SAR Analysis Research Articles

Classification models and SAR analysis of anaplastic lymphoma kinase (ALK) inhibitors using machine learning algorithms with two data division methods.

Anaplastic lymphoma kinase (ALK) plays a critical role in the development of various cancers. In this study, the dataset of 1810 collected inhibitors were divided into a training set and a test set by the self-organizing map (SOM) and random method, respectively. We developed 32 classification models using Support Vector Machines (SVM), Decision Trees (DT), Random Forests (RF), and Extreme Gradient Boosting (XGBoost) to distinguish between highly and weakly active ALK inhibitors, with the inhibitors represented by MACCS and ECFP4 fingerprints. Model 7D which was built by the RF algorithm using training set 1/test set 1 divided by the SOM method, provided the best performance with a prediction accuracy of 90.97% and a Matthews correlation coefficient (MCC) value of 0.79 on the test set. We clustered the 1810 inhibitors into 10 subsets by K-Means algorithm to find out the structural characteristics of highly active ALK inhibitors. The main scaffolds of highly active ALK inhibitors were also analyzed based on ECFP4 fingerprints. It was found that some substructures have a significant effect on high activity, such as 2,4-diarylaminopyrimidine analogues, pyrrolo[2,1-f][1,2,4]triazin, indolo[2,3-b]quinoline-11-one, benzo[d]imidazol and pyrrolo[2,3-b]pyridine. In addition, the subsets were summarized into several clusters, among which four clusters showed a significant relationship with ALK inhibitory activity. Finally, Shapley additive explanations (SHAP) was also used to explain the influence of modeling features on model prediction results. The SHAP results indicated that our models can well reflect the structural features of ALK inhibitors.

Novel pyrrole based triazole moiety as therapeutic hybrid: synthesis, characterization and anti-Alzheimer potential with molecular mechanism of protein ligand profile

As a springboard to explore novel potent inhibitors of cholinesterase enzymes (AChE and BChE) responsible for causing Alzheimer disorder, the current study was conducted to synthesize pyrrole derived triazole based Schiff base scaffolds by facile synthetic route. These compounds were validated by 1HNMR, 13CNMR and HREI-MS. All these scaffolds (1–16) were examined for their inhibitory activity against AChE and BChE in contrast to Donepezil (10.20 ± 0.10 and 10.80 ± 0.20 µM) and Allanzanthone (12.40 ± 0.10 and 13.10 ± 0.10 µM). All pyrrole derived triazole based Schiff base scaffolds (1–16) showed varied range of inhibitory potentials against acetylcholinesterase and butyrylcholinesterase enzymes with lowest inhibition concentration values ranging from 5.10 ± 0.40–27.10 ± 0.10 µM (for AChE) and 5.60 ± 0.30–28.40 ± 0.30 µM (for BChE). SAR analysis of these derivatives revealed analog 7 as lead molecule against targeted enzyme, while analog 6 and 11 were ranked as second and third most potent scaffolds. Binding affinity and selectivity of potent molecules against targeted enzymes were examined by molecular docking and obtained results showed that potent molecule have versatile significant binding interactions with stated enzymes. Furthermore, safety profiles of potent analogues were predicted via ADMET protocols.Graphical

Neuroprotective Effect of Natural Indole and β-carboline Alkaloids against Parkinson's Disease: An Overview.

