Therapeutic Emergence of Rhein as a Potential Anticancer Drug: A Review of Its Molecular Targets and Anticancer Properties

The genus Polygonum: An updated comprehensive review of its ethnomedicinal, phytochemical, pharmacological activities, toxicology, and phytopharmaceutical formulation

Polygonum is a plant genus that includes annual and perennial species and is found at various temperatures, from northern temperate regions to tropical and subtropical areas. The genus Polygonum has been used for centuries for various disorders, including hypertension, intestinal and stomach pain, dysuria, jaundice, toothaches, skin allergies, hemorrhoids, cardiac disorders, kidney stones, hemostasis, hyperglycemia, and others. Various databases, including Google Scholar, Scifinder, ScienceDirect, PubMed, Scopus, ResearchGate, and Web of Science, were utilized to collect pertinent scientific literature data. According to bibliographic studies, the Polygonum genus possesses various compounds from different families, including phenolic acids (gallic acid, caffeic acid, quinic acid, p-coumaric acid, ferulic acid, protocatechuic acid, chlorogenic acid, and many other compounds), flavonoids (quercetin, catechin, epicatechin, quercitrin, kaempferol, myricetin, etc.), tannins, stilbenes (polydatin and resveratrol), terpenes (α-pinene, β-caryophyllene and β-caryophyllene oxide, bisabolene, β-farnesene, etc.), fatty acids (decanoic acid, lauric acid, linoleic acid, oleic acid, palmitic acid, stearic acid, dodecanoic acid), polysaccharides, and others. Various chemical and biological activities (in vitro and in vivo), such as antioxidant, antimicrobial, anticancer, antitumor, anti-inflammatory, antidiabetic, antiparasitic, hepatoprotective, neuropharmacological, gastroprotective, diuretic, antipyretic, and others, have been described in several biological studies involving this species. An updated summary of Polygonum species and their ethnomedicinal, phytochemical, toxicological, pharmacological, and phytopharmaceutical formulations is necessary. Considering the numerous potentialities of the Polygonum species and their wide-ranging use, it is extremely essential to provide knowledge by compiling the accessible literature to identify the topics of intense investigation and the main gaps to better design future studies. The objective of this review is to give readers a better understanding, greater comprehension, and in-depth knowledge of the genus Polygonum's traditional applications, phytochemistry, pharmacology, toxicological features, and galenic formulation. Several species of this genus have been detailed in this review, including those that were frequently used in traditional medicine (P. minus, P. aviculare, P. hydropiper, P. cuspidatum, and P. multiflorum) and many of the genus' therapeutic species, like P. equisetiforme, which do not get enough attention.

Design, synthesis and biological evaluation of rhein-piperazine-furanone hybrids as potential anticancer agents

Novel rhein-piperazine-furanone hybrids, 5, were designed and synthesized efficiently from rhein. Cytotoxicity of all hybrids 5a-j against A549 human lung cancer cells was superior to the parent rhein and the reference cytarabine (CAR). Hybrid 5e (IC50 = 5.74 μM), the most potent compound, was 46- and 35-fold more toxic against A549 cells than rhein (IC50 = 265.59 μM) and CAR (IC50 = 202.57 μM), respectively. Moreover, hybrid 5e (IC50 = 69.28 μM) was less toxic to normal WI-38 human lung fibroblast cells with good selectivity (WI-38/A549, SI ≈ 12), being much higher than rhein (SI ≈ 1) and CAR (SI ≈ 2). Structure-activity relationship (SAR) analysis showed that cytotoxicity and selectivity against A549 lung cancer cells were greatly enhanced when methoxy-containing furanone was introduced to the hybrids (5e and 5h). Further, hybrid 5e showed better cytotoxicity against four types of human lung cancer cells (H460, A549, PC-9, and Calu-1; IC50 = 4.35-15.39 μM) than six other types of human cancer cells (SK-BR-3, SK-OV-3, 786-O, Huh-7, HCT116, and HeLa; IC50 = 13.77-60.45 μM), showing specificity. In particular, hybrid 5e showed the highest cytotoxicity (IC50 = 4.35 μM) and the highest selectivity (WI-38/H460, SI ≈ 16) against H460 human lung cancer cells. Flow cytometric analysis showed that hybrid 5e induced apoptosis in a concentration-dependent manner in H460 cells. The results show that the cytotoxicity and selectivity of rhein can be greatly enhanced by hybridization with furanone. Hybrid 5e is expected to be a leading candidate for anti-lung cancer drugs.

Delineating the role of nuclear receptors in colorectal cancer, a focused review

Colorectal cancer (CRC) stands as one of the most prevalent form of cancer globally, causing a significant number of deaths, surpassing 0.9 million in the year 2020. According to GLOBOCAN 2020, CRC ranks third in incidence and second in mortality in both males and females. Despite extensive studies over the years, there is still a need to establish novel therapeutic targets to enhance the patients' survival rate in CRC. Nuclear receptors (NRs) are ligand-activated transcription factors (TFs) that regulate numerous essential biological processes such as differentiation, development, physiology, reproduction, and cellular metabolism. Dysregulation and anomalous expression of different NRs has led to multiple alterations, such as impaired signaling cascades, mutations, and epigenetic changes, leading to various diseases, including cancer. It has been observed that differential expression of various NRs might lead to the initiation and progression of CRC, and are correlated with poor survival outcomes in CRC patients. Despite numerous studies on the mechanism and role of NRs in this cancer, it remains of significant scientific interest primarily due to the diverse functions that various NRs exhibit in regulating key hallmarks of this cancer. Thus, modulating the expression of NRs with their agonists and antagonists, based on their expression levels, holds an immense prospect in the diagnosis, prognosis, and therapeutical modalities of CRC. In this review, we primarily focus on the role and mechanism of NRs in the pathogenesis of CRC and emphasized the significance of targeting these NRs using a variety of agents, which may represent a novel and effective strategy for the prevention and treatment of this cancer.

