Effects of Electron-Withdrawing and Electron-Donating Groups on Aromaticity in Cyclic Conjugated Polyenes.

Determining the aromaticity of various fluorinated benzenes is challenging as easily obtained experimental aromaticity [Δδ(Houter - Hinner)] necessitates the chemical shifts of inner and outer protons. This issue was addressed in porphyrinoids by replacing the electron-withdrawing (E.W.) groups at the meso-positions of porphyrins and allyliporphyrins. Electronic effects on aromaticity in porphyrinoids have not been thoroughly examined in the literature. In porphyrins, the effect of E.W. groups is minimal, making it difficult to establish a clear relationship between the aromaticity strength and E.W. groups. Conversely, in allyliporphyrins, stronger E.W. groups, such as indandione (IND) derivatives, significantly reduce the aromaticity of the parent structure. The IND derivatives disrupted the aromatic pathway of allyliporphyrin more effectively than those attached to porphyrins. This is attributed to the absence of ß-carbons in allyliporphyrins. The effect of electron-donating (E.D.) groups on porphyrins and allyliporphyrins was further investigated. Contrary to the initial assumption that the E.D. groups might enhance aromaticity owing to their ability to increase electron density, as the strength of the E.D. groups increased, the aromaticity of the porphyrinoids decreased. Despite the modest reduction in aromaticity, any form of electron perturbation reduces aromaticity. The aromaticity of various fluorinated benzenes is expected to parallel our observations of porphyrinoids as representative aromatic polyenes.

Synthesis of Dioxa-1,7-naphthicorrole and Its Oxidized Porphyrinoid as a Potential Built-In Linker for Biomolecules.

The first aromatic benzicorrole termed naphthicorrole was synthesized with a carbon donor containing more than six members. Its oxidized (enedione-embedded) porphyrinoid was also obtained using different meso-aryl substitutions under sequential oxidation conditions. The resulting enedione motif of the nonaromatic porphyrinoid was regioselective to the C2 position for S or N nucleophiles. Thus, the oxidized porphyrinoid was tested as a built-in linker for biomolecules. The progress of the reaction was visually monitored due to their different conjugation pathways.

o-(2-Thienyl)vinylarene as an Alternative Synthetic Motif for Porphyrinoids: o-Arene-Connected Porphyrinoids.

o-Arene-connected porphyrinoids were synthesized with o-(2-thienyl)vinylarene motif as a new building block for porphyrinoids. This motif can replace meso-aryl-substituted dipyrromethene and serve as a command key arranging o-connectivity of porphyrinoid. While 6a (benzene version) is very weak, 6b (pyridine version) shows a substantial amount of diatropic ring current due to reduced steric hindrance (without H23) and rigidified Pd-6a became more aromatic than 6b.

Network pharmacology and molecular docking approaches to elucidate the potential compounds and targets of Saeng-Ji-Hwang-Ko for treatment of type 2 diabetes mellitus.

