Ana M López-Fernández, Jean C Neto, Rosa de Llanos, Juan F Miravet, Francisco Galindo
{"title":"Minimalistic bis-triarylpyridinium cations: effective antimicrobials against bacterial and fungal pathogens.","authors":"Ana M López-Fernández, Jean C Neto, Rosa de Llanos, Juan F Miravet, Francisco Galindo","doi":"10.1039/d4md00902a","DOIUrl":"10.1039/d4md00902a","url":null,"abstract":"<p><p>A series of twelve compounds from the family of 2,4,6-triarylpyridinium cations have been synthesized, chemically characterized (<sup>1</sup>H, <sup>13</sup>C NMR, HRMS), and microbiologically evaluated (MIC determination against <i>S. aureus</i>, <i>E. faecalis</i>, <i>E. coli</i>, <i>P. aeruginosa</i>, and <i>C. albicans</i>). These compounds are quaternary ammonium cations (QACs), classified as either mono-QACs or bis-QACs. The mono-QACs are further divided into those with short (three-carbon) and long (twelve-carbon) pendant chains. An additional structural variable is the number of bromine atoms attached to the aromatic rings, ranging from zero to three. The major findings of this study are: (a) bis-QACs exhibit notably higher antimicrobial activity than mono-QACs; (b) an increased number of bromine atoms on the structure appears to diminish antimicrobial properties and (c) one of the compounds (1a) shows particularly promising properties as a broad spectrum antimicrobial, given its low MICs across all five pathogenic microorganisms studied. Preliminary assays with <i>C. albicans</i> show that 1a has a strong mitochondrial activity, causing a remarkable mitochondrial membrane depolarization in this organelle. Taken together, this study positions triarylpyridinium cations-previously unexplored as antimicrobials-as promising candidates for future drug development, especially in light of the growing concern over drug-resistant microorganisms.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11969996/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143796289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Breanna L Zerfas, Yingpeng Liu, Jianwei Che, Katherine A Donovan, John M Hatcher, Fidel Huerta, Rebecca J Metivier, Radosław P Nowak, Leah Ragosta, Tiffany Tsang, Eric S Fischer, Lyn H Jones
{"title":"Structure-guided design of a truncated heterobivalent chemical probe degrader of IRE1α.","authors":"Breanna L Zerfas, Yingpeng Liu, Jianwei Che, Katherine A Donovan, John M Hatcher, Fidel Huerta, Rebecca J Metivier, Radosław P Nowak, Leah Ragosta, Tiffany Tsang, Eric S Fischer, Lyn H Jones","doi":"10.1039/d5md00028a","DOIUrl":"10.1039/d5md00028a","url":null,"abstract":"<p><p>IRE1α is an ER protein involved in the unfolded protein response (UPR) and dysregulation of the ER stress pathway has been implicated in several diseases. Inhibitors of the cytoplasmic endonuclease or kinase domains of the enzyme have limited utility and targeted degradation would address additional scaffolding functions of the protein. Here, we describe the design and development of IRE1α proteolysis targeting chimeras (PROTACs) based on a lysine-reactive salicylaldehyde RNase inhibitor, and present the structure-activity relationships (SARs) that delivered the first highly selective degraders of a native ER-membrane associated protein. Medicinal chemistry optimization exploited ternary complex computational modelling to inform design, HiBiT-SpyTag IRE1α degradation and NanoBRET cereblon occupancy cell-based assays to generate SARs, and mass spectrometry-based proteomics to assess broad selectivity in an unbiased manner. Merging IRE1α and CRBN ligand chemotypes provided the truncated chimera CPD-2828 with physicochemical properties more akin to an oral molecular glue degrader than a traditional PROTAC.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11938282/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143731477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silas L Wurnig, Maria Hanl, Thomas M Geiger, Shiyang Zhai, Ina Dressel, Dominika E Pieńkowska, Radosław P Nowak, Finn K Hansen
