BACKGROUND:Sesquiterpene lactones are secondary plant metabolites with a wide variety of biological activities. The process of lactone conjugation to other pharmacophores can increase the efficacy and specificity of the conjugated agent effect on molecular targets in various diseases, including brain pathologies. Derivatives of biogenic indoles, including neurotransmitter serotonin, are of considerable interest as potential pharmacophores. Most of these compounds have neurotropic activity and, therefore, can be used in the synthesis of new drugs with neuroprotective properties.AIM:The aim of this experimental synthesis was to generate potential treatment agents for Alzheimer's disease using serotonin conjugated with natural sesquiterpene lactones.METHODS:Three novel compounds were obtained via the Michael reaction and used for biological testing. The obtained conjugates demonstrated complex neuroprotective activities. Serotonin conjugated to isoalantolactone exhibited strong antioxidant and mitoprotective activities.RESULTS:The agent was also found to inhibit β-site amyloid precursor protein cleaving enzyme 1 (BACE-1), prevent the aggregation of β-amyloid peptide 1-42, and protect SH-SY5Y neuroblastoma cells from neurotoxins such as glutamate and H2O2. In a transgenic animal model of Alzheimer's disease (5xFAD line), the conjugated agent restored declined cognitive functions and improved learning and memory.CONCLUSION:In conclusion, the obtained results indicate that serotonin conjugates to sesquiterpene lactones are promising agents for the treatment of symptoms associated with Alzheimer's disease.

Here, we report the results of an investigation of the neuroprotective effects of securinine with tryptamine conjugate-allomargaritarine (2b), previously selected as the leading compound among a wide range of natural derivatives. 2b was synthesized from securinine using various Lewis acids as catalysts. In addition to the antioxidant and cytoprotective properties previously shown for 2b, in this work, in vitro analysis of the biological activity of the compound demonstrated that this conjugate is also able to influence the primary pathogenetic mechanism of Alzheimer's disease - proteinopathy, modulating the homeostasis of β-amyloid peptide. In particular, it was found that 2b is an effective inhibitor of β-secretase 1 - an enzyme responsible for initiating the generation of pathological forms of β-amyloid peptide, as well as directly preventing the pathological aggregation of Aβ1-42. As a compound with a promising biological activity profile found in vitro, 2b has also demonstrated excellent neuroprotective effects on the in vivo 5xFAD Alzheimer's disease transgenic mice model. Thus, 2b effectively restored cognitive dysfunction: short-term and long-term episodic and spatial memory, which in the post-mortem studies was also accompanied by a decrease in the number of amyloid deposits and the intensity of oxidative stress in brain samples. These results provide an opportunity to draw a line under years of research on the neuroprotective potential of 2b as a viable therapy for Alzheimer's disease.

Background The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) disease (COVID-19) triggers the development of numerous pathologies and infection-linked complications and exacerbates existing pathologies in nearly all body systems. Aside from the primarily targeted respiratory organs, adverse SARS-CoV-2 effects were observed in nervous, cardiovascular, gastrointestinal/metabolic, immune, and other systems in COVID-19 survivors. Long-term effects of this viral infection have been recently observed and represent distressing sequelae recognised by the World Health Organisation (WHO) as a distinct clinical entity defined as post-COVID-19 condition. Considering the pandemic is still ongoing, more time is required to confirm post COVID-19 condition diagnosis in the COVID-19 infected cohorts, although many reported post COVID-19 symptoms overlap with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Aims of Review In this study, COVID-19 clinical presentation and associated post-infection sequelae (post-COVID-19 condition) were reviewed and compared with ME/CFS symptomatology. Key Scientific Concepts of Review The onset, progression, and symptom profile of post COVID-19 condition patients have considerable overlap with ME/CFS. Considering the large scope and range of pro-inflammatory effects of this virus, it is reasonable to expect development of post COVID-19 clinical complications in a proportion of the affected population. There are reports of a later debilitating syndrome onset three months post COVID-19 infection (often described as long-COVID-19), marked by the presence of fatigue, headache, cognitive dysfunction, post-exertional malaise, orthostatic intolerance, and dyspnoea. Acute inflammation, oxidative stress, and increased levels of interleukin-6 (IL-6) and tumor necrosis factor α (TNFα), have been reported in SARS-CoV-2 infected patients. Longitudinal monitoring of post COVID-19 patients is warranted to understand the long-term effects of SARS-CoV-2 infection and the pathomechanism of post COVID-19 condition.

