Discovery of Novel 2-Aniline-1,4-naphthoquinones as Potential New Drug Treatment for Leber's Hereditary Optic Neuropathy (LHON)

Cytotoxic activity of quinolinequinones in cancer: In vitro studies, molecular docking, and ADME/PK profiling

Lead molecules containing 1,4-quinone moiety are intriguing novel compounds that can be utilized to treat cancer owing to their antiproliferative activities. Nine previously reported quinolinequinones (AQQ1-9) were studied to better understand their inhibitory profile to produce potent and possibly safe lead molecules. The National Cancer Institute (NCI) of Bethesda chose all quinolinequinones (AQQ1-9) based on the NCI Developmental Therapeutics Program and tested them against a panel of 60 cancer cell lines. At a single dose and five further doses, AQQ7 significantly inhibited the proliferation of all leukemia cell lines and some breast cancer cell lines. We investigated the in vitro cytotoxic activities of the most promising compounds, AQQ2 and AQQ7, in MCF7 and T-47D breast cancer cells, DU-145 prostate cancer cells, HCT-116 and COLO 205 colon cancer cell lines, and HaCaT human keratinocytes using the MTT assay. AQQ7 showed particularly high cytotoxicity against MCF7 cells. Further analysis showed that AQQ7 exhibits anticancer activity through the induction of apoptosis without causing cell cycle arrest or oxidative stress. Molecular docking simulations for AQQ2 and AQQ7 were conducted against the COX, PTEN, and EGFR proteins, which are commonly overexpressed in breast, cervical, and prostate cancers. The in vitro ADME and in vivo PK profiling of these compounds have also been reported.

Recent advances in small molecules for improving mitochondrial disorders

Mitochondrial disorders are observed in various human diseases, including rare genetic disorders and complex acquired pathologies. Recent advances in molecular biological techniques have dramatically expanded the understanding of multiple pathomechanisms involving mitochondrial disorders. However, the therapeutic methods for mitochondrial disorders are limited. For this reason, there is increasing interest in identifying safe and effective strategies to mitigate mitochondrial impairments. Small-molecule therapies hold promise for improving mitochondrial performance. This review focuses on the latest advances in developing bioactive compounds for treating mitochondrial disease, aiming to provide a broader perspective of fundamental studies that have been carried out to evaluate the effects of small molecules in regulating mitochondrial function. Novel-designed small molecules ameliorating mitochondrial functions are urgent for further research.

Theoretical Investigation of Regiodivergent Addition of Anilines and Phenolates to p-Benzoquinone Ring

Two different products were obtained by the regiodivergent reaction of benzoquinone derivatives with phenolates and anilines: 3-aryloxybenzoquinone and 2-phenylamino-3-bromobenzoquinone. Calculated density functional theory free energies of reaction values corroborate the experimental observation of the formation of the substitution product in the reaction with phenolates in acetonitrile and the product of addition/oxidation for the reaction with aniline in water. Calculated charges and Fukui functions are similar for C2 and C3 atoms, indicating an equal possibility to suffer a nucleophilic attack. The calculated energy barriers for nucleophilic attack steps indicated that the first steps of the substitution with phenolates and addition/oxidation with anilines are faster, which justifies the formation of the respective products. The natural bond order analysis for the transition states revealed that there is a strong interaction between lone pairs of N and O atoms and the π_C2C3 ^* for the O → C2 and N → C3 attacks and a weak interaction for the O → C3 and N → C2 attacks, which also agrees with experimental observations.

Leber hereditary optic neuropathy: new and emerging therapies

PURPOSE OF REVIEW

To review recent therapeutic advances in Leber hereditary optic neuropathy (LHON).

RECENT FINDINGS

Idebenone, a synthetic analog of ubiquinone (Coenzyme Q10) is an antioxidant and component of the mitochondrial electron transport chain. Since the initial approval of the drug in 2015 in Europe, recent trials have evaluated its role as prolonged treatment in LHON. Gene therapy has recently emerged as a promising alternative for the treatment of LHON. Among several investigations, RESCUE and REVERSE are two phase 3 clinical trials of gene therapy in patients with LHON in early stages. Results in these trials have shown a bilateral visual acuity improvement with unilateral intravitreal injections at 96 weeks and sustained visual improvement after 3 years of treatment. The most recent REFLECT phase 3 clinical trial in LHON has shown significant improvement of vision after bilateral intravitreal injections compared with the group that received unilateral injections.

SUMMARY

Historically, LHON has been considered an untreatable disease, but recent developments show that new pharmacological and gene therapy approaches may lead to visual recovery. Further studies are needed to support these data.

Metal-Free Aminohalogenation of Quinones With Alkylamines and NXS at Room Temperature

A simple and practical strategy for intermolecular aminohalogenation of quinone with alkyl amines and NXS was developed, in which haloamines generated in situ were employed as bifunctional reagents. The reaction system is reliable, efficient and wide in substrate range, which is suitable for the two-fold aminochlorination of 1, 4-benzoquinones, large-scale reaction and late-stage modification of pharmaceuticals.

