Design, synthesis and biological evaluation of gentiopicroside derivatives as potential antiviral inhibitors

Modification of iridoids in focus: Bridging structural complexity with biological innovation

Iridoids, a class of oxygenated monoterpene compounds with a methylcyclopentan-[c]-pyran skeletal, widely exist in plants and microorganisms. Iridoids are mainly classified into cyclopentane iridoids and secoiridoids. The unique structure makes it exhibit varieties of biological activities, such as neuroprotective, anti-tumor, anti-viral, anti-oxidant and anti-inflammatory effects. In order to take a deep dive into the structural properties of iridoid derivatives, as well as to facilitate the development of them, we recapitulate the modification strategies of representative iridoids and biological activities of iridoid derivatives, especially discuss their structure-activity relationship in this review. This article will provide the latest overview and offer insights for structural modification of iridoids in future.

Discovery of novel oleanolic acid glycoside derivatives targeting PTP1B/PI3K/AKT signaling pathway for the treatment of breast cancer

Protein tyrosine phosphatase 1B (PTP1B) has been identified as a key drug target for anti-tumor drug development. Oleanolic acid (OA) has been proved to be an inhibitor of PTP1B, but its poor water solubility, low bioavailability and poor activity in vivo limit its clinical efficacy. In this study, a total of 47 new OA derivatives including heteroatom derivatives, ester derivatives, amino substitution derivatives and Schiff base derivatives were designed and synthesized. Among them, OA-Br-1 had stronger inhibition and selectivity on PTP1B than OA, with IC50 value of 7.08 ± 5.05 μM for PTP1B and 222.28 ± 0.11 μM for TCPTP. In addition, OA-Br-1 significantly inhibited the proliferation and induced apoptosis of breast cancer cells, and in vivo nude mice experiments also showed that OA-Br-1 could inhibit the growth of breast tumors. Then network pharmacology was used to predict the targets of OA-Br-1, and the PPI network map between compound - breast cancer - target was constructed. The results showed that the probability value of PTPN1 ranked first among all predicted targets, which was consistent with the results of enzyme activity experiments in vitro. The enrichment results of KEGG pathway and GO functional annotation analysis showed that the effect of OA-Br-1 on breast cancer was significantly correlated with the PI3K/AKT pathway. Subsequent Western Blot results also proved that OA-Br-1 could significantly inhibit the expression of PTP1B, p-PI3K and p-AKT, indicating that OA-Br-1 played an anti-breast cancer role through the PTP1B/PI3K/AKT signaling pathway. Collectively, these findings identify OA-Br-1 as a promising PTP1B inhibitor for breast cancer treatment.

Natural Product-Derived Phytochemicals for Influenza A Virus (H1N1) Prevention and Treatment

Influenza A (H1N1) viruses are prone to antigenic mutations and are more variable than other influenza viruses. Therefore, they have caused continuous harm to human public health since the pandemic in 2009 and in recent times. Influenza A (H1N1) can be prevented and treated in various ways, such as direct inhibition of the virus and regulation of human immunity. Among antiviral drugs, the use of natural products in treating influenza has a long history, and natural medicine has been widely considered the focus of development programs for new, safe anti-influenza drugs. In this paper, we focus on influenza A (H1N1) and summarize the natural product-derived phytochemicals for influenza A virus (H1N1) prevention and treatment, including marine natural products, flavonoids, alkaloids, terpenoids and their derivatives, phenols and their derivatives, polysaccharides, and derivatives of natural products for prevention and treatment of influenza A (H1N1) virus. We further discuss the toxicity and antiviral mechanism against influenza A (H1N1) as well as the druggability of natural products. We hope that this review will facilitate the study of the role of natural products against influenza A (H1N1) activity and provide a promising alternative for further anti-influenza A drug development.