BACKGROUND: Saeng-Ji-Hwang-Ko (SJHK) is a traditional Korean medicine formula derived from Donguibogam, a classic medical textbook, published in 1613. It is described as a general treatment for So-gal (wasting-thirst, ) known as type 2 diabetes mellitus (T2DM) in a modern clinical term. It is necessary to elucidate the potential compounds and targets of SJHK for T2DM treatment by conducting network pharmacology and molecular docking analyses. METHODS: Information about the chemical constituents of SJHK were collected, and druggable compounds were screened based on oral bioavailability and drug-likeness. Putative target genes of druggable compounds and T2DM-related genes were retrieved from public databases. A compound-target network was constructed to visualize the relationship between the druggable compounds in SJHK and common targets related to T2DM. The constructed network was further investigated through Protein-Protein Interaction, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway analyses, and molecular docking. RESULTS: Compound-target network analysis demonstrated that kaempferol, salicylic acid, estrone, and ß-sitosterol were key compounds of SJHK with PTGS2, ESR1, PRKAA2, PRKAB1, and CYP19A1 being its key targets. Estrogen signaling, AGE-RAGE signaling, insulin resistance, non-alcoholic fatty liver disease, and TNF signaling pathway were potential pathways involved in the effect of SJHK on T2DM. Molecular docking simulations revealed that estrone and ß-sitosterol had the strong binding energies for all the key target proteins. CONCLUSIONS: This study demonstrates that network pharmacology and molecular docking analyses help to better understand the potential key compounds and targets of SJHK for treating T2DM as a complementary medicine. SUMMARY: Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder caused by genetic and/or environmental factors. There has been a growing attention to new therapeutic approaches to treat T2DM using traditional medicine as a complementary treatment which is expected to have synergistic effects with few side effects. Saeng-Ji-Hwang-Ko (SJHK) is a traditional Korean medicine (TKM) formula derived from Donguibogam, a classic medical textbook, published in 1613. It is described as a general treatment for So-gal (wasting-thirst, ) known as type 2 diabetes mellitus (T2DM) in a modern clinical term. It is necessary to elucidate the potential compounds and targets of SJHK for T2DM treatment by conducting network pharmacology and molecular docking analyses. Compound-target network analysis demonstrated that kaempferol, salicylic acid, estrone, and ß-sitosterol were key compounds of SJHK with PTGS2, ESR1, PRKAA2, PRKAB1, and CYP19A1 being its key targets. Estrogen signaling, AGE-RAGE signaling, insulin resistance, non-alcoholic fatty liver disease, and TNF signaling pathway were potential pathways involved in the effect of SJHK on T2DM. Molecular docking evaluation revealed that estrone and ß-sitosterol had the highest binding energies for all key target proteins, suggesting potential key compounds of SJHK. Although additional future studies including further experimental and clinical validation are needed, this study demonstrates that SJHK has a great potential for treating T2DM as a complementary medicine.

A Comparative Study of the Hepatoprotective Effect of Centella asiatica Extract (CA-HE50) on Lipopolysaccharide/d-galactosamine-Induced Acute Liver Injury in C57BL/6 Mice.

Acute liver failure (ALF) refers to the sudden loss of liver function and is accompanied by several complications. In a previous study, we revealed the protective effect of Centella asiatica 50% ethanol extract (CA-HE50) on acetaminophen-induced liver injury. In the present study, we investigate the hepatoprotective effect of CA-HE50 in a lipopolysaccharide/galactosamine (LPS-D-Gal)-induced ALF animal model and compare it to existing therapeutic silymarin, Lentinus edodes mycelia (LEM) extracts, ursodeoxycholic acid (UDCA) and dimethyl diphenyl bicarboxylate (DDB). Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were decreased in the CA-HE50, silymarin, LEM, UDCA and DDB groups compared to the vehicle control group. In particular, AST and ALT levels of the 200 mg/kg CA-HE50 group were significantly decreased compared to positive control groups. Lactate dehydrogenase (LDH) levels were significantly decreased in the CA-HE50, silymarin, LEM, UDCA and DDB groups compared to the vehicle control group and LDH levels of the 200 mg/kg CA-HE50 group were similar to those of the positive control groups. Superoxide dismutase (SOD) activity was significantly increased in the 100 mg/kg CA-HE50, LEM and UDCA groups compared to the vehicle control group and, in particular, the 100 mg/kg CA-HE50 group increased significantly compared to positive control groups. In addition, the histopathological lesion score was significantly decreased in the CA-HE50 and positive control groups compared with the vehicle control group and the histopathological lesion score of the 200 mg/kg CA-HE50 group was similar to that of the positive control groups. These results show that CA-HE50 has antioxidant and hepatoprotective effects at a level similar to that of silymarin, LEM, UDCA and DDB, which are known to have hepatoprotective effects; further, CA-HE50 has potential as a prophylactic and therapeutic agent in ALF.

Potent antiviral activity of Agrimonia pilosa, Galla rhois, and their components against SARS-CoV-2.