The treatment of central nervous system (CNS) malignancies, including brain cancers, is limited by a number of obstructions, including the blood-brain barrier (BBB), the heterogeneity and high invasiveness of tumors, the inaccessibility of tissues for early diagnosis and effective surgery, and anti-cancer drug resistance. Therapies employing nanomedicine have been shown to facilitate drug penetration across the BBB and maintain biodistribution and accumulation of therapeutic agents at the desired target site. The application of lipid-, polymer-, or metal-based nanocarriers represents an advanced drug delivery system for a growing group of anti-cancer chemicals. The nanocarrier surface is designed to contain an active ligand (cancer cell marker or antibody)-binding structure which can be modified to target specific cancer cells. Glioblastoma, ependymoma, neuroblastoma, medulloblastoma, and primary CNS lymphomas were recently targeted by easily absorbed nanocarriers. The metal- (such as transferrin drug-loaded systems), polymer- (nanocapsules and nanospheres), or lipid- (such as sulfatide-containing nanoliposomes)-based nano-vehicles were loaded with apoptosis- and/or ferroptosis-stimulating agents and demonstrated promising anti-cancer effects. This review aims to discuss effective nanomedicine approaches designed to overcome the current limitations in the therapy of brain cancers and age-dependent neurodegenerative disorders. To accent current obstacles for successful CNS-based cancer therapy, we discuss nanomedicine perspectives and limitations of nanodrug use associated with the specificity of nervous tissue characteristics and the effects nanocarriers have on cognition.

Sesquiterpene lactones (SL) are widely distributed in nature (formed biosynthetically in plants from farnesyl pyrophosphate) and are a structurally diverse class of terpenoids with 15 carbon atoms in the skeleton and, in addition to the lactone cycle, can contain various functional groups. Some of them exhibit biological activity both in a rather wide range and in relation to a specific target. An increase in the number of undescribed natural plant compounds of this class, as well as detection in various plant species, opens up new possibilities for their use for the purposes of medical chemistry, phytochemistry, pharmacognosy, chemotaxonomy, and related fields. Using the example of SL of the eudesmane structural type found in plants of the genus Inula, this review attempts to show the relevance of studies of such compounds that investigate the mechanism of action on various biological models, including the goal of developing new effective antitumor agents.

Alkaloids, secondary plant metabolites, are used in traditional medicine in many countries to treat various pathological conditions. Securinine, a unique indolizidine alkaloid combining four cycles, "6-azobicyclo[3.2.1]octane" as a key structure fused with α,β-unsaturated-γ-lactone and piperidine ring, has a broad spectrum of actions including anti-inflammatory, antibacterial, neuroprotective and antitumor, and has been previously used in medical practice. It has several reactive centers, which are double bonds at positions 12-13 and 14-15, and this is a challenging scaffold for the synthesis of biologically active compounds. In this review, works on the production of modified securinine derivatives and their biological activity are addressed. Both monovalent and bivalent derivatives that are most promising in our opinion, and have potential for further research, are considered.

Sesquiterpene lactones (SL) are widely distributed in nature (formed biosynthetically in plants from farnesyl pyrophosphate) and are a structurally diverse class of terpenoids with 15 carbon atoms in the skeleton and, in addition to the lactone cycle, can contain various functional groups. Some of them exhibit biological activity both in a rather wide range and in relation to a specific target. An increase in the number of undescribed natural plant compounds of this class, as well as detection in various plant species, opens up new possibilities for their use for the purposes of medical chemistry, phytochemistry, pharmacognosy, chemotaxonomy, and related fields. Using the example of SL of the eudesmane structural type found in plants of the genus Inula, this review attempts to show the relevance of studies of such compounds that investigate the mechanism of action on various biological models, including the goal of developing new effective antitumor agents.

Inflammatory gastrointestinal (GI) diseases and malignancies are associated with growing morbidity and cancer-related mortality worldwide. GI tumor and inflammatory cells contain activated sphingolipid-metabolizing enzymes, including sphingosine kinase 1 (SphK1) and SphK2, that generate sphingosine-1-phosphate (S1P), a highly bioactive compound. Many inflammatory responses, including lymphocyte trafficking, are directed by circulatory S1P, present in high concentrations in both the plasma and the lymph of cancer patients. High fat and sugar diet, disbalanced intestinal flora, and obesity have recently been linked to activation of inflammation and SphK/S1P/S1P receptor (S1PR) signaling in various GI pathologies, including cancer. SphK1 overexpression and activation facilitate and enhance the development and progression of esophageal, gastric, and colon cancers. SphK/S1P axis, a mediator of inflammation in the tumor microenvironment, has recently been defined as a target for the treatment of GI disease states, including inflammatory bowel disease and colitis. Several SphK1 inhibitors and S1PR antagonists have been developed as novel anti-inflammatory and anticancer agents. In this review, we analyze the mechanisms of SphK/S1P signaling in GI tissues and critically appraise recent studies on the role of SphK/S1P/S1PR in inflammatory GI disorders and cancers. The potential role of SphK/S1PR inhibitors in the prevention and treatment of inflammation-mediated GI diseases, including GI cancer, is also evaluated.

