Motility of Acinetobacter baumannii: regulatory systems and controlling strategies

Acinetobacter baumannii is a Gram-negative opportunistic zoonotic pathogenic bacterium that causes nosocomial infections ranging from minor to life-threatening. The clinical importance of this zoonotic pathogen is rapidly increasing due to the development of multiple resistance mechanisms and the synthesis of numerous virulence factors. Although no flagellum-mediated motility exists, it may move through twitching or surface-associated motility. Twitching motility is a coordinated multicellular movement caused by the extension, attachment, and retraction of type IV pili, which are involved in surface adherence and biofilm formation. Surface-associated motility is a kind of movement that does not need appendages and is most likely driven by the release of extra polymeric molecules. This kind of motility is linked to the production of 1,3-diaminopropane, lipooligosaccharide formation, natural competence, and efflux pump proteins. Since A. baumannii's virulence qualities are directly tied to motility, it is possible that its motility may be used as a specialized preventative or therapeutic measure. The current review detailed the signaling mechanism and involvement of various proteins in controlling A. baumannii motility. As a result, we have thoroughly addressed the role of natural and synthetic compounds that impede A. baumannii motility, as well as the underlying action mechanisms. Understanding the regulatory mechanisms behind A. baumannii's motility features will aid in the development of therapeutic drugs to control its infection. KEY POINTS: • Acinetobacter baumannii exhibits multiple resistance mechanisms. • A. baumannii can move owing to twitching and surface-associated motility. • Natural and synthetic compounds can attenuate A. baumannii motility.

Tubulin inhibitors. Selected scaffolds and main trends in the design of novel anticancer and antiparasitic agents

Design of tubulin inhibitors as anticancer drugs dynamically developed over the past 20 years. The modern arsenal of potential tubulin-targeting anticancer agents is represented by small molecules, monoclonal antibodies, and antibody-drug conjugates. Moreover, targeting tubulin has been a successful strategy in the development of antiparasitic drugs. In the present review, an overall picture of the research and development of potential tubulin-targeting agents using small molecules between 2018 and 2023 is provided. The data about some most often used and prospective chemotypes of small molecules (privileged heterocycles, moieties of natural molecules) and synthetic methodologies (analogue-based, fragment-based drug design, molecular hybridization) applied for the design of novel agents with an impact on the tubulin system are summarized. The design and prospects of multi-target agents with an impact on the tubulin system were also highlighted. Reported in the review data contribute to the "structure-activity" profile of tubulin-targeting small molecules as anticancer and antiparasitic agents and will be useful for the application by medicinal chemists in further exploration, design, improvement, and optimization of this class of molecules.

Engineering natural molecule-triggered genetic control systems for tunable gene- and cell-based therapies

The ability to precisely control activities of engineered designer cells provides a novel strategy for modern precision medicine. Dynamically adjustable gene- and cell-based precision therapies are recognized as next generation medicines. However, the translation of these controllable therapeutics into clinical practice is severely hampered by the lack of safe and highly specific genetic switches controlled by triggers that are nontoxic and side-effect free. Recently, natural products derived from plants have been extensively explored as trigger molecules to control genetic switches and synthetic gene networks for multiple applications. These controlled genetic switches could be further introduced into mammalian cells to obtain synthetic designer cells for adjustable and fine tunable cell-based precision therapy. In this review, we introduce various available natural molecules that were engineered to control genetic switches for controllable transgene expression, complex logic computation, and therapeutic drug delivery to achieve precision therapy. We also discuss current challenges and prospects in translating these natural molecule-controlled genetic switches developed for biomedical applications from the laboratory to the clinic.

