Among presently used pharmaceuticals, about 60% were developed from natural products with unique chemical diversity and biological activities. Hence, the discovery of new bioactive compounds from natural products is still important for further drug development. In addition, breakthroughs in synthetic biology have also begun to produce many useful compounds through manipulations of the biosynthetic genes for secondary metabolites. Theoretically, this approach can also be exploited to generate new unnatural compounds by intermixing the genes from different biosynthetic pathways and/or engineering the secondary metabolite enzyme(s) with expanded substrate and product specificities. Δ⁹-Tetrahydrocannabinol (Δ⁹-THC), the heat-decarboxylated tetrahydrocannabinolic acid (Δ⁹-THCA) produced by Cannabis sativa, is the most important therapeutic cannabinoid due to its useful pharmacological features, such as analgesic, anti-emetic, anti-inflammatory, and anti-epileptic activities. In the structures of cannabinoids, the resorcinyl alkyl chain is a critical pharmacophore, and the therapeutic effects of Δ⁹-THC can be enhanced by converting the pentyl (C₅) moiety at C-3 to other acyl moieties. Thus, the expansion of unnatural cannabinoids with different C-3 alkyl moiety analogs might establish an excellent platform for the further development of therapeutically beneficial cannabinoids. This article reviews the structure-based dual engineering of both enzymes responsible for the formation of the resorcinyl core of Δ⁹-THC and describes the effect of C-6 alkyl-length extension of olivetolic acid, along with related analogs, on the antibacterial activities against Bacillus subtilis and Staphylococcus aureus.

This study investigates the stability of nitrazepam (NZP), a benzodiazepine drug, under basic conditions, since alkaline putrefactive amines and ammonia are produced once bodies are left to decompose for a long period postmortem after a murder involving NZP or an accidental overdose of NZP. The degradation of NZP in an aqueous alkaline solution was investigated by LC/photodiode array detector (PDA) where the NZP degradation product was isolated and purified by solid-phase extraction using Oasis^® MCX, and its chemical structure was determined by LC/time-of-flight (TOF)-MS, NMR spectroscopy, and single-crystal X-ray crystallography. The results revealed that NZP was immediately degraded under basic conditions with 2-amino-5-nitrobenzophenone being an intermediate which further degraded to provide 2-hydroxy-5-nitrobenzophenone as the final degradation product. These results are expected to be useful in clinical chemistry and forensic science, such as the detection of drugs during postmortem examination and suspected addiction.

Triplex DNA formation has generated much interest as a genomic targeting tool that directly targets duplex DNA. However, fundamental limitations in the base pairs of target duplex DNA sequences that can form stable triplex DNA have limited the application. Recently, we have reported on the recognition of CG and ^5mCG base pairs by artificial nucleic acid derivatives with a 2′-deoxynebularine skeleton. Therefore, we attempted to explore the basic skeleton that is important for the development of new artificial nucleic acids allowing for the recognition of TA base pairs. In this study, we focused on a benzimidazole skeleton and introduced a hydroxyl group to enable one-point hydrogen bonding. We have synthesized artificial nucleoside analogues with hydroxyl group on the benzimidazole and incorporated their amidite derivatives into triplex forming oligonucleotides (TFOs). The gel shift assay was performed to evaluate the triplex DNA formation ability of synthesized TFOs, and TFOs containing hydroxybenzimidazole were successfully recognized TA base pairs for all four different sequences. Moreover, compared to the results for the TFOs containing benzimidazole, which suggested hydrogen bonding formation at the hydroxyl group. Therefore, hydroxybenzimidazole would be an important artificial nucleic acid skeleton for TA base pair recognition.