Exploring the nexus of nuclear receptors in hematological malignancies

Hematological malignancies (HM) represent a subset of neoplasms affecting the blood, bone marrow, and lymphatic systems, categorized primarily into leukemia, lymphoma, and multiple myeloma. Their prognosis varies considerably, with a frequent risk of relapse despite ongoing treatments. While contemporary therapeutic strategies have extended overall patient survival, they do not offer cures for advanced stages and often lead to challenges such as acquisition of drug resistance, recurrence, and severe side effects. The need for innovative therapeutic targets is vital to elevate both survival rates and patients' quality of life. Recent research has pivoted towards nuclear receptors (NRs) due to their role in modulating tumor cell characteristics including uncontrolled proliferation, differentiation, apoptosis evasion, invasion and migration. Existing evidence emphasizes NRs' critical role in HM. The regulation of NR expression through agonists, antagonists, or selective modulators, contingent upon their levels, offers promising clinical implications in HM management. Moreover, several anticancer agents targeting NRs have been approved by the Food and Drug Administration (FDA). This review highlights the integral function of NRs in HM's pathophysiology and the potential benefits of therapeutically targeting these receptors, suggesting a prospective avenue for more efficient therapeutic interventions against HM.

Role of Nutraceuticals in Counteracting Inflammation in In Vitro Macrophages Obtained from Childhood Cancer Survivors

The advancement of anti-cancer therapies has markedly improved the survival rate of children with cancer, making them long-term childhood cancer survivors (CCS). Nevertheless, these treatments cause a low-grade inflammatory state, determining inflamm-aging and, thus, favoring the early onset of chronic diseases normally associated with old age. Identification of novel and safer therapeutic strategies is needed to counteract and prevent inflamm-aging. Macrophages are cells involved in immune and inflammatory responses, with a pivotal role in iron metabolism, which is related to inflammation. We obtained macrophages from CCS patients and evaluated their phenotype markers, inflammatory states, and iron metabolism by Western blotting, ELISA, and iron assays. We observed a strong increase in classically activated phenotype markers (M1) and iron metabolism alteration in CCS, with an increase in intracellular iron concentration and inflammatory markers. These results suggest that the prevalence of M1 macrophages and alteration of iron metabolism could be involved in the worsening of inflammation in CCS. Therefore, we propose macrophages and iron metabolism as novel therapeutic targets to counteract inflamm-aging. To avoid toxic regimens, we tested some nutraceuticals (resveratrol, curcumin, and oil-enriched lycopene), which are already known to exert anti-inflammatory properties. After their administration, we observed a macrophage switch towards the anti-inflammatory phenotype M2, as well as reductions in pro-inflammatory cytokines and the intracellular iron concentration. Therefore, we suggest-for the first time-that nutraceuticals reduce inflammation in CCS macrophages through a novel anti-inflammatory mechanism of action, modulating iron metabolism.

Current stage of preclinical and clinical development of guggulsterone in cancers: Challenges and promises

Throughout human history, the utilization of medicinal herbs has been recognized as a crucial defense against various ailments, including cancer. Natural products with potential anticancer properties, capable of inducing apoptosis in cancer cells, have garnered substantial attention. One such agent under investigation is guggulsterone (GS), a phytosterol derived from the gum resin of the Commiphora mukul tree. This review aims to provide a comprehensive summary of recent studies elucidating the anticancer molecular mechanisms and molecular targets of GS, guiding future research and potential applications as an adjuvant drug in cancer therapy. Recent in vivo and in vitro studies have explored the biological activities of the active ingredients in Commiphora mukul. Specifically, GS emerges as a potential cancer chemopreventive and therapeutic agent. The investigations delve into the impact of GS on constitutively activated survival pathways, including Janus kinase/signal transducer and activator of transcription (JAK/STAT), nuclear factor-kappa B (NF-kB), and PI3-kinase/AKT signaling pathways. These pathways regulate antiapoptotic and proinflammatory genes, exerting control over growth and inflammatory responses. The findings highlight the potential of GS in disrupting survival pathways crucial for cancer cell viability. The inhibition of JAK/STAT, NF-kB, and PI3-kinase/AKT signaling pathways positions GS as a promising candidate for cancer therapy. The review synthesizes evidence from diverse studies, underscoring the multifaceted biological activities of GS in cancer prevention and treatment. To advance our understanding, future clinical and translational studies are imperative to determine effective doses in humans. Additionally, there is a need for the development of new pharmaceutical forms of GS to optimize therapeutic effects. This comprehensive review provides a foundation for ongoing research, offering insights into the potential of GS as a valuable addition to the armamentarium against cancer.

Microalgae-Based Hydrogel for Inflammatory Bowel Disease and Its Associated Anxiety and Depression

Patients diagnosed with inflammatory bowel disease (IBD) exhibit a notable prevalence of psychiatric disorders, such as anxiety and depression. Nevertheless, the etiology of psychiatric disorders associated with IBD remains uncertain, and an efficacious treatment approach has yet to be established. Herein, an oral hydrogel strategy (SP@Rh-gel) is proposed for co-delivery of Spirulina platensis and rhein to treat IBD and IBD-associated anxiety and depression by modulating the microbiota-gut-brain axis. SP@Rh-gel improves the solubility, release characteristics and intestinal retention capacity of the drug, leading to a significant improvement in the oral therapeutic efficacy. Oral administration of SP@Rh-gel can reduce intestinal inflammation and rebalance the disrupted intestinal microbial community. Furthermore, SP@Rh-gel maintains intestinal barrier integrity and reduces the release of pro-inflammatory factors and their entry into the hippocampus through the blood-brain barrier, thereby inhibiting neuroinflammation and maintaining neuroplasticity. SP@Rh-gel significantly alleviates the colitis symptoms, as well as anxiety- and depression-like behaviors, in a chronic colitis mouse model. This study demonstrates the significant involvement of the microbiota-gut-brain axis in the development of IBD with psychiatric disorders and proposes a safe, simple, and highly efficient therapeutic approach for managing IBD and comorbid psychiatric disorders.

Harnessing Sulforaphane Potential as a Chemosensitizing Agent: A Comprehensive Review

Recent advances in oncological research have highlighted the potential of naturally derived compounds in cancer prevention and treatment. Notably, sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables including broccoli and cabbage, has exhibited potent chemosensitizing capabilities across diverse cancer types of bone, brain, breast, lung, skin, etc. Chemosensitization refers to the enhancement of cancer cell sensitivity to chemotherapy agents, counteracting the chemoresistance often developed by tumor cells. Mechanistically, SFN orchestrates this sensitization by modulating an array of cellular signaling pathways (e.g., Akt/mTOR, NF-κB, Wnt/β-catenin), and regulating the expression and activity of pivotal genes, proteins, and enzymes (e.g., p53, p21, survivin, Bcl-2, caspases). When combined with conventional chemotherapeutic agents, SFN synergistically inhibits cancer cell proliferation, invasion, migration, and metastasis while potentiating drug-induced apoptosis. This positions SFN as a potential adjunct in cancer therapy to augment the efficacy of standard treatments. Ongoing preclinical and clinical investigations aim to further delineate the therapeutic potential of SFN in oncology. This review illuminates the multifaceted role of this phytochemical, emphasizing its potential to enhance the therapeutic efficacy of anti-cancer agents, suggesting its prospective contributions to cancer chemosensitization and management.

