2-Oxoglutarate-dependent non-heme iron oxygenases (2OGX) catalyze a broad spectrum of oxidative transformations, including hydroxylation, halogenation, desaturation, cyclization, rearrangement, and endoperoxidation, through a conserved HxD/E…H facial triad and Fe(IV)=O chemistry. Their functional diversity arises from structural elements that define the catalytic pocket. Substrate-binding architectures can be categorized into four recurrent motifs—the conserved lip (CLip), conserved lid (CLid), specific lid (SL), and dimer lid (DL)—together with the major β-sheet framework (βI–βVI); mutations in these lid/lip elements and within β-strands collectively govern substrate entry, positioning, and radical partitioning. This review discusses representative case studies organized by reaction class—hydroxylation/halogenation, cyclization/rearrangement, endoperoxidation, and free amino acid oxidation—to illustrate how targeted substitutions in these motifs enable rational reprogramming of reactivity. Examples include hydroxylases converted to halogenases, fungal enzymes redirected to construct alternative meroterpenoid scaffolds, endoperoxidases generating non-natural products, and amino acid hydroxylases engineered for halogenation, desaturation, or aziridination. These studies highlight the structural plasticity of 2OGX scaffolds and establish them as programmable biocatalysts, with advances in structural biology and computational design expected to accelerate their application in synthetic biology, natural product discovery, and drug development. The literature published from 2015 through September 2025 is reviewed.

Biologics represent a major advance in therapy, offering highly specific and potent treatment options for diseases previously difficult to manage; however, their administration routes are commonly limited to injection due to poor oral bioavailability, which can lead to patient inconvenience and adherence challenges. The pulmonary route offers a promising alternative, leveraging the lung’s large absorptive surface area, thin alveolar-capillary barrier, rich vascularization, and avoidance of first-pass metabolism to enable both local and systemic delivery. Effective inhaled biologic therapies require harmonizing the drug’s physicochemical properties with aerosol aerodynamic behavior and dissolution. The pharmacokinetic fate of inhaled biologics is further influenced by lung physiology, including airflow dynamics, airway structure, mucociliary clearance, and respiratory lining fluid composition. These factors present significant barriers to the stability, absorption, and retention of inhaled biologics. Extensive research efforts focus on optimizing formulations, inhalation devices, and excipients, alongside deepening the understanding of the biopharmaceutical characteristics of inhaled biologics. This review summarizes recent advances in inhalation systems of therapeutic peptides and proteins for systemic and local effects, emphasizing practical strategies to overcome key biopharmaceutical and physicochemical challenges, thus advancing the clinical potential of next-generation inhaled biologics.

Inhalation delivery of protein therapeutics has emerged as a promising non-invasive alternative to traditional injectable formulations that offers potential for both localized and systemic treatment of pulmonary diseases. This review comprehensively summarizes the current advances in inhalable protein formulations, with emphasis on design strategies, formulation technologies, barriers to effective delivery, and disease-specific applications. Key aspects include the role of particle size, surface charge, and protein engineering in optimizing lung deposition and cellular uptake, as well as techniques such as spray freeze drying and PEGylation to enhance protein stability. The review also explores novel therapeutic approaches that target cystic fibrosis, asthma, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, lung infections, and cancer, including the use of antibodies, nanobodies, exosomes, and albumin-based carriers. Clinical translation remains limited, but ongoing innovation in delivery systems and molecular design is thought to hold significant promise for expanding the therapeutic landscape of inhaled protein drugs.

This study aimed to develop inhalable dry powder formulations of naked plasmid DNA (pDNA) for pulmonary gene delivery using an electrospinning (ES) technique. Nanofiber mats comprising polyvinyl alcohol (PVA), pDNA encoding firefly luciferase, and either D(−)-mannitol (Man) or lactose monohydrate (Lac) were fabricated and subsequently cryomilled into fine, respirable particles. Agarose gel electrophoresis revealed partial degradation of pDNA during both ES and milling processes, with Lac-based nanofiber mat and powder showing greater pDNA integrity than Man-based formulations. Intratracheal administration of the ES-derived powders in mice led to successful in vivo gene expression, with Man-based powders milled for 0.5 min yielding the highest luciferase activity. Pulmonary imaging using indocyanine green showed that dry powders exhibited extended lung residence compared to aqueous formulations, likely due to improved mucosal adhesion and slower dissolution. Remarkably, the ES-generated pDNA powders demonstrated superior transfection efficiency over both naked pDNA and pDNA–polyethyleneimine complexes, despite some loss in pDNA integrity. These findings highlight the importance of dispersibility and lung retention in achieving effective pulmonary gene transfer. The ES approach represents a promising platform for producing inhalable pDNA powders, offering a non-invasive gene therapy option for respiratory diseases.

