized and evaluated for their anti-inflammatory and analgesic activities. Molecular docking and predicted pharmacokinetic parameters were done for the most active compounds. A new LC-MS/MS method was developed and validated for the quantification of 4h in rat plasma. Results: Compounds 4h, 6d, 6f, 6j and 7m revealed % edema inhibition up to 100.00%; also, 4l and 7j showed 100.00% writhing protection. Compound 4h showed dual inhibitory activity with IC50 = 0.0533 and 0.4195 μM for COX-2 and 5-LOX, respectively. Molecular docking rationalized the obtained biological activity. The pharmacokinetic parameters of 4h from rat plasma were obtained.

The untold story of starch as a catalyst for organic reactions

Starch is one of the members of the polysaccharide family. This biopolymer has shown many potential applications in different fields such as catalytic reactions, water treatment, packaging, and food industries. In recent years, using starch as a catalyst has attracted much attention. From a catalytic point of view, starch can be used in organic chemistry reactions as a catalyst or catalyst support. Reports show that as a catalyst, simple starch can promote many heterocyclic compound reactions. On the other hand, functionalized starch is not only capable of advancing the synthesis of heterocycles but also is a good candidate catalyst for other reactions including oxidation and coupling reactions. This review tries to provide a fair survey of published organic reactions which include using starch as a catalyst or a part of the main catalyst. Therefore, the other types of starch applications are not the subject of this review.

Design, synthesis, and anticancer evaluation of 1-benzo[1,3]dioxol-5-yl-3-N-fused heteroaryl indoles

A series of 1-benzo[1,3]dioxol-5-yl-indoles bearing 3-N-fused heteroaryl moieties have been designed based on literature reports of the activity of indoles against various cancer cell lines, synthesized via a Pd-catalyzed C-N cross-coupling, and evaluated for their anticancer activity against prostate (LNCaP), pancreatic (MIA PaCa-2), and acute lymphoblastic leukemia (CCRF-CEM) cancer cell lines. A detailed structure-activity relationship study culminated in the identification of 3-N-benzo[1,2,5]oxadiazole 17 and 3-N-2-methylquinoline 20, whose IC50 values ranged from 328 to 644 nM against CCRF-CEM and MIA PaCa-2. Further mechanistic studies revealed that 20 caused cell cycle arrest at the S phase and induced apoptosis in CCRF-CEM cancer cells. These 1-benzo[1,3]dioxol-5-yl-3-N-fused heteroaryl indoles may serve as a template for further optimization to afford more active analogs and develop a comprehensive understanding of the structure-activity relationships of indole anticancer molecules.

Volatilome: Smells like microbial spirit

In recent years, the study of volatile compounds has sparked interest due to their implications in signaling and the enormous variety of bioactive properties attributed to them. Despite the absence of analysis methods standardization, there are a multitude of tools and databases that allow the identification and quantification of volatile compounds. These compounds are chemically heterogeneous and their diverse properties are exploited by various fields such as cosmetics, the food industry, agriculture and medicine, some of which will be discussed here. In virtue of volatile compounds being ubiquitous and fast chemical messengers, these molecules mediate a large number of interspecific and intraspecific interactions, which are key at an ecological level to maintaining the balance and correct functioning of ecosystems. This review briefly summarized the role of volatile compounds in inter- and intra-specific relationships as well as industrial applications associated with the use of these compounds that is emerging as a promising field of study.

Annulated Heterocyclic[g]Coumarin Composites: Synthetic Approaches and Bioactive Profiling

Coumarins, widely abundant natural heterocyclic compounds, are extensively employed in creating various biologically and pharmacologically potent substances. The hybridization of heterocycles presents a key opportunity to craft innovative multicyclic compounds with enhanced biological activity. Fusing different heterocyclic rings with the coumarin structure presents an intriguing method for crafting fresh hybrid compounds possessing remarkable biological effects. In the pursuit of creating heterocyclic-fused coumarins, a wide range of annulated heterocyclic[g]coumarin composites has been introduced, displaying impressive biological potency. The influence of the linear attachment of heterocyclic rings to the coumarin structure on the biological performance of the resulting compounds has been investigated. This review centers on the synthetic methodologies, structural activity relationship investigation, and biological potentials of annulated heterocyclic[g]coumarin composites. We conducted searches across several databases, including Web of Science, Google Scholar, PubMed, and Scopus. After sieving, we ultimately identified and included 71 pertinent studies published between 2000 and the middle of 2023. This will provide valuable perspectives for medicinal chemists in the prospective design and synthesis of lead compounds with significant therapeutic effects, centered around heterocycle-fused coumarin frameworks.

Unlocking Diversity: From Simple to Cutting-Edge Synthetic Methodologies of Bis(indolyl)methanes

From a synthetic perspective, bis(indolyl)methanes have undergone extensive investigation over the past two to three decades owing to their remarkable pharmacological activities, encompassing anticancer, antimicrobial, antioxidant, and antiinflammatory properties. These highly desirable attributes have spurred significant interest within the scientific community, leading to the development of various synthetic strategies that are not only more efficient but also ecofriendly. This synthesis-based literature review delves into the advancements made in the past 5 years, focusing on the synthesis of symmetrical as well as unsymmetrical bis(indolyl)methanes. The review encompasses a wide array of methods, ranging from well-established techniques to more unconventional and innovative approaches. Furthermore, it highlights the exploration of various substrates, encompassing readily available chemicals such as indole, aldehydes/ketones, indolyl methanols, etc. as well as the use of some specific compounds as starting materials to achieve the synthesis of this invaluable molecule. By encapsulating the latest developments in this field, this review provides insights into the expanding horizons of bis(indolyl)methane synthesis.

