Potent Activity Research Articles

Assessing the efficacy of iso-mukaadial acetate and betulinic acid against selected Plasmodium falciparum glycolytic pathway proteins: in silico and in vitro studies

Malaria is the extensive health concern in sub-Saharan Africa, with Plasmodium falciparum being the most lethal strain. The continued emergence of drug-resistant P. falciparum advocates for the development of new antimalarials. Our current study aimed to effectively explore the interaction capabilities of iso-mukaadial acetate (IMA) and betulinic acid (BA) against two essential P. falciparum glycolytic pathway proteins, PfLDH and PfHk. Recombinant PfLDH and PfHk were independently expressed in E. coli BL21 (DE3) cells and subsequently purified using affinity chromatography. Protein–ligand interaction studies probed in silico and in vitro approaches. Parasite inhibition studies confirmed potent antimalarial activity against the P. falciparum NF54 strains, with BA and IMA showing IC50 values of 1.27 µg/ml and 1.03 µg/ml against the asexual stage of P. falciparum, respectively. FTIR experiments confirmed interactions between the compounds and the secondary structure of the proteins. Direct protein–ligand interaction studies analysis using microscale thermophoresis (MST) showed a KD value of 0.1036 ± 0.6001 µM for the PfLDH-BA complex and 0.7473 ± 0.3554 µM KD value for PfLDH-IMA. Meanwhile, PfHk-IMA had 0.39701 ± 0.16298 µM KD value, while the PfHk-BA complex had no interaction detected. Molecular docking and molecular dynamics simulation studies were used to measure and confirm the interactive strength of complexes. Molecular docking reported a binding score of − 1.155 kcal/mol for the PfLDH-BA complex and a binding score of − 3.200 kcal/mol for PfLDH-IMA. The PfHk-BA complex had − 2.871 kcal/mol and PfHk-IMA complex had − 4.225 kcal/mol binding score. In conclusion, BA and IMA compounds had better interactions and remained bound within the binding sites of the glycolytic pathway proteins (PfLDH and PfHk).

Isolation of Antiplasmodial Oxazoles and Isoflavonoids from the Roots of Oxytropis trichophysa and Total Synthesis of Oxazole-type Alkaloids.

A chemical examination of a root extract of Oxytropis trichophysa led to the isolation and identification of 23 compounds, including oxazole-type alkaloids and isoflavonoid derivatives. Notably, three oxazole-type alkaloids (1, 2, and 3) and two isoflavonoid derivatives (7 and 10) were obtained from a natural source for the first time. In addition, O. trichophysa derived 2,5-diphenyloxazoles and their derivatives were synthesized. Despite their potential activity, the antiplasmodial activities of naturally occurring 2,5-diphenyloxazoles and certain isoflavonoids remain unexplored. Therefore, the antiplasmodial activities of both the naturally occurring and synthesized compounds were evaluated against Plasmodium falciparum strain 3D7. Among the tested compounds, three naturally occurring oxazole-type alkaloids (1, 5, and 6), one synthesized alkaloid (34), and two isoflavonoid derivatives (13 and 15) demonstrated significant inhibitory effects, with half-maximal inhibitory concentration (IC50) values ranging from 3.1 to 6.2 μM and selective indices between 0.9 and 18.8. Compound 1 showed the most potent inhibitory activity, with an IC50 of 3.1 μM, while its cytotoxic concentration 50% value against human foreskin fibroblasts was found to be 8.5 μM. The oxazole-type alkaloids and isoflavonoids isolated from this plant provide valuable insights into its chemical composition and may help elucidate the antiplasmodial properties of O. trichophysa.