Agrimonia pilosa (AP), Galla rhois (RG), and their mixture (APRG64) strongly inhibited SARS-CoV-2 by interfering with multiple steps of the viral life cycle including viral entry and replication. Furthermore, among 12 components identified in APRG64, three displayed strong antiviral activity, ursolic acid (1), quercetin (7), and 1,2,3,4,6-penta-O-galloyl-ß-d-glucose (12). Molecular docking analysis showed these components to bind potently to the spike receptor-binding-domain (RBD) of the SARS-CoV-2 and its variant B.1.1.7. Taken together, these findings indicate APRG64 as a potent drug candidate to treat SARS-CoV-2 and its variants.

Tuned Cd2+ Selectivity: Showcase of Electronic and Regio-Effect of π-Extended Di-2-Picolylamine-Substituted Quinoline-Based Tolans.

π-Extended di-2-picolylamine (DPA)-substituted 8-hydroxyquinoline (8-HQ) tolans (2) were synthesized for testing electronic and regio-effects. The electron-poor CN-tolan (2b) showed clear selectivity for Cd2+ (>>Zn2+) over other metal ions via turn-on fluorescence, while the electron-rich MeO-tolan (2a) displayed no clear metal selectivity. Furthermore, considering that there was no significant energy difference between the Cd2+ complexes of 1 and 2b, the intended regio-effect (7- vs. 5-substituted effect) did not induce steric hindrance. Thus, the regio-effect is mainly electronic. Considering the above, 2a and 2b constitute a complete showcase in which electronic and regio-effects modulate the metal selectivity. The fluorescence titration of 2b (10 mM) with Cd2+ showed that the limit of detection (LOD) of the Cd2+-selective 2b was 158 nM in PBS (phosphate-buffered saline) (10 mM, pH 7.2) containing 50% MeOH.

Carbaporphyrin Dimers That Bear a Rigid Naphthalene Motif as an Internal Strap.

The first fully connected aromatic carbaporphyrin dimer (6) and its bis-Pd complex (6-Pd2) that bear a rigid naphthalene motif as an internal strap were synthesized. These dimers consisted of two aromatic carbaporphyrins that shared a naphthalene motif. The π-electron conjugation of the obtained macrocycles was proposed to have two separated local 22 π-electron pathways and a 34 π-electron pathway. Their weak aromaticity was fully supported by 1H NMR spectroscopy, NICS values, ACID calculations, and ICSS plots.

Systematic Modifications of a Simple Tolan: Another Category of Viscosity Sensor.

The first tolan derivative-based viscosity sensor (5d) has been synthesized, and its fluorescence intensity and lifetime increase when the viscosity of the solvent increases in methanol-glycerol mixtures. Phthalide (5d) was selected among structurally diverse tolan derivatives through systematic modifications of a simple tolan. To test 5d as a viscosity sensor, fluorescence lifetime imaging (FLIM) images of HeLa cells were obtained upon treatment with 5 µM of 5d to map the viscosity of the HeLa cells.

Bond Rotation in an Aromatic Carbaporphyrin: Allyliporphyrin.

Allyliporphyrin is a carbaporphyrin that has replaced one pyrrole with an allyl group. Dynamic behavior (bond rotation) was observed by variable temperature 1 H NMR and 2D-NOESY NMR spectroscopy and theoretically examined by DFT calculations. These studies revealed that well-defined bond rotation was first observed in the limited space of the carbaporphyrin from 2 through cis-2 and the calculated rotational barrier was low enough, with the relative energy level of cis-2 only 0.65 kcal mol-1 higher than 2. The synthesized allyliporphyrin (2) is a strongly aromatic macrocycle as indicated by the chemical shifts of its inner NH and CH signals. However, its palladium complex displayed reduced aromaticity due to the tilted thiophene of Pd-2.

Fluorescent and cooperative ion pair receptor based on tolan for Na+ (or Li+) and HSO4-: logic AND gate.

A tolan derivative was synthesized as a fluorescent and cooperative ion pair receptor. As both Na+ and HSO4- ions were complexed to the receptor, only substantial fluorescence was quenched. Thus, it also acts as a logic AND gate.