Synthetic Protocols, Structural Activity Relationship, and Biological Activity of Piperazine and its Derivatives

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six-membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure-activity relationship concerning different biological activities of various piperazine-containing drugs was also highlighted to provide a good understanding to researchers for future research on piperazines.

Antimicrobial Potential of Polyphenols: An Update on Alternative for Combating Antimicrobial Resistance

The last decade has encountered an increasing demand for plant-based natural antibiotics. This demand has led to more research-based investigations for natural sources of antimicrobial agents and published reports demonstrating that plant extracts are widely applied in modern medicine, reporting potential activity that may be due to polyphenol compounds. Interestingly, the effects of polyphenols on the sensitivity of bacteria to antibiotics have not been well-studied. Hence, the current review encompasses the prospective application of plant-based phenolic extracts from plants of Indian origin. The emergence of resistance to antimicrobial agents has increased the inefficacy of many antimicrobial drugs. Several strategies have been developed in recent times to overcome this issue. A combination of antimicrobial agents is employed for the failing antibiotics, which restores the desirable effect but may have toxicity-related issues. Phytochemicals such as some polyphenols have demonstrated their potent activity as antimicrobial agents of natural origin to work against resistance issues. These agents alone or in combination with certain antibiotics have been shown to enhance the antimicrobial activity against a spectrum of microbes. However, the information regarding the mechanisms and structure-activity relationships remains elusive. The present review also focuses on the possible mechanisms of natural compounds based on their structure- activity relationships for incorporating polyphenolic compounds in the drug-development processes. Besides this work, polyphenols could reduce drug dosage and may diminish the unhidden or hidden side effects of antibiotics. Pre-clinical findings have provided strong evidence that polyphenolic compounds, individually and in combination with already approved antibiotics, work well against the development of resistance. However, more studies must focus on in vivo results, and clinical research needs to specify the importance of polyphenol-based antibacterials in clinical trials.

Alleviating Neurodegenerative Diseases Associated with Mitochondrial Defects by Therapeutic Biomolecules

Neurodegenerative diseases are emerging as a global health concern in the current sce-nario, and their association with mitochondrial defects has been a potential area of research. Mi-tochondria, one of the essential organelles of the cell, serve as the cell's powerhouse, producing energy and ensuring cellular health. Neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, amyotrophic lateral sclerosis, and Pelizaeus-Merzbacher disease have been found to be primarily triggered by mitochondrial malfunction. One of the key byproducts of mitochondrial respiration, reactive oxygen species, also contributes significantly to mitochondrial DNA muta-tions that eventually cause mitochondrial breakdown. This review paper comprehensively examines the potential of therapeutic biomolecules, specifi-cally mitochondria-specific antioxidants, in mitigating the impact of mitochondrial defects on neurodegenerative diseases. It provides a detailed analysis of the mechanisms involved in mito-chondrial dysfunction, the potential therapeutic targets of these biomolecules, and their structure-activity relationship information are also discussed in this review. Various research articles and publications were used extensively in compiling the data, and the structures of biomolecules were prepared using software such as ChemDraw and ChemSketch. Crucial elements triggering mitochondrial abnormalities were identified and a tabular compilation of bioactive antioxidant compounds along with their therapeutic targets, was presented. Mitochondria-specific antioxidant therapy is an innovative and promising strategy for the man-agement of neurodegenerative diseases associated with mitochondrial defects. This review pro-vides a thorough summary of the current state of research and promising avenues of research and development in this field, emphasizing the importance of further investigations and clinical trials to elucidate their therapeutic benefits.

Recent Advancement in Bioactive Chalcone Hybrids as Potential Antimicrobial Agents in Medicinal Chemistry

Chalcones are flavonoid-related aromatic ketones and enones generated from plants. The chalcones have a wide range of biological activities, such as anti-tumor, calming, and antimicrobial activities. In the present review, we have focused on the recently published original research articles on chalcones as a unique antibacterial framework in medicinal chemistry. Chalcones are structurally diverse moieties and can be split into simple and hybrid chalcones, with both having core pharmacophore 1,3-diaryl-2-propen-1-one. Chalcones are isolated from natural sources and also synthesized by using various methods. Their structure-activity relationship, mechanisms, and list of patents are also summarized in this paper. This review article outlines the currently published antimicrobial chalcone hybrids and suggests that chalcone derivatives may be potential antimicrobial agents in the future.