One-pot synthesis of indole-fused nitrogen heterocycles via the direct C(sp2)–H functionalization of naphthoquinones; accessibility for deep red emitting materials

A convenient one-pot, two-step methodology was developed for the transformation of readily available planar naphthoquinone derivatives into structurally complex indole-fused nitrogen heterocycles under aerobic conditions.

Natural-product-inspired design and synthesis of thiolated coenzyme Q analogs as promising agents against Gram-positive bacterial strains: insights into structure–activity relationship, activity profile, mode of action, and molecular docking

In an attempt to develop effective and potentially active antibacterial and/or antifungal agents, we designed, synthesized, and characterized thiolated CoQ analogs (CoQ1–8) with an extensive antimicrobial study. The antimicrobial profile of these analogs was determined using four Gram-negative bacteria, three Gram-positive bacteria, and three fungi. Because of the fact that the thiolated CoQ analogs were quite effective on all tested Gram-positive bacterial strains, including Staphylococcus aureus (ATCC® 29213) and Enterococcus faecalis (ATCC® 29212), the first two thiolated CoQ analogs emerged as potentially the most desirable ones in this series. Importantly, after the evaluation of the antibacterial and antifungal activity, we presented an initial structure–activity relationship for these CoQ analogs. In addition, the most promising thiolated CoQ analogs (CoQ1 and CoQ2) having the lowest MIC values on all tested Gram-positive bacterial strains, were further evaluated for their inhibition capacities of biofilm formation after evaluating their in vitro potential antimicrobial activity against each of 20 clinically obtained resistant strains of Gram-positive bacteria. CoQ1 and CoQ2 exhibited potential molecular interactions with S. aureus DNA gyrase in addition to excellent pharmacokinetics and lead-likeness profiles. Our findings offer important implications for a potential antimicrobial drug candidate, in particular for the treatment of infections caused by clinically resistant MRSA isolates.

In an attempt to develop effective and potentially active antibacterial and/or antifungal agents, we designed, synthesized, and characterized thiolated CoQ analogs (CoQ1–8) with an extensive antimicrobial study.

Recent advances of quinones as a privileged structure in drug discovery

Privileged structures are conductive to discover novel bioactive substances because they can bind to multiple targets with high affinity. Quinones are considered to be a privileged structure and useful template for the design of new compounds with potential pharmacological activity. This article presents the recent developments (2014-2021 update) of quinones in the fields of antitumor, antibacterial, antifungal, antiviral, anti-Alzheimer's disease (AD) and antimalarial, mainly focusing on biological activities, structural modification and mechanism of action.

New avenues for therapy in mitochondrial optic neuropathies

Mitochondrial optic neuropathies are a group of optic nerve atrophies exemplified by the two commonest conditions in this group, autosomal dominant optic atrophy (ADOA) and Leber's hereditary optic neuropathy (LHON). Their clinical features comprise reduced visual acuity, colour vision deficits, centro-caecal scotomas and optic disc pallor with thinning of the retinal nerve fibre layer. The primary aetiology is genetic, with underlying nuclear or mitochondrial gene mutations. The primary pathology is owing to retinal ganglion cell dysfunction and degeneration. There is currently only one approved treatment and no curative therapy is available. In this review we summarise the genetic and clinical features of ADOA and LHON and then examine what new avenues there may be for therapeutic intervention. The therapeutic strategies to manage LHON and ADOA can be split into four categories: prevention, compensation, replacement and repair. Prevention is technically an option by modifying risk factors such as smoking cessation, or by utilising pre-implantation genetic diagnosis, although this is unlikely to be applied in mitochondrial optic neuropathies due to the non-life threatening and variable nature of these conditions. Compensation involves pharmacological interventions that ameliorate the mitochondrial dysfunction at a cellular and tissue level. Replacement and repair are exciting new emerging areas. Clinical trials, both published and underway, in this area are likely to reveal future potential benefits, since new therapies are desperately needed.

Plain language summary

Optic nerve damage leading to loss of vision can be caused by a variety of insults. One group of conditions leading to optic nerve damage is caused by defects in genes that are essential for cells to make energy in small organelles called mitochondria. These conditions are known as mitochondrial optic neuropathies and two predominant examples are called autosomal dominant optic atrophy and Leber's hereditary optic neuropathy. Both conditions are caused by problems with the energy powerhouse of cells: mitochondria. The cells that are most vulnerable to this mitochondrial malfunction are called retinal ganglion cells, otherwise collectively known as the optic nerve, and they take the electrical impulse from the retina in the eye to the brain. The malfunction leads to death of some of the optic nerve cells, the degree of vision loss being linked to the number of those cells which are impacted in this way. Patients will lose visual acuity and colour vision and develop a central blind spot in their field of vision. There is currently no cure and very few treatment options. New treatments are desperately needed for patients affected by these devastating diseases. New treatments can potentially arise in four ways: prevention, compensation, replacement and repair of the defects. Here we explore how present and possible future treatments might provide hope for those suffering from these conditions.