Therapeutic potential of natural molecules against Alzheimer's disease via SIRT1 modulation

Alzheimer's disease (AD) is a neurodegenerative disease mainly characterized by progressive cognitive dysfunction and memory impairment. Recent studies have shown that regulating silent information regulator 1 (SIRT1) expression has a significant neuroprotective effect, and SIRT1 may become a new therapeutic target for AD. Natural molecules are an important source of drug development for use in AD therapy and may regulate a wide range of biological events by regulating SIRT1 as well as other SIRT1-mediated signaling pathways. This review aims to summarize the correlation between SIRT1 and AD and to identify in vivo and in vitro studies investigating the anti-AD properties of natural molecules as modulators of SIRT1 and SIRT1-mediated signaling pathways. A literature search was conducted for studies published between January 2000 and October 2022 using various literature databases, including Web of Science, PubMed, Google Scholar, Science Direct, and EMBASE. Natural molecules, such as resveratrol, quercetin, icariin, bisdemethoxycurcumin, dihydromyricetin, salidroside, patchouli, sesamin, rhein, ligustilide, tetramethoxyflavanone, 1-theanine, schisandrin, curcumin, betaine, pterostilbene, ampelopsin, schisanhenol, and eriodictyol, have the potential to modulate SIRT1 and SIRT1 signaling pathways, thereby combating AD. The natural molecules modulating SIRT1 discussed in this review provide a potentially novel multi-mechanistic therapeutic strategy for AD. However, future clinical trials need to be conducted to further investigate their beneficial properties and to determine the safety and efficacy of SIRT1 natural activators against AD.

Validating methods for testing natural molecules on molecular pathways of interest in silico and in vitro

Differentially expressed genes can serve as drug targets and are used to predict drug response and disease progression. In silico drug analysis based on the expression of these genetic biomarkers allows the detection of putative therapeutic agents, which could be used to reverse a pathological gene expression signature. Indeed, a set of bioinformatics tools can increase the accuracy of drug discovery, helping in biomarker identification. Once a drug target is identified, in vitro cell line models of disease are used to evaluate and validate the therapeutic potential of putative drugs and novel natural molecules. This study describes the development of efficacious PCR primers that can be used to identify gene expression of specific genetic pathways, which can lead to the identification of natural molecules as therapeutic agents in specific molecular pathways. For this study, genes involved in health conditions and processes were considered. In particular, the expression of genes involved in obesity, xenobiotics metabolism, endocannabinoid pathway, leukotriene B4 metabolism and signaling, inflammation, endocytosis, hypoxia, lifespan, and neurotrophins were evaluated. Exploiting the expression of specific genes in different cell lines can be useful in in vitro to evaluate the therapeutic effects of small natural molecules.

Natural products modulating interleukins and other inflammatory mediators in tumor-bearing animals: A systematic review

BACKGROUND

Cancer is a group of diseases characterized by abnormal cell growth and proliferation. Natural products are a potentially important source for bioactive phytochemicals in the management of cancer, which regulate a broad range of biological events via the modulation of interleukins (ILs), pro- and anti-inflammatory modulators, and other cancer hallmark-mediated signaling pathways.

PURPOSE

To systematically review the literature to identify in vivo studies investigating the anticancer properties of medicinal plants and natural molecules as modulators of ILs and their related pro- and anti-inflammatory signaling markers in tumor-bearing animals.

METHODS

Articles published in English were searched, without any constraint in respect of countries. The electronic databases PubMed, Embase, Scopus, and Web of Science were used for the literature search for studies published between January 2010 and January 2022. The search terms used included medicinal plants, anticancer, antineoplasic agent, ILs, cytokine, and their combinations. A manual search to detect any articles not found in the databases was also made. The identified studies were then critically reviewed and relevant data were extracted and summarized.

RESULTS

Natural products were found to modulate ILs, including IL-1β, IL-2, IL-4, IL-6, IL-8, IL-18, IL-23, and IL-12, and interferon gamma; increase tissue inhibitor metalloprotease; decrease vascular endothelial growth factor, tumor necrosis factor alpha, granulocyte macrophage colony-stimulating factor, and nuclear factor kappa B; augment immunity by increasing the major histocompatibility complexes II and CD4+, cluster of differentiation 8 + T cell and class II trans-activator expression; and heighten the action of antioxidant enzymes, which are involved in the detoxification of free radicals and reactive oxygen species.