1,3,4-Oxadiazoles as Anticancer Agents: A Review

Among the deadliest diseases, cancer is characterized by tumors or an increased number of a specific type of cell because of uncontrolled divisions during mitosis. Researchers in the current era concentrated on the development of highly selective anticancer medications due to the substantial toxicities of conventional cytotoxic drugs. Several marketed drug molecules have provided resistance against cancer through interaction with certain targets/growth factors/enzymes, such as Telomerase, Histone Deacetylase (HDAC), Methionine Aminopeptidase (MetAP II), Thymidylate Synthase (TS), Glycogen Synthase Kinase-3 (GSK), Epidermal Growth Factor (EGF), Vascular Endothelial Growth Factor (VEGF), Focal Adhesion Kinase (FAK), STAT3, Thymidine phosphorylase, and Alkaline phosphatase. The molecular structure of these drug molecules contains various heterocyclic moieties that act as pharmacophores. Recently, 1,3,4- oxadiazole (five-membered heterocyclic moiety) and its derivatives attracted researchers as these have been reported with a wide range of pharmacological activities, including anti-cancer. 1,3,4- oxadiazoles have exhibited anti-cancer potential via acting on any of the above targets. The presented study highlights the synthesis of anti-cancer 1,3,4-oxadiazoles, their mechanism of interactions with targets, along with structure-activity relationship concerning anti-cancer potential.

Design, Synthesis, and Anti-Breast Cancer Activity of Novel Fluorinated 7-O-Modified Genistein Derivatives

BACKGROUND

Genistein has been limited in clinical application due to its low bioavailability, extremely poor liposolubility, and fast glycosylation rate, though it possesses anti-breast cancer activity. Therefore, the discovery of novel genistein derivatives is an urgency.

OBJECTIVE

To enhance the anti-breast cancer activity of genistein, a series of novel fluorinated genistein derivatives were synthesized.

METHODS

Their in vitro antitumor activity was investigated by the MTT assay against three cancer cell lines, via, MDA-MB-231, MCF-7, and MDA-MB-435, respectively.

RESULTS

Analogs 1d, 2b, and 3b showed remarkable anticancer activities compared to tamoxifen, a clinical anti-breast cancer drug on the market.

CONCLUSION

The activities against breast cancer of genistein were enhanced by introducing the 7- alkoxyl group and fluorine atom into the B-ring. Therefore, these compounds may be potential candidates for treating breast cancer.

Medicinal attributes of heterocyclic compounds in rheumatoid arthritis: Recent developments and SAR studies

Rheumatoid arthritis (RA) is an autoimmune disorder that can attack anyone at any age, but it is most common in those between the ages of 30 and 50. It can impact joints or create joint stiffness, as well as the eyes, skin, and lungs. In the absence of a clear mechanism underlying the occurrence of rheumatoid arthritis in humans, scientists have successfully identified and marked some of the most commonly involved biological targets, such as enzymes or receptors, such as human carbonic anhydrase, Janus kinase, Bruton kinase, protein kinase, and so on. It is plausible to anticipate that any of the above-mentioned targets will provide a respite in the search for effective rheumatoid arthritis treatments. This article attempted to compile recent advances in this sector over the last six years (2016-2021) and successfully documented the positive outcomes of each significant research project. Without prejudice to any remaining research in this topic, the current compilation should serve as a starting point for future researchers in this field. The structure-activity relationships, mechanistic research, and molecular modelling of each class covered, as well as any clinical trial developments, have all been given special attention. This review discusses the design and development of numerous inhibitors for diverse targets such as BTK, JAKs, MAPK-PDE4, SYK, NSAIDs-CAIs, PKC, and others.

Recent advances in chalcone-based anticancer heterocycles: A structural and molecular target perspective

Chalcones are an interesting class of compounds endowed with a plethora of biological activities beneficial to human health. These chemo types have continued to attract increased research attention over the years; hence, numerous natural and synthetic chalcones have found with interesting anticancer activities through the inhibition of various molecular targets including ABCG2, BCRP, P-glycoprotein, 5α-reductase, Androgen receptor (AR), Histone deacetylases (HDAC), Sirtuin 1, proteasome, Vascular endothelial growth factor (VEGF), Cathepsin-K, tubulin, CDC25B phosphatase, Topoisomerase, EBV, NF-κB, mTOR, BRAF and Wnt/β-catenin. Moreover, the study of intrinsic mechanisms of action, particularly relating to specific cellular pathways and modes of engagement with molecular targets, may help medicinal chemists to develop a more effective, selective, and cost-effective chalcone-based anticancer drugs. This review, therefore, sheds light on the effect of structural variations on the anticancer potency of chalcone hybrids reported in 2018-2019 alongside their mechanism of action, molecular targets, and potential impacts on effective cancer chemotherapy.