Parkinson's disease (PD) is a devastating neurodegenerative condition that mostly damages dopaminergic neurons in the substantia nigra and impairs human motor function. Males are more likely than females to have PD. There are two main pathways associated with PD: one involves the misfolding of α-synuclein, which causes neurodegeneration, and the other is the catalytic oxidation of dopamine via MAO-B, which produces hydrogen peroxide that can cause mitochondrial damage. Parkin (PRKN), α-synuclein (SNCA), heat shock protein (HSP), and leucine-rich repeat kinase-2 (LRRK2) are some of the target areas for genetic alterations that cause neurodegeneration in Parkinson's disease (PD). Under the impact of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which is also important in Parkinson's disease (PD), inhibition of mitochondrial complex 1 results in enhanced ROS generation in neuronal cells. Natural products are still a superior option in the age of synthetic pharmaceuticals because of their lower toxicity and moderate side effects. A promising treatment for PD has been discovered using beta-carboline (also known as " β-carboline") and indole alkaloids. However, there are not many studies done on this particular topic. In the herbs containing β-carbolines and indoles, the secondary metabolites and alkaloids, β-carbolines and indoles, have shown neuroprotective and cognitive-enhancing properties. In this review, we have presented results from 18 years of research on the effects of indole and β-carboline alkaloids against oxidative stress and MAO inhibition, two key targets in PD. In the SAR analysis, the activity has been correlated with their unique structural characteristics. This study will undoubtedly aid researchers in looking for new PD treatment options.

A Comprehensive Analysis on Galantamine Based Hybrids for the Management of Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive chronic age-related neurodegenerative brain disorder characterized by the loss of memory and other cognitive functions. The exact etiology of AD is still under investigation, however several factors such as low level of neurotransmitter acetylcholine (ACh), aggregation of amyloid beta (Aβ) in the form of Aβ plaques, hyperphosphorylation of tau protein into neurofibrillary tangles (NFTs), oxidative stress, and metal ion imbalance are the major hallmarks of this disease. Of the multiple hypotheses for AD, the amyloid-β (Aβ) and cholinergic hypothesis are the main targeting hypotheses for AD. Some researchers hypothesized that the primary event associated with the cholinergic neurotransmitter (acetylcholine) is memory loss and cognitive impairment. Due to the disease's complicated pathogenesis, long-term therapy with a single target candidate is futile. As a result, multitargeted and multifunctional therapies have emerged. Various research teams are concentrating on addressing multiple disease factors through hybridization techniques. Consequently, this hybridization approach has been applied to all core scaffolds, including galantamine. In this article, we tried to provide a thorough overview of the most recent developments on galantamine, a prospective AChE inhibitor, and its hybrid analogs as possible therapeutic agents for treating AD. Furthermore, we also provided the design, synthesis, and SAR analysis of the galantamine-based compounds used in the last decades for the management of AD.

Multi-functional tyrosinase inhibitors derived from kojic acid and hydroquinone-like diphenols for treatment of hyperpigmentation: Synthesis and in vitro biological evaluation.

A series of multi-functional tyrosinase inhibitors derived from kojic acid (KA) and hydroquinone-like diphenols were designed and synthesized using click chemistry. The in vitro enzymatic assay revealed that all compounds containing a free enolic structure showed excellent activity against tyrosinase (IC50 = 0.14-3.7 µM), being significantly more potent than KA. The most active compounds were catechol (6c) and α-naphthol (6i) analogs with 138- and 96-fold higher potency than KA. On the other hand, all free phenolic compounds (6a-c and 6g-j) derived from aromatic diols showed outstanding free radical scavenging activities superior to KA. Certainly, the α-naphthol derivative 6i with IC50 = 10.1 µM was the most active anti-oxidant, being as potent as quercetin. The SAR analysis indicated that the enolic head of the conjugate molecules mainly contributes to the anti-tyrosinase activity, and the free phenolic part of the molecules can offer anti-oxidant potency. The anti-melanogenic assay of the most promising derivative, 6i, against melanoma (B16F10) cells demonstrated that the prototype compound 6i can significantly reduce the melanin content, more effectively than KA. By using a conjugation strategy, we have improved the tyrosinase inhibitory and radical scavenging activity in the multi-functional agents such as 6i over the parent compound KA, being potentially useful in the treatment of hyperpigmentation and other skin disorders.

Pharmacophore-based SAR Analysis and Synthetic Route Review of Imidazole Core Analogues

Pharmacophore-based SAR Analysis and Synthetic Route Review of Imidazole Core Analogues

Recent Advances in Medicinal Chemistry of Memantine Against Alzheimer's Disease.

