Design, synthesis, in vitro and in vivo evaluation of benzylpiperidine-linked 1,3-dimethylbenzimidazolinones as cholinesterase inhibitors against Alzheimer's disease

Cholinesterase inhibitor plays an important role in the treatment of patients with Alzheimer's disease (AD). Herein, we report the medicinal chemistry efforts leading to a new series of 1,3-dimethylbenzimidazolinone derivatives. Among the synthesised compounds, 15b and 15j showed submicromolar IC₅₀ values (15b, eeAChE IC₅₀ = 0.39 ± 0.11 µM; 15j, eqBChE IC₅₀ = 0.16 ± 0.04 µM) towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Kinetic and molecular modelling studies revealed that 15b and 15j act in a competitive manner. 15b and 15j showed neuroprotective effect against H₂O₂-induced oxidative damage on PC12 cells. This effect was further supported by their antioxidant activity determined in a DPPH assay in vitro. Morris water maze test confirmed the memory amelioration effect of the two compounds in a scopolamine-induced mouse model. Moreover, the hepatotoxicity of 15b and 15j was lower than tacrine. In summary, these data suggest 15b and 15j are promising multifunctional agents against AD.

Development of Coumarin-Based Hydroxamates as Histone Deacetylase Inhibitors with Antitumor Activities

Histone deacetylases (HDACs) have been proved to be promising targets for the treatment of cancer, and five histone deacetylase inhibitors (HDACis) have been approved on the market for the treatment of different lymphomas. In our previous work, we designed a series of novel coumarin-containing hydroxamate HDACis, among which compounds 6 and 7 displayed promising activities against tumor growth. Based on a molecular docking study, we further developed 26 additional analogues with the aim to improve activity of designed compounds. Several of these new derivatives not only showed excellent HDAC1 inhibitory effects, but also displayed significant growth inhibitory activities against four human cancer cell lines. Representative compounds, 13a and 13c, showed potent anti-proliferative activities against solid tumor cell lines with IC50 values of 0.36-2.91 M and low cytotoxicity against Beas-2B and L-02 normal cells. Immunoblot analysis revealed that 13a and 13c dose-dependently increased the acetylation of histone H3 and H4. Importantly, the two compounds displayed much better anti-metastatic effects than SAHA against the MDA-MB-231 cell line. Moreover, 13a and 13c arrested MDA-MB-231 cells at G2/M phase and induced MDA-MB-231 cell apoptosis. Finally, the molecular docking study rationalized the high potency of compound 13c.

How to Start a Total Synthesis from the Wieland-Miescher Ketone?

BACKGROUND

The Wieland-Miescher ketone consists of a couple of enantiomers of 9-methyl- Δ5(10)-octalin-1,6-dione, in which the configuration at 9-position is S- or R-type. The Robinson annulation of 2-methyl-1,3-cyclohexanedione with methyl vinyl ketone is able to afford the Wieland-Miescher ketone. As widely used in the total synthesis, the Wieland-Miescher ketone is treated at the beginning of total synthesis, and protocols for treating the Wieland-Miescher ketone are worthy to be addressed.

OBJECTIVE

The presented review provides the progress of the usage of Wieland-Miescher ketone for the total synthesis, while treatments on C=C and C=O in the Wieland-Miescher ketone at the beginning of total synthesis are exemplified herein.

CONCLUSION

Modifications of the Wieland-Miescher ketone are composed of oxidation, reduction, and electrophilic or nucleophilic addition. In addition, protection of non-conjugated C=O with glycol or protection of conjugated C=O with ethanedithiol, and the introduction of substituents into α-position of C=C can also be used to modify the structure of the Wieland-Miescher ketone. It is reasonably believed that many novel strategies will be found to treat the Wieland-Miescher ketone in the future total synthesis.