Single Heterocyclic Compounds as Monoamine Oxidase Inhibitors: From Past to Present

Inhibitors of monoamine oxidase (MAO) have shown therapeutic values in a variety of neurodegenerative diseases such as depression, Parkinson's disease and Alzheimer's disease. Heterocyclic compounds exhibit a broad spectrum of biological activities and vital leading compounds for the development of chemical drugs. Herein, we focus on the synthesis and screening of novel single heterocyclic derivatives with MAO inhibitory activities during the past decade. This review covers recent pharmacological advancements of single heterocyclic moiety along with structure- activity relationship to provide better correlation among different structures and their receptor interactions.

Legume Proteins as a Promising Source of Anti-Inflammatory Peptides

Legume proteins are precursors of bioactive components, such as peptides. In the present paper, different types of legume as sources of bioactive peptides and hydrolysates are considered and discussed based on their anti-inflammatory effect. Peptides with anti-inflammatory activity were included from in vitro and in vivo studies. Current strategies for obtaining bioactive peptides, as well as their structure and impact on health, were also reviewed. It was discovered that peptides derived from legume protein, mainly soybean and bean, can regulate several inflammatory markers, which include prostaglandin E2 (PGE2), nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX- 2), cytokines, and chemokines. So far, lunasin, VPY and γ-glutamyl peptides have been identified with anti-inflammatory activity but their mechanisms have not been fully elucidated. Furthermore, it is necessary to gather more information about hydrolysates containing peptides and single peptides with antiinflammatory activity. Considering the wide diversity, legume may be promising components to produce peptides efficient to ameliorate inflammatory disorders.

Synthesis, Biological Evaluation and Molecular Docking Studies of New Pyrazolines as an Antitubercular and Cytotoxic Agents

BACKGROUND

Many synthetic procedures were reported till date to prepare pyrazoline derivatives. Some have published pyrazolines from different chalcone derivatives in the literature.

OBJECTIVE

A series of new pyrazolines containing novel 2,5-dichloro-3-acetylthiophene chalcone moiety (PZT1-PZT20) have been synthesized, characterized by 1HNMR and 13CNMR and evaluated for them in vitro antitubercular activity against M. tuberculosis H37Rv strain and in vitro anticancer activity against DU-145 prostate cancer cell lines and all compounds were also screened for molecular docking studies against specific targeted protein domains.

METHODS

All compounds were screened for potential activity against Mycobacterium tuberculosis H37Rv (MTB) strain and anticancer activity against DU-149 prostate cancer cell lines using MTT cytotoxicity assay.

RESULTS

Among the series, compound PZT5 with 2", 4"-dichlorophenyl group at 5-position on the pyrazoline ring exhibited the most potent antitubercular activity (MIC=1.60 µg/mL) and compounds PZT2, PZT9, PZT11, PZT15, and PZT20 showed similar antitubercular activity against standard pyrazinamide (MIC=3.12 µg/mL) by broth dilution assay. PZT15 and PZT17 with 4"- pyridinyl and 2"-pyrrolyl groups on pyrazoline ring were found to exhibit better anticancer activity against DU-149 prostate cancer cell lines with IC50 values of 2.0±0.2 µg/mL and 6.0±0.3 µg/mL respectively by MTT assay. The preliminary structure-activity relationship has been summarized. The molecular docking studies with crystalline structures of enoyl acyl carrier protein reductase InhA interaction with target protein (2NSD; PDB and 3FNG; PDB) of Mycobacterium tuberculosis H37Rv (MTB) strain have also exhibited good ligand interaction and binding affinity. Ligand interaction and binding affinity were estimated using crystal structures of both types of enoyl acyl carrier protein reductase InhA (3FNG.pdb) and found to be much higher (-16.70 to - 19.20 kcal/mol) compared with pyrazinamide (-10.70 kcal/mol) as a standard target molecule. Whereas the binding affinities of six active compounds with crystal structure of other type of enoyl acyl carrier protein reductase InhA (2NSD.pdb) were much similar and higher (-9.30 to - 11.20 kcal/mole) than pyrazinamide (-11.10 kcal/mole).