Pirarubicin (THP) shows more rapid intracellular uptake, more effective antitumor activity, and less cardiac toxicity, compared to doxorubicin. However, THP is distributed to both tumor and normal tissues indiscriminately. This study aimed to develop a nanosuspension to deliver THP to tumor tissues more efficiently. Fatty-acid-modified THPs (FA-THPs; octanoic acid, dodecanoic acid, palmitic acid-THPs) were synthesized to increase the hydrophobicity of THP. Nanosuspensions of these FA-THPs were then prepared using an antisolvent precipitation technique. Among the FA-THPs, the most efficiently drug-loaded nanosuspension was obtained from palmitic acid-THP (pal-THP) using an aqueous antisolvent containing bovine serum albumin as a stabilizer. The pal-THP nanoparticles in the nanosuspension were confirmed to be of optimal size (100–125 nm) for delivery to tumor tissues using dynamic light scattering and transmission electron microscopy. The pal-THP nanosuspension showed cytotoxicity in colon 26 cells. The nanosuspension was shown to disintegrate in the presence of surfactants such as lecithin, liberating pal-THP, which was converted to free THP in acidic media. It is therefore proposed that pal-THP nanoparticles that reach tumor cells after intravenous administration would exert antitumor effect by liberating pal-THP (i.e., disintegration of nanoparticles by the interaction with cell membrane), followed by the release of free THP in the acidic milieu of tumor cells. These findings indicate that FA-THP nanosuspensions, particularly pal-THP nanosuspension, hold promise as a candidate for cancer treatment. However, further in vivo studies are necessary.

The development of generic pharmaceuticals involves a bioequivalence study to ensure the therapeutic equivalence of the test formulation to the original innovative product. The formulation characteristics of generic products are expected to be maintained in the long term after approval. This study analyzed the factors contributing to the changes in the dissolution profiles of approved products during their life cycles. Cumulative data on the dissolution similarity of 1675 products of 127 ingredients tested by official laboratories in Japan were assessed according to Japanese bioequivalence guidelines with slight modifications. The products showing dissimilarities in dissolution profiles were analyzed for reporting year, therapeutic category, co-development, physical properties of the active pharmaceutical ingredient (API), and suspected reasons for dissolution change. The increase in the number of dissimilar products is related to the co-development of generic products. Although the solubility of the API was not associated with the dissolution change in the analysis of the total dissolution data, control of the API particle size is suggested to be important for drugs with poorly soluble APIs. Additionally, a risk factor for dissolution changes in the test solutions at a certain pH was the presence of acidic or basic residues. These results indicate the importance of proper development through a thorough evaluation of the formulation and process factors affecting the dissolution properties throughout the product lifecycle.

The spectrum of ³¹P-NMR is fundamentally simpler than that of ¹H-NMR; consequently identifying the target signal(s) for quantitation is simpler using quantitative ³¹P-NMR (³¹P-qNMR) than using quantitative ¹H-NMR (¹H-qNMR), which has been already established as an absolute determination method. We have previously reported a ³¹P-qNMR method for the absolute determination of cyclophosphamide hydrate and sofosbuvir as water-soluble and water-insoluble organophosphorus compounds, respectively. This study introduces the purity determination of brigatinib (BR), an organophosphorus compound with limited water solubility, using ³¹P-qNMR at multiple laboratories. Phosphonoacetic acid (PAA) and 1,4-BTMSB-d₄ were selected as the reference standards (RSs) for ³¹P-qNMR and ¹H-qNMR, respectively. The qNMR solvents were chosen based on the solubilities of BR and the RSs for qNMR. CD₃OH was selected as the solvent for ³¹P-qNMR measurements to prevent the influence of deuterium exchange caused by the presence of exchangeable intramolecular protons of BR and PAA on the quantitative values, while CD₃OD was the solvent of choice for the ¹H-qNMR measurements to prevent the influence of water signals and the exchangeable intramolecular protons of BR and PAA. The mean purity of BR determined by ³¹P-qNMR was 97.94 ± 0.69%, which was in agreement with that determined by ¹H-qNMR (97.26 ± 0.71%), thus indicating the feasibility of purity determination of BR by ³¹P-qNMR. Therefore, the findings of this study may provide an effective method that is simpler than conventional ¹H-qNMR for the determination of organophosphorus compounds.