Alzheimer's disease (AD) is a chronic progressive, age-related neurodegenerative brain disorder characterized by the irreversible decline of memory and other cognitive functions. It is one of the major health threat of the 21st century, which affects around 60% of the population over the age of 60 years. The problem of this disease is even more major because the existing pharmacotherapies only provide symptomatic relief without addressing the basic factors of the disease. It is characterized by the extracellular deposition of amyloid β (Aβ) to form senile plaques, and the intracellular hyperphosphorylation of tau to form neurofibrillary tangles (NFTs). Due to the complex pathophysiology of this disease, various hypotheseshave been proposed, including the cholinergic, Aβ, tau, oxidative stress, and the metal-ion hypothesis. Among these, the cholinergic and Aβ hypotheses are the primary targets for addressing AD. Therefore, continuous advances have been made in developing potential cholinesterase inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists to delay disease progression and restore cholinergic neurotransmission. In this review article, we tried to comprehensively summarize the recent advancement in NMDA receptor antagonist (memantine) and their hybrid analogs as potential disease-modifying agents for the treatment of AD. Furthermore, we also depicted the design, rationale, and SAR analysis of the memantine-based hybrids used in the last decade for the treatment of AD.

Design, synthesis, in vitro and in silico studies of novel piperidine derived thiosemicarbazones as inhibitors of dihydrofolate reductase.

Dihydrofolate reductase (DHFR), an essential enzyme in folate metabolism, presents a promising target for drug development against various diseases, including cancer and tuberculosis. Herein, we present an integrated approach combining in vitro biochemical assays with in silico molecular docking analysis to evaluate the inhibitory potential of 4-piperidine-based thiosemicarbazones 5(a-s) against DHFR. In our in vitro study, a novel series of 4-piperidine-based thiosemicarbazones 5(a-s) were assessed for their inhibitory activity against DHFR enzyme. The synthesized compounds 5(a-s) exhibited potent inhibition with IC50 values in the range of 13.70 ± 0.25 µM to 47.30 ± 0.86 µM. Among all the derivatives 5p displayed highest inhibitory activity. Simultaneously, in silico analysis were performed and compared with standard drug (Methotrexate) to predict the binding affinity and interaction pattern of synthesized compounds with DHFR active site. SAR analysis was done to elucidate how structural modifications impact compound's biological activity, guiding the rational design of potent and selective drug candidates for targeted diseases. These findings may provide a comprehensive assessment of 4-piperdine-based thiosemicarbazones as DHFR inhibitors and contribute to the development of novel therapeutics targeting DHFR-associated diseases.

Design, synthesis, and evaluation of chalcone derivatives as xanthine oxidase inhibitors

Xanthine oxidase (XO) is an important enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid in the catabolism of purines in humans. This makes XO a well-recognized target in alleviating hyperuricemia. The present study adapted a structure-based drug discovery approach to develop potent and low-toxicity XO inhibitors with the chalcone skeleton. We introduced a carboxyl group and a hydroxyl group to the B ring and modified the A ring. 35 chalcone derivatives were designed and synthesized. All the 35 derivatives exhibited higher XO inhibition activities (IC50 = 0.064–0.559 μM) compared with allopurinol (IC50 = 2.588 μM). Their high affinity was attributed to strong hydrogen bond interactions formed between the introduced carboxyl and hydroxyl groups with key amino acid residues in XO. SAR analysis disclosed that carboxyl, hydroxyl, ethyl (12c), methylamino (12h), dimethylamino (12i), indolin (13k), and indol (13l) groups played important roles in improving the whole molecules’ inhibition potency against XO. ADME predictions and cytotoxicity assays suggested their pharmacokinetic characteristics and biocompatibility were desirable. Additionally, 12c exhibited a significant hypouricemic effect on potassium oxonate-induced hyperuricemia rats after orally administrated at a dose range of 10–40 mg/kg, representing a promising anti-hyperuricemia potential for further optimization and development.