Silver(I)/Dirhodium(II) Catalytic Platform for Asymmetric N-H Insertion Reaction of Heteroaromatics

Transition-metal-catalyzed enantioselective N-H insertion reactions of carbene species offer a powerful and straightforward strategy to produce chiral nitrogen-containing compounds. Developing highly selective insertion reactions using indole variants can meet synthetic demand. Herein we present an asymmetric insertion reaction into N-H bonds of the aromatic heterocycles using donor/acceptor-substituted diazo compounds based on a heteronuclear catalytic platform. Although a previously developed catalysis comprising chiral silver catalyst or dirhodium(II,II) paddlewheel complexes with and without chiral phosphoric acid showed modest performance, a unique combination of widely available Rh2(OAc)4 and silver(I) phosphate dimer [(S)-TRIP-Ag]2 enabled asymmetric carbene insertion reactions (up to 98% ee). Moreover, the Ag/Rh catalytic system facilitated regioselective and enantioselective C-H functionalization of protic indoles. Mechanistic investigation based on density functional theory indicated that an in situ-generated Ag-Rh trimetallic enolate is protonated in a chiral environment.

One-Flow Synthesis of Substituted Indoles via Sequential 1,2-Addition/Nucleophilic Substitution of Indolyl-3-Carbaldehydes

Substituted indoles are important as drugs. A number of valuable indoles have been synthesized via nucleophilic substitution at the 3'-position of indoles. However, the preparation of an indolylmethyl electrophile containing a tertiary carbon at the 3'-position and its subsequent nucleophilic substitution are challenging owing to the instability of the electrophile. Herein, we demonstrated the rapid one-flow synthesis of indoles via sequential 1,2-addition/nucleophilic substitution of indolyl-3-carbaldehydes. The use of a microflow technology helped in suppressing the undesired reactions caused by the unstable intermediates, resulting in significantly higher yields and reproducibility compared to those under batch conditions. A crown ether was effective when 1-alkylindole-3-carboxaldehyde was used as a substrate. However, the crown ether exerted a detrimental effect when 1H-indole-3-carboxaldehyde was used. A total of 15 structurally diverse indole derivatives were obtained in generally acceptable to good yields.

Recent Development in the Search for Epidermal Growth Factor Receptor (EGFR) Inhibitors based on the Indole Pharmacophore

The signal transduction and cell proliferation are regulated by the epidermal growth factor receptor. The proliferation of tumor cells, apoptosis, invasion, and angiogenesis is inhibited by the epidermal growth factor receptor. Thus, breast cancer, non-small cell lung cancer, cervical cancer, glioma, and bladder cancer can be treated by targeting the epidermal growth factor receptor. Although third-generation epidermal growth factor receptor inhibitors are potent drugs, patients exhibit drug resistance after treatment. Thus, the search for new drugs is being continued. Among the different potent epidermal growth factor receptor inhibitors, we have reviewed the indole-based inhibitors. We have discussed the structure-activity relationship of the compounds with the active sites of the epidermal growth factor receptor receptors, their synthesis, and molecular docking studies.

In Vitro Hypoglycemic and Antioxidant Activities of Dichloromethane Extract of Xerophyta spekei

Diabetes mellitus is a chronic metabolic disorder which has greatly led to an increase in morbidity and mortality globally. Although Xerophyta spekei is widely used for the management of diabetes among the Embu and Mbeere communities in Kenya, it has never been empirically evaluated for its hypoglycemic activity. This study was carried out to verify the hypoglycemic activity of dichloromethane (DCM) extract of Xerophyta spekei as well as its antioxidant activity using various in vitro techniques. Phytochemicals associated with its antioxidant activity were identified through GC-MS. Data were subjected to descriptive statistics and expressed as mean ± standard error of the mean (X̄ ± SEM). Comparison between various variables was performed by using unpaired Student's t-test and one-way analysis of variance (ANOVA), followed by Tukey's post-hoc test. The confidence interval was set at 95%. The obtained results were presented in tables and graphs. Results showed that there was no difference in α-amylase inhibition activity between the plant extract and the standard (IC50 525.9 ± 12.34 and 475.1 ± 9.115, respectively; p  >  0.05). Besides, the glucose adsorption activity of the extract increased with an increase in glucose concentration (from 5.89 to 32.64 mg/dl at 5 mmol and 30 mmol of glucose, respectively; p  <  0.05). The extract also limited the diffusion of glucose more than the negative control (7.49 and 17.63 mg/dl, respectively; p  <  0.05). It also enhanced glucose uptake by yeast cells. In addition, the studied plant extract showed notable antioxidant activities. The therapeutic effects exhibited by this plant in managing diabetes mellitus and other ailments could be due to its antioxidant as well as its hypoglycemic activity. The study recommends the evaluation of X. spekei for in vivo hypoglycemic and antioxidant activities. Besides, the isolation of bioactive phytochemicals from the plant may lead to the development of new hypoglycaemic agents.

Synthesis of 3-sulfenylindole derivatives from 4-hydroxy-2H-chromene-2-thione and indole using oxidative cross-dehydrogenative coupling reaction and anti-proliferative activity study of some of their sulfone derivatives

The synthesis of hitherto unreported 3-sulfenylindole derivatives is achieved from 4-hydroxy-2H-chromene-2-thione (1) and indole (2) by employing an oxidative cross-dehydrogenative coupling reaction using a combination of 10 mol% of molecular iodine and 1 equivalent of TBHP in DMSO at room temperature. Then, the 3-sulfenylindole derivatives 3a, 3b, 3d, 3f, 3 h, and 3 k were converted into their corresponding sulfone derivatives because of lead likeness properties. Subsequently, a target prediction and docking study of six sulfone derivatives (5a-f) was performed, and four sulfones, namely 5a, 5d, 5e, and 5f, were selected for further in-vitro studies. The four sulfones mentioned above exhibited prominent anti-proliferative activity on breast cancer (MCF7) cell lines. In addition, this reaction was exergonic through quantum chemical analysis of the mechanistic steps. The salient features of this reaction are mild reaction conditions, good yields, and broad substrate scope.