Rhubarb charcoal-crosslinked chitosan/silk fibroin sponge scaffold with efficient hemostasis, inflammation, and angiogenesis for promoting diabetic wound healing

Diabetic patients often experience long-term risks due to chronic inflammation and delayed re-epithelialization during impaired wound healing. Although the severity of this condition is well known, the treatment options for diabetic wounds are limited. Rhubarb charcoal, a well-known traditional Chinese medicine, has been used to treat skin wounds for thousands of years. We produced a chitosan/silk fibroin sponge scaffold loaded with natural carbonized rhubarb and crosslinked it by freeze-drying to create a highly efficient RCS/SF scaffold. Rhubarb carbon and carboxymethyl chitosan exhibit antibacterial activity and promote wound healing. Owing to its 3D porous structure, this scaffold is antibacterial and pro-angiogenic. It also possesses remarkable properties, such as excellent swelling and biocompatibility. The supportive effect of carbonized rhubarb on mouse fibroblast migration is mediated at the cellular/tissue level by increased skin neovascularization and re-epithelization. Compared to the control group, RCS/SF scaffolds promoted faster healing, increased neovascularization, enhanced collagen deposition, and re-epithelialization within two weeks. The scaffold's pro-healing properties and efficient release of carbonized rhubarb, with rapid hemostatic and good sterilization effects, make it an outstanding candidate for treating diabetic wounds and novel therapeutic interventions for diabetic ulcers.

Therapeutic Potential of 1,8-Dihydroanthraquinone Derivatives for Breast Cancer

Breast cancer (BC) is the most common malignancy among women worldwide. In recent years, significant progress has been made in BC therapy. However, serious side effects resulting from the use of standard chemotherapeutic drugs, as well as the phenomenon of multidrug resistance (MDR), limit the effectiveness of approved therapies. Advanced research in the BC area is necessary to create more effective and safer forms of therapy to improve the outlook for individuals diagnosed with this aggressive neoplasm. For decades, plants and natural products with anticancer properties have been successfully utilized in treating various medical conditions. Anthraquinone derivatives are tricyclic secondary metabolites of natural origin that have been identified in plants, lichens, and fungi. They represent a few botanical families, e.g., Rhamnaceae, Rubiaceae, Fabaceae, Polygonaceae, and others. The review comprehensively covers and analyzes the most recent advances in the anticancer activity of 1,8-dihydroanthraquinone derivatives (emodin, aloe-emodin, hypericin, chrysophanol, rhein, and physcion) applied both individually, or in combination with other chemotherapeutic agents, in in vitro and in vivo BC models. The application of nanoparticles for in vitro and in vivo evidence in the context of 1,8-dihydroanthraquinone derivatives was also described.

Photo- and Sono-Active Food Colorants Inactivating Bacteria

Food colorants are commonly used as excipients in pharmaceutical and nutraceutical fields, but they have a wide range of other potential applications, for instance, as cytotoxic drugs or mediators of physical antimicrobial treatments. The photodynamic antibacterial activity of several edible food colorants is reported here, including E127, E129, E124, E122, E133, and E150a, alongside Rhein, a natural lipophilic antibacterial and anticancer compound found in medicinal plants. Minimal inhibitory concentration (MIC) values for S. aureus and E. coli showed that E127 and Rhein were effective against both bacteria, while other colorants exhibited low activity against E. coli. In some cases, dark pre-incubation of the colorants with Gram-positive S. aureus increased their photodynamic activity. Adding Rhein to E127 increased the photodynamic activity of the latter in a supportive mode. Optional sensing mechanism pathways of combined E127/Rhein action were suggested. The antibacterial activity of the studied colorants can be ranged as follows: E127/Rhein >> E127 >> E150a > E122 > E124 >> E129 ≈ E133. E127 was also found to exhibit photodynamic properties. Short ultrasonic treatment before illumination caused intensification of E127 photodynamic activity against E. coli when applied alone and especially in combination with Rhein. Food colorants exhibiting photo- and sonodynamic properties may have good potential in food preservation.

Enhancing Gastric Cancer Therapeutic Efficacy through Synergistic Cotreatment of Linderae Radix and Hyperthermia in AGS Cells

Gastric cancer remains a global health threat, particularly in Asian countries. Current treatment methods include surgery, chemotherapy, and radiation therapy. However, they all have limitations, such as adverse side effects, tumor resistance, and patient tolerance. Hyperthermia therapy uses heat to selectively target and destroy cancer cells, but it has limited efficacy when used alone. Linderae Radix (LR), a natural compound with thermogenic effects, has the potential to enhance the therapeutic efficacy of hyperthermia treatment. In this study, we investigated the synergistic anticancer effects of cotreatment with LR and 43 °C hyperthermia in AGS gastric cancer cells. The cotreatment inhibited AGS cell proliferation, induced apoptosis, caused cell cycle arrest, suppressed heat-induced heat shock responses, increased reactive oxygen species (ROS) generation, and promoted mitogen-activated protein kinase phosphorylation. N-acetylcysteine pretreatment abolished the apoptotic effect of LR and hyperthermia cotreatment, indicating the crucial role of ROS in mediating the observed anticancer effects. These findings highlight the potential of LR as an adjuvant to hyperthermia therapy for gastric cancer. Further research is needed to validate these findings in vivo, explore the underlying molecular pathways, and optimize treatment protocols for the development of novel and effective therapeutic strategies for patients with gastric cancer.