The structural integrity of inhalable liposomal carriers is a key determinant of drug release behavior, pulmonary residence time, and therapeutic efficacy. This study aimed to establish a compensated Förster resonance energy transfer (FRET)-based platform for the quantitative assessment of liposome integrity throughout the inhalation delivery process. By compensation for donor fluorescence bleed-through and direct acceptor excitation, the method enables accurate quantification of FRET signals from liposomes co-loaded with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindodicarbocyanine, 4-chlorobenzenesulfonate (DiD, donor)/1,1′-dioctadecyl-3,3,3′,3′-tetramethylindotricarbocyanine iodide (DiR, acceptor), using both spectrofluorometry and macroscopic imaging. Upon treatment with Triton X-100, decreases in the compensated FRET/donor ratio were detected at lower concentrations than those required to induce measurable changes in membrane anisotropy and within the same concentration range as the onset of encapsulated 6-carboxyfluorescein release. Using this platform, in vitro aerosol characterization with an Andersen cascade impactor enabled simultaneous analysis of aerodynamic particle size distribution and stage-specific liposome integrity. In vivo experiments in mice—including ex vivo lung imaging and bronchoalveolar lavage fluid analysis—revealed a time-dependent decline in liposome integrity during pulmonary residence. This ability to monitor carrier structural stability from initial deposition through residence—an aspect not readily achieved with conventional single-fluorophore labeling—offers significant advantages for formulation development, stabilization strategies, and dosing regimen optimization. The FRET-based platform could, in principle, be adapted for use with other standardized cascade impactors such as the Next Generation Impactor and is expected to be applicable to a wide range of lipid-based or polymeric nanocarriers, including inhalable vaccines and nucleic acid therapeutics.

Mucociliary clearance is a unique defense mechanism that forcibly transfers micron-sized substances deposited on the airway epithelium from the lungs, but may interfere with inhalation therapy. The application of mucoadhesive agents to inhaled formulations is expected to improve their efficacy by prolonging the drug residence time in the lungs through inhibited mucociliary clearance. In the present study, we attempted to develop new inhaled spray-freeze-dried (SFD) powders with high deagglomeration and pulmonary retention abilities by combining hydroxypropyl cellulose (HPC) of different molecular weights as a mucoadhesive agent and dileucine (diLeu) as a dispersion enhancer. The incorporation of diLeu into SFD powders resulted in a rough surface structure with large cavities and improved their deagglomeration abilities. In addition, the incorporation of HPC of lower molecular weights resulted in SFD powders with higher deagglomeration abilities. On the other hand, SFD powders with HPC and diLeu showed similar particle size distributions to that with trehalose (Tre) and diLeu after emission from a device regardless of the molecular weight of HPC incorporated. A biodistribution study through intratracheal administration to mice revealed that pulmonary drug retention was longer with SFD powders with HPC and diLeu than with a drug solution or SFD powder with Tre and diLeu, and also that HPC of a high molecular weight (approx.100000) provided the highest pulmonary retention ability of the SFD powder. These results strongly indicate that the molecular weight of HPC incorporated is a critical factor that markedly affects both the deagglomeration and pulmonary retention abilities of SFD powders.

Through the heterologous expression of a highly reducing polyketide synthase and a thioesterase from the apeml cluster, a putative macrolide biosynthetic gene cluster on the genome of Aspergillus petrakii, we obtained a naturally new 10-membered macrolide (1) and recifeiolide (2), a known 12-membered macrolide. To obtain modified macrolides, feeding experiments using Aspergillus oryzae transformants expressing individual modification enzymes were employed, resulting in the isolation of aspinolide A (3) and 2 new macrolides, petrakilides A (4) and B (5). These findings highlight a promiscuous enzymatic cascade capable of generating macrolides with distinct scaffolds and different ring sizes.

In this study, two novel thiabendazole (TBZ) cocrystals were successfully prepared by the solvent evaporation method through the selection of structurally similar, highly water-soluble resorcinol (RES) and phloroglucinol (PHG) as cocrystal formers (CCFs), together with TBZ, which is inherently water-insoluble. The two TBZ cocrystals were comprehensively characterized by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), thermogravimetric-differential scanning calorimetry (TG-DSC), and Fourier-transform IR spectroscopy (FT-IR). Hirshfeld surface analysis was employed to visually illustrate the types and distributions of intermolecular interactions in the two TBZ cocrystals. The solubility and dissolution of the two TBZ cocrystals were measured, respectively. Both cocrystals exhibited superior aqueous solubility compared with TBZ. Specifically, the thiabendazole-phloroglucinol (TBZ-PHG) cocrystal demonstrates that the increased density of hydroxyl groups in the coformer enhances the hydrogen bonding interactions, leading to the formation of a 2 : 1 (TBZ:PHG) stoichiometric cocrystal. The non-parallel arrangement of TBZ molecules in the cocrystal disrupts the close π–π stacking, thereby enhancing solvent penetration. Consequently, its aqueous solubility is improved to a greater extent.

