Design, synthesis and biological evaluation of novel chiral oxazino-indoles as potential and selective neuroprotective agents against Aβ25–35-induced neuronal damage

TMAO as a potential biomarker and therapeutic target for chronic kidney disease: A review

The gut microbiota and its metabolites have become a hotspot of recent research. Trimethylamine N-oxide (TMAO) metabolized by the gut microbiota is closely related to many diseases such as cardiovascular disease, chronic kidney disease, type 2 diabetes, etc. Chronic kidney disease (CKD) is an important contributor to morbidity and mortality from non-communicable diseases. Recently, increasing focus has been put on the role of TMAO in the development and progress of chronic kidney disease. The level of TMAO in patients with chronic kidney disease is significantly increased, and a high level of TMAO deteriorates chronic kidney disease. This article describes the relationship between TMAO and chronic kidney disease and the research progress of drugs targeted TMAO, providing a reference for the development of anti-chronic kidney disease drugs targeted TMAO.

Rational drug design strategies for the development of promising multi-target directed indole hybrids as Anti-Alzheimer agents

Alzheimer's disease (AD) is a neurological disorder that leads to dementia i.e., progressive memory loss accompanied with worsening of thinking ability of an individual. The cause of AD is not fully understood but it progresses with age where brain cells gradually die over time. According to the World Health Organization (WHO), currently 50 million people worldwide are affected by dementia and 60-70% of the cases belong to AD. Cumulative research over the past few decades have shown that molecules that act at a single target possess limited efficacy since these investigational drugs are not able to act against complex pathologies and thus do not provide permanent cure. Designing of multi-target directed ligands (MTDLs) appears to be more beneficial and a rational approach to treat chronic complex diseases including neurodegenerative diseases. Recently, MTDLs are being extensively researched by the medicinal chemists for the development of drugs for the treatment of various multifactorial diseases. Indole is one of the privileged scaffolds which is considered as an essential mediator between the gut-brain axis because of its neuroprotective, anti-inflammatory, β-amyloid anti-aggregation and antioxidant activities. Herein, we have reviewed the potential of some indole-hybrids acting at multiple targets in the pathogenesis of AD. We have reviewed research articles from the year 2014-2021 from various scientific databases and highlighted the synthetic strategies, mechanisms of neuroprotection, toxicity, structure activity relationships and molecular docking studies of various indole-hybrid derivatives. This literature review of published data on indole derivatives indicated that developing indole hybrids have improved the pharmacokinetic profile with lower toxicity, provided synergistic effect, helped to develop more potent compounds and prevented drug-drug interactions. It is evident that this class of compounds have potential to inhibit multiple enzymes targets involved in the pathogenesis of AD and therefore indole hybrids as MTDLs may play an important role in the development of anti-AD molecules.

Synthesis of Indofulvin Pseudo-Natural Products Yields a New Autophagy Inhibitor Chemotype

Chemical and biological limitations in bioactive compound design based on natural product (NP) structure can be overcome by the combination of NP-derived fragments in unprecedented arrangements to afford "pseudo-natural products" (pseudo-NPs). A new pseudo-NP design principle is described, i.e., the combination of NP-fragments by transformations that are not part of current biosynthesis pathways. A collection of indofulvin pseudo-NPs is obtained from 2-hydroxyethyl-indoles and ketones derived from the fragment-sized NP griseofulvin by means of an iso-oxa-Pictet-Spengler reaction. Cheminformatic analysis indicates that the indofulvins reside in an area of chemical space sparsely covered by NPs, drugs, and drug-like compounds and they may combine favorable properties of these compound classes. Biological evaluation of the compound collection in different cell-based assays and the unbiased high content cell painting assay reveal that the indofulvins define a new autophagy inhibitor chemotype that targets mitochondrial respiration.

Synthesis of Oxazino[4,3-a]indoles and biological applications

This review brings together the various pathways to the oxazino[4,3-a]indole motif over the last decades. Representative examples showing the scope of these processes will illustrate the synthetic pathways and the biological activity of the synthesized oxazinoindoles will be mentioned wherever possible.

Drug Discovery and Development of Novel Therapeutics for Inhibiting TMAO in Models of Atherosclerosis and Diabetes

Diabetes mellitus exists as a comorbidity with congestive heart failure (CHF). However, the exact molecular signaling mechanism linking CHF as the major form of mortality from diabetes remains unknown. Type 2 diabetic patients display abnormally high levels of metabolic products associated with gut dysbiosis. One such metabolite, trimethylamine N-oxide (TMAO), has been observed to be directly related with increased incidence of cardiovascular diseases (CVD) in human patients. TMAO a gut-liver metabolite, comes from the metabolic degenerative product trimethylamine (TMA) that is produced from gut microbial metabolism. Elevated levels of TMAO in diabetics and obese patients are observed to have a direct correlation with increased risk for major adverse cardiovascular events. The pro-atherogenic effect of TMAO is attributed to enhancing inflammatory pathways with cholesterol and bile acid dysregulation, promoting foam cell formation. Recent studies have revealed several potential therapeutic strategies for reducing TMAO levels and will be the central focus for the current review. However, few have focused on developing rational drug therapeutics and may be due to the gaps in knowledge for understanding the mechanism by which microbial TMA producing enzymes and hepatic flavin-containing monoxygenase (FMO) can work together in preventing elevation of TMAO levels. Therefore, it is critical to understand the advantages of developing a novel rational drug design strategy that manipulates FMO production of TMAO and TMA production by microbial enzymes. This review will focus on the inspection of FMO manipulation, as well as gut microbiota dysbiosis and its influence on metabolic disorders including cardiovascular disease and describe novel potential pharmacological therapeutic development.

Effects of Picrasma quassioides and its active constituents on Alzheimer's disease in vitro and in vivo

Alzheimer disease (AD), a prevalent neurodegenerative disorder, is one of the leading causes of dementia. However, there is no effective drug for this disease to date. Picrasma quassioides (D.Don) Benn, a Chinese traditional medicine, was used mainly for the treatment of inflammation, fever, microbial infection and dysentery. In this paper, we reported that the EtOAc extract of Picrasma quassioides stems showed potential neuroprotective activities in l-glutamate-stimulated PC12 and Aβ_25-35-stimulated SH-SY5Y cell models, as well as improved memory and cognitive abilities in AD mice induced by amyloid-β peptide. Moreover, it was revealed that the anti-AD mechanism was related to suppressing neuroinflammatory and reducing Aβ_1-42 deposition using ELISA assay kits. To clarify the active components of the EtOAc extract of Picrasma quassioides stems, a systematic phytochemistry study led to isolate and identify six β-carboline alkaloids (1-6), seven canthin-6-one alkaloids (7-13), and five quassinoids (14-18). Among them, four β-carbolines (1-3, and 6) and six canthin-6-ones (7-11, and 13) exhibited potential neuroprotective activities in vitro. Based on these date, the structure-activity relationships of alkaloids were discussed. Furthermore, molecular docking experiments showed that compounds 2 and 3 have high affinity for both of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYPKIA) and butyrylcholinesterase (BuChE).

One-pot mild and efficient synthesis of [1,3]thiazino[3,2-a]indol-4-ones and their anti-proliferative activity

One-pot synthesis of [1,3]thiazino[3,2-a]indol-4-one frameworks is developed in aqueous medium and the anti-proliferative activity of the synthesized compounds is evaluated against two triple negative breast cancer cell lines.