Design, synthesis, and biological evaluation of hederagenin derivatives with improved aqueous solubility and tumor resistance reversal activity

Discovery and biological evaluation of hederagenin derivatives as non-substrate inhibitors of P-glycoprotein-mediated multidrug resistance

Multidrug Resistance (MDR) is an essential cause of failure of tumor chemotherapy, and P-glycoprotein (P-gp) overexpression is one of the major causes of MDR in tumor cells. Hederagenin (HRG) derivatives showed significant inhibitory effects in P-gp-mediated tumor MDR. Herein, we designed and synthesized 30 HRG derivatives and evaluated these compounds' tumor MDR reversal ability. For the first time, we identified a potential P-gp non-substrate inhibitor of the HRG derivatives 15, which binds to non-substrate active sites in transmembrane structural domains (TMDs) with high binding affinity. Subsequent assays confirmed that 15 exerted significant tumor MDR reversal activity by binding to P-gp and inhibiting P-gp function rather than affecting its expression. It could not be pumped out of the cell by P-gp. In addition, 15 inhibited Rhodamine123 efflux, rendered the KBV cells sensitive to paclitaxel (Ptx), blocked the cells in the G2/M phase, and induced apoptosis. Notably, 15 increased Ptx sensitivity in vivo, significantly inhibited the growth of KBV cell-derived xenograft tumors in nude mice, with a tumor suppression rate as high as 63.71 %.

Current Progress of Hederagenin and Its Derivatives for Disease Therapy (2017-Present)

Natural products have emerged as crucial sources of biologically active compounds, holding promise for applications in drug development. Among the extensively researched pentacyclic triterpenes, hederagenin (HG) stands out for its diverse biological activities and serves as a valuable scaffold for synthesizing novel derivatives. These derivatives hold significant promise for the development of novel therapeutic agents aimed at treating a wide range of diseases. Over the past years, a multitude of HG derivatives with varied bioactivities have been synthesized through chemical modifications. This review article consolidates the most recent findings (since 2017) on HG derivatives, emphasizing their biological effects and mechanisms of action in both in vitro and in vivo models. The objective of this compilation is to offer insights and direct future research endeavors in the realm of HG.

Innovative medicinal chemistry strategies for enhancing drug solubility

Drug candidates with poor solubility have been recognized as the cause of many drug development failures, owing to the fact that low solubility is unfavorable for physicochemical, pharmacokinetic (PK) and pharmacodynamic (PD) properties. Given the imperative role of solubility during drug development, we herein summarize various strategies for solubility optimizations from a medicinal chemistry perspective, including introduction of polar group, salt formation, structural simplification, disruption of molecular planarity and symmetry, optimizations on the solvent exposed region as well as prodrug design. In addition, methods for solubility assessment and prediction are reviewed. Besides, we have deeply discussed the strategies for solubility improvement. This paper is expected to be beneficial for the development of drug-like molecules with good solubility.

An updated review of the pharmacological effects and potential mechanisms of hederagenin and its derivatives

Hederagenin (HG) is a natural pentacyclic triterpenoid that can be isolated from various medicinal herbs. By modifying the structure of HG, multiple derivatives with superior biological activities and safety profiles have been designed and synthesized. Accumulating evidence has demonstrated that HG and its derivatives display multiple pharmacological activities against cancers, inflammatory diseases, infectious diseases, metabolic diseases, fibrotic diseases, cerebrovascular and neurodegenerative diseases, and depression. Previous studies have confirmed that HG and its derivatives combat cancer by exerting cytotoxicity, inhibiting proliferation, inducing apoptosis, modulating autophagy, and reversing chemotherapy resistance in cancer cells, and the action targets involved mainly include STAT3, Aurora B, KIF7, PI3K/AKT, NF-κB, Nrf2/ARE, Drp1, and P-gp. In addition, HG and its derivatives antagonize inflammation through inhibiting the production and release of pro-inflammatory cytokines and inflammatory mediators by regulating inflammation-related pathways and targets, such as NF-κB, MAPK, JAK2/STAT3, Keap1-Nrf2/HO-1, and LncRNA A33/Axin2/β-catenin. Moreover, anti-pathogen, anti-metabolic disorder, anti-fibrosis, neuroprotection, and anti-depression mechanisms of HG and its derivatives have been partially elucidated. The diverse pharmacological properties of HG and its derivatives hold significant implications for future research and development of new drugs derived from HG, which can lead to improved effectiveness and safety profiles.