Natural compounds targeting nuclear receptors for effective cancer therapy

Human nuclear receptors (NRs) are a family of forty-eight transcription factors that modulate gene expression both spatially and temporally. Numerous biochemical, physiological, and pathological processes including cell survival, proliferation, differentiation, metabolism, immune modulation, development, reproduction, and aging are extensively orchestrated by different NRs. The involvement of dysregulated NRs and NR-mediated signaling pathways in driving cancer cell hallmarks has been thoroughly investigated. Targeting NRs has been one of the major focuses of drug development strategies for cancer interventions. Interestingly, rapid progress in molecular biology and drug screening reveals that the naturally occurring compounds are promising modern oncology drugs which are free of potentially inevitable repercussions that are associated with synthetic compounds. Therefore, the purpose of this review is to draw our attention to the potential therapeutic effects of various classes of natural compounds that target NRs such as phytochemicals, dietary components, venom constituents, royal jelly-derived compounds, and microbial derivatives in the establishment of novel and safe medications for cancer treatment. This review also emphasizes molecular mechanisms and signaling pathways that are leveraged to promote the anti-cancer effects of these natural compounds. We have also critically reviewed and assessed the advantages and limitations of current preclinical and clinical studies on this subject for cancer prophylaxis. This might subsequently pave the way for new paradigms in the discovery of drugs that target specific cancer types.

Targeting Cell Signaling Pathways in Lung Cancer by Bioactive Phytocompounds

Lung cancer is a heterogeneous group of malignancies with high incidence worldwide. It is the most frequently occurring cancer in men and the second most common in women. Due to its frequent diagnosis and variable response to treatment, lung cancer was reported as the top cause of cancer-related deaths worldwide in 2020. Many aberrant signaling cascades are implicated in the pathogenesis of lung cancer, including those involved in apoptosis (B cell lymphoma protein, Bcl-2-associated X protein, first apoptosis signal ligand), growth inhibition (tumor suppressor protein or gene and serine/threonine kinase 11), and growth promotion (epidermal growth factor receptor/proto-oncogenes/phosphatidylinositol-3 kinase). Accordingly, these pathways and their signaling molecules have become promising targets for chemopreventive and chemotherapeutic agents. Recent research provides compelling evidence for the use of plant-based compounds, known collectively as phytochemicals, as anticancer agents. This review discusses major contributing signaling pathways involved in the pathophysiology of lung cancer, as well as currently available treatments and prospective drug candidates. The anticancer potential of naturally occurring bioactive compounds in the context of lung cancer is also discussed, with critical analysis of their mechanistic actions presented by preclinical and clinical studies.

Fibrin glue delivery system containing rhein ameliorates intervertebral disc degeneration by anti-inflammatory efficacy

PURPOSE

To construct an injectable, sustained-release fibrin gel containing rhein to solve the problem of low bioavailability of rhein, and observe its efficacy in the treatment of intervertebral disc degeneration.

METHODS

The fibrin gel containing rhein was first synthesized in advance. Subsequently, the materials were characterized by various experimental methods. Secondly, the degenerative cell model was constructed by stimulating nucleus pulposus cells with lipopolysaccharide (LPS), and the corresponding intervention treatment was carried out to observe the effect in vitro. Finally, the rat tail intervertebral disc was acupunctured by needles to establish the intervertebral disc degeneration model, and the effect of the material was observed through intradiscal injection.

RESULTS

The fibrin glue containing rhein (rhein@FG) showed good injectability, sustained release and biocompatibility. Rhein@FG can improve the LPS-induced inflammatory microenvironment, regulate ECM metabolic disorders of nucleus pulposus cells and aggregation of the NLRP3 inflammasome in vitro, and inhibit cell pyroptosis. Furthermore, in vivo experiments, rhein@FG effectively prevented needle puncture-induced intervertebral disc degeneration in rats.

CONCLUSIONS

Rhein@FG has better efficacy than rhein or FG alone due to its slow release and mechanical properties, which can be used as a potential replacement therapy for intervertebral disc degeneration.

Elucidation of the Anticancer Mechanism of Durian Fruit (Durio zibethinus) Pulp Extract in Human Leukemia (HL-60) Cancer Cells

Durian (Durio zibethinus L.) grows widely in Southeast Asia. The pulp of the durian fruit contains carbohydrates, proteins, lipids, fibers, various vitamins, minerals, and fatty acids. This study was carried out to elucidate the anticancer mechanism of action of the methanolic extract of the fruit of Durio zibethinus (D. zibethinus) on human leukemia (HL-60) cells. The methanolic extract of D. zibethinus fruits exhibited its anticancer effect on HL-60 cells by inducing DNA damage and apoptosis. The DNA damage was confirmed by comet and DNA fragmentation assays. The methanolic extract of D. zibethinus fruits has been shown to cause cell cycle arrest in HL-60 cells during the S phase and G2/M phase. Additionally, the methanolic extract caused induction of the apoptotic pathway in the HL-60 cell line. This was confirmed by increased expression in pro-apoptotic proteins, viz., Bax protein expression, and a substantial reduction (p < 0.001) in anti-apoptotic proteins, viz., Bcl-2 and Bcl-xL expressions. Therefore, this study confirms that the methanolic extract of D. zibethinus exerts its anticancer effects on the HL-60 cell line, causing cell cycle arrest and induction of apoptosis by an intrinsic mechanism.

Tetramethylpyrazine-Rhein Derivative inhibits the migration of canine inflammatory mammary carcinoma cells by mitochondrial damage-mediated apoptosis and cadherins downregulation

BACKGROUND

Canine inflammatory mammary carcinoma (CIMC) has a high incidence of metastasis, high lethality, and poor prognosis, which needs novel adjuvant agents. Tetramethylpyrazine-Rhein Derivative (TRD) has been shown to have antitumor activity, which is a potential research direction for CIMC.

PURPOSE

This study evaluated the efficacy of TRD on CIMC in vitro and in vivo, and provided possibilities for the application of active compounds in traditional Chinese medicine.

METHODS

In vitro, TRD cytotoxicity was measured with CCK-8. Flow cytometry and transmission electron microscope were used to detect the cell cycle, cell death, and changes in mitochondria. Wound-healing assay, cell invasion assay, and scanning electron microscope were used to evaluate the suppression of cell migration and invasion. Expression changes were detected by RT-qPCR and western blot assay. In vivo, the lung metastasis models were randomly divided into control, low-dose TRD, high-dose TRD, and positive groups. Each group was administered orally once a day for 18 days and took in vivo imaging photos.

RESULTS

The IC₅₀ of TRD in CHMp and MDCK were 42.59 and 79.37 μM, respectively. TRD mediated cell apoptosis by mitochondrial damage and caused S and G₂/M phase arrest by downregulating cyclin B1. Moreover, TRD reduced filopodia and inhibited cell migration by downregulating cadherins. In CIMC lung metastasis models, TRD could effectively inhibit tumor growth (P < 0.001) in the lungs without significant toxicity.