Recent developments on the synthesis of biologically active glycohybrids

The exploration of hybridization emerges as a potent tool in advancing drug discovery research, with a significant emphasis on carbohydrate-containing hybrid scaffolds. Evidence indicates that linking carbohydrate molecules to privileged bioactive scaffolds enhances the bioactivity of drug molecules. This synergy results in a diverse range of activities, making carbohydrate scaffolds pivotal for synthesizing compound libraries with significant functional and structural diversity. Beyond their synthesis utility, these scaffolds offer applications in screening bioactive molecules, presenting alternative avenues for drug development. This comprehensive review spanning 2015 to 2023 focuses on synthesized glycohybrid molecules, revealing their bioactivity in areas such as anti-microbial, anti-cancer, anti-diabetic, anti-inflammatory activities, enzyme inhibition and pesticides. Numerous novel glycohybrids surpass positive control drugs in biological activity. This focused study not only highlights the diverse bioactivities of glycohybrids but also underscores their promising role in innovative drug development strategies.

Regulatory mechanisms of Gentiopicroside on human diseases: a brief review

Gentiopicroside (GPS), a single compound isolated from Gentiana lutea L. and the crucial representative of secoiridoid constituent, has been permitted for centuries in traditional Chinese medicine. GPS and its metabolites have been increasingly used in the search for clinical management with therapeutic properties and fewer side effects. The objective of this review was to provide a comprehensive overview of the involvement of molecular pathways in the therapeutic effects of GPS on human diseases and chronic conditions. This study presents a meticulously conducted comprehensive search of the PubMed and Google Scholar databases (from 1983 to 2023), aimed at identifying articles relating to regulatory mechanisms of GPS on human diseases and the pharmacokinetics of GPS. The inclusion criteria were meticulously and precisely defined to encompass original research papers that explicitly focused on elucidating the regulatory mechanisms of GPS in various human diseases through in vitro and animal studies. Notably, these studies were mandated to integrate specific genetic markers or pathways as essential components of their research inquiries. The evaluated pharmacokinetic parameters included maximum plasma concentration (Cmax), time to reach maximum plasma concentration (Tmax), area under the curve (AUC), clearance, and plasma half-life (t1/2). Subsequently, through a rigorous screening process of titles and abstracts, studies conducted in vitro or on animals, as well as those reporting pharmacokinetic data related to drugs other than GPS or language barriers, were systematically excluded. Drawing from the data and studies pertaining to this review, we conducted a thorough and informative analysis of the pharmacological characteristics and biological functions of GPS. These encompassed a wide range of effects, including hepatoprotective, anti-inflammatory, antifibrotic, antioxidant, analgesic, antitumor, and immunomodulatory properties. The analysis provided a comprehensive and insightful understanding of GPS's pharmacological profile and its diverse activities. Enhancing theoretical and experimental methodologies could prove advantageous in expanding the clinical applications of GPS. This could involve optimizing the bioavailability and pharmacokinetics of GPS, uncovering additional biomarkers and potential biotransformation pathways, and investigating its combined effects with standard-of-care medications.

Gentiopicroside-An Insight into Its Pharmacological Significance and Future Perspectives

Gentiopicroside (GPS) is a leading component of several plant species from the Gentianaceae botanical family. As a compound with plenty of biological activities and a component of herbal drugs, GPS has an important role in the regulation of physiological processes in humans. The results of recently published scientific studies underline a meaningful role of this molecule as an active factor in metabolic pathways and mechanisms, which may have an influence in the treatment of different diseases, including digestive tract disorders, malignant changes, neurological disorders, microbial infections, bone formation disorders, inflammatory conditions, and others. This review aims to collect previously published reports on the biological properties of GPS as a single compound that were confirmed by in vitro and in vivo studies, and to draw attention to the newly discovered role of this bitter-tasting secoiridoid. Thanks to these properties, the research on this substance could be revisited.

Research progress on hydroxyl protection of iridoid glycosides

Iridoids, an important active ingredient, are widely distributed in varieties of Chinese herbal medicines and have varieties of pharmacological activities, such as anti-tumor, hypoglycemic, anti-inflammatory and so on, most of which exist in the form of glycosides in nature. However, its clinical application is limited by poor lipid solubility, low bioavailability and short half-life. It is necessary to optimize the structure of iridoids. It is hard to modify the hydroxyl groups at specific sites because iridoid glycosides are polyhydroxy compounds and very complex. In this paper, the words of ‘Iridoid glycosides’ and ‘Hydroxyl protection’ were used as the keywords, more than 200 articles from 1965 to 2021 were obtained from databases, such as CNKI, PubMed, Scifinder and so on. Finally, 60 articles were selected to summarize the hydroxyl protection of iridoid glycosides, which will provide a theoretical basis for their structural modification and stimulate their application potential in the field of drug research and development.