{"title":"Light-activatable photochemically targeting chimeras (PHOTACs) enable the optical control of targeted protein degradation of HDAC6.","authors":"Silas L Wurnig, Maria Hanl, Thomas M Geiger, Shiyang Zhai, Ina Dressel, Dominika E Pieńkowska, Radosław P Nowak, Finn K Hansen","doi":"10.1039/d4md00972j","DOIUrl":"10.1039/d4md00972j","url":null,"abstract":"<p><p>Proteolysis targeting chimeras (PROTACs) are heterobifunctional modalities that induce protein degradation <i>via</i> a catalytic mode of action. Photochemically targeting chimeras (PHOTACs) are a subset of PROTACs designed for light-activated protein degradation, thereby offering precise spatiotemporal control. In this study, we report the design, solid-phase synthesis, and characterization of the first PHOTACs targeting histone deacetylase 6 (HDAC6). We achieved this by incorporating an azobenzene photoswitch into our previously developed HDAC6-selective PROTAC A6. Among the synthesized compounds, PHOTAC 12 demonstrated no HDAC6 degradation in the absence of light but showed significant degradation upon activation to its <i>cis</i>-state with 390 nm light irradiation. Notably, we find that PHOTAC 12 in the <i>cis</i>-state shows significantly improved ternary complex formation compared to the <i>trans</i>-state correlating with its degradation efficacy. Overall, PHOTAC 12 is a promising lead compound for the development of light-activatable HDAC6 degraders.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11931564/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143711138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Asmaa M Atta, Nouran Rihan, Ahmad M Abdelwaly, Mohamed S Nafie, Mohamed S Elgawish, Samia M Moustafa, Mohamed A Helal, Khaled M Darwish
{"title":"Development, biological evaluation, and molecular modelling of novel isocytosine and guanidine derivatives as BACE1 inhibitors using a fragment growing strategy.","authors":"Asmaa M Atta, Nouran Rihan, Ahmad M Abdelwaly, Mohamed S Nafie, Mohamed S Elgawish, Samia M Moustafa, Mohamed A Helal, Khaled M Darwish","doi":"10.1039/d4md00698d","DOIUrl":"https://doi.org/10.1039/d4md00698d","url":null,"abstract":"<p><p>Alzheimer's disease (AD) is a neurodegenerative condition characterized by significant synaptic loss and neuronal death in brain regions critical for cognitive functions. The disease is characterized by the formation of amyloid plaques, which are extracellular constructs consisting mainly of aggregated Aβ42. The latter is a peptide formed by the proteolytic cleavage of β-amyloid precursor protein (APP) by two enzymes, β- and γ-secretase. Therefore, inhibition of the aspartic protease β-secretase (BACE1) is considered a promising therapeutic approach for the treatment and prevention of Alzheimer's disease. Unfortunately, a limited number of β-secretase inhibitors have reached human trials and eventually failed due to inconclusive therapeutic and/or safety profiles. In this study, we developed drug-like molecules with a β-secretase inhibitory activity using a fragment growing strategy on isocytosine and acyl guanidine warheads. Our approach is based on optimizing the hydrophobic part of the molecules to obtain a conformationally restrained scaffold complementary to the hydrophobic pockets within the enzyme active site. We developed 32 compounds with promising <i>in vitro</i> inhibitory activity against BACE1 down to sub-micromolar IC<sub>50</sub>. Docking simulation studies were performed to understand the mode of binding of the prepared compounds. We demonstrated that compounds with superior activities, such as 16b and 16g, are able to provide the best balance between the steric shape and position of the polar substituent for achieving preferential anchoring into the S1, S3, S1', and S2' sub-pockets. Further, <i>in vivo</i> characterization of selected drug-like candidates of the benzimidazole series AMK-IV, namely 16a and 16k, demonstrated their ability to reduce oxidation stress and their safety within brain and liver tissues.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11904611/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143650241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marwa Alsulaimany, Faizah A Binjubair, Esra Tatar, Diane E Kelly, Steven L Kelly, Andrew G Warrilow, Mikhail V Keniya, Brian C Monk, Josie E Parker, Claire Simons