CONCLUSION

TRD showed potential activity to inhibit CIMC lung metastasis with multi-target and low toxicity.

Role of Turmeric and Curcumin in Prevention and Treatment of Chronic Diseases: Lessons Learned from Clinical Trials

Turmeric (Curcuma longa) has been used for thousands of years for the prevention and treatment of various chronic diseases. Curcumin is just one of >200 ingredients in turmeric. Almost 7000 scientific papers on turmeric and almost 20,000 on curcumin have been published in PubMed. Scientific reports based on cell culture or animal studies are often not reproducible in humans. Therefore, human clinical trials are the best indicators for the prevention and treatment of a disease using a given agent/drug. Herein, we conducted an extensive literature survey on PubMed and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The keywords "turmeric and clinical trials" and "curcumin and clinical trials" were considered for data mining. A total of 148 references were found to be relevant for the key term "turmeric and clinical trials", of which 70 were common in both PubMed and Scopus, 44 were unique to PubMed, and 34 were unique to Scopus. Similarly, for the search term "curcumin and clinical trials", 440 references were found to be relevant, of which 70 were unique to PubMed, 110 were unique to Scopus, and 260 were common to both databases. These studies show that the golden spice has enormous health and medicinal benefits for humans. This Review will extract and summarize the lessons learned about turmeric and curcumin in the prevention and treatment of chronic diseases based on clinical trials.

Therapeutically important bioactive compounds of the genus Polygonum L. and their possible interventions in clinical medicine

OBJECTIVES

Increasing literature data have suggested that the genus Polygonum L. possesses pharmacologically important plant secondary metabolites. These bioactive compounds are implicated as effective agents in preclinical and clinical practice due to their pharmacological effects such as anti-inflammatory, anticancer, antidiabetic, antiaging, neuroprotective or immunomodulatory properties among many others. However, elaborate pharmacological and clinical data concerning the bioavailability, tissue distribution pattern, dosage and pharmacokinetic profiles of these compounds are still scanty.

KEY FINDINGS

The major bioactive compounds implicated in the therapeutic effects of Polygonum genus include phenolic and flavonoid compounds, anthraquinones and stilbenes, such as quercetin, resveratrol, polydatin and others, and could serve as potential drug leads or as adjuvant agents. Data from in-silico network pharmacology and computational molecular docking studies are also highly helpful in identifying the possible drug target of pathogens or host cell machinery.

SUMMARY

We provide an up-to-date overview of the data from pharmacodynamic, pharmacokinetic profiles and preclinical (in-vitro and in-vivo) investigations and the available clinical data on some of the therapeutically important compounds of genus Polygonum L. and their medical interventions, including combating the outbreak of the COVID-19 pandemic.

Nanoparticles loaded with pharmacologically active plant-derived natural products: Biomedical applications and toxicity

Pharmacologically active natural products have played a significant role in the history of drug development. They have acted as sources of therapeutic drugs for various diseases such as cancer and infectious diseases. However, most natural products suffer from poor water solubility and low bioavailability, limiting their clinical applications. The rapid development of nanotechnology has opened up new directions for applying natural products and numerous studies have explored the biomedical applications of nanomaterials loaded with natural products. This review covers the recent research on applying plant-derived natural products (PDNPs) nanomaterials, including nanomedicines loaded with flavonoids, non-flavonoid polyphenols, alkaloids, and quinones, especially their use in treating various diseases. Furthermore, some drugs derived from natural products can be toxic to the body, so the toxicity of them is discussed. This comprehensive review includes fundamental discoveries and exploratory advances in natural product-loaded nanomaterials that may be helpful for future clinical development.

The Journey of Resveratrol from Vineyards to Clinics

With rising technological advancements, several factors influence the lifestyle of people and stimulate chronic inflammation that severely affects the human body. Chronic inflammation leads to a broad range of physical and pathophysiological distress. For many years, non-steroidal drugs and corticosteroids were most frequently used in treating inflammation and related ailments. However, long-term usage of these drugs aggravates the conditions of chronic diseases and is presented with morbid side effects, especially in old age. Hence, the quest for safe and less toxic anti-inflammatory compounds of high therapeutic potential with least adverse side effects has shifted researchers' attention to ancient medicinal system. Resveratrol (RSV) - 3,4,5^' trihydroxystilbene is one such naturally available polyphenolic stilbene derivative obtained from various plant sources. For over 2000 years, these plants have been used in Asian medicinal system for curing inflammation-associated disorders. There is a wealth of in vitro, in vivo and clinical evidence that shows RSV could induce anti-aging health benefits including, anti-cancer, anti-inflammatory, anti-oxidant, phytoesterogenic, and cardio protective properties. However, the issue of rapid elimination of RSV through the metabolic system and its low bio-availability is of paramount importance which is being studied extensively. Therefore, in this article, we scientifically reviewed the molecular targets, biological activities, beneficial and contradicting effects of RSV as evinced by clinical studies for the prevention and treatment of inflammation-mediated chronic disorders.

Novel anthraquinone derivatives trigger endoplasmic reticulum stress response and induce apoptosis

Background: Endoplasmic reticulum (ER) stress is a therapeutic target in cancer given its regulation of bioenergetics and cell death. Methodology & results: We synthesized 14 ER stress-triggered anthraquinone derivatives by introducing an amino group at the 3-position side chain of the lead compound obtained previously. Most of the anthraquinone derivatives exhibited good antitumor activity due to their ability to induce ER damage through cytoplasmic vacuoles. The mechanisms of ER stress caused by compound KA-4c were related to increasing the expression levels of the ATF6 and Bip proteins and upregulating CHOP and cleaved PARP. Conclusion: Compound KA-4c triggers ER stress response and induces apoptosis via the ATF6-CHOP signaling pathway.