Rhodium(II)-catalyzed transannulation approach to N-fluoroalkylated indoles

Copper(I)-catalyzed cycloaddition of substituted cyclohexenyl acetylenes with azido(per)fluoroalkanes afforded 4-cyclohexenyl-substituted N-(per)fluoroalkylated 1,2,3-triazoles. Their rhodium(II)-catalyzed transannulation led to fused N-(per)fluoroalkyl pyrroles and subsequent oxidation provided N-(per)fluoroalkyl indoles.

Anti-Inflammatory Activity of N'-(3-(1H-indol-3-yl)benzylidene)-2-cyanoacetohydrazide Derivative via sGC-NO/Cytokine Pathway

The N-acylhydrazone function has been reported as a pharmacophore group of molecules with diverse pharmacological activities, including anti-inflammatory effects. Therefore, this study was designed to evaluate the anti-inflammatory potential of the compound N'-(3-(1H-indol-3-yl)benzylidene)-2-cyanoacetohydrazide (JR19) in vivo. The study started with the carrageenan-induced peritonitis model, followed by an investigation of leukocyte migration using the subcutaneous air pouch test and an assessment of the antinociceptive profile using formalin-induced pain. A preliminary molecular docking study focusing on the crystallographic structures of NFκB, iNOS, and sGC was performed to determine the likely mechanism of action. The computational study revealed satisfactory interaction energies with the selected targets, and the same peritonitis model was used to validate the involvement of the nitric oxide pathway and cytokine expression in the peritoneal exudate of mice pretreated with L-NAME or methylene blue. In the peritonitis assay, JR19 (10 and 20 mg/kg) reduced leukocyte migration by 59% and 52%, respectively, compared to the vehicle group, with the 10 mg/kg dose used in subsequent assays. In the subcutaneous air pouch assay, the reduction in cell migration was 66%, and the response to intraplantar formalin was reduced by 39%, particularly during the inflammatory phase, suggesting that the compound lacks central analgesic activity. In addition, a reversal of the anti-inflammatory effect was observed in mice pretreated with L-NAME or methylene blue, indicating the involvement of iNOS and sGC in the anti-inflammatory response of JR19. The compound effectively and significantly decreased the levels of IL-6, TNF-α, IL-17, and IFN-γ, and this effect was reversed in animals pretreated with L-NAME, supporting a NO-dependent anti-inflammatory effect. In contrast, pretreatment with methylene blue only reversed the reduction in TNF-α levels. Therefore, these results demonstrate the pharmacological potential of the novel N-acylhydrazone derivative, which acts through the nitric oxide pathway and cytokine signaling, making it a strong candidate as an anti-inflammatory and immunomodulatory agent.

Screening of potential inhibitors against structural proteins from Monkeypox and related viruses of Poxviridae family via docking and molecular dynamics simulation

Monkeypox virus (MPXV) is an orthopoxvirus which causes zoonotic infection in humans. Even though sporadic cases of this infection are limited to the African continent, but if the infection continues to increase unabated, it can be a cause of serious concern for the human populace. Smallpox vaccination has been in use against monkeypox infection but it only provides mild protection. In the current study, we have screened novel small molecules (estrone fused heterocycles (EH1-EH7)) exhibiting good binding with monkeypox virus protein and related proteins from Poxviridae family of viruses via computational approaches. EH1-7 series of small molecules selected for the work have been synthesized via cycloaddition methodology. Docking and Molecular Dynamics (MD) results highlight EH4 compound to have strong binding affinity towards monkeypox and other related viral proteins selected for the study. Thus, computational outcomes suggest EH4 as a good candidate against monkeypox. Currently, no antiviral medication has been approved against monkeypox and the treatment is only via therapeutics available for smallpox and related conditions that may be helpful against monkeypox. Our study is thus an attempt to screen novel compounds against monkeypox infection, which would, in turn, facilitate development of novel therapeutics against Poxviridae family. HIGHLIGHTSMonkeypox infection is a public health emergency and necessitates immediate drug discovery.Molecular docking study to screen estrone-fused heterocycles compounds against Monkeypox and other orthopoxviruses.Molecular dynamics simulations revealed interaction/high binding affinities among EH4 heterocyclic compound and profilin-like protein from the monkeypox virus.Estrone-fused heterocycles compounds are promising anti-viral agents as per our in silico analysis.Our study provides evidence for investigating estrone-fused heterocycles compounds for further pharmacological interventions.Communicated by Ramaswamy H. Sarma.

Design, Synthesis, Molecular Modelling and in Vitro Evaluation of Indolyl Ketohydrazide-Hydrazone Analogs as Potential Pancreatic Lipase Inhibitors

Inhibition of Pancreatic lipase (PL) is considered to be a promising target for the management of obesity, owing to its crucial role in the digestion of dietary triglycerides. A series of 31 indolyl ketohydrazide-hydrazone analogs (5 aa-cm) were designed, synthesized and evaluated for their PL inhibitory potential. The analogs were designed using molecular modelling studies. The designed analogs were then synthesized by condensation of indolyl oxoacetohydrazide with various substituted benzaldehydes. All the synthesized analogs showed PL inhibitory activity in the range of 4.13-48.35 μM, as compared with orlistat (0.86±0.09 μM). The most potent analog 5 bi (IC50 =4.13±0.95 μM) was found to show a competitive type of inhibition with Ki value of 0.725 μM. Additionally, the molecular docking study proved the binding of analog 5 bi at the active site of PL (PDB ID: 1LPB) with MolDock score of -141.279 kcal/mol. It also exhibited various interactions with the key amino acids namely Phe77, Phe215, Tyr114, Ser152, Arg256, His263, etc. Furthermore, the protein-ligand complex of analog 5 bi was found to be stable in molecular dynamics simulation for 100 ns with RMSD of less than 3.2 and 4 Å for the protein and ligand, respectively. The current work hereby provides a basis for the potential role of indolyl ketohydrazide-hydrazone analogs in PL inhibition and further optimization could result in the generation of new leads as anti-obesity agents.

