A new investigation for some steroidal derivatives as anti-Alzheimer agents

Recent advances in the natural product analogues for the treatment of neurodegenerative diseases

Neurodegenerative diseases (NDs) represent a hallmark of numerous incapacitating and untreatable conditions, the incidence of which is escalating swiftly, exemplified by Alzheimer's disease and Parkinson's disease. There is an urgent necessity to create pharmaceuticals that exhibit high efficacy and minimal toxicity in order to address these debilitating diseases. The structural complexity and diversity of natural products confer upon them a broad spectrum of biological activities, thereby significantly contributing to the history of drug discovery. Nevertheless, natural products present challenges in drug discovery, including time-consuming separation processes, low content, low bioavailability, and other related issues. To address these challenges, numerous analogs of natural products have been synthesized. This methodology enables the rapid synthesis of analogs of natural products with the potential to serve as lead compounds for drug development, thereby paving the way for the discovery of novel pharmaceuticals. This paper provides a summary of 127 synthetic analogues featuring various natural product structures, including flavonoids, alkaloids, coumarins, phenylpropanoids, terpenoids, polyphenols, and amides. The compounds are categorized based on their efficacy in treating various diseases. Furthermore, this article delves into the structure-activity relationship (SAR) of certain analogues, offering a thorough point of reference for the systematic development of pharmaceuticals aimed at addressing neurodegenerative conditions.

Chiral resolution of (±)-flurbiprofen using molecularly imprinted hydrazidine-modified cellulose microparticles

Flurbiprofen (FP) is one of the non-steroidal anti-inflammatory drugs (NSAIDs) commonly used to treat arthritic conditions. FP has two enantiomers: S-FP and R-FP. S-FP has potent anti-inflammatory effects, while R-FP has nearly no such effects. Herein, molecularly imprinted microparticles produced from hydrazidine-cellulose (CHD) biopolymer for the preferential uptake of S-FP and chiral resolution of (±)-FP were developed. First, cyanoethylcellulose (CECN) was synthesized, and the -CN units were transformed into hydrazidine groups. The developed CHD was subsequently shaped into microparticles and ionically interacted with the S-FP enantiomer. The particles were then imprinted after being cross-linked with glutaraldehyde, and then the S-FP was removed to provide the S-FP enantio-selective sorbent (S-FPCHD). After characterization, the optimal removal settings for the S- and R-FP enantiomers were determined. The results indicated a capacity of 125 mg/g under the optimum pH range of 5-7. Also, S-FPCHD displayed a noticeable affinity toward S-FP with a 12-fold increase compared to the R-FP enantiomer. The chiral resolution of the (±)-FP was successfully attempted using separation columns, and the outlet sample of the loading solution displayed an enantiomeric excess (ee) of 93 % related to the R-FP, while the eluent solution displayed an ee value of 95 % related to the S-FP.

A Review on Medicinally Important Heterocyclic Compounds

Heterocyclic compounds account for the most prominent and diverse class of organic compounds. A significant number of heterocyclic compounds have been synthesized up to this point. Heterocyclic compounds are rapidly increasing in number due to extensive synthetic research and also their synthetic utility. Such compounds have a wide range of uses in the field of medicinal chemistry. Dyestuff, sanitizers, corrosion inhibitors, antioxidants, and copolymer synthesis are additional well-known applications. There are always distinguishing characteristics of an efficient approach for producing newly discovered heterocyclic compounds and their moieties. According to prior research, more than 90% of medicines containing heterocyclic compounds have been developed after the obtainment of a thorough scientific grasp of the biological system. It was discovered in the neoteric developments of heterocyclic compounds that these play a vital role in curative chemistry, and exert anticancer, anti-inflammatory, antifungal, antiallergic, antibacterial, anti-HIV, antiviral, anti-convulsant, and other biological activities. The present article provides detailed information regarding such heterocyclic compounds.