Advances in the anti-tumor potential of hederagenin and its analogs

Hederagenin is a pentacyclic triterpenoid that is widely distributed as the main pharmaceutical ingredient in various medicinal plants. Similarly as other pentacyclic triterpenoids, hederagenin has various pharmacological effects such as anti-tumor, anti-inflammatory, anti-depressant, and anti-viral activities. In particular, the anti-tumor activity of hederagenin indicates its potential for development into highly effective chemotherapeutic agents. Studies revealed that hederagenin effectively suppresses the growth of various tumor cell lines in vitro and interacts with several molecular targets that play essential roles in various cellular signaling pathways. The compound suppresses transformation, inhibits proliferation, and induces apoptosis in tumor cells. In this review, we highlight research progress on the source, pharmacokinetics, pharmacological activity, and mechanism of action of hederagenin and the anti-tumor activity of its analogs by integrating and analyzing relevant domestic and international studies and providing a basis for their further development and application.

Natural Products-Pyrazine Hybrids: A Review of Developments in Medicinal Chemistry

Pyrazine is a six-membered heterocyclic ring containing nitrogen, and many of its derivatives are biologically active compounds. References have been downloaded through Web of Science, PubMed, Science Direct, and SciFinder Scholar. The structure, biological activity, and mechanism of natural product derivatives containing pyrazine fragments reported from 2000 to September 2023 were reviewed. Publications reporting only the chemistry of pyrazine derivatives are beyond the scope of this review and have not been included. The results of research work show that pyrazine-modified natural product derivatives have a wide range of biological activities, including anti-inflammatory, anticancer, antibacterial, antiparasitic, and antioxidant activities. Many of these derivatives exhibit stronger pharmacodynamic activity and less toxicity than their parent compounds. This review has a certain reference value for the development of heterocyclic compounds, especially pyrazine natural product derivatives.

Pharmacological overview of hederagenin and its derivatives

Hederagenin is a pentacyclic triterpenoid isolated from plants and widely distributed in a variety of medicinal plants. By integrating and analyzing external related literature reports, the latest research progress on the pharmacological effects and structural modification of hederagenin was reviewed. Hederagenin has a wide range of pharmacological activities, including antitumor, anti-inflammatory, antidepressant, anti-neurodegenerative, antihyperlipidemic, antidiabetic, anti-leishmaniasis, and antiviral activities. Among them, it shows high potential in the field of anti-tumor treatment. This paper also reviews the structural modifications of hederagenin, including carboxyl group modifications and two hydroxyl group modifications. Future research on hederagenin will focus on prolonging its half-life, improving its bioavailability and structural modification to enhance its pharmacological activity, accelerating the preclinical research stage of hederagenin for it to enter the clinical research stage as soon as possible.

Targeting tumor-derived exosome-mediated premetastatic niche formation: The metastasis-preventive value of traditional Chinese medicine

Tumor-derived exosome (TDE)-mediated premetastatic niche (PMN) formation is a potential mechanism underlying the organotropic metastasis of primary tumors. Traditional Chinese medicine (TCM) has shown considerable success in preventing and treating tumor metastasis. However, the underlying mechanisms remain elusive. In this review, we discussed PMN formation from the perspectives of TDE biogenesis, cargo sorting, and TDE recipient cell alterations, which are critical for metastatic outgrowth. We also reviewed the metastasis-preventive effects of TCM, which act by targeting the physicochemical materials and functional mediators of TDE biogenesis, regulating the cargo sorting machinery and secretory molecules in TDEs, and targeting the TDE-recipient cells involved in PMN formation.