{"title":"Exploring medium and long arm extensions of 1,2,4-triazole derivatives as <i>Candida albicans</i> 14α-demethylase (CYP51) inhibitors.","authors":"Marwa Alsulaimany, Faizah A Binjubair, Esra Tatar, Diane E Kelly, Steven L Kelly, Andrew G Warrilow, Mikhail V Keniya, Brian C Monk, Josie E Parker, Claire Simons","doi":"10.1039/d4md00863d","DOIUrl":"10.1039/d4md00863d","url":null,"abstract":"<p><p>Fungal infections have been described as a silent crisis affecting more than one billion people each year. At least 150 million of these cases involve severe and life threatening invasive fungal infections, accounting for approximately 1.7 million deaths annually. 1,2,4-Trizoles such as fluconazole and posaconazole are widely used antifungal agents, but azole resistance is an increasing problem requiring further study. 1,2,4-Triazole derivatives with medium and long arm extensions designed to bind within the <i>Candida albicans</i> CYP51 (CaCYP51) access channel were synthesised to study their inhibition of CaCYP51 (IC<sub>50</sub>, MIC) and binding affinity (<i>K</i> <sub>d</sub>). A long arm extension using the amide linker was found to be most effective (<i>e.g.</i>13), giving an antifungal profile <i>vs.</i> wild-type and resistant model fungal strains comparable with posaconazole.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11931565/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143711100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P K Hashim, Ashwin T Shaji, Ammathnadu S Amrutha, Shifa Ahmad
{"title":"Conceptual expansion of photomedicine for spatiotemporal treatment methods.","authors":"P K Hashim, Ashwin T Shaji, Ammathnadu S Amrutha, Shifa Ahmad","doi":"10.1039/d4md01005a","DOIUrl":"10.1039/d4md01005a","url":null,"abstract":"<p><p>Photomedicine has evolved from basic phototherapy to a broad range of light-based technologies to achieve precise and minimally invasive therapeutic outcomes. Recent advances in light sources, photochemical reactions, and photoswitches have facilitated the development of light-activated methodologies for modulating biological processes. This review discusses the history of light therapy that leads to the emergence of a new field known as photopharmacology, mode of actions in photopharmacology such as photodynamic, photo-uncaging and photoswitchable methods, a few representative examples in photopharmacology, and a brief overview of its associated challenges. The current developments in photopharmacology hold great promise for the treatment of diseases such as cancer, with enhanced therapeutic precision, and minimal side effects. We foresee further expansion of photomedicine for novel approaches in precision medicine and healthcare, and unprecedented treatment methods.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11959407/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143773137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohinder Maheshbhai Naiya, Ivy A Guan, Matthew Sullivan, Chatchakorn Eurtivong, Euphemia Leung, Lisa I Pilkington, David Barker
{"title":"Design, synthesis, and SAR of antiproliferative activity of trioxatriangulene derivatives.","authors":"Mohinder Maheshbhai Naiya, Ivy A Guan, Matthew Sullivan, Chatchakorn Eurtivong, Euphemia Leung, Lisa I Pilkington, David Barker","doi":"10.1039/d4md00867g","DOIUrl":"10.1039/d4md00867g","url":null,"abstract":"<p><p>Trioxatriangulene (TOTA<sup>+</sup>) and its derivatives, which are primarily used as dyes in biological systems, have received considerable attention owing to their photophysical and electronic properties. Notably, their DNA-intercalating properties have been well established. Previous studies have identified TOTA<sup>+</sup> derivatives, particularly