Phoslactomycins and leustroducsins are highly functionalized polyketides. In this paper, we report the new synthetic method for the C1–C13 fragment. This method involves a Suzuki–Miyaura coupling reaction between the C3–C7 acetylene and C8–C13 iodoolefin, followed by construction of the lactone part. The C8–C9 diol is constructed by dihydroxylation in the late stage of the synthesis.

Dendrobium Sw. is one of the largest genera in the Orchidaceae. Most species belong to one of two major clades (the Asian and the Australasian clades) based on morphology and phylogenetic analyses using DNA sequences. Several Dendrobium species in the Asian clade are used in traditional herbal medicine, and many compounds have been isolated from them (e.g., phenanthrene derivatives, bibenzyl derivatives, and polysaccharides). Conversely, there are only a few reports on the compounds contained in the Australasian clade species. Due to its size and diversity, the Australasian clade could be expected to contain compounds of potential medicinal value as well. Previously, we constructed the HPLC profile of 18 Dendrobium species and identified the phenanthrene derivative 1,5-dimethoxyphenanthrene-2,7-diol (1) as a characteristic compound in certain species of the Australasian clade. In this study, we performed metabolic analyses based on ¹H-NMR to identify lineage-correlated metabolites for the Australasian clade. NMR profiling analysis also showed that 1 is a characteristic compound of the Australasian clade species. Additionally, pinoresinol (2) was predominantly detected in the Australasian clade. While syringaresinol (3) was widely detected in species from both clades, specimens from the Australasian clade tended to have higher concentrations. The simple ¹H-NMR profiling method enables rapid comparison of metabolites across multiple species, providing new insights into metabolic differences associated with evolutionary lineages that were not detectable by the previous HPLC profiling.

The development of scalable synthesis of the C21–C34 segment, a key intermediate for aplyronine A and its analogs, is reported. Marshall propargylation and Noyori asymmetric hydrogen transfer served as key reactions for the stereoselective construction of the desired C21–C34 segment on a gram scale. Further transformation of the segment successfully afforded the side chain analog that exhibited actin depolymerization activity similar to that previously reported.

Twelve side-chain fluorinated 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D₃ (AH-1) analogs were designed, synthesized, and evaluated regarding their biological activities. Synthesis was carried out employing the palladium-catalyzed Trost coupling reaction between side-chain fluorinated CD-ring bromo-olefins 41–52 and A-ring enyne 53. Some analogs, including C26,27-hexafluoro-AH-1 (31) and 24,24-difluoro-AH-1 (34), exhibited much higher human vitamin D receptor binding affinity, VDR-ligand binding domain transcriptional activity, osteocalcin promoter transactivation activity, and metabolic resistance to CYP24A1-mediated inactivation than 1α,25(OH)₂D₃.

Bioequivalence (BE) studies are essential for confirming therapeutic equivalence. However, current compendial dissolution tests do not necessarily provide a reliable prediction of clinical BE. We aimed to develop a biorelevant dissolution test that predicts clinical bioequivalence (BE). Three enteric-coated pellets of esomeprazole magnesium trihydrate (ECP-ESO), either clinically BE or non-BE (NBE), were evaluated. Dissolution tests were performed using the paddle method (pH 6.5 or 6.8, 25–100 rpm, 500 mL, 37°C). Biorelevant bicarbonate buffer (BCB) was used as a simulated intestinal fluid, with a floating lid applied to prevent CO₂ escape and maintain pH. Hydrodynamics that suppresses artifact cone formation (coning) were produced using an apex vessel (Apex-V). These biorelevant conditions were compared with the compendial phosphate buffer (PPB) and the round-bottom vessel (RB-V). RB-V is considered less biorelevant as it causes coning at the vessel bottom. When PPB and RB-V were used, BE and NBE formulations could not be distinguished. Substitution of RB-V with Apex-V eliminated coning but lacked discriminative power. This outcome was also observed with BCB and RB-V. Combining both BCB and Apex-V successfully differentiated between BE and NBE formulations, consistent with the clinical BE results. Dissolution testing using biorelevant BCB and Apex-V predicted the clinical BE/NBE of ECP-ESOs. The floating lid method enabled the practical use of BCB, while Apex-V prevented coning. This simple, yet biorelevant, dissolution test could help to predict clinical BE in formulation development.

Herein, we report the catalytic asymmetric intramolecular dearomative coupling of tethered phenols in ortho-para fashion under aerobic conditions. Cooperative catalysis with a chromium-salen complex/nitroxyl radical enabled the desired transformation to proceed at ambient temperature under oxygen atmosphere. A range of tethered phenols were efficiently converted into spirocyclic 2,4-dienones in moderate to good yields and enantioselectivities (up to 68% enantiomeric excess (ee)).