New conjugates of daunorubicin with sesquiterpene lactones at the 3 '-amino group of anthracycline were synthesized and their effect on the viability of cell lines (HL60, Jurkat, K562, and A549) was assessed using a resazurin test. The effect on the cell cycle and apoptosis by flow cytometry was studied. The following natural lactones were used for modification: telekin, isotelekin, reynosin, costunolide, dehydrocostuslactone, santamarine and epoxyisoalantolactone. The synthesized conjugates are characterized by a general high toxicity (8 horizontal ellipsis 0.14 mu M) in relation to tumor cell lines (in some cases, higher than the toxicity of the initial antibiotic), as well as a comparable effect on the cell cycle (arrest in the G2/M-phase) with a relatively low the effect on the initiation of apoptosis at concentrations close to the IC50.

— The reaction of DL-valine hydroxamic acid with triacetonamine proceeds as the N , N '-regioselective condensation to form (±)-1-hydroxy-3-isopropyl-7,7,9,9-tetramethyl-1,4,8-triazaspiro[4,5]decan-2-one. A study of the antimetastatic and antitumor activities of the resulting hydroxamic acid in vivo by the combined therapy with a cytostatic of the alkylation type on a model of experimental transplanted mouse melanoma B16 showed that the compound is capable of increasing the sensitivity of the tumor to the known antitumor drug cyclophosphamide applied at a subtherapeutic dose. The chemosensitizing activity of hydroxamic acid combined with cyclophosphamide led to an almost twofold increase in the antitumor effect of the cytostatic and a marked decrease in the number of metastases, which showed up as an increase in the metastasis inhibition index (MII) to 74%.

Hydroxamic acids are one of the most promising and actively studied classes of chemical compounds in medicinal chemistry. In this study, we describe the directed synthesis and effects of HDAC6 inhibitors. Fragments of adamantane and natural terpenes camphane and fenchane, combined with linkers of various nature with an amide group, were used as the CAP groups. Accordingly, 11 original target compounds were developed, synthesized, and exposed to in vitro and in vivo biological evaluations, including in silico methods. In silico studies showed that all synthesized compounds were drug-like and could penetrate through the blood–brain barrier. According to the in vitro testing, hydroxamic acids 15 and 25, which effectively inhibited HDAC6 and exhibited anti-aggregation properties against β-amyloid peptides, were chosen as the most promising substances to study their neuroprotective activities in vivo. All in vivo studies were performed using 5xFAD transgenic mice simulating Alzheimer’s disease. In these animals, the Novel Object Recognition and Morris Water Maze Test showed that the formation of hippocampus-dependent long-term episodic and spatial memory was deteriorated. Hydroxamic acid 15 restored normal memory functions to the level observed in control wild-type animals. Notably, this effect was precisely associated with the ability to restore lost cognitive functions, but not with the effect on motor and exploratory activities or on the level of anxiety in animals. Conclusively, hydroxamic acid 15 containing an adamantane fragment linked by an amide bond to a hydrocarbon linker is a possible potential multitarget agent against Alzheimer’s disease.

Anthracycline antitumor antibiotics are one of the promising classes of chemotherapeutic agents for cancer treatment. The main deterrent to their use is high toxicity to a healthy environment, including cumulative cardiotoxicity. In our work, bipharmacophore molecules containing in their structure a fragment of the known anthracycline antibiotics daunorubicin and doxorubicin and natural sesquiterpene lactones were obtained for the first time. When studying the biological activity of the synthesized compounds, it was found that with equal and, in some cases, higher cytotoxicity and glycolysis inhibition by anthracycline antibiotics conjugates with sesquiterpene lactones in comparison with doxo- and daunorubicin, a reduced damaging effect on the functioning of rat heart mitochondria was observed. The results obtained allow us to confirm the assumption that the chemical modification of the anthracycline antibiotics molecules doxo- and daunorubicin by natural sesquiterpene lactones can be a promising strategy for creating potential antitumor chemotherapeutic drugs with a pronounced cytotoxic effect on tumor cells and a reduced damaging effect on healthy cells of the human organism.

The use of nanoparticles dramatically increases the safety and efficacy of the most common anticancer drugs. The main advantages of nano-drugs and delivery systems based on nano-technology are effective targeting, delayed release, increased half-life, and less systemic toxicity. The use of nano-carriers has led to significant improvements in drug delivery to targets compared with traditional administration of these drugs. In this review, the main tendencies in nano-drug formulations as well as factors limiting their use in clinical settings are discussed. Additionally, the current status of approved nano-drugs for cancer treatment is reviewed.

Derivatives of sesquiterpene lactones modified at the lactone ring with a thiophenol residue have been synthesized. The resulting conjugates with thiophenol have capacity for the oxidation–elimination reaction by the action of ROS of a tumor cell with the release of initial cytotoxic lactones. It has been proposed to use the resulting sulfur-containing conjugates as ROS-activated prodrugs of sesquiterpene lactones. The antiproliferative properties of the conjugates have been examined on tumor and pseudonormal cell lines. The cytotoxicity of the conjugates is lower than that of parent lactones; however, in some cases, as with the conjugates of alantolactone with artemisiten, it remains moderate in all tumor cell lines tested.