Identification of novel KRASG12D neoantigen specific TCRs and a strategy to eliminate off-target recognition

BackgroundT cell receptor (TCR)–engineered T cells targeting neoantigens originated from mutations in KRAS gene have demonstrated promising outcomes in clinical trials against solid tumors. However, the challenge lies in developing tumor-specific TCRs that avoid cross-reactivity with self-antigens to minimize the possibility of severe clinical toxicities. Current research efforts have been put towards strategies to eliminate TCR off-target recognition.MethodsNaive T cell repertoire was used for screening KRASG12D-reactive TCRs. Specific TCRs were subsequently identified and their functionality was assessed using TCR Jurkat cells and TCR T cells. Peptide specificity was evaluated using the X-scan assay. To enhance TCR specificity for KRASG12D and reduce their reactivity to self-peptide SMC1A29-38, mammalian TCR display libraries were employed for the design of modification in the complementarity-determining region (CDR).ResultsHLA-A*11:01-restricted TCRs targeting the KRASG12D epitope were isolated, and TCR1 was characterized with superior functional avidity and specificity. Alongside a robust recognition of endogenous KRASG12D epitope, this TCR displayed cross-reactivity with the SMC1A29-38 epitope. With an approach utilizing structural-guided mutations in the CDR-1A region of TCR1, we obtained an engineered TCR variant (TCR1a7). Functional characterization of TCR1a7 showed that this TCR not only exhibited enhanced specificity towards KRASG12D, but also demonstrated successful elimination of the off-target recognition of SMC1A29-38.ConclusionsTCRs targeting the KRASG12D peptide could be isolated from naive T cell repertoires. Integrating the TCR-peptide-HLA complex structure with a mammalian TCR library system could serve as a functional strategy to reduce potential TCR cross-reactivity with self-antigens, such as SMC1A29-38. Our findings evidenced an operable method to enhance TCR peptide specificity, while maintaining advanced functional avidity and potent anti-tumor activity.

Novel Quinazoline Derivatives Inhibit Splicing of Fungal Group II Introns.

We report the discovery of small molecules that target the RNA tertiary structure of self-splicing group II introns and display potent antifungal activity against yeasts, including the major public health threat Candida parapsilosis. High-throughput screening efforts against a yeast group II intron resulted in an inhibitor class which was then synthetically optimized for enhanced inhibitory activity and antifungal efficacy. The most highly refined compounds in this series display strong, gene-specific antifungal activity against C. parapsilosis. This work demonstrates the utility of combining advanced RNA screening methodologies with medicinal chemistry pipelines to identify high-affinity ligands targeting RNA tertiary structures with important roles in human health and disease.

Ellagic Acid from Geranium thunbergii and Antimalarial Activity of Korean Medicinal Plants

This study investigates the antimalarial potential of extracts and compounds from various plants used in traditional Korean medicine, in response to the increasing resistance of Plasmodium falciparum to standard treatments such as chloroquine and artemisinin. The antimalarial activity screening was conducted on 151 extracts, identifying the top seven candidates, including Geranium thunbergii (50% ethanol and 100% methanol extract), Reynoutria japonica, Amomum villosum (hot water and 50% ethanol extract), Cinnamomum zeylanicum, and Platycodon grandiflorum. Among these, G. thunbergii was identified as the top priority for further analysis due to its high antimalarial activity and high yield of bioactive compounds. The plant extracts were fractionated using ethyl acetate, chloroform, and hot water, and their efficacy against P. falciparum was evaluated through IC50 determination and microscopic analysis. The compounds evaluated included ellagic acid, gallic acid, afzelin, quercetin, and protocatechuic acid. Among the tested compounds, ellagic acid showed the most potent antimalarial activity with an IC50 of 1.60 ± 0.09 µM, followed by gallic acid (39.43 ± 1.48 µM) and afzelin (52.77 ± 1.84 µM). In contrast, quercetin (116.8 ± 3.78 µM) and protocatechuic acid (1.23 ± 0.02 mM) exhibited minimal antimalarial effects. Giemsa staining was employed to visualize parasite morphology and confirmed that ellagic acid is effective in inhibiting growth at the late trophozoite stage. These findings suggest that ellagic acid could serve as a promising lead compound for developing a novel antimalarial agent. This study highlights the importance of exploring plant-based compounds as alternative strategies against drug-resistant malaria. Further investigation into the mechanisms underlying the antimalarial activity of these compounds is necessary to fully validate their therapeutic potential.