CONCLUSION

Natural products discussed in this review show great potential to regulate ILs and weaken associated pro- and anti-inflammatory signaling markers in tumor-bearing animals. Flavonoids, polyphenols, polysaccharides, alkaloids and tannins are important phytochemicals in the modulation of ILs, especially pro-inflammatory ones. However, in terms of future research, the importance of clinical trials to investigate their beneficial properties should be warranted.

From Achille Bertelli onward: more than 100 years of research and production of dietary supplements based on natural molecules typical of the Mediterranean diet

Achille Bertelli was an aeronautics pioneer and an innovative entrepreneur of the pharmaceutical industry. After graduating in Chemistry in Italy, he moved to the United States of America where he opened a chemical-pharmaceutical laboratory in San Francisco in 1879, and later moved back to Italy where he opened a chemical and pharmaceutical industry in Milan (1886). The "A. Bertelli" pharmaceutical company developed the famous cough pills "Catramina Bertelli", as well as new cosmetics and perfumes. Apart from his chemical experience, Achille Bertelli was a passionate aeronautics expert. He wrote many essays on this topic and devoted himself to aeronautical experiments by designing the apparatus "Autovol", "Aerocurvo", "Autovol no. 2", "Autovol no. 3", and "Aerostave", which are considered the prototypes of the helicopter. Achille Bertelli was also the president of the Electric Company of Salò, which installed an electrical system that served the lighting in many cities on Lake Garda (Italy). Finally, Achille Bertelli also participated in the Italian revival after the First World War, especially by supporting the agricultural revival. Throughout his life, Achille Bertelli teamed with several famous people from all over Italy, such as Gabriele D'Annunzio, Cesare Lombroso and Cordero di Montezemolo. Today, Achille Bertelli's interest for natural molecules, his ideas, and his entrepreneurial approach are carried forward by his descendant, Matteo Bertelli.

Natural compounds in the regulation of proteostatic pathways: An invincible artillery against stress, ageing, and diseases

Cells have different sets of molecules for performing an array of physiological functions. Nucleic acids have stored and carried the information throughout evolution, whereas proteins have been attributed to performing most of the cellular functions. To perform these functions, proteins need to have a unique conformation and a definite lifespan. These attributes are achieved by a highly coordinated protein quality control (PQC) system comprising chaperones to fold the proteins in a proper three-dimensional structure, ubiquitin-proteasome system for selective degradation of proteins, and autophagy for bulk clearance of cell debris. Many kinds of stresses and perturbations may lead to the weakening of these protective cellular machinery, leading to the unfolding and aggregation of cellular proteins and the occurrence of numerous pathological conditions. However, modulating the expression and functional efficiency of molecular chaperones, E3 ubiquitin ligases, and autophagic proteins may diminish cellular proteotoxic load and mitigate various pathological effects. Natural medicine and small molecule-based therapies have been well-documented for their effectiveness in modulating these pathways and reestablishing the lost proteostasis inside the cells to combat disease conditions. The present article summarizes various similar reports and highlights the importance of the molecules obtained from natural sources in disease therapeutics.

Medicinal plants and natural molecules with in vitro and in vivo activity against rotavirus: A systematic review

BACKGROUND

Rotaviruses can cause life-threatening health disorders, such as severe dehydrating gastroenteritis and diarrhea in children. Vaccination is the main preventive strategy to reduce rotavirus diarrhea and the severity of episodes, but vaccines are not fully effective and new episodes may occur, even in vaccinated children. The WHO recommends oral rehydration therapy and zinc supplementation for rotavirus-induced diarrhea management. There is little preclinical evidence to support the use of phytotherapeutics in the management of rotaviral infections.