New light on treatment of cervical cancer: Chinese medicine monomers can be effective for cervical cancer by inhibiting the PI3K/Akt signaling pathway

Cervical cancer (CC), as the most common malignant tumor of the female reproductive system, is infamous for its high morbidity and mortality rates. Its development and metastasis are intricate because numerous signaling pathways are involved. Since the cancer and the PI3K/Akt signaling pathway are closely intertwined, direct inhibition of either the PI3K/Akt pathway or its target genes and molecules may be remarkably constructive for treatment. Albeit remarkable advances in the treatment of CC, existing common anti-cancer medications are not without problems. These problems include myelotoxicity, cardiotoxicity, genotoxicity, and vasospasm, which are the most common and well-recognized toxicities associated with these medications. Therefore, it is necessary and urgent to develop novel, potent, secure, and more reasonably priced anticancer medications that are void of the above problems. Against this backdrop, Chinese medicine monomers have received more attention in recent years owing to their safety, low toxicity, few side effects, and anti-tumor properties. By regulating the PI3K/Akt signaling pathway, Chinese medicine monomers are effective not only in inhibiting CC growth, proliferation, apoptosis, invasion, migration, and reversing drug resistance but also in a variety of targets. Most previous earlier studies focused on the use of a single traditional Chinese medicine monomer to treat CC by regulating the PI3K/Akt signaling pathway rather than a combination of several such monomers. More importantly, to our knowledge, there has hardly been any study providing an exhaustive and comprehensive review of all the Chinese medicine monomers at CC. In response to this scarcity, we attempt in this paper to provide a comprehensive review of all the literature to date on traditional Chinese medicine monomers at cervical cancer, highlight the mechanisms and future prospects for their use in the prevention and treatment of cervical cancer.

Tea Plant (Camellia sinensis): A Current Update on Use in Diabetes, Obesity, and Cardiovascular Disease

The tea plant (C. sinensis) has traditionally been consumed worldwide as "tea" for its many health benefits, with the potential for the prevention and therapy of various conditions. Regardless of its long history, the use of tea plants in modern times seems not to have changed much, as the beverage remains the most popular form. This review aimed to compile scientific information about the role and action of tea plants, as well as their status concerning clinical applications, based on the currently available evidence, with a focus on metabolic syndrome, mainly covering obesity, diabetes, and cardiovascular disease. It has been recognized that these diseases pose a significant threat to public health, and the development of effective treatment and prevention strategies is necessary but still challenging. In this article, the potential benefits of tea plants and their derived bioactive components (such as epigallocatechin-3-gallate) as anti-obesity, anti-diabetic, and anti-cardiovascular agents are clearly shown and emphasized, along with their mechanisms of action. However, according to the status of the clinical translation of tea plants, particularly in drug development, more substantial efforts in well-designed, randomized, controlled trials are required to expand their applications in treating the three major metabolic disorders and avoiding the toxicity caused by overconsumption.

The effects of rhein on D-GalN/LPS-induced acute liver injury in mice: Results from gut microbiome-metabolomics and host transcriptome analysis

Background

Rhubarb is an important traditional Chinese medicine, and rhein is one of its most important active ingredients. Studies have found that rhein can improve ulcerative colitis by regulating gut microbes, but there are few reports on its effects on liver diseases. Therefore, this study aims to investigate these effects and underlying mechanisms.

Methods

Mice were given rhein (100 mg/kg), with both a normal control group and a model group receiving the same amount of normal saline for one week. Acute liver injury was induced in mice by intraperitoneal injection of D-GalN (800 mg/kg)/LPS (10 ug/kg). Samples (blood, liver, and stool) were then collected and assessed for histological lesions and used for 16S rRNA gene sequencing, high-performance liquid chromatography-mass spectrometry (LC-MS) and RNA-seq analysis.

Results

The levels of ALT and AST in the Model group were abnormal higher compared to the normal control group, and the levels of ALT and AST were significantly relieved in the rhein group. Hepatic HE staining showed that the degree of liver injury in the rhein group was lighter than that in the model group, and microbiological results showed that norank_o:Clostridia_UCG-014, Lachnoclostridium, and Roseburia were more abundant in the model group compared to the normal control group. Notably, the rhein treatment group showed reshaped disturbance of intestinal microbial community by D-GalN/LPS and these mice also had higher levels of Verrucomicrobia, Akkermansiaceae and Bacteroidetes. Additionally, There were multiple metabolites that were significantly different between the normal control group and the model group, such as L-α-amino acid, ofloxacin-N-oxide, 1-hydroxy-1,3-diphenylpropan-2-one,and L-4-hydroxyglutamate semialdehyde, but that returned to normal levels after rhein treatment. The gene expression level in the model group also changed significantly, various genes such as Cxcl2, S100a9, Tnf, Ereg, and IL-10 were up-regulated, while Mfsd2a and Bhlhe41 were down-regulated, which were recovered after rhein treatment.

Conclusion

Overall, our results show that rhein alleviated D-GalN/LPS-induced acute liver injury in mice. It may help modulate gut microbiota in mice, thereby changing metabolism in the intestine. Meanwhile, rhein also may help regulate genes expression level to alleviate D-GalN/LPS-induced acute liver injury.

Unraveling the Potential Role of NEDD4-like E3 Ligases in Cancer

Cancer is a deadly disease worldwide, with an anticipated 19.3 million new cases and 10.0 million deaths occurring in 2020 according to GLOBOCAN 2020. It is well established that carcinogenesis and cancer development are strongly linked to genetic changes and post-translational modifications (PTMs). An important PTM process, ubiquitination, regulates every aspect of cellular activity, and the crucial enzymes in the ubiquitination process are E3 ubiquitin ligases (E3s) that affect substrate specificity and must therefore be carefully regulated. A surfeit of studies suggests that, among the E3 ubiquitin ligases, neuronal precursor cell-expressed developmentally downregulated 4 (NEDD4)/NEDD4-like E3 ligases show key functions in cellular processes by controlling subsequent protein degradation and substrate ubiquitination. In addition, it was demonstrated that NEDD4 mainly acts as an oncogene in various cancers, but also plays a tumor-suppressive role in some cancers. In this review, to comprehend the proper function of NEDD4 in cancer development, we summarize its function, both its tumor-suppressive and oncogenic role, in multiple types of malignancies. Moreover, we briefly explain the role of NEDD4 in carcinogenesis and progression, including cell survival, cell proliferation, autophagy, cell migration, invasion, metastasis, epithelial-mesenchymal transition (EMT), chemoresistance, and multiple signaling pathways. In addition, we briefly explain the significance of NEDD4 as a possible target for cancer treatment. Therefore, we conclude that targeting NEDD4 as a therapeutic method for treating human tumors could be a practical possibility.