The capsid of human immunodeficiency virus type 1 (HIV-1) forms a conical structure by assembling oligomers of capsid (CA) proteins and is a virion shell that encapsulates viral RNA. The inhibition of the CA function could be an appropriate target for suppression of HIV-1 replication because the CA proteins are highly conserved among many strains of HIV-1, and the drug targeting CA, lenacapavir, has been clinically developed by Gilead Sciences, Inc. Interface hydrophobic interactions between two CA molecules via the Trp184 and Met185 residues in the CA sequence are indispensable for conformational stabilization of the CA multimer. Our continuous studies found two types of small molecules with different scaffolds, MKN-1 and MKN-3, designed by in silico screening as a dipeptide mimic of Trp184 and Met185 have significant anti-HIV-1 activity. In the present study, MKN-1 derivatives have been designed and synthesized. Their structure–activity relationship studies found some compounds having potent anti-HIV activity. The present results should be useful in the design of novel CA-targeting molecules with anti-HIV activity.

In order to create and offer superior pharmaceuticals for consumers who wish to be relieved of headache and fever as soon as possible, we established HYDROFLASH manufacturing method that enables us to offer fast disintegration tablets containing loxoprofen sodium (LX), which are difficult to disintegrate. As a result of screening excipients, tablets using mannitol showed the fastest disintegration time, about 2 min. From the result of viscosity measurement, we found that LX produced higher viscosity when dissolved in water. This suggests that tablets containing LX disintegrate slower by inhibiting the penetration of water into the tablet due to the viscosity caused of LX. Therefore, we created a manufacturing method to make it easy for water to penetrate the tablet. It is possible to achieve fastest disintegration in about 30 s for tablets containing LX by granulating in a fluidized-bed with spraying of the dispersion of light anhydrous silicic acid (LASA). LX-containing tablets manufactured by the HYDROFLASH method disintegrated immediately after contact with water. Furthermore, it was observed that LASA was uniformly dotted on the surface of tablets by HYDROFLASH method, compared with other manufacturing methods. We considered that by fluidized-bed granulation with LASA dispersion (HYDROFLASH manufacturing method), water permeates through LASA on the tablet surface regardless of viscosity of LX. Futhermore, LX-containing tablets by the HYDROFLASH method showed that the dissolution rate of LX was nearly 100% at 5 min after starting the test. We considered that the initial dissolution became faster because of the fast disintegration.

Twenty natural-product-like 2,8-dioxabicyclo[3.3.1]nonane derivatives were synthesized and their neuroprotective activities were tested using human monoamine oxidases (MAO) A and B and acetyl and butyryl cholinesterases (ChE). Compound 1s showed inhibitory activity for MAO-A, MAO-B and acetylcholinesterase (AChE) (IC₅₀ values 34.0, 2.3 and 11.0 µM, respectively). The inhibition mode of (−)-1s for MAO-B was investigated. Chiral HPLC of (±)-1s separated the enantiomers and (−)-1s showed MAO-B inhibitory activity. Molecular docking simulation of (−)-1s and MAO-B revealed the binding mode.

Two novel series of quinazolinone-based hybrids, including quinazolinone-1,3,4-oxadiazoles (10a–l) and quinazolinone-1,3,4-oxadiazole-benzimidazoles (8a–e), were designed and synthesized and their cytotoxic activities against three human cancer cell lines, lung cancer (A549), cervical cancer (HeLa), and breast cancer (MCF-7), were evaluated. The cytotoxic assays revealed that 10i with a lipophilic 4-fluoro-phenyl moiety at the C-2 position of the quinazolinone ring displayed good cytotoxicities against the A549 and MCF-7 cell lines, while 8b–d with the thioether-linked benzimidazole moiety incorporated on the right side of the oxadiazole ring induced comparable stronger activities toward the MCF-7 cell line, relative to the simple two-heterocycle-containing hybrid 10i. These novel quinazolinone-based hybrids could be considered as lead compounds that merit further optimization and development as anti-cancer agents.

The first enantioselective total synthesis of kopsiyunnanine B, which has a unique folded and complex pentacyclic structure containing six contiguous chiral centers, has been achieved along our originally proposed biosynthetic pathway. The key reaction of this synthesis includes a bioinspired cascade that builds three ring structures and three chiral centers in one step and features the stereoselective reduction of a β-acrylate and oxidation to an oxindole.

The oxidative cleavage reaction of pyrrolidine-2-methanols to γ-lactams has been described. In this reaction, [4-iodo-3-(isopropylcarbamoyl)phenoxy]acetic acid and powdered Oxone (2KHSO₅·KHSO₄·K₂SO₄) were employed as the catalyst and co-oxidant, respectively. The reaction is efficient and environmentally benign because it produces various lactams from readily available substrates in moderate to excellent yields using organocatalyst and inorganic non-toxic co-oxidant.