Gentiopicroside prevents alcoholic liver damage by improving mitochondrial dysfunction in the rat model

Gentianae Radix et Rhizoma is a medical plant that is widely cultivated in China, North Korea, Japan, and Russia, and gentiopicroside is one of its major active compounds. In this study, the hepatoprotective activity of gentiopicroside on rats with alcoholic liver damage (ALD) was evaluated using the transaminase and blood lipid levels and antioxidant capacity. The potential mechanism of hepatoprotective effect of gentiopicroside was evaluated by mitochondrial function detection, gas chromatography-mass spectrometry (GC-MS) metabolomic analysis, and anti-apoptosis analysis. Results showed that the gentiopicroside exhibited good hepatoprotective activity on rats with ALD by decreasing the transaminase levels, regulating the blood lipid levels, and increasing the antioxidant capacity. The potential mechanisms were related to regulating mitochondrial dysfunction by recovering mitochondrial membrane potential level, adenosine triphosphate concentration, activities of key enzymes in tricarboxylic acid cycle, and activities of complex I-V, regulating micromolecular metabolism and anti-apoptosis. These findings supported the further exploration of Gentianae Radix et Rhizoma as effective phytotherapy to prevent and treat ALD.

Screening and isolation of potential neuraminidase inhibitors from leaves of Ligustrum lucidum Ait. based on ultrafiltration, LC/MS, and online extraction-separation methods

Ultrafiltration liquid chromatography-mass spectrometry (ultrafiltration LC/MS) is introduced as an efficient method that can be applied to rapidly screen and identify ligands from the leaves of Ligustrum lucidum Ait. Using this method, we identified 13 compounds, including organic acids, flavonoids, and glycosides, as potent neuraminidase inhibitors. A continuous online method, employing pressurized liquid extraction followed by parallel centrifugal partition chromatography and preparative liquid chromatography PLE-(parallel-CPC/PLC), was developed for the efficient, scaled-up production of 12 compounds with high purities. The bioactivities of the separated compounds were assessed by an in vitro enzyme inhibition assay. The use of ultrafiltration LC/MS combined with PLE-(parallel-CPC/PLC), and an in vitro enzyme inhibition assay facilitated the efficient screening and isolation of neuraminidase inhibitors from complex samples, and could serve as an important platform for the large-scale production of functional ingredients.

Design, synthesis and biological evaluation of water-soluble per-O-methylated cyclodextrin-C60 conjugates as anti-influenza virus agents

The most common fullerene member C₆₀ displays many biological applications, such as, anticancer, human immunodeficiency virus and hepatitis C virus inhibitors, O₂ uptake inhibitor and vectors for drug and DNA. Nevertheless, the innate hydrophobicity of C₆₀ constrains its further development. We introduced cyclodextrins to enhance the water-solubility of C₆₀. Nine cyclodextrin-C₆₀ conjugates, including seven α-cyclodextrin-C₆₀ conjugates and two γ-cyclodextrin-C₆₀ conjugates, were designed and synthesized. All of these conjugates did not show obvious cytotoxicity. The anti-influenza virus activity of nine conjugates was assessed. Two γ-cyclodextrin-C₆₀ conjugates, which were relatively more water-soluble, exerted higher inhibition with IC₅₀ values of 87.73 μM and 75.06 μM, respectively, than seven α-cyclodextrin-C₆₀ conjugates.

Preparation of Substituted 2H-Pyrans via a Cascade Reaction from Methyl Coumalate and Activated Methylene Nucleophiles

The reaction of methyl coumalate with a wide range of methylene active compounds, such as keto-esters or keto-sulfones and cyclic or acyclic diketones, afforded more than 30 2,3,5,6-tetrasubstituted 2H-pyrans. The reaction proceeds via a cascade reaction involving a Michael addition-6π-electrocyclic ring opening-proton transfer and 6π electrocyclization, in which a variety of functional groups were tolerated.

Drug design based on pentaerythritol tetranitrate reductase: synthesis and antibacterial activity of Pogostone derivatives

We performed molecular docking studies of Pogostone with PETNR and analyzed structure–activity relationships, which guided the structure design and the subsequent facile organocatalytic synthesis of Pogostone derivatives.