Design, Synthesis, and Evaluation of Acetylcholinesterase and Butyrylcholinesterase Dual-Target Inhibitors against Alzheimer's Diseases

A series of novel compounds 6a-h, 8i-1, 10s-v, and 16a-d were synthesized and evaluated, together with the known analogs 11a-f, for their inhibitory activities towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The inhibitory activities of AChE and BChE were evaluated in vitro by Ellman method. The results show that some compounds have good inhibitory activity against AChE and BChE. Among them, compound 8i showed the strongest inhibitory effect on both AChE (eeAChE IC50 = 0.39 μM) and BChE (eqBChE IC50 = 0.28 μM). Enzyme inhibition kinetics and molecular modeling studies have shown that compound 8i bind simultaneously to the peripheral anionic site (PAS) and the catalytic sites (CAS) of AChE and BChE. In addition, the cytotoxicity of compound 8i is lower than that of Tacrine, indicating its potential safety as anti-Alzheimer's disease (anti-AD) agents. In summary, these data suggest that compound 8i is a promising multipotent agent for the treatment of AD.

Solubility and Bioavailability Enhancement of Oridonin: A Review

Oridonin (ORI), an ent-kaurene tetracyclic diterpenoid compound, is isolated from Chinese herb Rabdosia rubescens with various biological and pharmacological activities including anti-tumor, anti-microbial and anti-inflammatory effects. However, the clinical application of ORI is limited due to its low solubility and poor bioavailability. In order to overcome these shortcomings, many strategies have been explored such as structural modification, new dosage form, etc. This review provides a detailed discussion on the research progress to increase the solubility and bioavailability of ORI.

Structural Modifications of a Flaxseed Lignan in Pursuit of Higher Liposolubility: Evaluation of the Antioxidant and Permeability Properties of the Resulting Derivatives

While lignans and their biogenetic precursors can have various health benefits, the poor liposolubilities of such phenolic systems have restricted their application as antioxidants in the food industry. The research reported here was aimed at addressing these matters through derivatizing certain forms of such compounds and then assessing their properties as potential nutraceuticals. In particular, crude flaxseed lignan was purified to afford secoisolariciresinol diglucoside (SDG, 1) that was then subjected to structural modification. By such means, the SDG long-chain fatty acid esters 4-9 and 11-13, the fully acetylated SDG 10, secoisolariciresinol (SECO, 2), and anhydrosecoisolariciresinol (ASECO, 14) were obtained. The antioxidant activities of these derivatives were determined while their permeability properties were evaluated. Such studies revealed that certain SDG derivatives possessing useful liposolubilities also retained their antioxidative properties, as well as being capable of permeating Caco-2 cell monolayers while being nontoxic to them. SDG fatty acid esters 4-9 and 11-13 could be developed into emulsifiers with enhanced health benefits, especially considering their improved antioxidative (ca. <11 000 μmol Trolox/g) and permeability properties. This study thus highlights strategies for the structural modification of SDG so as to generate derivatives with superior properties in terms of their utility in the food and pharmaceutical industries.

Preparation of Matrinic/Oxymatrinic Amide Derivatives as Insecticidal/Acaricidal Agents and Study on the Mechanisms of Action against Tetranychus cinnabarinus

In continuation of our program to develop natural-product-based pesticidal candidates, matrinic/oxymatrinic amides were obtained through structural optimization of matrine. N'-(4-Fluoro)phenyl-N-(4-bromo)phenylsulfonyloxymatrinic amide (IIm) showed potent insecticidal activity against Mythimna separata. N-(Un)substituted phenylsulfonylmatrinic acids (3a-c) exhibited promising acaricidal activity against Tetranychus cinnabarinus. By qRT-PCR analysis of nAChR subunits and AChE genes and determination of AChE activity of (un)treated T. cinnabarinus, it suggested that the open lactam ring of matrine and carboxyl group and (4-methyl)phenylsulfonyl of N-(4-methyl)phenylsulfonylmatrinic acid (3b) were necessary for action with α2, α4, α5, and β3 nAChR subunits; compound 3b was an inhibitor of AChE in T. cinnabarinus, and AChE was one possible target of action in T. cinnabarinus against 3b; and compound 3b may be an antagonist of nAChR and AChE in T. cinnabarinus.