Carrier-free nanoplatforms from natural plants for enhanced bioactivity

BACKGROUND

Natural plants as well as traditional Chinese medicine have made outstanding contributions to the health and reproduction of human beings and remain the basis and major resource for drug innovation. Carrier-free nanoplatforms completely self-assembled by pure molecules or therapeutic components have attracted increasing attention due to their advantages of improved pharmacodynamics/pharmacokinetics, reduced toxicity, and high drug loading. In recent years, carrier-free nanoplatforms produced by self-assembly from natural plants have contributed to progress in a variety of therapeutic modalities. Notably, these nanoplatforms based on the interactions of components from different natural plants improve efficiency and depress toxicity.

AIM OF REVIEW

In this review, different types of self-assembled nanoplatforms are first summarized, mainly including nanoassemblies of pure small molecules isolated from different plants, extracellular vesicles separated from fresh plants, charcoal nanocomponents obtained from charred plants, and nanoaggregates from plants formulae decoctions. Key Scientific Concepts of Review: We mainly focus on composition, self-assembly mechanisms, biological activity and modes of action. Finally, a future perspective of existing challenges with respect to the clinical application of plant-based carrier-free nanoplatforms is discussed, which may be instructive to further develop effective carrier-free nanoplatforms from natural plants in the future.

Research Progress on the Positive and Negative Regulatory Effects of Rhein on the Kidney: A Review of Its Molecular Targets

Currently, both acute kidney injury (AKI) and chronic kidney disease (CKD) are considered to be the leading public health problems with gradually increasing incidence rates around the world. Rhein is a monomeric component of anthraquinone isolated from rhubarb, a traditional Chinese medicine. It has anti-inflammation, anti-oxidation, anti-apoptosis, anti-bacterial and other pharmacological activities, as well as a renal protective effects. Rhein exerts its nephroprotective effects mainly through decreasing hypoglycemic and hypolipidemic, playing anti-inflammatory, antioxidant and anti-fibrotic effects and regulating drug-transporters. However, the latest studies show that rhein also has potential kidney toxicity in case of large dosages and long use times. The present review highlights rhein's molecular targets and its different effects on the kidney based on the available literature and clarifies that rhein regulates the function of the kidney in a positive and negative way. It will be helpful to conduct further studies on how to make full use of rhein in the kidney and to avoid kidney damage so as to make it an effective kidney protection drug.

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

Betulinic acid: A natural promising anticancer drug, current situation, and future perspectives

Natural products serve as the single most productive source for the discovery of drugs and pharmaceutical leads. Among the various chemicals derived from microbes, plants, and animals, phytochemicals have emerged as potential candidates for the development of anticancer drugs due to their structural diversities, complexities, and pleiotropic effects. Herein, we discuss betulinic acid (BA), a ubiquitously distributed lupane structured pentacyclic triterpenoid, scrutinized as a promising natural agent for the prevention, suppression, and management of various human malignancies. Ease of availability, common occurrences, cell-specific cytotoxicity, and astonishing selectivity are the important factors that contribute to the development of BA as an anticancer agent. The current review delineates the mechanistic framework of BA-mediated cancer suppression through the modulation of multiple signaling pathways and also summarizes the key outcomes of BA in preclinical investigations.

The progress and prospect of natural components in rhubarb (Rheum ribes L.) in the treatment of renal fibrosis

Background: Renal fibrosis is a key pathological change that occurs in the progression of almost all chronic kidney diseases . CKD has the characteristics of high morbidity and mortality. Its prevalence is increasing each year on a global scale, which seriously affects people’s health and quality of life. Natural products have been used for new drug development and disease treatment for many years. The abundant natural products in R. ribes L. can intervene in the process of renal fibrosis in different ways and have considerable therapeutic prospects.

Purpose: The etiology and pathology of renal fibrosis were analyzed, and the different ways in which the natural components of R. ribes L. can intervene and provide curative effects on the process of renal fibrosis were summarized. Methods: Electronic databases, such as PubMed, Life Science, MEDLINE, and Web of Science, were searched using the keywords ‘R. ribes L.’, ‘kidney fibrosis’, ‘emodin’ and ‘rhein’, and the various ways in which the natural ingredients protect against renal fibrosis were collected and sorted out.

Results: We analyzed several factors that play a leading role in the pathogenesis of renal fibrosis, such as the mechanism of the TGF-β/Smad and Wnt/β-catenin signaling pathways. Additionally, we reviewed the progress of the treatment of renal fibrosis with natural components in R. ribes L. and the intervention mechanism of the crucial therapeutic targets.

Conclusion: The natural components of R. ribes L. have a wide range of intervention effects on renal fibrosis targets, which provides new ideas for the development of new anti-kidney fibrosis drugs.

Rhein ameliorates transverse aortic constriction-induced cardiac hypertrophy via regulating STAT3 and p38 MAPK signaling pathways

The progression from compensatory hypertrophy to heart failure is difficult to reverse, in part due to extracellular matrix fibrosis and continuous activation of abnormal signaling pathways. Although the anthraquinone rhein has been examined for its many biological properties, it is not clear whether it has therapeutic value in the treatment of cardiac hypertrophy and heart failure. In this study, we report for the first time that rhein can ameliorate transverse aortic constriction (TAC)-induced cardiac hypertrophy and other cardiac damage in vivo and in vitro. In addition, rhein can reduce cardiac hypertrophy by attenuating atrial natriuretic peptide, brain natriuretic peptide, and β-MHC expression; cardiac fibrosis; and ERK phosphorylation and transport into the nucleus. Furthermore, the inhibitory effect of rhein on myocardial hypertrophy was similar to that of specific inhibitors of STAT3 and ERK signaling. In addition, rhein at therapeutic doses had no significant adverse effects or toxicity on liver and kidney function. We conclude that rhein reduces TAC-induced cardiac hypertrophy via targeted inhibition of the molecular function of ERK and downregulates STAT3 and p38 MAPK signaling. Therefore, rhein might be a novel and effective agent for treating cardiac hypertrophy and other cardiovascular diseases.