16-Substituted steroids alleviate LPS-induced neurodegenerative disorders in rats

The neuroprotective effects of some 16-substituted steroidal derivatives against the locomotive impairment and cognitive deficits in the lipopolysaccharide (LPS)-induced neuroinflammation model of rats have been investigated. The in vivo and in vitro evaluations include behavioural tests (actophotometer, block tests, Morris water maize and elevated plus maize), estimation of the biochemical parameters such as acetylcholinesterase, lipid peroxide, reactive oxygen, and nitric oxide species and molecular assays for the key proinflammatory mediators like Tumour Necrosis Factor alpha (TNF-α) and Interleukin 1 beta (IL- 1β) after 21 days of the treatment with the steroids. Behavioural and biochemical studies indicated impairment in the locomotor activity and cognitive dysfunction in rats after LPS treatment. In addition, higher levels of TNF-α and IL-1β in the blood serum of the rats were also noticed. However, significant alleviation of LPS-induced movement and memory disorders was observed in LPS-injected rats after treatment with 16-substituted steroidal derivatives 1-11. Furthermore the biochemical and molecular studies revealed suppression of oxidative and nitrosative stress, decreased acetylcholinesterase activity, and reduction of TNF-α and IL-1β levels after treatment with compounds 1-11. Among all the 16-substituted steroidal derivatives, the compounds 8 and 11 were found to be the most active neuroprotective agents and produced effects marginally better than standard drug dexamethasone.

Naturally Inspired Pyrimidines Analogues for Alzheimer's Disease

Alzheimer's disease (AD) is a multifarious and developing neurodegenerative disorder. The treatment of AD is still a challenge and availability of drug therapy on the basis of symptoms is not up to the mark. In the context of existence, which is getting worse for the human brain, it is necessary to take care of all critical measures. The disease is caused due to multidirectional pathology of the body, which demands the multi-target-directed ligand (MTDL) approach. This gives hope for new drugs for AD, summarized here in with the pyrimidine based natural product inspired molecule as a lead. The review is sufficient in providing a list of chemical ingredients of the plant to cure AD and screen them against various potential targets of AD. The synthesis of a highly functionalized scaffold in one step in a single pot without isolating the intermediate is a challenging task. In few examples, we have highlighted the importance of this kind of reaction, generally known as multi-component reaction. Multi-component is a widely accepted technique by the drug discovery people due to its high atom economy. It reduces multi-step process to a one-step process, therefore the compounds library can be made in minimum time and cost. This review has highlighted the importance of multicomponent reactions by giving the example of active scaffolds of pyrimidine/fused pyrimidines. This would bring importance to the fast as well as smart synthesis of bio-relevant molecules.

Heterocyclic steroids: Efficient routes for annulation of pentacyclic steroidal pyrimidines

Steroids are components of cell membranes, signaling molecules and are a type of secondary metabolites as a result of their high impact of biological significance. The present review described the literature reports of pentacyclic steroidal pyrimidines as a type of heterocyclic steroids. The main sections included the synthesis of the investigated steroids fused at rings-A or B or D of steroid skeleton, synthesis of binary or linked-type pyrimidines, pyrimidine oxides, macromolecules and mono- or di- or tri-peptides linked-steroidal pyrimidines. Besides, the present research highlighted the biological significance of steroidal pyrimidines, in which the compounds revealed potent anticancer, antioxidant, antibacterial, and anti-Alzheimer agents. In addition, some hetero-steroids were screened for binding DNA assay and gene expression analysis. It was settled that the incorporation of pyrimidine scaffold into steroid basic skeleton is crucial for better biological results.