Semisynthesis of novel N-acyl/sulfonyl derivatives of 5(3,5)-(di)halogenocytisines/cytisine and their pesticidal activities against Mythimna separata Walker, Tetranychus cinnabarinus Boisduval, and Sitobion avenae Fabricius

BACKGROUND

To discover novel natural product-based pesticidal agents for crop protection, a series of N-acyl/sulfonyl derivatives of 5(3,5)-(di)halogenocytisines/cytisine were prepared by structural modifications of cytisine. Their pesticidal activities were evaluated against three typically crop-threatening agricultural pests, Mythimna separata Walker, Tetranychus cinnabarinus Boisduval, and Sitobion avenae Fabricius.

RESULTS

Compound 5f exhibited the promising pesticidal activities against three tested pests. All N-phenylsulfonylcytisine derivatives showed potent acaricidal activity. Compound 5j exhibited 2.5-fold more potent acaricidal activity than cytisine, and showed good control effects. Intermediates 2, and 3/3' displayed pronounced aphicidal activity. Some interesting results of structure-activity relationships were also obtained.

CONCLUSION

These results demonstrate that compounds 5f and 5j could be further modified as pesticidal agents. © 2019 Society of Chemical Industry.

Recent Achievements in Medicinal and Supramolecular Chemistry of Betulinic Acid and Its Derivatives ‡

The subject of this review article refers to the recent achievements in the investigation of pharmacological activity and supramolecular characteristics of betulinic acid and its diverse derivatives, with special focus on their cytotoxic effect, antitumor activity, and antiviral effect, and mostly covers a period 2015–2018. Literature sources published earlier are referred to in required coherences or from historical points of view. Relationships between pharmacological activity and supramolecular characteristics are included if such investigation has been done in the original literature sources. A wide practical applicability of betulinic acid and its derivatives demonstrated in the literature sources is also included in this review article. Several literature sources also focused on in silico calculation of physicochemical and ADME parameters of the developed compounds, and on a comparison between the experimental and calculated data.

Tuning Gel State Properties of Supramolecular Gels by Functional Group Modification

The factors affecting the self-assembly process in low molecular weight gelators (LMWGs) were investigated by tuning the gelation properties of a well-known gelator N-(4-pyridyl)isonicotinamide (4PINA). The N-H∙∙∙N interactions responsible for gel formation in 4PINA were disrupted by altering the functional groups of 4PINA, which was achieved by modifying pyridyl moieties of the gelator to pyridyl N-oxides. We synthesized two mono-N-oxides (INO and PNO) and a di-N-oxide (diNO) and the gelation studies revealed selective gelation of diNO in water, but the two mono-N-oxides formed crystals. The mechanical strength and thermal stabilities of the gelators were evaluated by rheology and transition temperature (Tgel) experiments, respectively, and the analysis of the gel strength indicated that diNO formed weak gels compared to 4PINA. The SEM image of diNO xerogels showed fibrous microcrystalline networks compared to the efficient fibrous morphology in 4PINA. Single-crystal X-ray analysis of diNO gelator revealed that a hydrogen-bonded dimer interacts with adjacent dimers via C-H∙∙∙O interactions. The non-gelator with similar dimers interacted via C-H∙∙∙N interaction, which indicates the importance of specific non-bonding interactions in the formation of the gel network. The solvated forms of mono-N-oxides support the fact that these compounds prefer crystalline state rather than gelation due to the increased hydrophilic interactions. The reduced gelation ability (minimum gel concentration (MGC)) and thermal strength of diNO may be attributed to the weak intermolecular C-H∙∙∙O interaction compared to the strong and unidirectional N-H∙∙∙N interactions in 4PINA.