(E)-1-(3-(3-Hydroxy-4-Methoxyphenyl)-1-(3,4,5-Trimethoxyphenyl)allyl)-1H-1,2,4-Triazole and Related Compounds: Their Synthesis and Biological Evaluation as Novel Antimitotic Agents Targeting Breast Cancer

Background/Objectives: The synthesis of (E)-1-(1,3-diphenylallyl)-1H-1,2,4-triazoles and related compounds as anti-mitotic agents with activity in breast cancer was investigated. These compounds were designed as hybrids of the microtubule-targeting chalcones, indanones, and the aromatase inhibitor letrozole. Methods: A panel of 29 compounds was synthesized and examined by a preliminary screening in estrogen receptor (ER) and progesterone receptor (PR)-positive MCF-7 breast cancer cells together with cell cycle analysis and tubulin polymerization inhibition. Results: (E)-5-(3-(1H-1,2,4-triazol-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-1-en-1-yl)-2-methoxyphenol 22b was identified as a potent antiproliferative compound with an IC50 value of 0.39 mM in MCF-7 breast cancer cells, 0.77 mM in triple-negative MDA-MB-231 breast cancer cells, and 0.37 mM in leukemia HL-60 cells. In addition, compound 22b demonstrated potent activity in the sub-micromolar range against the NCI 60 cancer cell line panel including prostate, melanoma, colon, leukemia, and non-small cell lung cancers. G2/M phase cell cycle arrest and the induction of apoptosis in MCF-7 cells together with inhibition of tubulin polymerization were demonstrated. Immunofluorescence studies confirmed that compound 22b targeted tubulin in MCF-7 cells, while computational docking studies predicted binding conformations for 22b in the colchicine binding site of tubulin. Compound 22b also selectively inhibited aromatase. Conclusions: Based on the results obtained, these novel compounds are suitable candidates for further investigation as antiproliferative microtubule-targeting agents for breast cancer.

Discovery of Novel RNA Demethylase FTO Inhibitors Featuring an Acylhydrazone Scaffold with Potent Antileukemia Activity.

Fat mass obesity-associated protein (FTO) has been emerging as a potential therapeutic target for drug discovery in RNA epigenetics. In this work, a series of novel FTO inhibitors featuring an acylhydrazone scaffold were identified, and the optimized compounds 8t-v showed potent FTO inhibitory activities with IC50 values ranging from 7.1 to 9.4 μM. FTO inhibitor 8t, as the lead compound, exhibited potent antiproliferative capacities against MOLM13, NB4, and THP-1 with IC50 values of 0.35, 0.59, and 0.70 μM, respectively, and remarkably induced NB4 cell apoptosis. Compound 8t also inhibited the FTO demethylation, enhanced the abundance of m6A, stabilized FTO protein folding, and regulated the oncogenic FTO signaling pathway. Importantly, compound 8t significantly caused a tumor volume reduction and tumor weight loss with a tumor growth inhibition (TGI) value of 51% in NB4 xenograft mice. Overall, our work provided valuable lead compounds for FTO inhibitors featuring an acylhydrazone scaffold with potent antileukemia activity both in vitro and in vivo.

Bioactive Molecules, Ethnomedicinal Uses, Toxicology, and Pharmacology of Peltophorum africanum Sond (Fabaceae): Systematic Review