Indole-Acrylonitrile Derivatives as Potential Antitumor and Antimicrobial Agents-Synthesis, In Vitro and In Silico Studies

A series of 2-(1H-indol-2-yl)-3-acrylonitrile derivatives, 2a-x, 3, 4a-b, 5a-d, 6a-b, and 7, were synthesized as potential antitumor and antimicrobial agents. The structures of the prepared compounds were evaluated based on elemental analysis, IR, ¹H- and ¹³NMR, as well as MS spectra. X-ray crystal analysis of the representative 2-(1H-indol-2-yl)-3-acrylonitrile 2l showed that the acrylonitrile double bond was Z-configured. All compounds were screened at the National Cancer Institute (USA) for their activities against a panel of approximately 60 human tumor cell lines and the relationship between structure and in vitro antitumor activity is discussed. Compounds of interest 2l and 5a-d showed significant growth inhibition potency against various tumor cell lines with the mean midpoint GI₅₀ values of all tests in the range of 0.38-7.91 μM. The prominent compound with remarkable activity (GI₅₀ = 0.0244-5.06 μM) and high potency (TGI = 0.0866-0.938 μM) against some cell lines of leukemia (HL-60(TB)), non-small cell lung cancer (NCI-H522), colon cancer (COLO 205), CNS cancer (SF-539, SNB-75), ovarian cancer ((OVCAR-3), renal cancer (A498, RXF 393), and breast cancer (MDA-MB-468) was 3-[4-(dimethylamino)phenyl]-2-(1-methyl-1H-indol-2-yl)acrylonitrile (5c). Moreover, the selected 2-(1H-indol-2-yl)-3-acrylonitriles 2a-c and 2e-x were evaluated for their antibacterial and antifungal activities against Gram-positive and Gram-negative pathogens as well as Candida albicans. Among them, 2-(1H-indol-2-yl)-3-(1H-pyrrol-2-yl)acrylonitrile (2x) showed the most potent antimicrobial activity and therefore it can be considered as a lead structure for further development of antimicrobial agents. Finally, molecular docking studies as well as drug-likeness and ADME profile prediction were carried out.

Ameliorative effect of ethanolic extract of Carica papaya leaves on hyper-cholesterolemic rats: The egg yolk induced model

Cardiovascular disease is one of the leading killers in the world today, and hyperlipidemia is one of the main risk factors. The prevalence of hyperlipidemia is rising dramatically worldwide and is mostly felt in poorer nations. The majority of communities and individuals in Africa are known to turn to ethnomedicine for their medical requirements. The tropical plant Carica papaya, which is grown for its edible, ripe fruit in Africa, was used in folk medicine for treatment of cardiovascular issues as well as a number of serious illnesses. This study assessed the anticholesterolemic property of the ethanolic extracts of Carica papaya leaves, adapting the egg yolk-induced hyperlipidaemia model in Wistar albino rats. This study prepared egg yolk to induce hyperlipidaemia in the Wistar rats, then treated some groups with the extract of Carica papaya leaves, and other groups with the standard drug Fenofibrate. The Wistar rats in the control group were given 2% acacia instead of egg yolk. The total cholesterol, triglycerides, as well as biological and haematological parameters, were determined. The Carica papaya leaves extracts significantly (p<0.05) decreased the total cholesterol and LDL cholesterol levels at all doses administered, but the extract and the standard drug had no significant effect on HDL cholesterol. An inverse relationship between the Carica papaya leaves extract doses and the cholesterol levels was observed placing the efficacy in the order of 100 mg/kg > 250 mg/kg > Fenofibrate (2.29 mg/kg) > 500 mg/kg. With the potential efficacy of Carica papaya leaves extract in the treatment of hypercholesterolemia and, as a result, cardiovascular diseases, more research on bioactive molecule isolation/characterisation for pharmaceutical use or incorporation into functional food products for CVD management is required.

Straightforward synthesis of N-arylindoles via one-pot Fischer indolisation-indole N-arylation

A microwave-promoted, one-pot, three-component synthesis of N-arylindoles has been developed, utilising sequential Fischer indolisation then copper(i)-catalysed indole N-arylation. Novel arylation conditions were identified that use a simple and cheap catalyst/base system (Cu₂O/K₃PO₄) in an environmentally benign solvent (ethanol), with no requirement for ligands, additives or exclusion of air or water, and microwave irradiation enabled significant acceleration of this commonly sluggish process. These conditions were designed to dovetail with Fischer indolisation, and the resulting one-pot, two-step sequence is rapid (total reaction time = 40 minutes), operationally straightforward, generally high yielding and it draws upon readily available hydrazine, ketone/aldehyde and aryl iodide building blocks. This process shows broad substrate tolerance and we have demonstrated its utility in the synthesis of 18 N-arylindoles bearing varied and useful functionality.

Synthesis, Structure and Biological Activity of Indole-Imidazole Complexes with ZnCl2: Can Coordination Enhance the Functionality of Bioactive Ligands?