Investigations of Processing-Induced Structural Changes in Horse Type-I Collagen at Sub and Supramolecular Levels

The aim of this work is to evaluate the effects of different extraction and material processing protocols on the collagen structure and hierarchical organization of equine tendons. Wide and Small Angle X-ray Scattering investigations on raw powders and thin films revealed that not only the extraction and purification treatments, but also the processing conditions may affect the extent of the protein crystalline domain and induce a nanoscale “shield effect.” This is due to the supramolecular fiber organization, which protects the atomic scale structure from the modifications that occur during fabrication protocols. Moreover, X-ray analyses and Fourier Transform Infrared spectroscopy performed on the biomaterial sheds light on the relationship between processing conditions, triple helical content and the organization in atomic and nanoscale domains. It was found that the mechanical homogenization of the slurry in acidic solution is a treatment that ensures a high content of super-organization of collagen into triple helices and a lower crystalline domain in the material. Finally, mechanical tensile tests were carried out, proving that the acidic solution is the condition which most enhances both mechanical stiffness and supramolecular fiber organization of the films.

Synthesis of 9-O-arylated berberines via copper-catalyzed CAr-O coupling reactions

Berberine is a widely used antimicrobial agent in clinic. However, a high dosage is often required due to its low lipophilicity and bioavailability. The current study explores the structural modifications of berberines with potentially lipophilic aryl groups to address this problem. A series of 15 9-O-aryl-substituted berberines (3a–o) and one 9-O-phenylene-bridged berberine dimer (5) was synthesized by copper-catalyzed cross-coupling of tetrahydroberberrubine and aryl iodides, followed by oxidation with I₂.

The history of extensive structural modifications of pyrethroids

The structural modification of natural pyrethrins has led to a number of synthetic pyrethroid insecticides, and each compound has its own characteristics. At present, pyrethroid insecticides are applied not only for household use, the original use for pyrethrins, but also for a wide range of uses such as crop protection, pharmaceuticals, and veterinary applications. Quoting primary sources, this review describes the historical view of structural modifications of pyrethroids, with a focus on structural similarities, and their use.

Research progress on adenosine in central nervous system diseases

As an endogenous neuroprotectant agent, adenosine is extensively distributed and is particularly abundant in the central nervous system (CNS). Under physiological conditions, the concentration of adenosine is low intra- and extracellularly, but increases significantly in response to stress. The majority of adenosine functions are receptor-mediated, and primarily include the A1, A2A, A2B, and A3 receptors (A1R, A2AR, A2BR, and A3R). Adenosine is currently widely used in the treatment of diseases of the CNS and the cardiovascular systems, and the mechanisms are related to the disease types, disease locations, and the adenosine receptors distribution in the CNS. For example, the main infarction sites of cerebral ischemia are cortex and striatum, which have high levels of A1 and A2A receptors. Cerebral ischemia is manifested with A1R decrease and A2AR increase, as well as reduction in the A1R-mediated inhibitory processes and enhancement of the A2AR-mediated excitatory process. Adenosine receptor dysfunction is also involved in the pathology of Alzheimer's disease (AD), depression, and epilepsy. Thus, the adenosine receptor balance theory is important for brain disease treatment. The concentration of adenosine can be increased by endogenous or exogenous pathways due to its short half-life and high inactivation properties. Therefore, we will discuss the function of adenosine and its receptors, adenosine formation, and metabolism, and its role for the treatment of CNS diseases (such as cerebral ischemia, AD, depression, Parkinson's disease, epilepsy, and sleep disorders). This article will provide a scientific basis for the development of novel adenosine derivatives through adenosine structure modification, which will lead to experimental applications.

Marine-Derived Natural Lead Compound Disulfide-Linked Dimer Psammaplin A: Biological Activity and Structural Modification

Marine natural products are considered to be valuable resources that are furnished with diverse chemical structures and various bioactivities. To date, there are seven compounds derived from marine natural products which have been approved as therapeutic drugs by the U.S. Food and Drug Administration. Numerous bromotyrosine derivatives have been isolated as a type of marine natural products. Among them, psammaplin A, including the oxime groups and carbon-sulfur bonds, was the first identified symmetrical bromotyrosine-derived disulfide dimer. It has been found to have a broad bioactive spectrum, especially in terms of antimicrobial and antiproliferative activities. The highest potential indole-derived psammaplin A derivative, UVI5008, is used as an epigenetic modulator with multiple enzyme inhibitory activities. Inspired by these reasons, psammaplin A has gradually become a research focus for pharmacologists and chemists. To the best of our knowledge, there is no systematic review about the biological activity and structural modification of psammaplin A. In this review, the pharmacological effects, total synthesis, and synthesized derivatives of psammaplin A are summarized.