Plants have long been used to treat serious illnesses in both humans and animals. A significant underappreciated medicinal tree, Peltophorum africanum Sond is utilized by many different ethnic groups to cure a wide range of illnesses. A variety of electronic databases, including ScienceDirect, Scopus, Scielo, Scifinder, PubMed, Web of Science, Medline, and Google Scholar, were used to search the literature on P. africanum, using key words such as uses, survey, pharmacology, antigonococcal, toxicity, phytochemistry and others. Further data was obtained from several scholarly theses, dissertations, and books on general plant sciences, ethnomedicine, and other pertinent ethnobotanical topics. The plant species possess very important pharmacological activities in vitro, which includes antimicrobial, anti-HIV, antioxidant, anticancer, antidiabetic, and other activities. Phytochemically, the plant possesses various classes of compounds, dominated by flavonols, which may well explain its wider range of pharmacological activities. Although the plant is promising anti-HIV activity, the mode of action and safety profiles of the plant also need to be explored as its extracts exerted some degree of mutagenicity. It is also important to further explore its ethnoveterinary use against a plethora of nematodes that infects both wild and domestic animals. Given its potent pharmacological activity, the further in vivo studies need to be explored to ascertain the comprehensive toxicology of the plant species, thereby developing possible medications. The plant species may further be elevated to a potent pharmaceutical product against plethora of infections.

High-level biosynthesis and purification of the antimicrobial peptide Kiadin based on non-chromatographic purification and acid cleavage methods

Antimicrobial peptides (AMPs) are renowned for their potent bacteriostatic activity and safety, rendering them invaluable in animal husbandry, food safety, and medicine. Despite their potential, the physiological toxicity of AMPs to host cells significantly hampers their biosynthetic production. This study presents a novel approach for the biosynthesis of the antimicrobial peptide Kiadin by engineering a DAMP4–DPS–Kiadin fusion protein to mitigate host cell toxicity and achieve high-level expression. Leveraging the unique properties of the DAMP4 protein, we developed a non-chromatographic purification method to isolate the DAMP4–DPS–Kiadin fusion protein with high purity. The instability of the D–P peptide bond under acidic conditions, combined with the thermal and saline stability of DAMP4, enabled efficient separation of Kiadin through acid cleavage and isoelectric precipitation, yielding Kiadin with 96% purity and a production yield of 29.3 mg/L. Our optimization of acid cleavage temperature, duration, and isoelectric precipitation conditions proved critical for maximizing the purification efficiency and expression levels of Kiadin. The biosynthesized Kiadin exhibited robust bacteriostatic activity against Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Bacillus cereus and Staphylococcus aureus. Notably, Kiadin demonstrated significant post-antibiotic effects by disrupting bacterial membrane integrity, inducing cytoplasmic leakage, and inhibiting biofilm formation in E. coli K88 and S. aureus Mu50, without cytotoxicity towards mouse macrophages. In vivo studies further confirmed Kiadin's exceptional therapeutic efficacy against abdominal infections caused by E. coli K88. The acid cleavage and non-chromatographic purification techniques developed in this study offer a cost-effective and efficient strategy for the high-purity production of AMPs.

RED light promotes flavonoid and phenolic accumulation in Cichorium spp. callus culture as anti-candida agent

Chicory species, particularly Cichorium endive Supp. Pumillum, also, known as Egyptian chicory, are globally recognized for their rich content of bioactive secondary metabolites such as flavonoids and phenolics. These metabolites are highly valued for their pharmaceutical, dietary, and commercial applications. Light exposure, particularly through red and blue wavelengths, is a potent natural elicitor that influences the biosynthesis of secondary metabolites and impacts plant morphology. This study investigates the effects of red and blue LED light exposure on the callus culture of Egyptian chicory (Cichorium endive Supp. Pumillum), with the aim of enhancing flavonoid accumulation for potential use as an anti-Candida agent. Callus cultures of Cichorium intybus, Cichorium endive Supp. Pumillum, and Taraxacum officinale (Italian chicory) were grown on MS media supplemented with 4 mg/L 2iP and 0.5 mg/L NAA for 4 weeks. The cultures were then exposed to 12 days of red and blue LED light. After extraction using liquid nitrogen and methanol, the resulting callus extracts were tested against Candida albicans NRRL477 at various concentrations (1/8, 1/4, and 1/2 MIC) for 20 to 120 min. The antifungal activity was assessed by determining the effects on acid-soluble phosphorus, total lipids, and soluble proteins in the Candida cells. Our results demonstrate that the red LED light-exposed Cichorium endive Supp. Pumillum callus extract exhibited the most potent antifungal activity, significantly inhibiting the growth of Candida species compared to blue light and control treatments. Notably, the red light-treated callus culture accumulated higher concentrations of flavonoids and phenolic compounds, which contributed to its effectiveness as an anti-Candida agent. These findings suggest that LED red light elicitation is an effective method for enhancing the production of bioactive compounds in Egyptian chicory, offering potential for its use in natural antifungal therapies. Future research will explore the mechanistic pathways of flavonoid accumulation under different light conditions and investigate the broader applications of this elicitation technique for other medicinal plants.