CONCLUSION

These new pyrazolines would be promising potent inhibitors of drug sensitive and drug resistant Mycobacterium tuberculosis strain and potential anticancer agents against prostate cancer and other prototypes of cancers.

Discovery of N-Phenyl-4-(1H-pyrrol-3-yl)pyrimidin-2-amine Derivatives as Potent Mnk2 Inhibitors: Design, Synthesis, SAR Analysis, and Evaluation of in vitro Anti-leukaemic Activity

BACKGROUND

Aberrant expression of eukaryotic translation initiation factor 4E (eIF4E) is common in many types of cancer including acute myeloid leukaemia (AML). Phosphorylation of eIF4E by MAPK-interacting kinases (Mnks) is essential for the eIF4E-mediated oncogenic activity. As such, the pharmacological inhibition of Mnks can be an effective strategy for the treatment of cancer.

METHODS

A series of N-phenyl-4-(1H-pyrrol-3-yl)pyrimidin-2-amine derivatives was designed and synthesised. The Mnk inhibitory activity of these derivatives as well as their anti-proliferative activity against MV4-11 AML cells was determined.

RESULTS

These compounds were identified as potent Mnk2 inhibitors. Most of them demonstrated potent anti-proliferative activity against MV4-11 AML cells. The cellular mechanistic studies of the representative inhibitors revealed that they reduced the level of phosphorylated eIF4E and induced apoptosis by down-regulating the anti-apoptotic protein myeloid cell leukaemia 1 (Mcl-1) and by cleaving poly(ADP-ribose)polymerase (PARP). The lead compound 7k possessed desirable pharmacokinetic properties and oral bioavailability.

CONCLUSION

This work proposes that exploration of the structural diversity in the context of Nphenyl- 4-(1H-pyrrol-3-yl)pyrimidin-2-amine would offer potent and selective Mnk inhibitors.

Xanthone Conjugated Amino Acids as Potential Anticancer and DNA Binding Agents: Molecular Docking, Cytotoxicity and SAR Studies

BACKGROUND

Amino acids conjugated with heterocyclic molecules are well known for their effective bioactive properties. In search of effective anticancer agents, a series of xanthone linked amino acids 2-23 were synthesized and tested for in vitro anticancer activity.

METHODS

In vitro anticancer activity of the synthesized xanthone linked amino acids 2-23 are tested against three different cancer cell lines MCF-7, MDA-MB-435 and A549 by MTT assay and validated by DNA binding and molecular docking approaches. Doxorubicin and ethidium bromide used as standard and positive control respectively.

RESULTS

Compounds 7, 8 and 9 exhibited potent anticancer activity against tested cancer cell lines and DNA binding study using methyl green. In the molecular docking study, binding interactions of the most active compounds 7, 8 and 9 were confirmed to molecular surface of DNA.

CONCLUSION

Structure-Activity Relationship (SAR) showed that the aromatic and hydrophobic amino acids (phenylalanine, tyrosine, and tryptophan) favoured the DNA binding studies and anticancer activity whereas, aliphatic amino acids showed least anticancer activity.

Structure - Function Analysis of Peptide Analogs of SQSPA with Respect to α-glucosidase and α-amylase Inhibition

BACKGROUND

Peptide-based therapeutics offer a unique avenue for the development of novel agents for the treatment of diabetes mellitus including α-glucosidase inhibitors. The peptide, SQSPA, was reported to possess to α -glucosidase inhibitory activity in addition to resistance to Gastrointestinal Tract (GIT) digestion.

METHODS

In this study, the in silico and in vitro structure-activity analyses of the peptide was conducted using alanine scanning to identify key amino acid residues.