Rational design of novel sirtuin 1 activators via structure-activity insights from application of QSAR modeling

Sirtuin 1 (SIRT1) enzyme regulates major cell activities, and its activation offers lucrative therapeutic potentials for aging diseases including Alzheimer's disease (AD). Regarding the global aging society, continual attention has been given to various chemical scaffolds as a source for the discovery of novel SIRT1 activators since the discovery of the pioneer activator, resveratrol. Understanding structure-activity relationship (SAR) is essential for screening, designing as well as improving the properties of drugs. In this study, an in silico approach based on quantitative structure-activity relationship (QSAR) modeling, was employed for understanding the SAR of currently available SIRT1 fused-aromatic activators (i.e., imidazothiazole, oxazolopyridine, and azabenzimidazole analogs). Three QSAR models constructed using multiple linear regression (MLR) provided good predictive performance (R ² _LOOCV = 0.729 - 0.863 and RMSE _LOOCV = 0.165 - 0.325). An additional novel set of 181 structurally modified compounds were rationally designed according to key descriptors deduced from the QSAR findings and their SIRT1 activities were predicted using the constructed models. In overview, the study provides insightful SAR findings of currently available SIRT1 activators that would be useful for guiding the rational design, screening, and development of further potent SIRT1 activators for managing age-related clinical conditions. A series of promising compounds as well as important scaffolds and molecular properties for potent SIRT1 activator were highlighted. This study demonstrated the efficacious role of QSAR-driven structural modification for the rational design of novel leads.

Widespread Existence of Quorum Sensing Inhibitors in Marine Bacteria: Potential Drugs to Combat Pathogens with Novel Strategies

Quorum sensing (QS) is a phenomenon of intercellular communication discovered mainly in bacteria. A QS system consisting of QS signal molecules and regulatory protein components could control physiological behaviors and virulence gene expression of bacterial pathogens. Therefore, QS inhibition could be a novel strategy to combat pathogens and related diseases. QS inhibitors (QSIs), mainly categorized into small chemical molecules and quorum quenching enzymes, could be extracted from diverse sources in marine environment and terrestrial environment. With the focus on the exploitation of marine resources in recent years, more and more QSIs from the marine environment have been investigated. In this article, we present a comprehensive review of QSIs from marine bacteria. Firstly, screening work of marine bacteria with potential QSIs was concluded and these marine bacteria were classified. Afterwards, two categories of marine bacteria-derived QSIs were summarized from the aspects of sources, structures, QS inhibition mechanisms, environmental tolerance, effects/applications, etc. Next, structural modification of natural small molecule QSIs for future drug development was discussed. Finally, potential applications of QSIs from marine bacteria in human healthcare, aquaculture, crop cultivation, etc. were elucidated, indicating promising and extensive application perspectives of QS disruption as a novel antimicrobial strategy.

Toward the Development of an Innovative Implant: NiTi Alloy Functionalized by Multifunctional β-TCP+Ag/SiO2 Coatings