Novel Cationic Bolaamphiphiles for Protein and DNA Binding, Gene Delivery, and Antimicrobial Applications.

In this study, we have designed and developed a cationic bolaform C12-(2,3-dihydroxy-N, N-dimethyl-N-(2-ureidoethyl)propan-1-aminium chloride)2 (C12(DDUPAC)2) that is derived from biocompatible molecules. The bolaform C12(DDUPAC)2 has hydroxyl (OH) functionality at both the cationic head groups. The impact of head group structure on the self-assembly and effectiveness of gene transfection and antimicrobial activity was investigated and compared with that of the hydrochloride salt C12-(N, N-dimethyl-N-(2-ureidoethan-1-aminium chloride)2 (C12(DUAC)2) of its precursor molecule. The formation of spherical as well as rod-like self-assembled structures was found to occur above a relatively low critical aggregation concentration (CAC) by the bolaforms. The results of calorimetric measurements demonstrated thermodynamically favorable aggregation in water. Interaction studies of the cationic bolaforms with the calf thymus DNA revealed stronger binding of C12(DDUPAC)2 in comparison to C12(DUAC)2, which explained higher in vitro gene transfection efficiency of C12(DDUPAC)2 than C12(DUAC)2. Both bolaforms interact weakly with the bovine serum albumin protein. MTT-based in vitro cytotoxicity assay was performed and both bolaforms were found to have marginal cytotoxicity. Further, both bolaforms exhibit advantageous antibacterial activity against E. coli and potent antifungal activity against Fusarium oxysporum at high dosages.

Network-Based Drug Optimization toward the Treatment of Parkinson's Disease: NRF2, MAO-B, Oxidative Stress, and Chronic Neuroinflammation.

Parkinson's disease (PD), the second most common neurodegenerative disorder, affects around 10 million people worldwide. It is a multifactorial disease marked by dopaminergic neuron loss with oxidative stress (OS) and neuroinflammation as key pathological drivers. Current treatments focus on dopamine replacement and are symptomatic, underscoring the urgent need for disease-modifying therapies. Here, we present a novel class of dual MAO-B inhibitors and NRF2 inducers with neuroprotective properties in in vitro PD models. Through an optimization program, we enhanced their MAO-B inhibitory potency, selectivity, and NRF2 induction capacity while achieving favorable pharmacokinetic profiles. Virtual library screening identified two core derivatives, leading to the development of compound 11, which exhibited potent anti-inflammatory and neuroprotective activity in OS-related in vitro models. Compound 11 also demonstrated high liver microsomal stability and favorable pharmacokinetics in mice, making it a promising candidate for further investigation as a potential PD therapy.

Bactericidal Hemostatic Sponge: A Point of Care Solution to Combat Traumatic Injury.

Uncontrollable haemorrhage and associated microbial contamination in the battlefield and civilian injuries pose a tremendous threat to healthcare professionals. Such traumatic wounds often necessitate an effective point-of-care solution to prevent the consequent morbidity owing to blood loss or haemorrhage. However, developing superior hemostatic materials with anti-infective properties remains a challenge. To address this, an injectable, cationic dextran-mesoporous silica nanoparticle-based bactericidal hemostatic sponge (BACSTAT) has been developed. A dual crosslinking approach is adopted through in situ covalent cross-linking through photo polymerization and silica nanoparticle-induced non-covalent interactions. This interconnected macroporous BACSTAT sponge has superior fluid absorption properties and fluid-induced rapid shape recovery of the sponge helps to seal the irregularly shaped wound. Furthermore, this sponge can stimulate a coagulation cascade for rapid blood clotting in mice femoral vein incision and liver puncture model. The optimum sponge exhibited potent antibacterial activity against wide-spectrum Gram-positive and Gram-negative pathogens. Notably, it is completely biocompatible with mammalian cells and mice skin. Significantly, this sponge reduces Pseudomonas aeruginosa burden >99% in mice subcutaneous infection model with substantially lessening inflammatory responses in infected tissues. Collectively, the optimized sponge bears immense potential to be developed as point-of-care solution for military and civilian traumatic injury.