RESULTS

The alanine scanning led to four analogs viz; AQSPA, SASPA, SQAPA and SQSAA which were GIT stable. Initially, the peptides were subjected to molecular docking on human α- glucosidase and α -amylase where the binding affinities to the enzymes were in the order; AQSPA>SASPA>SQSPA>SQAPA> SQSAA and AQSPA>SQSAA>SASPA>SQSPA> SQAPA, respectively. Hydrogen bond were important for the binding of all peptides but SASPA and AQSPA had the highest hydrogen bonds interactions with the α-glucosidase and α-amylase, respectively. In vitro analysis revealed that the α -glucosidase and α-amylase inhibitory activities of the peptides were in the order AQSPA>SQSPA>SQAPA>SASPA>SQSAA and AQSPA>SASPA> SQAPA>SQSPA>SQSAA, respectively. Using inhibition kinetics, SQSPA was a mixed inhibitor of α-glucosidase while AQSPA, SQAPA and SQSAA showed non-competitive inhibition. For α- amylase inhibition, SQSPA was a non-competitive inhibitor while AQSPA and SQSAA were mixed inhibitors; SASPA and SQAPA showed uncompetitive inhibition.

CONCLUSION

The results indicated that P4 and Q2 are important requirements for the α-glucosidase and α-amylase inhibitory activities of the parent peptide, SQSPA. Furthermore, alanine scanning has led to the design of a novel α-glucosidase inhibitory peptide, AQSPA, with increased activities.

Phenolic Acids Derivatives - Biotechnological Methods of Synthesis and Bioactivity

Phenolic acids are secondary plant metabolites belonging to polyphenol classes, widely spread throughout the plant kingdom. The name "phenolic acids", in general, describes phenols that possess one carboxylic acid functionality and they could be divided into three major subclasses: hydroxybenzoic, hydroxycinnamic and hydroxyphenylacetic acids. The great interest in phenolic acids is associated with their high potential for food preservation (antioxidant and antimicrobial activity) and, last but not least, high therapeutic potential. The aim of this review is to summarise the current knowledge concerning phenolic acids and the topics discussed include natural sources of phenolic acids, biosynthesis and metabolism, health benefits of phenolic acids (first of all the antioxidant activity of dietary phenolics and also anticarcinogenic and anti-inflammatory effect), their antimicrobial activity for selected groups of bacteria and fungi (yeasts) and structural modifications of the molecule especially those increasing lipophilicity and improving solubility in lipids. Recent advances in the methods of enzymatic synthesis of phenolic acid derivatives are described and some conclusions referring to Structure-Property-Activity Relationships of phenolic acids, particularly important from the point of view of their pharmaceutical and nutritional applications, are discussed.

Anticancer and Reversing Multidrug Resistance Activities of Natural Isoquinoline Alkaloids and their Structure-activity Relationship

The severe anticancer situation as well as the emergence of multidrug-resistant (MDR) cancer cells has created an urgent need for the development of novel anticancer drugs with different mechanisms of action. A large number of natural alkaloids, such as paclitaxel, vinblastine and camptothecin have already been successfully developed into chemotherapy agents. Following the success of these natural products, in this review, twenty-six types of isoquinoline alkaloids (a total of 379 alkaloids), including benzyltetrahydroisoquinoline, aporphine, oxoaporphine, isooxoaporphine, dimeric aporphine, bisbenzylisoquinoline, tetrahydroprotoberberine, protoberberine, protopine, dihydrobenzophenanthridine, benzophenanthridine, benzophenanthridine dimer, ipecac, simple isoquinoline, pavine, montanine, erythrina, chelidonine, tropoloisoquinoline, azafluoranthene, phthalideisoquinoline, naphthylisoquinoline, lycorine, crinane, narciclasine, and phenanthridone, were summarized based on their cytotoxic and MDR reversing activities against various cancer cells. Additionally, the structure-activity relationships of different types of isoquinoline alkaloid were also discussed. Interestingly, some aporphine, oxoaporphine, isooxoaporphine, bisbenzylisoquinoline, and protoberberine alkaloids display more potent anticancer activities or anti-MDR effects than positive control against the tested cancer cells and are regarded as attractive targets for discovery new anticancer drugs or lead compounds.

Recent Development of Oridonin Derivatives with Diverse Pharmacological Activities

Oridonin is one of the major components isolated from Isodon rubescens, a traditional Chinese medicine, and it has been confirmed to exhibit many kinds of biological activities including anticancer, anti-inflammation, antibacterial and so on. However, the poor pharmaceutical property limits the clinical applications of oridonin. So many strategies have been explored in the purpose of improving the potencies of oridonin, and structure modification is one thus way. This review outlines the landscape of the recent development of oridonin derivatives with diverse pharmacological activities, mainly focusing on the biological properties, structure-activity relationships, and mechanism of actions.