Rational Design and Synthesis of Novel Benzimidazole Derivatives as Potential β-Glucosidase Inhibitors

Background: β-Glucosidase has a variety of biological functions. A structural model for a potential β-glucosidase inhibitor has been proposed in the previous studies. Objective: A series f new diaryl derivatives linked through benzimidazole have been randomly and rationally designed, synthesized, and evaluated for their inhibitory activities against β-glucosidase (almond). The proposed structural model provides a new strategy for the design of potent β-glucosidase inhibitors. Methods: According to the model, a series of benzimidazole derivatives were designed and synthesized, and their inhibitory activity, Ki value, inhibitory type, and binding mode analysis (PDB ID: 2J7C) on β-glucosidase (almond) were evaluated. Results: Two compounds 7b and 7d were the best inhibitors with IC50 values of 7.86 M and 3.52 μM, respectively. Their Ki values were calculated to be 9.91 μM and 5.81 μM, respectively. Conclusion: The SAR analysis suggested that such benzimidazole derivatives might bind to the active site of β-glucosidase mainly through hydrogen bonds on o-trihydroxyphenol; the additional phenyl ring on the other side towards the solvent-exposed region played a very important role in improving their inhibitory activity against β-glucosidase

Novel pyrimidine-anthraquinone dyes: Design, synthesis, textile applications & their computational SAR analysis

The integration of functional textiles production approach, correlated with organic synthesis and computational elaboration of synthesized anthraquinone-based pyrimidine dyes, makes a significant contribution in multidisciplinary research. The central focus of this project is the production of multipurpose chemical moieties, addressing the current imperative to reduce the human consumption and mitigate the depletion of natural resources by employing cost-effective methods. The present study is focused to synthesize some new molecules as dyes having antibacterial and UV-protection ability. These synthesized dyes were characterized by UV, FT-IR, 1H NMR, 13C NMR spectroscopic analysis that confirmed the structures of targeted molecules. These targeted dyes were applied to fabric and their colorfastness properties were checked according to ISO recommended procedures. The fastness results supported efficient fixation and fading resistance. The Ultraviolet Protection Factor (UPF) studies were conducted to measure the UV-protection ability of the dyed fabric. Furthermore, antibacterial ability of dyes was also checked, and experimental results were compared through molecular docking study. Dyes were screened for their absorbance under solvents of different polarity, and these were further analyzed by TD-DFT and DFT analysis.

Discovery of membrane-targeting amphiphilic honokiol derivatives containing an oxazolethione moiety to combat methicillin-resistant Staphylococcus aureus (MRSA) infections

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major pathogen causing infections in hospitals and the community, and there is an urgent need for the development of novel antibacterials to combat MRSA infections. Herein, a series of amphiphilic honokiol derivatives containing an oxazolethione moiety were prepared and evaluated for their in vitro antibacterial and hemolytic activities. The screened optimal derivative, I3, exhibited potent in vitro antibacterial activity against S. aureus and clinical MRSA isolates with MIC values of 2–4 μg/mL, which was superior to vancomycin in terms of its rapid bactericidal properties and was less susceptible to the development of resistance. The SARs analysis indicated that amphiphilic honokiol derivatives with fluorine substituents had better antibacterial activity than those with chlorine and bromine substituents. In vitro and in vivo toxicity studies revealed that I3 has relatively low toxicity. In a MRSA-infected mouse skin abscess model, I3 (5 mg/kg) effectively killed MRSA at the infected site and attenuated the inflammation effects, comparable to vancomycin. In a MRSA-infected mouse sepsis model, I3 (12 mg/kg) was found to significantly reduce the bacterial load in infected mice and increase survival of infected mice. Mechanistic studies indicated that I3 has membrane targeting properties and can interact with phosphatidylglycerol (PG) and cardiolipin (CL) of MRSA cell membranes, thereby disrupting MRSA cell membranes, further inducing the increase of reactive oxygen species (ROS), protein and DNA leakage to achieve rapid bactericidal effects. Finally, we hope that I3 is a potential candidate molecule for the development of antibiotics to conquer superbacteria-related infections.