In recent years, one of the more important and costly problems of modern medicine is the need to replace or supplement organs in order to improve the quality of human life. In this field, promising solutions seem to have been implants which are based on NiTi alloys with shape memory effects. Unfortunately, this material is susceptible to the corrosion and release of toxic nickel to the human organism. Hence, its application as a long-term material is strongly limited. Therefore, this paper presents a new solution which should help to improve the functionality of the NiTi alloy and elongate its medical stability to use. The idea was focused on functionalization of the implant surface by a biocompatible, multifunctional coating without any impact on the features of the substrate, i.e., the martensitic transformation responsible for shape memory effects. For this purpose, we prepared a colloidal suspension, composed of β-TCP (particle size ∼450 nm) and the Ag/SiO₂ nanocomposite which due to the electrophoretic deposition (EPD) led to the formation of structurally atypical calcium phosphosilicate coating. Those biomaterials formed a crack-free coating, adhering well to the NiTi surface when distributed over the entire surface, with low concentration of metallic and oxide silver (<3 at. %). At the same time, the coat-forming materials had resulted in the growth of a Gram-negative bacterial biofilm. Additionally, the additive of the silver-silica composite enhances cell proliferation, effectively a few times higher than commonly used coat-forming materials (e.g., pure β-TCP).

Semisynthesis of Matrinic Acid/Alcohol/Ester Derivatives, Their Pesticidal Activities, and Investigation of Mechanisms of Action against Tetranychus cinnabarinus

To discover new natural-product-based potential pesticides, 85 matrinic acid/alcohol/ester derivatives were synthesized by structural modifications of a quinolizidine alkaloid matrine. N-(4-Methyl)benzylmatrinyl n-decylate (76) and N-(2-chloro)benzylmatrinyl n-undecylate (86) exhibited greater than seven-fold more pronounced acaricidal activity than matrine against Tetranychus cinnabarinus; N-(2-chloro)benzylmatrinyl benzoate (80) showed the most promising insecticidal activity against Mythimna separata. The carboxyl group of matrinic acids and introduction of n-decyl/ n-undecylcarbonyl into matrinic alcohols were important for the acaricidal activity; introduction of alkyloxy into the carboxyl of matrinic acids and introduction of the electron-withdrawing groups on the N-benzyl of matrinic esters were necessary for the insecticidal activity. Through RT-PCR and qRT-PCR analysis, it was shown that the lactam ring of matrine was vital for action on VGSC; opening the lactam ring of matrine and the alkylcarbonyl of side-chain were two important factors for acting with α1, α2, and α4 nAChR subunits; α1, α2, α4, and β3 subunits may be the target of action of compound 86 against T. cinnabarinus.

On the Efficient Separation of Gas Mixtures with the Mixed-Linker Zeolitic-Imidazolate Framework-7-8

A recently reported modification of the zeolitic-imidazolate framework-8 (ZIF-8) with partial replacement of the 2-methylimidazolate (mIm) linker with benzimidazolate (bIm), namely ZIF-7-8, is investigated with molecular simulations using a first-time reported force field. The size of the ZIF-7-8 aperture, which governs the gas-separation efficiency of this material and which has not been estimated before for this modification, is smaller than that of the original ZIF-8. The diffusivities of CO₂, N₂, and CH₄ estimated through transition state theory calculations result in remarkably high diffusion selectivities for CO₂/CH₄ and CO₂/N₂ mixtures. This performance enhancement is investigated in terms of structural flexibility in the form of the aperture motion through extensive estimation of the effective diameter, the total effective area, and the motion of the aperture linkers, of both ZIF-8 and ZIF-7-8. Both apertures exhibit an oscillation through the rotation of the linkers, which are adjusted according to the size of the penetrant molecules the moment they pass through it. Finally, a subsequent analysis reveals that there is strong dependency of the separation performance on the bIm-to-mIm ratio: below 33% bIm incorporation, the appearance of ZIF-8-alike wide apertures decreases dramatically the size-based selectivity of the mixtures in ZIF-7-8.

[Chemical and pharmacological progress on usnic acid and its derivatives]

Usnic acid and its derivatives, a group of organic molecules with great importance, are characteristic to lichens, possessing pharmacological activities such as anti-virus, anti-bacteria, anti-humor, anti-inflammatory, analgesic, and anaesthetic effects. Many of them have been widely used as medicine, but also bring side effects such as dermatitis and liver damages. In the past decades, great efforts by isolation, organic synthesis, and structure modification methods were put on discovery of UA derivatives with higher biological activities or less side effects. This paper describes herein the most progress on natural sources, isolation and structure elucidation, structural characteristics, synthesis and modification results, pharmacological activities and toxicities of UA and its derivatives, hopefully to provide valuable reference for further research.