Small molecule inhibits KCNQ channels with a non-blocking mechanism.

Voltage-gated ion channels (VGICs) are crucial targets for neuropsychiatric therapeutics owing to their role in controlling neuronal excitability and the established link between their dysfunction and neurological diseases, highlighting the importance of identifying modulators with distinct mechanisms. Here we report two small-molecule modulators with the same chemical scaffold, Ebio2 and Ebio3, targeting a potassium channel KCNQ2, with opposite effects: Ebio2 acts as a potent activator, whereas Ebio3 serves as a potent and selective inhibitor. Guided by cryogenic electron microscopy, patch-clamp recordings and molecular dynamics simulations, we reveal that Ebio3 attaches to the outside of the inner gate, employing a unique non-blocking inhibitory mechanism that directly squeezes the S6 pore helix to inactivate the KCNQ2 channel. Ebio3 also showed efficacy in inhibiting currents of KCNQ2 pathogenic gain-of-function mutations, presenting an avenue for VGIC-targeted therapies. Overall, these findings contribute to the understanding of KCNQ2 inhibition and provide insights into developing selective, non-blocking VGIC inhibitors.

Targeting InhA in drug-resistant Mycobacterium tuberculosis: potent antimycobacterial activity of diaryl ether dehydrozingerone derivatives.

Tuberculosis (TB) remains a major global threat, with 10 million new cases and 1.5 million deaths each year. In multidrug-resistant tuberculosis (MDR-TB), resistance is most commonly observed against isoniazid (INH) and rifampicin (RIF), the two frontline drugs. Isoniazid resistance is predominantly linked to mutations in the InhA gene, which encodes an enzyme involved in mycolic acid synthesis, a vital component of the mycobacterial cell wall. Mutations in InhA reduce drug binding, rendering INH ineffective. These morbidity and mortality figures, along with the fact that the rise and global spread of drug-resistant TB, underscores the need for the discovery of novel therapeutics. In this direction, we have previously synthesized, characterized, and screened a library of diaryl ether dehydrozingerone derivatives against mycobacteria and identified two best hits, 7 and 14, based on bacteriostatic activities. The present study aimed to thoroughly investigate the antituberculosis potential of these compounds, particularly regarding drug-resistant TB. Our findings revealed that both compounds exhibited tuberculocidal activity against the standard laboratory strain Mycobacterium tuberculosis (M. tb) H37Rv, with minimal bactericidal concentrations (MBC) of 4μg/ml for compound 7 and 8μg/ml for compound 14. Next, concentration vs time-kill kinetics of both these compounds showed concentration-dependent bactericidal activities against M. tb and complete pathogen eradication from culture at just 16× MIC. Both compounds were found to be suitable for combination regimens as their interactions with isoniazid and rifampicin against M. tb were observed to be synergistic. Additionally, 7 and 14 exhibited minimal hemolysis against human RBCs and less cytotoxicity was observed against three human cell lines up to 1000μM. Molecular docking revealed that these compounds bind more effectively to M. tb InhA, including its mutant forms where isoniazid binding is impaired, outperforming both isoniazid and triclosan in binding affinity. Importantly 7 and 14 showed potent activity against drug-susceptible clinical isolates and two isoniazid-resistant M. tb clinical isolates equivalent to that against M. tb H37Rv. The most interesting observation was that both compounds were found to be effective against three multi-drug resistant (MDR) strains of M. tb, thereby depicting their potential against drug-resistant TB. An ex vivo assay on RAW 264 cells infected with M. tb demonstrated a significant reduction in bacterial load at 8× MIC, revealing the fact that these compounds are highly effective against intracellular M. tb H37Rv. To the best of our knowledge, this is the first study that reports promising antimycobacterial potential of 7 and 14 against drug-susceptible, isoniazid-resistant, and MDR tuberculosis which warrants further exploration considering the need for new anti-TB medicine.