Design, synthesis, and in vitro and in silico study of 1-benzyl-indole hybrid thiosemicarbazones as competitive tyrosinase inhibitors.

Developing new anti-tyrosinase drugs seems crucial for the medical and industrial fields since irregular melanin synthesis is linked to the resurgence of several skin conditions, including melanoma, and the browning of fruits and vegetables. A novel series of N-1 and C-3 substituted indole-based thiosemicarbazones 5(a-r) are synthesized and further analyzed for their inhibition potential against tyrosinase enzyme through in vitro assays. The synthesized compounds displayed very good to moderate inhibition with half maximal inhibitory concentration in the range of 12.40 ± 0.26 μM to 47.24 ± 1.27 μM. Among all the derivatives 5k displayed the highest inhibitory activity. According to SAR analysis, the derivatives with 4-substitution at the benzyl or phenyl ring of the thiosemicarbazones exhibited better inhibitory potential against tyrosinase. In silico analysis (including ADMET prediction and molecular docking) was conducted and compared with the standard drug (kojic acid). These findings may help the hunt for new melanogenesis inhibitors that the food and cosmetics industries may find valuable.

Design and Assessment of Fighter Pilot Assistance Systems for Air-to-Air Refuelling with Probe-and-Drogue-Equipment

Air-to-air refuelling (AAR) with a probe-and-drogue system is a highly demanding process for fighter pilots. In the frame of the project “Future Air-to-Air Refuelling” (F(AI)2R) the German Aerospace Center (DLR) is designing concepts for assistance systems to support fighter pilots during this manoeuvre. The AAR process was examined using a hierarchical task analysis (HTA) based on a literature review and semi-structured interviews with Eurofighter-, Tornado- and test pilots. “Situation Awareness Requirements” (SAR), which represent relevant parameters for the situation awareness of the fighter pilot were derived from the HTA and rated by pilots according to their relevance. The collected data was then used to design different concepts of pilot assistance systems using a morphological box and a decision matrix. The concepts were visualised as storyboards, assessed by test pilots of the “Wehrtechnische Dienststelle 61” (WTD 61) and optimized based on their feedback. In this paper, the used methodology as well as the results of the HTA and SAR analysis are presented. Besides that, storyboards for pilot assistance systems displaying the overtake speed “German Patent No. 10.2022.110.505” and the “Contact Assistance, Status and Warning System” (CASWS) “German Patent No. 10.2022.123.653” are described. Additionally, the planned implementation using a HoloLens 2 is explained and the strategy for the subsequent simulator study on the DLR fighter aircraft simulator “Military AiR vehicle Simulator – Fast Integration Testbed” (MARS-FIT) is described.

In-Silico Screening of Natural Compound Library against COVID-19 Main Protease

Aims: To perform in-silico screening of the natural phytoconstituents against COVID-19 main protease Background: COVID-19 is an atypical virus that is universal around the globe. WHO (World Health Organization) has also affirmed the emergency public health concerns regarding COVID-19. As COVID-19 spreads globally within a shorter duration, there is a great demand for effective therapy with minimal side effects. Objective: To perform SP and XP docking of the naturally obtained ligand Quercetin (flavonoid) based on HTVS. To identify the effectiveness of natural phytoconstituents for COVID-19 main protease virus. Methods: In the present study, natural ligands were used for performing the virtual screening, which was obtained from Prestwick Phytochemical Library by applying hierarchal screening. Several docking protocols, such as SP and XP, are used to screen the best natural hit compounds. The three best-hit compounds and hydroxychloroquine were further studied for SAR analysis. Moreover, the ADME study by QikProp and the identification of biological sources were carried out by Duke's Phytochemical and Ethnobotanical Databases. result: The results suggest that Quercetin showed good binding affinity towards 6LU7 (-56.689 kcal/mol) which could be the effective natural compound for COVID-19. Results: The results suggest that Quercetin showed good binding affinity towards 6LU7 (-56.689 kcal/mol), which could be an effective natural phytoconstituent for COVID-19. Conclusion: Based on HTVS, SP, and XP docking, the naturally obtained ligand Quercetin (a flavonoid) can be used in place of Hydroxychloroquine against COVID-19's main protease virus. This scientific exploration will help to identify the effective natural compound for the COVID-19 main protease virus.