Five new viridogriseins B–F were isolated from Streptomyces niveoruber, along with viridogrisein and griseoviridin which belong to streptogramin family antibiotics. A combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and the advanced Marfey’s method elucidated the structures of viridogriseins B–F, each featuring distinct constituent amino acids. Consistent with other streptogramin family antibiotics, these viridogrisein analogs exhibited potent antibacterial activity against Staphylococcus aureus. Furthermore, equimolar mixtures of each viridogrisein analog and griseoviridin inhibited the growth of S. aureus more potently than each analog treatment alone. Finally, an in vitro functional analysis of SgvY, encoded in the viridogrisein biosynthetic gene cluster, revealed that SgvY detoxifies viridogrisein against S. aureus by linearization. Considering that viridogrisein is not autotoxic to S. niveoruber, SgvY likely contributes to the self-resistance system against viridogrisein in S. niveoruber.

For powder compaction, the Kawakita equation has been used to estimate the powder behavior inside the die. The compression pressure exerted on powders is not homogeneous because of the friction on the die wall. However, the yield pressure and porosity estimated using the Kawakita equation are defined based on the assumption that homogeneous voids and compression pressure are distributed throughout the powder bed. In this study, an extended Kawakita equation was derived by considering the variation in the compression pressure as it corresponds to the distance from the loading punch surface. The yield time section estimated from the extended Kawakita equation was wider than that which was estimated via the classical equation. This result is consistent with the assumptions used to derive the extended Kawakita equation. Furthermore, a comparison of the porosity changes before and after the yield pressure was applied indicate that the direct cause of the yield is the spatial constraints of the powder particles. Equivalent stresses were defined to clarify the critical factor that constitutes the extended Kawakita equation. As a result, “taking into account the die wall friction” was considered to be the critical factor in the extended Kawakita equation. As these findings were theoretically determined by the extended Kawakita equation, a useful model was derived for a better understanding of powder compaction in die.

Sunflower seed extract, an antioxidant agent registered on the List of Existing Food Additives in Japan, was evaluated using HPLC, and three common constituents were detected. These peaks were identified as monocaffeoylquinic acids (3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, and 5-O-caffeoylquinic acid [chlorogenic acid]). Upon scrutinizing other components, dicaffeoylquinic acids (isochlorogenic acids; 3,4-di-O-caffeoylquinic, 3,5-di-O-caffeoylquinic, and 4,5-di-O-caffeoylquinic acids) were also identified. Structures of two newly isolated compounds were determined to be 3-O-(3S-2-oxo-3-hydroxy-indole-3-acetyl)-5-O-caffeoylquinic and 4-O-(3S-2-oxo-3-hydroxy-indole-3-acetyl)-5-O-caffeoylquinic acids. To identify the components that contribute to the antioxidant activity of sunflower seed extract, we fractionated the food additive sample solution and examined the active fractions for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Monocaffeoylquinic and dicaffeoylquinic acids showed high DPPH activity, including their contribution to the antioxidant activity of this food additive. DPPH radical scavenging activity of the new compounds showed almost the same value as that of the positive control, Trolox. Therefore, the contribution of these compounds was also considered.

A novel tricyclic polyketide, curvulanone (1), was isolated from the marine-derived fungus Curvularia aeria. The structure of 1 was determined by NMR and single-crystal X-ray crystallography. 1 had a cyclopentabenzopyranone with 3-acetic acid structure that is rarely found in natural compounds. Monoamine oxidase and sirtuin 1 inhibitory test was exhibited and 1 showed their inhibitory activity.

For taste masking of fexofenadine hydrochloride (FXD), ethylcellulose (EC) microparticles with FXD were developed. The amounts of EC, Tween 80, and polyvinyl alcohol (PVA) in the composition had little effect on initial drug release properties. Based on the results of the drug recovery and the drug release properties, FXD(EC200) was the optimal FXD microparticle formulation. From the results of Fourier transform infrared spectroscopy spectra and X-ray diffraction patterns of FXD(EC200), FXD amorphization in the microparticles and interaction between FXD and other components were suggested, and the formation of a solid dispersion of FXD was suggested. Because the possibility of the complex of PVA and FXD on the particle surface was suggested, sodium lauryl sulfate (SLS) was added to the composition. The initial drug release from FXD microparticles with SLS was further suppressed compared with FXD(EC200). From these results, FXD microparticles with SLS can be prepared as a controlled-release formulation and are expected to be useful for masking the bitter tasting particulates.