Limonoids Containing a C₁⁻O⁻C29 Moiety: Isolation, Structural Modification, and Antiviral Activity

Five new limonoids named thaigranatins A⁻E (1⁻5), containing a C₁⁻O⁻C₂₉ moiety, were isolated from seeds of the Thai Xylocarpus granatum, collected at the mangrove swamp of Trang Province, together with the known limonoid, granatumin L (6). The structures of these compounds were established by HR-ESIMS and extensive NMR spectroscopic data. The absolute configuration of 1 was unequivocally determined by single-crystal X-ray diffraction analysis, conducted with Cu Kα radiation; whereas that of 2 or 6 was established to be the same as that of 1 by the similarity of their electronic circular dichroism (ECD) spectra. In view of the marked antiviral activity of 6, its structure was modified via hydrolysis with alkaline KOH, esterification with diazomethane and various organic acids, and oximization with hydroxyamine. Finally, 18 derivatives, viz. 7⁻10, 8a⁻8i, 9a⁻9b, and 10a⁻10c, were obtained. In vitro antiviral activities of these derivatives against human immunodeficiency virus 1 (HIV-1) and influenza A virus (IAV) were evaluated. Most notably, 8i exhibited marked inhibitory activity against HIV-1 with an IC₅₀ value of 15.98 ± 6.87 μM and a CC₅₀ value greater than 100.0 μM; whereas 10b showed significant inhibitory activity against IAV with an IC₅₀ value of 14.02 ± 3.54 μM and a CC₅₀ value greater than 100.0 μM.

Synthesis of Piperine Analogs Containing Isoxazoline/Pyrazoline Scaffold and Their Pesticidal Bioactivities

In continuation of our program to discover new potential pesticidal agents, thirty-one piperine analogs containing isoxazoline/pyrazoline scaffold were prepared, and confirmed by infrared spectra, proton/carbon-13 nuclear magnetic resonance spectra, and high-resolution mass spectra. The structures of compounds VIIb and VIIIc were further determined by ¹H-¹H COSY spectra. Especially the configuration of compound VIIIc was unambiguously confirmed by single-crystal X-ray diffraction. Their pesticidal activities were evaluated against three serious and typically crop-threatening agricultural pests, Tetranychus cinnabarinus Boisduval (spider mite), Mythimna separata Walker (Oriental armyworm), and Plutella xylostella Linnaeus (diamondback moth). Compounds VIIIb and VIIIc exhibited greater than 40-fold more potent acaricidal activity than the lead compound piperine against T. cinnabarinus. Notably, compounds VIa-c exhibited more pronounced oral toxicity against P. xylostella than toosendanin; compounds VIb and VIc displayed more promising growth inhibitory activity against M. separata than toosendanin. It demonstrated that the methylenedioxy and isoxazoline scaffolds were important for the oral toxicity and growth inhibitory activity against P. xylostella and M. separata, respectively; the ethylenedioxy and isoxazoline scaffolds were vital for the acaricidal activity against T. cinnabarinus. Moreover, compounds VIb, VIIf, and VIIIc showed very low toxicity against NRK-52E cells.

Antiproliferative Effects of Alkaloid Evodiamine and Its Derivatives

Alkaloids, a category of natural products with ring structures and nitrogen atoms, include most U.S. Food and Drug Administration approved plant derived anti-cancer agents. Evodiamine is an alkaloid with attractive multitargeting antiproliferative activity. Its high content in the natural source ensures its adequate supply on the market and guarantees further medicinal study. To the best of our knowledge, there is no systematic review about the antiproliferative effects of evodiamine derivatives. Therefore, in this article the review of the antiproliferative activities of evodiamine will be updated. More importantly, the antiproliferative activities of structurally modified new analogues of evodiamine will be summarized for the first time.

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.