Synthesis, antioxidant, antimicrobial activities and molecular modeling analysis of some 5-Nitro-N-phenyl-3-(phenylamino)-1H-indazole-1-carboxamide derivatives: Docking, SAR, toxicity and molecular dynamics analysis

This study reports the synthesis and characterization of a novel series of 5-nitro-N-phenyl-3-(phenylamino)-1H-indazole-1-carboxamide derivatives (5a-5v) obtained through the reaction of 3-chloro-5-nitro-N-phenyl-1H-indazole-1-carboxamide (4) with diverse aniline derivatives in isopropanol. The compounds underwent thorough biological evaluation encompassing antibacterial, antifungal, and in addition to antioxidant potential assessed through DPPH (IC50 = 0.105-0.513 μmol/mL) and ABTS assays (IC50 = 0.124-0.538 μmol/mL). Remarkably, compound 5b displayed exceptional antibacterial efficacy, while compounds 5k, 5p, and 5q exhibited noteworthy antifungal potential. Compound 5k showed the most significant antioxidant activity. Molecular docking studies unveiled robust binding interactions with target enzymes (PDB ID: 3SRG), and molecular dynamics simulations indicated the stability of the most active compound at the binding site. Additionally, favourable drug-likeness and ADMET properties underscore the promising therapeutic potential of these derivatives, urging further investigations for potential clinical applications. The multifaceted activities, including antibacterial, antifungal, and antioxidant properties, make these derivatives compelling candidates for in-depth exploration in the pursuit of novel therapeutic agents.

Exploring highly selective polymethoxy fenamate isosteres as novel anti-prostate cancer agents: Synthesis, biological activity, molecular docking, molecular dynamics, and ADME studies

In this study, we synthesized and characterized sixteen new polymethoxy-substituted hydrazone derivatives. These compounds were evaluated for their in vitro cytotoxic activity against human prostate cancer (PC3) and human umbilical vein endothelial (HUVEC) cell lines. Compounds 5, 6, 7, and 11 exhibited significant cytotoxic effects with high selectivity index. Molecular docking studies and MM-GBSA binding free energy calculations were performed against tubulin protein. Compound 7 emerged as a particularly promising candidate, displaying an IC50 value of 1.49 µM against PC3 cells and a selectivity index of 264. Compound 7 achieved impressive docking score -13.655 kcal/mol against tubulin and formed stable hydrogen bonds and π-π stacking interactions with key residues in this protein. MD simulations confirmed the stability of the 7-tubulin complex. ADME analysis indicated that compound 7 has favorable absorption, solubility, and permeability properties, with minimal rule violations. The SAR analysis highlighted the significance of specific functional groups in enhancing the compound's cytotoxic and binding properties. Overall, compound 7 is identified as a leading candidate due to its exceptional cytotoxicity, high selectivity index, strong binding affinities, and favorable pharmacokinetic profile, making it a top candidate for further investigation and development as a novel anticancer agent.