Synthesis and anticonvulsant activity of 6-methyl-2-((2-oxo-2-arylethyl)thio)pyrimidin-4(3 H)-one derivatives and products of their cyclization

The alkylation of 6-methyl-2-thioxo-2,3-dihydro-1H-pyrimidine-4-one phenacyl bromides under different conditions was investigated. It was found that during the reaction in the medium of DMF/K2CO3 a mixture of 2-(2-aryl-2-oxoethyl)thio-6-methyl-pyrimidine-4(3H)-one and 3-hydroxy-3-aryl-7-methyl-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-5-one was formed. The holding of the resulting mixture in the concentrated sulphuric acid leads to the formation of cyclization products - derivatives of 3-aryl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one with high yields. Individual S-alkylated derivatives – 2-(2-aryl-2-oxoethyl)thio-6-methyl-pyrimidine-4(3H)-one - were obtained by reacting in methanol in the presence of sodium methoxide. Pharmacological screening of synthesized compounds for anticonvulsant activity on the model of pentylenetetrazole seizures in rats was carried out and some regularity “structure-activity” was established.

16,17-N'-(alky/arylsulfonyl)pyrazoline substituted neuroprotective heterosteroids: Synthesis, molecular docking and preclinical efficacy/toxicity studies in rodents

The synthesis and neuroprotective efficacy and toxicity studies of a new series of 16,17-N'-(alkyl/arylsulfonyl)pyrazolinyl steroids is presented. Significant suppression of the overexpressed acetylcholinesterase and lipid peroxidation, marked reduction of nitrite, oxidative stress and TNF-α levels and noticeable improvement in cognitive and locomotor functions were observed after treatment with the newly synthesized steroids 2-4a-d in the LPS-treated animal models. Higher neuroprotective effects were produced by some of the pyrazolinyl steroids in comparison to the reference drugs celecoxib and dexamethasone. N'-(4-fluorobenzenesulfonyl) derivative 4c showed the most promising effects on all the analyzed parameters and is the most potent molecule among all compounds of this series. Acute toxicity studies on the most active steroids 2-4c at 50 mg/kg did not reveal any toxic effects on animals, however hepatitis and chronic nephritis were observed in histological examination of liver and kidney of mice after 28 days of treatment. The pyrazolinyl steroids 2-4a-d could be considered as promising candidates for the designing of novel multitarget-directed neuroprotectives for an effective therapy of AD and PD.

Synthesis, Characterization, and Cytotoxic Evaluation of Some Newly Substituted Diazene Candidates

A series of azocompounds containing methyl salicylate 4a–k and 1-naphthyl moiety 6–8 was synthesized and tested as anticancer agents. Nitrosation of methyl 5-amino-2-hydroxybenzoate or 1-aminonaphthalene by using NaNO2 in the presence of HCl afforded diazonium salt derivatives 2 and 5, which were treated with substituted imino or substituted amino derivatives, to give the corresponding substituted amino-pent-2-en-3-yl-diazenylbenzoate 4a–k or 2-substituted-1-(naphthalen-1-yl)diazene derivatives 6a–h, 7a,b, and 8a,b. All the synthesized compounds were elucidated by elemental analysis and spectroscopic evidence.

Studies on 16,17-Pyrazoline Substituted Heterosteroids as Anti-Alzheimer and Anti-Parkinsonian Agents Using LPS Induced Neuroinflammation Models of Mice and Rats

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common forms of neurodegenerative disorders. Dehydroepiandrosterone (DHEA) has been reported as a neuroprotective steroid useful in the therapeutic management of neurodegenerative disorders such as AD and PD. Herein we report the synthesis and evaluation of a new series of 16,17-pyrazolinyl DHEA analogues 2-4a-d as neuroprotective agents using LPS-induced neuroinflammation animal models. Treatment with the pyrazoline substituted steroids considerably improved the LPS-induced learning, memory and movement deficits in animal models. Suppression of biochemical parameters of oxidative and nitrosative stress, acetylcholinesterase activity, and TNF-α levels was also observed. 16,17-Pyrazolinyl steroids 2c-4c substituted with a 4-pyridyl moiety at the 5-position of the heterocyclic ring were found to be the most potent agents and produced neuroprotective effects better than standard drugs celecoxib and dexamethasone. Of these pyrazoline substituted steroids, the N-acetyl analogue 3c displayed neuroprotective effects better than N-phenyl (4c), which in turn showed potency more than N-unsubstituted analogue 2c.