The ability of the indole-imidazole hybrid ligands to coordinate with the Zn(II) ion and the resulting structures of this new class of coordination compounds were analyzed in order to determine their structural properties and biological functionalities. For this purpose, six novel Zn(II) complexes, [Zn(InIm)₂Cl₂] (1), [Zn(InMeIm)₂Cl₂] (2), [Zn(IniPrIm)₂Cl₂] (3), [Zn(InEtMeIm)₂Cl₂] (4), [Zn(InPhIm)₂Cl₂] (5) and [Zn₂(InBzIm)₂Cl₂] (6) (where InIm is 3-((1H-imidazol-1-yl)methyl)-1H-indole), were synthesized by the reactions of ZnCl₂ and the corresponding ligand in a 1:2 molar ratio in methanol solvent at an ambient temperature. The structural and spectral characterization of these complexes was performed using NMR, FT-IR and ESI-MS spectrometry and elemental analysis, and the crystal structures of 1-5 were determined using single-crystal X-ray diffraction. Complexes 1-5 form polar supramolecular aggregates by utilizing, for this purpose, the N-H(indole)∙∙∙Cl(chloride) intermolecular hydrogen bonds. The assemblies thus formed differ depending on the distinctive molecular shape, which can be either compact or extended. All complexes were screened for their hemolytic, cytoprotective, antifungal, and antibacterial activities. The results show that the cytoprotective activity of the indole/imidazole ligand significantly increases upon its complexation with ZnCl₂ up to a value comparable with the standard antioxidant Trolox, while the response of its substituted analogues is diverse and less pronounced.

Verification of preparations of (1H-indol-3-yl)methyl electrophiles and development of their microflow rapid generation and substitution

Although highly reactive (1H-indol-3-yl)methyl electrophiles such as (1H-indol-3-yl)methyl halides are potential precursors for the synthesis of various indole derivatives, some researchers have reported difficulties in their preparation due to concomitant undesired dimerization/oligomerization. Nevertheless, there have been some reports on the preparation of (1H-indol-3-yl)methyl halides. To resolve this contradiction, all the previously reported preparations of (1H-indol-3-yl)methyl halides were examined. However, we could not reproduce any of these preparations, and we revised several structures of indole derivatives. Here we show the rapid (0.02 s) and mild (25 °C) generation of an (1H-indol-3-yl)methyl electrophile that enables the rapid (0.1 s) and mild (25 °C) nucleophilic substitution in a microflow reactor. Eighteen unprotected indole analogues can be successfully synthesized using the developed microflow nucleophilic substitution with various nucleophiles.

Synthesis, biological activity of newly designed sulfonamide based indole derivative as anti-microbial agent

Background

In medicinal chemistry, indole and its derivative play an important role. Indole is gaining a lot of importance in medicinal chemistry due to its physiological activity which includes anticancer, antitubercular, antimicrobial, antiviral, antimalarial, anti-inflammatory activities, antileishmanial agents, anti-cholinesterase, and enzyme inhibitory. The spread of antimicrobial resistance becomes a threat to both humans and animals. Antimicrobial resistance has been declared in the top 10 global major health risks by WHO including reported data of 2020 of AMR with 3,106,002 confirmed infections in humans across 70 countries.

Result

In this present work some new sulfonamide-based indole derivatives were synthesized by using 1H-indole -2 carboxylic acid as a starting material. The structure of all synthesized sulfonamide-based indole derivatives was confirmed by 1H NMR and LCMS Spectroscopy.

Conclusion

All the synthesized compounds were screened for anti-microbial activity against Gram Positive Staphylococcus aureus, Bacillus megaterium, and Gram Negative Klebsiella pneumonia, Escherichia coli, Salmonellatyphiae, Shigella sp., Enterobacter aerogenes. Among gram-positive Staphylococcus aureus, and Bacillus megaterium. The compound shows activity against Staphylococcus aureus, and among all gram-negative bacteria against Klebsiella pneumonia shows good activity.

Chemical Profile, Antioxidant and Antibacterial Activities, Mechanisms of Action of the Leaf Extract of Aloe arborescens Mill

Aloe arborescens Mill's extracts have been explored for antibacterial and antioxidant efficacies. However, there is limited information on its chemical composition and mechanism of action. The purpose of this study was to assess the chemical composition, antibacterial and antioxidant activities and mechanism of the whole leaf extract of A. arborescens Mill. The phytochemical profile was analysed with gas chromatography mass spectrometry (GC-MS). The antioxidant and antibacterial activities were screened using 1,1diphenyl2picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and micro-dilution assays, respectively. The effects of the extract on the bacterial respiratory chain dehydrogenase, membrane integrity and permeability were analysed using iodonitrotetrazolium chloride, 260 absorbing materials and relative electrical conductivity assays. GC-MS spectrum revealed 26 compounds with N,N'-trimethyleneurea (10.56%), xanthine (8.57%) and 4-hexyl-1-(7-ethoxycarbonylheptyl)bicyclo[4.4.0]deca-2,5,7-triene (7.10%), being the major components. The extract also exhibited antioxidant activity with median concentration (IC₅₀) values of 0.65 mg/mL on DPPH and 0.052 mg/mL on ABTS. The extract exhibited minimum inhibitory concentration (MIC) values ranging from 0.07 to 1.13 mg/mL. The extract inhibited the bacterial growth by destructing the activity of the respiratory chain dehydrogenase, membrane integrity and permeability. Therefore, the leaf extract has the potential to serve as a source of antibacterial and antioxidant compounds.