ADOTA<sup>+</sup> (R = -C<sub>3</sub>H<sub>7</sub>) and DAOTA<sup>+</sup> (R = R' = -C<sub>3</sub>H<sub>7</sub>), as potent antiproliferative agents in triple-negative breast cancer (MDA-MB-231) and colorectal cancer (HCT-116) cell lines. However, the potential to enhance antiproliferative activity through different side chains prompted further investigation. In addition, partially cyclized tetramethoxyphenyl acridinium ion (TMPA<sup>+</sup>8) and dimethoxy quinacridinium ion (DMQA<sup>+</sup>9) intermediates were assessed to elucidate the structure-activity relationship (SAR) of the triangulenium core for antiproliferative activity. In this study, 83 molecules with various side chains were synthesized, including planar, partially planar, and non-planar derivatives. Evaluation of their antiproliferative activity in MDA-MB-231 and HCT-116 cell lines revealed that compound 6l (R = -C<sub>4</sub>H<sub>9</sub>, R' = -C<sub>2</sub>H<sub>4</sub>N(Me)<sub>2</sub>) was the most potent inhibitor, with IC<sub>50</sub> values of 18 ± 3 nM and 32 ± 14 nM, respectively. A new one-pot method was developed to synthesize symmetrically and asymmetrically substituted DAOTA<sup>+</sup> molecules, enabling the introduction of acid-labile functional groups, such as alcohols, ethers, and alkylamines, in moderate to good yields.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11969997/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143796287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Akshay S Kulkarni, Sreenivasa Rao Ramana, Vijay K Nuthakki, Shipra Bhatt, Ashiya Jamwal, Laxman D Nandawadekar, Anshika Jotshi, Ajay Kumar, Utpal Nandi, Sandip B Bharate, D Srinivasa Reddy
{"title":"Silicon incorporated tacrine: design, synthesis, and evaluation of biological and pharmacokinetic parameters.","authors":"Akshay S Kulkarni, Sreenivasa Rao Ramana, Vijay K Nuthakki, Shipra Bhatt, Ashiya Jamwal, Laxman D Nandawadekar, Anshika Jotshi, Ajay Kumar, Utpal Nandi, Sandip B Bharate, D Srinivasa Reddy","doi":"10.1039/d5md00019j","DOIUrl":"10.1039/d5md00019j","url":null,"abstract":"<p><p>Tacrine, an orally bioavailable cholinesterase inhibitor, was previously used to treat Alzheimer's disease but was withdrawn due to hepatotoxicity. The unique structural features of tacrine have once again captured the interest of medicinal chemists. However, the blood-brain barrier (BBB) permeability hampered the development of the majority of its new analogs. Herein, we employed a silicon switch approach for improving the BBB permeability of CNS drugs with tacrine as a tool compound. The replacement of C2 methylene of tacrine with dimethyl silicon yielded 'sila-tacrine' that inhibits acetylcholinesterase as well as butyrylcholinesterase with IC<sub>50</sub> values of 3.18 and 6.09 μM, respectively. Sila-tacrine competitively inhibits acetylcholinesterase while it is a non-competitive inhibitor of butyrylcholinesterase. The molecular docking results corroborated with the <i>in vitro</i> cholinesterase inhibition activity of tacrine <i>vs.</i> sila-tacrine. Sila-tacrine demonstrated metabolic stability in HLM and MLM and exhibited superior plasma exposure in an oral pharmacokinetic study in Swiss albino mice. However, tissue distribution studies revealed lower-than-expected brain levels due to efflux pump-mediated transport. This study offers a proof-of-concept for the silicon switch approach in improving the BBB permeability of CNS-active compounds.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11959489/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143773140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmed H E Hassan, Eun Seo Bae, Youngdo Jeong, Chae Won Ock, Selwan M El-Sayed, Minji Kim, Mohamed F Radwan, Tarek S Ibrahim, Jun-Young Cho, Boyoung Y Park, Jaehoon Sim, Sang Kook Lee, Yong Sup Lee