Exploring the potential of natural and synthetic neuroprotective steroids against neurodegenerative disorders: A literature review

Neurodegeneration is a complex process, which leads to progressive brain damage due to loss of neurons. Despite exhaustive research, the cause of neuronal loss in various degenerative disorders is not entirely understood. Neuroprotective steroids constitute an important line of attack, which could play a major role against the common mechanisms associated with various neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Natural endogenous steroids induce the neuroprotection by protecting the nerve cells from neuronal injury through multiple mechanisms, therefore the structural modifications of the endogenous steroids could be helpful in the generation of new therapeutically useful neuroprotective agents. The review article will keep the readers apprised of the detailed description of natural as well as synthetic neuroprotective steroids from the medicinal chemistry point of view, which would be helpful in drug discovery efforts aimed toward neurodegenerative diseases.

Investigations on 16-Arylideno Steroids as a New Class of Neuroprotective Agents for the Treatment of Alzheimer's and Parkinson's Diseases

Neuroinflammatory mechanisms mediated by activated glial and cytokines (TNF-α, IL-1β) might contribute to neuronal degeneration leading to Alzheimer's (AD) and Parkinson's disease (PD). Lipopolysaccharide (LPS) is an inflammogen derived from the cell wall of Gram-negative bacteria, which promotes neuroinflammation and subsequent neurodegeneration. Dehydroepiandrosterone (DHEA) and testosterone have been reported as neuroprotective steroids useful for the treatment of various neurodegenerative disorders. In the present study, several 16-arylidene steroidal derivatives have been evaluated as neuroprotective agents in LPS-treated animal models. It was observed that 16-arylidene steroidal derivatives 1a-d and 6a-h considerably improve LPS-induced learning, memory, and movement deficits in animal models. Biochemical estimations of brain serum of treated animals revealed suppression of oxidative and nitrosative stress, acetylcholinesterase activity, and reduction in TNF-α levels, which were induced through LPS mediated neuroinflammatory mechanisms leading to neurodegeneration of brain. Of all the steroidal derivatives, 16-(4-pyridylidene) steroid 1c and its 4-aza analogue 6c were found to be the most active neuroprotective agents and produced effects comparable to standard drug celecoxib at a much lower dose and better than dexamethasone at the same dose in terms of behavioral, biochemical, and molecular aspects.

Heterocyclic ring extension of androstenedione: synthesis and cytotoxicity of fused pyran, pyrimidine and thiazole derivatives

The reaction of androstenedione with either malononitrile or ethyl cyanoacetate and aromatic aldehydes 2a-c gave the pyran derivatives 4a-f, respectively. On the other hand, the reaction of androstenedione with thiourea and the aromatic aldehydes 2a-c gave the pyrimidine derivatives 6a-c, respectively. Compound 6b reacted with 2-bromo-1-arylethanone derivatives 7a-d to give the indeno[2,1-e]thiazole derivatives 8a-d. Some of the produced compounds were used for further heterocyclization reactions. The cytotoxicity of the newly obtained products was evaluated against some cancer cell lines and a normal cell line.

Anti-arthritic and immunosuppressive activities of substituted triterpenoidal candidates

We herein report the anti-arthritic and immunosuppressive activities of some synthesized substituted terpenoidal structure. Forty-four triterpenoid derivatives 1-21 containing a carboxylic, ester, amide and ketone groups attached to a triterpene moiety were conveniently synthesized and screened for their anti-arthritic and immunosuppressive activities. Synthetic triterpenoidal structures linked to a different function groups seem to be a promising approach in the search for novel leads for potent anti-arthritic and immunosuppressive agents. The detailed synthetic pathways of obtained compounds and anti-arthritic and immunosuppressive activities were reported.