Methyl 9-(1-methyl-1H-indol-3-yl)-9-oxononanoate

Methyl 9-(1-methyl-1H-indol-3-yl)-9-oxononanoate was synthesized using Friedel–Crafts acylation between N-methyl indole and methyl 9-chloro-9-oxononanoate. The structure of the newly synthesized compound was elucidated using 1H-NMR, 13C-NMR, NOESY-1D, ESI-MS, FT-IR, and UV-Vis spectroscopy.

Synthesis, antimicrobial activity and molecular docking studies of spiroquinoline-indoline-dione and spiropyrazolo-indoline-dione derivatives

Spiro[benzo[h]quinoline-7,3'-indoline]diones and spiro[indoline-3,4'-pyrazolo[3,4-b]quinoline]diones were efficiently synthesized via one-pot multi-component reactions under ultrasound-promoted conditions. Spiro[benzo[h]quinoline-7,3'-indoline]dione derivatives were successfully developed by the reaction of isatins, naphthalene-1-amine and 1,3-dicarbonyl compounds. The spiro[indoline-3,4'-pyrazolo[3,4-b]quinoline]dione derivatives were prepared by the reaction of isatins, 5-amino-1-methyl-3-pheylpyrazole, and 1,3-dicarbonyl compounds by using ( ±)-camphor-10-sulfonic acid as a catalyst in H₂O/EtOH (3:1 v/v) solvent mixture. The antibacterial activity of the synthesized compounds was evaluated against, Enterococcus faecalis, Staphylococcus aureus and Candida albicans. Compounds 4b, 4h, and 6h showed the strongest antimicrobial activity toward both bacteria. The MIC values of these compounds ranged from 375-3000 µg/mL. The effect of these compounds (4b, 4h, 6h) as a function of applied dose and time was investigated by a kinetic study, and the interaction with these antimicrobial results was simulated by a molecular docking study. We also used the docking approach with Covid-19 since secondary bacterial infections. Docking showed that indoline-quinoline hybrid compounds 4b and 4h exerted the strongest docking binding value against the active sites of 6LU7. In addition, the synthesized compounds had a moderate to good free radical scavenging activity.

Revisiting the Solubility-Permeability Relationship with Hydrophobic Drug Umifenovir in Pluronic Solutions: Impact of pH and Co-Solvent

This study describes the influence of pluronic F-127 (F-127) and ethanol (EtOH) on the solubility of umifenovir (UMF) in buffer solutions of pH 2.0 and pH 7.4, and its permeability through cellulose membranes. A 44.4-fold greater UMF solubility in acidic medium as compared to an alkaline one was estimated at 310.15 K. The concentration of UMF in the saturated solution was enhanced by the interaction with F-127 micelles. The combined positive effect of EtOH and F-127 on the solubility was estimated. The aggregation number of F-127 micelles in the presence of 10% and 20% ethanol appeared to be reduced by 2.1-fold and 4.1-fold, respectively, as compared to buffer pH 7.4. The presence of ethanol in buffer pH 7.4 solution provided better solvent conditions but inhibited the formation of F-127 micelles. The impact of UMF on the aggregation number of F-127 was not pronounced and was expressed only by a slight increase of 1 and 3 units in 10% and 20% EtOH, respectively. According to the values of zeta potential, addition of EtOH reduced the stability of the system. The permeation of UMF in buffer pH 7.4 measured through the cellulose membrane MWCO 12-14 kDa was increased 1.4-fold by 10% EtOH. An increase in EtOH content to 20% reduced this effect to 1.2-fold. Decreasing effect of 1.5% F-127 on the permeability was inhibited by using 10% EtOH. The solution containing 1.5% F-127 and 10% EtOH was shown to be an advantageous system for UMF in view of the solubility-permeability balance. The authors suppose the findings of the study to be useful for the design of pharmaceutical formulations based on UMF antiviral drugs.

A literature perspective on the pharmacological applications of yohimbine

Introduction: Phytochemicals have garnered much attention because they are useful in managing several human diseases. Yohimbine is one such phytochemical with significant pharmacological potential and could be exploited for research by medicinal chemists. It is an indole alkaloid obtained from various natural/synthetic sources.Aims and Results: The research on yohimbine started early, and its use as a stimulant and aphrodisiac by humans has been reported for a long time. The pharmacological activity of yohimbine is mediated by the combined action of the central and peripheral nervous systems. It selectively blocks the pre and postsynaptic α₂-adrenergic receptors and has a moderate affinity for α1 and α2 subtypes. Yohimbine also binds to other behaviourally relevant monoaminergic receptors in the following order: α-2 NE > 5HT-1A>, 5HT-1B > 1-D > D3 > D2 receptors.Conclusion: The current review highlights some significant findings that contribute to developing yohimbine-based drugs. It also highlights the therapeutic potential of yohimbine against selected human diseases. However, further research is recommended on the pharmacokinetics, molecular mechanisms, and drug safety requirements using well-designed randomized clinical trials to produce yohimbine as a pharmaceutical agent for human use.Key MessagesYohimbine is a natural indole alkaloid with significant pharmacological potential.Humans have used it as a stimulant and aphrodisiac from a relatively early time.It blocks the pre- and postsynaptic α2-adrenergic receptors that could be exploited for managing erectile dysfunction, myocardial dysfunction, inflammatory disorders, and cancer.