{"title":"Design, synthesis and evaluation of acetylcholine-antitumor lipid hybrids led to identification of a potential anticancer agent disrupting the CDK4/6-Rb pathway in lung cancer.","authors":"Ahmed H E Hassan, Eun Seo Bae, Youngdo Jeong, Chae Won Ock, Selwan M El-Sayed, Minji Kim, Mohamed F Radwan, Tarek S Ibrahim, Jun-Young Cho, Boyoung Y Park, Jaehoon Sim, Sang Kook Lee, Yong Sup Lee","doi":"10.1039/d4md01007h","DOIUrl":"10.1039/d4md01007h","url":null,"abstract":"<p><p>Hybridization of acetylcholine with antitumor lipids (ATLs) was explored to achieve novel potential anticancer agents. The combination with a 2-stearoxyphenyl moiety substantially enhanced the anticancer activity of the acetylcholine hybrids. Compounds 6, 8, 9 and 10 exhibited pronounced anticancer activities higher than edelfosine and stPEPC and NSC43067. Compounds 6, 8, 9 and 10 also showed broad-spectrum anticancer activity against diverse cancer cells including lung, ovarian, renal, prostate, leukaemia, colon, CNS, melanoma, and breast cancer cells. Compounds 6 and 8 were potent compounds eliciting single digit low micromolar GI<sub>50</sub> values. Compound 6 was the most potent against non-small cell lung cancer, ovarian cancer, renal cancer, and prostate cancer. Meanwhile, compound 8 was the most potent against leukaemia, colon cancer, CNS cancer, melanoma, and breast cancer. Exploration of the mechanism of action of compound 6 in A549 non-small cell lung cancer cells showed that it triggers cell cycle arrest in the G<sub>0</sub>/G<sub>1</sub> phase <i>via</i> disruption of the CDK4/6-Rb pathway and induces apoptosis <i>via</i> the activation of caspases, upregulation of BAX and cleavage of PARP. Overall, the results present acetylcholine-ATL hybrids 6 and 8 as potential anticancer agents for possible further development.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11931566/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143711111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthew T Tung, Tianyi Ma, Ivonne Rebeca Lopez-Miranda, Joshua N Milstein, Andrew A Beharry
{"title":"Nitroreductase-activatable photosensitizers for selective antimicrobial photodynamic therapy.","authors":"Matthew T Tung, Tianyi Ma, Ivonne Rebeca Lopez-Miranda, Joshua N Milstein, Andrew A Beharry","doi":"10.1039/d4md00890a","DOIUrl":"10.1039/d4md00890a","url":null,"abstract":"<p><p>Antimicrobial photodynamic therapy (aPDT) utilizes light, oxygen and a photosensitizer (PS) to enact cell death <i>via</i> the production of reactive oxygen species (ROS). This mechanism of cell death, <i>via</i> oxidative stress, has allowed aPDT to be effective against antibiotic-resistant bacterial strains, with the development of resistance being minimal as no specific pathway is targeted. While promising, as ambient light can activate PSs, damage to mammalian tissues can occur, leading to drug-induced photosensitivity. To mitigate this, we developed a nitroreductase-activatable PS containing a quenching group that inhibits fluorescence and ROS. Upon reaction with nitroreductase, the quenching group can be liberated, restoring fluorescence and ROS production. As nitroreductase is not present in healthy mammalian tissues but expressed in many bacteria, photosensitivity of mammalian cells can be reduced. Herein, the synthesis and photophysical characterization of the nitroreductase-activatable PS, <b>DB2</b>, is described. <b>DB2</b> was quenched compared to the free PS, <b>DB1</b>, and activation both <i>in vitro</i> by purified nitroreductase and in the gram-positive bacterial strain, <i>Bacillus subtilis</i>, was confirmed by fluorescence recovery. Cell viability studies in <i>B. subtilis</i> showed low dark toxicity and an IC<sub>50</sub> of 0.16 μM under 10-minute irradiation (530 nm, 42 mW cm<sup>-2</sup>). Minimal toxicity was observed under the same conditions in mammalian cell cultures demonstrating the potential of <b>DB2</b> to mitigate photosensitivity and provide a promising approach for aPDT.</p>","PeriodicalId":21462,"journal":{"name":"RSC medicinal chemistry","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11883423/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143586543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}