Phenolic Imidazole Derivatives with Dual Antioxidant/Antifungal Activity: Synthesis and Structure-Activity Relationship

BACKGROUND

Previous publications show that the addition of a phenolic antioxidant to an antifungal agent, considerably enhances the antifungal activity.

OBJECTIVE

Synthesis of novel compounds combining phenolic units with linear or cyclic nitrogencontaining organic molecules with antioxidant/antifungal activity using methodologies previously developed in the group.

METHODS

Several N- [1,2-dicyano-2- (arylidenamino) vinyl]-O-alkylformamidoximes 3 were synthesized and cyclized to 4,5-dicyano-N- (N´-alcoxyformimidoyl)-2-arylimidazoles 4 upon reflux in DMF, in the presence of manganese dioxide or to 6-cyano-8-arylpurines 5 when the reagent was refluxed in acetonitrile with an excess of triethylamine. These compounds were tested for their antioxidant activity by cyclic voltammetry, DPPH radical (DPPH•) assay and deoxyribose degradation assay. The minimum inhibitory concentration (MIC) of all compounds was evaluated against two yeast species, Saccharomyces cerevisiae and Candida albicans, and against bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram negative). Their cytotoxicity was evaluated in fibroblasts.

RESULTS

Among the synthetised compounds, five presented higher antioxidant activity than reference antioxidant Trolox and from these compounds, four presented antifungal activity without toxic effects in fibroblasts and bacteria.

CONCLUSION

Four novel compounds presented dual antioxidant/antifungal activity at concentrations that are not toxic to bacteria and fibroblasts. The active molecules can be used as an inspiration for further studies in this area.

QSAR Modeling of Histamine H3R Antagonists/inverse Agonists as Future Drugs for Neurodegenerative Diseases

Background

Histamine H₃ receptor (H₃R) is associated with several neuropsychological diseases, and thus it is an important target involved in several CNS disorders, such as narcolepsy, attention deficit hyperactivity disorder and schizophrenia. Since QSAR modeling is a feasible approach to explain the role of the molecular substituents in the biological activity, it can help in improving the design of better H₃R ligands for these conditions.

Methods

This article reviews papers previously published in literature to show the current status of the contribution from QSAR modeling to reach H₃R antagonists/inverse agonists.

Results

Classical and 3D-QSAR models were retrieved, showing that the steric and hydrophobic properties of the H₃R ligands are most important to reach good affinity.

Conclusion

Although QSAR methods are valuable to design better H₃R antagonists/inverse agonists, pharmacokinetics should also be considered in future models to ensure good CNS penetration.

A Systematic Review on the Sinomenine Derivatives

Sinomenine is one of the most widely known alkaloids owing to different therapeutic properties including anti-inflammatory and immunosuppressive activities, as well as the potency in neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. Sinomenine has been studied as a potential anti-inflammatory agent through appropriate structural modifications. Recently, a number of such approaches have been attempted in various laboratories with great success. Several series of derivatives have been synthesized with changes at rings A, B, C and D. Herein, we present an up to date review of modifications and bioactivities of important modified derivatives. These studies offer interesting knowledge on the bioactivity and structural specificity of sinomenine, providing better understanding of the structure-activity relationships (SAR) between designing and development of sinomenine derivative with better therapeutic and lower side effects.

Pyrogallol structure in polyphenols is involved in apoptosis-induction on HEK293T and K562 cells

As multiple mechanisms account for polyphenol-induced cytotoxicity, the development of structure-activity relationships (SARs) may facilitate research on cancer therapy. We studied SARs of representatives of 10 polyphenol structural types: (+)-catechin (1), (-)-epicatechin (2), (-)-epigallocatechin (3), (-)-epigallocatechin gallate (4), gallic acid (5), procyanidin B2 (6), procyanidin B3 (7), procyanidin B4 (8), procyanidin C1 (9), and procyanidin C2 (10). Amongst them, the polyphenols containing a pyrogallol moiety (3-5) showed the most potent cytotoxicic activity. These compounds evoked a typical DNA-laddering phenomenon in HEK293T, which indicated that the induction of apoptosis at least partly mediates their cytotoxic activity. Anti-oxidative capacity of compounds 3-5 were comparable to those of the trimers 9 and 10, which were not cytotoxic. Therefore, we suggest that pyrogallol moiety is important for fitting of polyphenols to their putative target molecule(s) in non-oxidative mechanism.