Design, Synthesis, and Unprecedented Interactions of Covalent Dipeptide-Based Inhibitors of SARS-CoV-2 Main Protease and Its Variants Displaying Potent Antiviral Activity.

The main protease (Mpro) of SARS-CoV-2 is a key drug target for the development of antiviral therapeutics. Here, we designed and synthesized a series of small-molecule peptidomimetics with various cysteine-reactive electrophiles. Several compounds were identified as potent SARS-CoV-2 Mpro inhibitors, including compounds 8n (IC50 = 0.0752 μM), 8p (IC50 = 0.0887 μM), 8r (IC50 = 0.0199 μM), 10a (IC50 = 0.0376 μM), 10c (IC50 = 0.0177 μM), and 10f (IC50 = 0.0130 μM). Most of them additionally inhibited cathepsin L and were also active against SARS-CoV-1 and MERS-CoV Mpro. In Calu-3 cells, several inhibitors, including 8r, 10a, and 10c, displayed high antiviral activity in the nanomolar range without showing cellular toxicity. The cocrystal structure of SARS-CoV-2 Mpro in complex with 8p revealed covalent binding to the enzyme's catalytic residue Cys145 and showed specific, unprecedented interactions within the substrate binding pocket. Compounds 10c and especially 8n were effective against a panel of naturally occurring nirmatrelvir-resistant mutants, particularly E166V, and showed metabolic stability and additional favorable pharmacokinetic properties, making it a suitable candidate for further preclinical development.

Delivery of Monomethyl Auristatin F to the Tumor Microenvironment with Noninternalizing Fibroblast Activation Protein-Cleavable Small Molecule-Drug Conjugates Elicits Potent In Vivo Anticancer Activity.

OncoFAP is an ultrahigh affinity ligand of fibroblast activation protein (FAP), a tumor-associated antigen overexpressed in the stroma of the majority of solid tumors. OncoFAP has been previously implemented as a tumor-homing moiety for the development of small molecule drug conjugates (SMDCs). In the same context, the glycine--proline dipeptide was included with the aim to selectively undergo cleavage only in the presence of the target FAP, triggering the consequent release of the cytotoxic payload in the tumor microenvironment. In this work, we evaluate the use of monomethyl auristatin F (MMAF) as a payload, a close derivative of MMAE bearing a charged carboxylic acid that hampers its cellular permeability, typically employed in the development of internalizing antibody-drug conjugates. The novel OncoFAP-GlyPro-MMAF and the previously described OncoFAP-GlyPro-MMAE were compared in a head-to-head therapeutic experiment in mice bearing FAP-positive tumors. Surprisingly, the MMAF conjugate mediated potent antitumor activity, despite its poor cellular permeability.

Novel tetracycline hybrids: synthesis, characterization, docking studies and in-vitro evaluation of antibacterial activity