Untargeted metabolite profiling of Enterococcus villorum SB2, isolated from the vagina of pregnant women, by HR-LCMS

Enterococcus bacteria are studied in various sectors including fermentation, food and dairy industries,as well as studied for their probiotic properties but have limited use due to their possible pathogenic behavior. The present report talks about the metabolites produced, by the previously isolated Enterococcus strain, E.villorum SB2 (accession number KX830968), from the vaginal source. The growth of the bacteria in three types of media (M17, MRS and LAPTg) was compared, where the M17 media gave better bacterial colonies, also maximum growth rate was observed in M17 media (T_d = 1.6 h & k = 0.4 h^-1), and thus was selected as the metabolite production media. Further, the studied bacteria did not show any hemolytic activity, making it safe for industrial applications. The HR-LCMS results showed the production of various amino acids, organic acids, peptides, and other metabolites like flavonoids (Quercetin 3-O-Manoglucoside), terpenoids (7',8',Dihydro-8'-hydroxycitraniaxanthin, O-Methylganoderic acid O, Thalicsessine, Austinol, Valdiate), indole derivatives produced by tryptophan metabolism (5-hydroxykynurenamine, 2S,4R)-4-(9H-Pyrido[3,4-b]indol-1-yl)-1,2,4-butanetriol, Indoleacrylic acid), antimicrobial compounds (Fortimicin A) and fatty acids (Stearic acid, Myristic acid), which were earlier unreported form Enterococcus species opening new scope for discovering new industrial applications of the strain. As the studied bacteria has been reported to be a potential probiotic, the detection of these industrially important metabolites can be studied further in future studies to reveal the potential industrial applications of the strain.

Annulation strategies for diverse heterocycles via the reductive transformation of 2-nitrostyrenes

Reduction of the stable nitro group is a fundamental and widely used transformation for the construction of complex and functionalized heterocyclic architectures. The unfolding of the reactivity of the nitro group in the 2-nitrostyrene moiety not only triggers the formation of carbon-nitrogen bonds, but also offers the opportunity for annulation and heteroannulation, thereby providing a cascade process for the synthesis of highly conjugated natural and unnatural molecules. In this review, we comprehensively discuss the use of 2-nitrostyrene motifs in the synthesis of various N-heterocycles. We offer readers an overview of the synthetic achievements achieved to date, highlighting their important features, reactivities, and mechanisms.

3-Formylindole-based chitosan Schiff base polymer: Antioxidant and in vitro cytotoxicity studies on THP-1 cells

Two imine derivatives of chitosan (i-CTs), namely 2FCT and 5MCT, were synthesized by reacting chitosan (CT) with 2-(3-formyl-1H-indol-1yl)acetonitrile (2F), and 5-methoxyindole-3-carbaldehyde (5M), respectively. The antimicrobial evaluation of i-CTs exhibited stronger inhibition effect against Staphylococcus aureus, Escherichia coli and Candida albicans. The antioxidant activity of 2FCT and 5MCT showed strong scavenging ability with IC₅₀ 2.31 and 6.92 μg/mL, respectively. The results of in vitro cytotoxicity of 2FCT and 5MCT examined using human monocyte leukemia (THP-1) cells indicate no cytotoxic effect on host cells and the value of cell viability was found to be 87.08 and 84.47%, respectively. Measurement of intracellular Reactive Oxygen Species (ROS) production by flow cytometry analysis revealed that the 2FCT and 5MCT reduced the ROS generation by 83 and 43%, respectively. In summary, these findings show that i-CTs synthesized to be promising biomaterial for biomedical applications such as wound healing.

A Quantum Chemical Deep-Dive into the π-π Interactions of 3-Methylindole and Its Halogenated Derivatives—Towards an Improved Ligand Design and Tryptophan Stacking

Non-covalent π-π stacking interactions often play a key role in the stability of the secondary and tertiary structures of peptides and proteins, respectively, and can be a means of ensuring the binding of ligands within protein and enzyme binding sites. It is generally accepted that minor structural changes to the aromatic ring, such as substitution, can have a large influence on these interactions. Nevertheless, a thorough understanding of underpinning phenomena guiding these key interactions is still limited. This is especially true for larger aromatic structures. To expand upon this knowledge, elaborate ab initio calculations were performed to investigate the effect of halogenation on the stability of 3-methylindole stacking. 3-Methylindole served as a representation of the tryptophan side chain, and is a frequently used motif in drug design and development. Moreover, an expression is derived that is able to accurately predict the interaction stability of stacked halogenated 3-methylindole dimers as well as halogenated toluene dimers, based on monomer level calculated DFT descriptors. We aim for this expression to provide the field with a straightforward and reliable method to assess the effect of halogenation on the π-π stacking interactions between aromatic scaffolds.

Synthesis, Molecular Docking and Biological Evaluation of N-Substituted Indole Derivatives as Potential Anti-Inflammatory and Antioxidant Agents

Novel N-substituted Indole derivatives with various hetero-cyclic moieties were synthesized via an ethyl linker in order to obtain highly potent anti-inflammatory and antioxidant agents. The structure of the obtained chemical compounds was determined using IR, ¹ H-NMR, and mass spectroscopy. Molecular docking was used to create selective and efficient COX-2 inhibitors from twelve novel indole derivatives (11a-c, 12a-c, 13a-c, and 14a-c). The compounds 13b and 14b had a high interaction energy, which inhibited the COX-2 enzyme. There is a relationship between anti-inflammatory activity and antioxidants, which is also defined by COX-2 inhibition, according to the mechanism of action. The Swiss ADME online programme was used to determine the drug-like properties of synthesized compounds. Two common and reliable methods were adopted to determine the antioxidant effect. In the DPPH assay, compounds 11a, 11b, and 14b, whereas compounds 11b, 13b, and 14b in the reducing power assay, were the most potent as compared with standard ascorbic acid. To evaluate the anti-inflammatory effect at an acute and chronic level, the carrageenan-induced paw edema method along with the formalin-induced inflammation method were used both at low dose and high dose. From the collected results, compounds 13b and 14b were the most potent against acute and chronic inflammation. The results showed that the synthesized compounds are unique as anti-inflammatory and antioxidant agents, and that they could be useful for drug discovery in the future.