PURPOSE

We aim to review the use of medicinal plants and natural molecules in the management of rotavirus infections in experimental studies.

METHODS

Articles, published in the English language between 1991 and 2016, were retrieved from PubMed, Scopus and Web of Science using relevant keywords. The scientific literature mainly focusing on plant natural products with therapeutic efficacies against experimental models of rotavirus, were identified and tabulated. In addition, an assessment of the reliability of animal experiments was determined under ``Risk of Bias'' criteria.

CHAPTERS

After an initial search and a revision of the inclusion criteria, 41 reports satisfied the objectives of the study. 36 articles were found concerning the anti-rotaviral potential in rotavirus infected cell lines. Among the active secondary metabolites screened for rotavirus inhibition, the polyphenols of flavonoid structure had acquired the highest number of studies in our survey, compared to phenolic acids, stilbenoids, tannins, pectins, terpenoids and flavonoid glycosides. Also, many phytochemicals reduced the efficacy of viral capsid proteins foremost to their elimination and improved the tendency of host-cell inhibiting virus absorption or by prevention of viral replication. Furthermore, five in vivo studies reported that herbs, as well its components, reduced the duration and severity of diarrhea in mice and piglets. The anti-rotavirus efficacy were highlighted based on improvements in reduction on liquid stool, fecal virus shedding, small intestinal histology, levels of inflammation related cytokines and signaling receptors. However, the quality of the experiments in animal studies contained certain types of bias in terms of how they were conducted and reported.

CONCLUSION

We identified and summarized studies on medicinal plants and natural molecules having anti-rotavirus activity in order to further future developments of cures for rotavirus gastroenteritis.

In silico approaches and proportional odds model towards identifying selective ADAM17 inhibitors from anti-inflammatory natural molecules

ADAM metallopeptidase domain 17 (ADAM17) is an attractive target for the development of new anti-inflammatory drugs. We aimed to identify selective inhibitors of ADAM17 against matrix metalloproteinase enzymes (MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-13, and MMP-16) which have substantial structural similarity. Target proteins were docked with 29 anti-inflammatory natural molecule ligands and a known selective inhibitor IK682. The ligands were screened based on Lipinski rules, interaction with the ADAM17 active site cavity, and then ranked using the proportional odds model multinomial logistic regression. Silymarin was the most selective inhibitor of ADAM17 exhibiting H-bonding with Glu 406, Gly 349, Glu 398, Asn 447, Tyr 433, and Lys 432. Molecular dynamics simulations were carried out for 10ns. The root mean square deviation (RMSD), root mean squared fluctuations (RMSF), radius of gyration (Rg), solvent accessible surface area (SASA), and H-bonding indicated the induced metastability. A comparison of the principal component analysis revealed that the silymarin complex also explored lesser region compared to IK682 complex. A control study on ADAM17 protein (2OI0) is included. These observations present silymarin (widely present in plants such as milk thistle (Silybum maianum), wild artichokes (Cynara cardunculus), turmeric (Curcuma longa) roots, coriander (Coriandrum sativum) seeds, etc.) as a promising natural template for development of ADAM17 selective drugs.

Complementary and alternative medications in hepatitis C infection

Chronic hepatitis C (CHC) infection affects almost 3% of the global population and can lead to cirrhosis, liver failure, and hepatocellular carcinoma in a significant number of those infected. Until recently, the only treatments available were pegylated interferon and ribavirin, which traditionally were not very effective and have considerable side effects. For this reason, interest in complementary and alternative medications (CAM) in the management of hepatitis C has been investigated. Some CAM has demonstrated therapeutic potential in chronic hepatitis C treatment. Unfortunately, some CAM has been shown to have the potential to cause drug-induced liver injury. This article will review and evaluate many of the natural molecules that interact with the hepatitis C virus (HCV) life cycle and discuss their potential use and safety in HCV therapy, as well as highlight some important interactions between medical and complementary treatments.