BackgroundThe biggest menace in the world today is the infection caused by pathogenic bacteria in humans, where majority of the available antibiotics fail to provide therapeutic results due to resistance. The discovery of new molecules is the need of the hour and several research groups worldwide are contributing to fight this scare. This work highlights our efforts towards discovering novel tetracycline hybrids that could serve as potent agents against several pathogenic bacterial strains causing infections. In total, ten compounds were synthesized which were chemically conjugates of Minocycline, an age-old tetracycline, and naturally occurring aldehydes and ketones available from the plant sources. Structural characterization of these compounds was done using Mass and 1HNMR. Molecular docking was carried out in order to predict the binding affinity of these compounds to various bacterial enzymes and known protein targets and to establish the structure–activity relationships. Molecular dynamic simulation studies and in silico pharmacokinetic and toxicity prediction studies were done to determine in silico pharmacokinetics and toxicity of compounds. In-vitro antibacterial activities were done using standard protocols against gram positive bacteria like Enterococcus faecalis, Staphylococcus aureus and gram-negative bacteria like Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli.ResultsPromising results were obtained viz. compound 1,2 and 10 were found to be more potent against Staphylococcus aureus, compound 1 against Enterococcus faecalis, compound 2 and 3 against Escherichia coli, compound 7 and 8 against Pseudomonas aeruginosa and compound 7 against Klebsiella pneumoniae when compared with minocycline as standard compound.ConclusionAll the synthesized compounds were screened for their anti-bacterial activity against gram positive and gram negative microorganisms. Amongst the ten synthesized minocycline hybrids, four minocycline hybrids exhibited potent antibacterial activity as compared to minocycline. These hybrids can serve as a promising lead compound for antibiotic drug discovery.

A novel broad-spectrum bacteriophage cocktail against methicillin-resistant Staphylococcus aureus: Isolation, characterization, and therapeutic potential in a mastitis mouse model.

Bovine mastitis is a considerable challenge within the dairy industry, causing significant financial losses and threatening public health. The increased occurrence of methicillin-resistant Staphylococcus aureus (MRSA) has provoked difficulties in managing bovine mastitis. Bacteriophage therapy presents a novel treatment strategy to combat MRSA infections, emerging as a possible substitute for antibiotics. This study evaluated the therapeutic potency of a novel bacteriophage cocktail against MRSA mastitis. Two new bacteriophages (vB_SauR_SW21 and vB_SauR_SW25) with potent lytic activity against MRSA were isolated and characterized. The one-step growth curve displayed a rapid latent period (20-35 min) and substantial burst size (418 and 316 PFU/ cell). In silico analyses have confirmed the absence of antimicrobial resistance or virulence factor-encoding genes within their genomes. According to the results, combining these phages augmented their host range and virulence. The phage cocktail significantly reduced bacterial burden in a BALB/c mastitis model, demonstrating efficacy comparable to antibiotic treatment. Moreover, its administration led to decreased concentrations of IL-1β and TNF-α compared to the negative control group. The bacteriophage cocktail (SW21-SW25) exhibits a promising profile for therapeutic applications and may represent a novel substitute to antibiotics for managing MRSA bovine mastitis.

Antimicrobial and Cytotoxic Potential of Endophytic Aspergillus versicolor Isolate from the Medicinal Plant Plectranthus amboinicus.

Endophytic fungi are non-pathogenic organisms that colonise healthy plant tissues asymptomatically. Endophytes derived from medicinal plants are sources for identifying natural products and bioactive compounds with potential uses for industry, medicine, agriculture, and related sectors. In the present study, ethyl acetate crude extracts of four endophytic fungal isolates (CALF1, CALF4, and CASF1) from the medicinal plant Plectranthus amboinicus showed potent antimicrobial activity against the test pathogenic bacteria Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis using disc diffusion assays. A colorimetric microdilution assay to detect the minimum inhibitory concentration (MIC) revealed that the extracellular extract (ECE) of CASF1 isolate had the lowest MIC values against the test pathogenic bacteria (0.19-6.25 mg/ml) compared to other CALF1 and CALF4.Cytotoxic activity of CASF1-ECE against the drug-resistant KB.CHR.8-5 cancer cell line tested by the MTT assay showed complete cell death at a concentration of 220 μg/mL and the half-maximum inhibitory concentration (IC50) was determined to be 77.9 ± 09 μg/mL.GC-MS analysis showed hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester, as the dominant compound among the bioactive compounds identified in the EXE of CASF1 isolate, with the highest peak in the GC chromatogram, indicating its role in the antimicrobial and cytotoxic activity of CASF1. Molecular identification of CASF1 using 18S rRNA sequencing and BLAST analysis detected CASF1 as an isolate of Aspergillus versicolor with 100% sequence identity.