Design, synthesis, and biological evaluation of ocotillol derivatives fused with 2-aminothiazole via A-ring as modulators of P-glycoprotein-mediated multidrug resistance

Overexpression of P-glycoprotein (P-gp) plays a key role in the development of multidrug resistance (MDR), the major reason for the failure of chemotherapy in clinics. Ocotillol and its derivatives had been reported with good P-gp-mediated tumor MDR reversal activity in vitro. Herein, a series of ocotillol derivatives fused with 2-aminothiazole (2-AT) via A-ring were designed and synthesized to further improve the tumor MDR reversal potency. These compounds were evaluated for their MDR reversal activity against the KBV cells by MTT assay. Among them, the most promising derivative against P-gp-mediated MDR was compound 12 with 2-AT and glycine in the A-ring. Rhodamine123 (Rh123) accumulation assay, Western blot assay, and P-gp-Glo™ assay showed that compound 12 efficiently inhibited the efflux function of P-gp by stimulating P-gp ATPase rather than downregulating its expression. Moreover, compound 12 sensitized KBV cells to paclitaxel arrested cells in the G₂/M phase and induced cell apoptosis. Importantly, compound 12 significantly inhibited the growth of KBV cell-derived xenograft tumors in nude mice by increasing the sensitivity of paclitaxel in vivo. Finally, the structure-activity relationships (SARs) of ocotillol derivatives were further investigated. In summary, compound 12 has the potential to overcome MDR in cancer caused by P-gp.

PEGylation and antioxidant effects of a human glutathione peroxidase 1 mutant

Human glutathione peroxidase1 (hGPx1) is a good antioxidant and potential drug, but the limited availability and poor stability of hGPx1 have affected its development and application. To solve this problem, we prepared a hGPx1 mutant (GPx1M) with high activity in an Escherichia coli BL21(DE3)cys auxotrophic strain using a single protein production (SPP) system. In this study, the GPx1M was conjugated with methoxypolyethylene glycol-succinimidyl succinate (SS-mPEG, M_w = 5 kDa) chains to enhance its stability. SS-mPEG-GPx1M and GPx1M exhibited similar enzymatic activity and stability toward pH and temperature change, and in a few cases, SS-mPEG-GPx1M was discovered to widen the range of pH stability and increase the temperature stability. Lys 38 was confirmed as PEGylated site by liquid-mass spectrometry. H9c2 cardiomyoblast cells and Sprague-Dawley (SD) rats were used to evaluate the effects of GPx1M and SS-mPEG-GPx1M on preventing or alleviating adriamycin (ADR)-mediated cardiotoxicity, respectively. The results indicated that GPx1M and SS-mPEG-GPx1M had good antioxidant effects in vitro and in vivo, and the effect of SS-mPEG-GPx1M is more prominent than GPx1M in vivo. Thus, PEGylation might be a promising method for the application of GPx1M as an important antioxidant and potential drug.

Improvement of stability and in vivo antioxidant effect of human glutathione peroxidase mutant by PEGylation

Human glutathione peroxidase (GPx), as an important kind of antioxidant enzyme, is often used for the removal of reactive oxygen species. Unfortunately, the application has been hindered by its limited source and poor stability. To solve these problems, human glutathione peroxidase mutant (GPxM) with high activity and yield was obtained using Escherichia coli BL21(DE3) cys auxotrophic strain and the single-protein production system in our previous work. However, the antioxidant effect of this novel recombinant protein drug in animals has not been demonstrated, and its immunogenicity and short biological half-life as a biological macromolecule may have seriously hindered its clinical application. Therefore, it is important to find an effective strategy to address the above issues. In this work, PEGylated GPxM was prepared by conjugating the corresponding mutant with monomethoxy polyethylene glycol succinimidyl succinate (SS-mPEG). We researched the structure, stability, pharmacokinetic properties, antioxidant effect in vivo and protective mechanism against adriamycin (ADR)-mediated cardiotoxicity of modified products, and compared with the above properties of GPxM. The results revealed that GPxM had an excellent antioxidant effect in vivo, and PEGylation can enhance the stability, half-life and antioxidant effect of GPxM while reducing immunogenicity. In addition, the above improvement of PEGylated GPx1M was stronger than that of monoPEGylated GPx4M. Hence, PEGylation might be an effective method to broaden the applications of GPxM as the important antioxidant drug, especially the PEGylated GPx1M with high antioxidant effect.