Seeking heterocyclic scaffolds as antivirals against dengue virus

Dengue is one of the most typical viral infection categorized in the Neglected Tropical Diseases (NTDs). It is transmitted via the female Aedes aegypti mosquito to humans and majorly puts risk to the lives of more than half of the world. Recent advancements in medicinal chemistry have led to the design and development of numerous potential heterocyclic scaffolds as antiviral drug candidates for the inhibition of the dengue virus (DENV). Thus, in this review, we have discussed the significance of inhibitory and antiviral activities of nitrogen, oxygen, and mixed (nitrogen-sulfur and nitrogen-oxygen) heterocyclic scaffolds that are published in the last seven years (2016–2022). Furthermore, we have also discussed the probable mechanisms of action and the diverse structure-activity relationships (SARs) of the heterocyclic scaffolds. In addition, this review has elaborately outlined the mechanism of viral infection and the life cycle of DENV in the host cells. The wide set of heterocycles and their SARs will aid in the development of pharmaceuticals that will allow the researchers to synthesize the promising anti-dengue drug candidate in the future.

Spectroscopic, electronic structure, molecular docking, and molecular dynamics simulation study of 7-Trifluoromethyl-1H-indole-2-carboxylic acid as an aromatase inhibitor

The present work encompasses a combined experimental and theoretical investigation of the molecular structure, vibrational wavenumbers, electronic structure at the ground and electronic excited states, molecular electrostatic potential surface of 7-(Trifluoromethyl)-1H-indole-2-carboxylic acid (TICA) and possibility of the title molecule as an aromatase inhibitor using molecular docking and molecular dynamic simulations. A stable conformer has been obtained using potential energy scans by varying appropriate dihedral angles. The obtained minimum energy conformer was further optimized at the 6-311++G (d, p) basis set by applying the most accepted B3LYP functional. A good agreement between experimental and calculated normal modes of vibration has been observed. The hydrogen-bonded interaction between two monomeric units of TICA has been investigated using NBO,QTAIM, and NCI (noncovalent interactions) analysis. Molecular docking of TICA with human placental aromatase (PDB ID: 3S79) reveals the formation of polar hydrogen bonds as well as hydrophobic interactions between the ligand and the protein, right in the binding cavity. TICA satisfies all pharmacokinetic filters (Lipinski rule of five, the Veber rule, Ghose rule, Egan rule, as well as the Muegge rule) and has a high bioavailability score of 0.85. Dynamic stability of the ligand within the binding pocket of the target protein has been confirmed by 100 ns molecular dynamics simulation results. The present study provides an excellent starting point for additional in vivo research, and TICA may eventually serve as a significant therapeutic candidate for the treatment of breast cancer.

Immunomodulatory Efficacy-Mediated Anti-HCV and Anti-HBV Potential of Kefir Grains; Unveiling the In Vitro Antibacterial, Antifungal, and Wound Healing Activities

The utilization of fermented foods with health-promoting properties is becoming more popular around the world. Consequently, kefir, a fermented milk beverage made from kefir grains, was shown in numerous studies to be a probiotic product providing significant health benefits. Herein, we assessed the antibacterial and antifungal potential of kefir against a variety of pathogenic bacteria and fungi. This study also showed the effectiveness of kefir in healing wounds in human gastric epithelial cells (GES-1) by (80.78%) compared with control (55.75%) within 48 h. The quantitative polymerase chain reaction (qPCR) results of kefir-treated HCV- or HBV- infected cells found that 200 µg/mL of kefir can eliminate 92.36% of HCV and 75.71% of HBV relative to the untreated infected cells, whereas 800 µg/mL (the highest concentration) completely eradicated HCV and HBV. Moreover, the estimated IC₅₀ values of kefir, at which HCV and HBV were eradicated by 50%, were 63.84 ± 5.81 µg/mL and 224.02 ± 14.36 µg/mL, correspondingly. Kefir can significantly suppress the elevation of TNF-α and upregulate IL-10 and INF-γ in both treated HCV- and HBV-infected cells. High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) analysis of kefir revealed the presence of numerous active metabolites which mainly contribute to the antimicrobial, antiviral, and immunomodulatory activities. This study demonstrated, for the first time, the anti-HBV efficacy of kefir while also illustrating the immunomodulatory impact in the treated HBV-infected cells. Accordingly, kefir represents a potent antiviral agent against both viral hepatitis C and B, as well as having antimicrobial and wound healing potential.

3-Alkynylindoles as Building Blocks for the Synthesis of Electronically Tunable Indole-Based Push-Pull Chromophores

In this study, two different classes of push–pull chromophores were synthesized in modest to excellent yields by formal [2+2] cycloaddition-retroelectrocyclization (CA-RE) reactions. N-Methyl indole was introduced as a new donor group to activate alkynes in the CA-RE transformations. Depending on the side groups’ size and donor/acceptor characteristics, N-methyl indole-containing compounds exhibited λ_max values ranging between 378 and 658 nm. The optoelectronic properties of the reported D–A-type structures were studied by UV/vis spectroscopy and computational studies. The complete regioselectivity observed in the products was elaborated by one-dimensional (1D) and two-dimensional (2D) NMR studies, and the electron donor strength order of N-alkyl indole and triazene donor groups was also established. The intramolecular charge-transfer characteristics of the target push–pull chromophores were investigated by frontier orbital depictions, electrostatic potential maps, and time-dependent density functional theory calculations. Overall, the computational and experimental results match each other. Integrating a new donor group, N-alkyl indole, into the substrates used in formal [2+2] cycloaddition-retroelectrocyclizations has significant potential to overcome the limited donor-substituted substrate scope problem of CA-RE reactions.