A series of 2-azolylmethylene-3-(2H)-benzofuranone derivatives, 2-indolylmethylene-3-(2H)-benzofuranone and 2-pyrrolylmethylene-3-(2H)-benzofuranone derivatives, were synthesized, and their monoamine oxidase (MAO) A and B inhibitory activities were evaluated. Compounds 1b, 3b, 6b, 7b, and 10b showed strong inhibitory activity against MAO-A, and compound 3b showed the highest potency and selectivity, with an IC₅₀ value of 21 nM and a MAO-A selectivity index of 48. Compounds 3c, 4c, 9a, 9c, 10c, 11a, and 11c showed strong inhibitory activity against MAO-B, and compound 4c showed the highest potency and selectivity, with an IC₅₀ value of 16 nM and a MAO-B selectivity index of >1100. Further analysis of these compounds indicated that compound 3b for MAO-A and compound 4c for MAO-B were competitive inhibitors, with K_i values of 10 and 6.1 nM, respectively. Furthermore, computational analyses, such as quantitative structure–activity relationship (QSAR) analysis of the 2-azolylmethylene-3-(2H)-benzofuranone derivatives conducting their pIC₅₀ values with the Molecular Operating Environment (MOE) and Mordred, and molecular docking analysis using MOE-Dock supported that the 2-azolylmethylene-3-(2H)-benzofuranone derivatives are a privileged scaffold for the design and development of novel MAO inhibitors.

In clinical diagnosis, fluorescent particles are applied to detect analytes in biofluids, such as blood and saliva. However, current fluorescence detection methods have not been optimized to account for the overlapping autofluorescence peaks of biological substances. Gold and silver nanoclusters are known to the novel fluorescent materials and their emission wavelengths depend on cluster size. In this study, we developed fluorescent silica nanoparticles using gold–silver alloy nanoclusters and chitosan (CS) (NH₂-SiO₂@Au@CS@AuAg) by the layer-by-layer method. Under UV-light irradiation at 365 nm, the emission wavelength of NH₂-SiO₂@Au@CS@AuAg reached 750 nm in the near-IR region. Scanning electron microscopy images revealed that the shape of NH₂-SiO₂@Au@CS@AuAg was uniform and spherical. The fluorescence spectrum of horse blood obtained in the presence of NH₂-SiO₂@Au@CS@AuAg contained a specific fluorescence peak attributed to NH₂-SiO₂@Au@CS@AuAg, which was distinguishable from the autofluorescence peaks. These results showed that NH₂-SiO₂@Au@CS@AuAg has advantageous fluorescence properties for clinical diagnostic applications.

Although curcumin and its analogs exhibit anticancer activity, they are still not used as anticancer drugs because of their water insolubility and extremely poor bioavailability. This study describes the development of water-soluble prodrugs of GO-Y030, a potent antitumor C5-curcuminoid, in an attempt to enhance its bioavailability. These prodrugs release the parent compound via a retro-thia-Michael reaction. To endow sufficient hydrophilicity onto GO-Y030 via a single thia-Michael reaction of an aqueous entity, we used a modified glycoconjugate with a thiol group. The water-solubilizing motif was installed on GO-Y030 by the thia-Michael reaction of propargyl-polyethylene glycol (PEG)-thiol and subsequent click chemistry (CuAAC) reaction with 1-glycosyl azide. Turbidity measurements revealed a significantly improved water solubility of the prodrugs, demonstrating that disaccharide conjugates were completely dissolved in water at 100 µM. Their cytotoxicity was comparable to that of the parent compound GO-Y030, indicating the gradual in situ release of GO-Y030. The release of GO-Y030 from GO-Y199 via the retro-thia-Michael reaction was demonstrated through a degradation study in water. Our retro-thia-Michael reaction-based prodrug system can be used for targeting cancer cells.