Eight element MIMO antenna for sub 6 GHz 5G cellular devices

This article introduces a wide-band MIMO antenna system with eight elements specifically designed for future handheld devices. The antenna is integrated into a 150 × 75 mm2 main board with a DGS antenna beneath it, connected to feed lines, and etched onto the ground plane. Covering two distinct 5G bands from 3 GHz to 3.6 GHz and from 3.6 GHz to 3.9 GHz, with 900 MHz impedance bandwidths, this antenna enables efficient data transmission and reception across these crucial frequency ranges. The system exhibits pattern and spatial diversity characteristics, achieving an overall efficiency of 40%–60% and a peak gain of 5.3 dBi, ensuring robust signal strength and isolation exceeding 10 dB among radiating elements. Furthermore, the antenna excels in key MIMO parameters, with an envelope correlation coefficient (ECC) below 0.19, well within the industry standard of less than 0.5, and it delivers more than 9.99 dB of diversity gain. Furthermore, Channel capacity Loss (CCL), Mean Effective Gain (MEG) and Total Active Reflection Co-efficient (TARC) across the entire operational band ensure good performance, promising enhanced diversity performance, superior data throughput, and heightened signal reliability. are The SAR analysis conducted yielded positive results within the human vicinity. The measurements obtained from the prototype matched well with simulations and through measurements obtained the proposed MIMO system can be termed as a potential candidate for future 5G Mobile Phones.

Synthesis, Characterization, In Vitro Anticancer Evaluation, ADMET Properties, and Molecular Docking of Novel 5-Sulfanyl Substituted (Thiazol-4-Yl)-Phosphonium Salts.

Seven TPP+ new 5-sulfanyl substituted (thiazol-4-yl) phosphonium salts functionalized with different substituents were designed, synthesized, and studied against the NCI-60 human cancer cell lines. Compounds 1-4 show the total average parameters GI50=0.7-2.7 μM, TGI=7.0-14.6 μM, and LC50=25.2-41.8 μM, and compounds 5-7 show GI50=0.3-0.5 μM, TGI=1.3-3.1 μM, and LC50=3.6-4.0 μM. The most active compound 7 demonstrated the best anticancer results against leukemia (K-562, GI50=0.141 μM; RPMI-8226, GI50=0.143 μM), ovarian cancer (NCI/ADR-RES, GI50=0.142 μM), breast cancer (HS578T, GI50=0.175 μM; MDA-MB-468, GI50=0.101 μM), melanoma (SK-MEL-5, GI50=0.155 μM), and colon cancer (COLO 205, GI50=0.163 μM). All compounds showed low cytotoxicity against the leukemia subpanel (LC50>100 μM). The SAR analysis reveals the critical role of the substitutes at the thiazole C2 and C5 positions. Adding the phenyl, p-tolyl, or 4-chlorophenyl group to the C2 position in compounds 5-7 increases anticancer effectiveness. According to the NCI COMPARE analysis, compounds 2-3 showed a very high (r=0.92, 0.81) correlation with morpholino-doxorubicin. Molecular docking-analyzing the antitumor mechanism of compounds 1-4 action demonstrated that the DNA chain is a probable biotarget. The ADMET analysis acknowledges the favorable prognosis using compounds as potential anticancer agents.

Synthesis and antiproliferative activity of (−)-cleistenolide, (6S)-cleistenolide and 4-substituted cleistenolide analogues

A new total synthesis of the natural δ-lactone cleistenolide (1) and its (6S)-stereoisomer 2 was achieved starting from d-glucose. Key steps in the synthesis of 1 involved: oxidative cleavage of the C1–C2 bond in partially protected d-glucose derivative (20), and chain extension of resulting aldehyde 20a with a single C2 fragment using (Z)-selective Wittig olefination. Synthesis of 2 involves the following key steps: periodate cleavage of the C5–C6 bond in the commercially available monoacetone d-glucose (24), followed by C2 chain elongation by using the (Z)-selective Wittig olefination. This new approach is also applied to prepare a few new 4-substituted cleistenolide analogues (3 – 18). Compounds 3 – 7 were designed using molecular hybridization, while the remaining eleven analogues were designed using the bioisosterism method. MTT assay showed that most analogues were more active than lead 1 against several malignant cells, but were completely inactive in the culture of normal foetal lung fibroblasts (MRC-5). The K562 cells appeared to be the most sensitive to the synthesized analogues. The strongest antiproliferative activity against this cell line was shown by 4-O-cinnamoyl derivative 3 and 4,6-di-O-benzyl derivative 17, with submicromolar IC50 values (0.76 and 0.67 μM, respectively). Structural features important for the activity of this class of compounds were identified by SAR analysis.