Evaluation and antitumor mechanism of functionalized chitosan-based polymeric micelles for oral delivery of paclitaxel

D-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS)-modified carboxymethyl chitosan-rhein (TCR) polymeric micelles (PMs) self-assembled by TCR conjugate were constructed for oral delivery of paclitaxel (PTX). PTX-loaded TCR PMs with a drug loading capacity of 47.52 ± 1.65 % significantly improved the intestinal absorption and oral bioavailability of PTX. TCR PMs loaded with PTX displayed time- and concentration-dependent cytotoxicity in Caco-2, MCF-7 and Taxol-resistant MCF-7 (MCF-7/Taxol) cells. In MCF-7/Taxol cells, PTX-loaded TCR PMs promoted apoptosis and changed cell cycle, and TCR conjugate exhibited a P-gp inhibition ability and caused ATP depletion. Moreover, confocal imaging of intestinal sections, Caco-2 cell uptake assay and in vivo bioimaging using environmental response fluorescence probe suggested that TCR PMs loaded with drugs can be absorbed as a whole through the intestinal epithelium after oral administration, enter systemic circulation, and then get to the tumor site. Remarkably, PTX-loaded TCR PMs displayed a significant antitumor effect in H22 tumor xenograft mice and the MCF-7 or MCF-7/Taxol xenograft zebrafish model, which was related to the inhibitory function of TCR conjugate for P-gp activity and P-gp and MDR1 expression. Functionalized TCR PMs are expected to improve the oral therapeutic efficacy of poorly water-soluble antitumor drugs and treat drug-resistant tumors.

The multifaceted role of STAT3 pathway and its implication as a potential therapeutic target in oral cancer

Oral cancer is one of the leading causes of cancer-related deaths, and it has become a matter of serious concern due to the alarming rise in its incidence rate worldwide. Despite recent advancements in oral cancer treatment strategies, there are no significant improvements in patient's survival rate. Among the numerous cell signaling pathways involved in oral cancer development and progression, STAT3 is known to play a multifaceted oncogenic role in shaping the tumor pathophysiology. STAT3 hyperactivation in oral cancer contributes to survival, proliferation, invasion, epithelial to mesenchymal transition, metastasis, immunosuppression, chemoresistance, and poor prognosis. A plethora of pre-clinical and clinical studies have documented the role of STAT3 in the initiation and development of oral cancer and showed that STAT3 inhibition holds significant potential in the prevention and treatment of this cancer. However, to date, targeting STAT3 activation mainly involves inhibiting the upstream signaling molecules such as JAK and IL-6 receptors. The major challenge in targeting STAT3 lies in the complexity of its phosphorylation- and dimerization-independent functions, which are not affected by disrupting the upstream regulators. The present review delineates the significance of the STAT3 pathway in regulating various hallmarks of oral cancer. In addition, it highlights the STAT3 inhibitors identified to date through various preclinical and clinical studies that can be employed for the therapeutic intervention in oral cancer treatment.

Rhein induces changes in the lysosomal compartment of HeLa cells

Rhein is an anthraquinone found in Rheum palmatum, used in Chinese medicine. Due to potential anticancer properties, the study assessed its effect on the lysosomal compartment, which indirectly influences cell death. The experiment was performed on HeLa cells by treating them with rhein at concentrations of 100-300 µM. LC3-II protein and caspase 3/7 activity, level of apoptosis, the concentration of reactive oxide species (ROS), and mitochondrial potential (Δψm) were evaluated by the cytometric method. To evaluate the permeability of the lysosomal membrane (LMP), staining with acridine orange and the assessment of activity of cathepsin D and L in the lysosomal and extralysosomal fractions were used. Cell viability was assessed by -(3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) (MTT) and neutral red (NR) assays. Changes in cells were also demonstrated at the level of electron, optical, confocal, and fluorescence microscopy. Inhibition of autophagy was done using chloroquine. Rhein-induced degradation processes were confirmed by an increase in the number of primary lysosomes, autophagosomes, and autolysosomes. At high concentrations, rhein caused the generation of ROS, which induced LMP expressed by quenching of acridine orange fluorescence. These results correlated with a reduction of lysosomes, as visualized in graphical modeling, with the decreased uptake of NR by lysosomes, and increased activity of cathepsin D and L in the extralysosomal fraction. The studies also showed an increase in the activity of caspase 3/7 and a decrease in the expression of Bcl-2 protein, indicative of rhein-stimulated apoptosis. At the same time, we demonstrated that preincubation of cells with chloroquine inhibited rhein-induced autophagy and contributed to increased cytotoxicity to HeLa cells. Rhein also induced DNA damage and led to cycle arrest in the S phase. Our results indicate that rhein, by inducing changes in the lysosomal compartment, indirectly affects apoptosis of HeLa cells and in combination with autophagy inhibitors may be an effective form of anticancer therapy.

Inhibition of hypoxia-induced HIF-1α-mediated autophagy enhances the in vitro anti-tumor activity of rhein in pancreatic cancer cells

A hypoxic microenvironment results in significantly elevated hypoxia-inducible factor-1 (HIF-1) level in pancreatic cancer. HIF-1 functions to maintain the survival of cancer cells. The present study was performed to investigate whether inhibition of HIF-1α expression was involved in the in vitro anti-tumor effect of rhein in pancreatic cancer cells and to explore the underlying mechanism. sh-RNA knockout technique and western blotting were used to investigate the role of HIF-1α in autophagy activation in MiaPaCa-2 and PANC-1 cells. The survival and glycolysis were assessed using MTT assay and colorimetric kits, respectively. Apoptosis was evaluated by detecting the levels of apoptosis-related proteins using western blotting. Among the five pancreatic cancer cell lines, MiaPaCa-2 and PANC-1 cells were more sensitive to hypoxia-induced autophagy. HIF-1α regulated hypoxia-induced autophagy in MiaPaCa-2 and PANC-1 cells. Treatment with rhein inhibited the survival and suppressed glycolysis in MiaPaCa-2 and PANC-1 cells exposed to hypoxia. Bafilomycin A1 enhanced the suppressive effects of rhein on cell survival and glycolysis under hypoxia. Treatment with rhein, but not bafilomycin A1, significantly reduced HIF-1α expression. In conclusion, inhibition of HIF-1α-mediated autophagy enhances the in vitro anti-tumor activity of rhein in pancreatic cancer cells under hypoxia.

The Role of m6A RNA Methylation in Cancer: Implication for Nature Products Anti-Cancer Research

N6-methyladenosine (m6A) RNA methylation is identified as the most common, abundant and reversible RNA epigenetic modification in messenger RNA (mRNA) and non-coding RNA, especially within eukaryotic messenger RNAs (mRNAs), which post-transcriptionally directs many important processes of RNA. It has also been demonstrated that m6A modification plays a pivotal role in the occurrence and development of tumors by regulating RNA splicing, localization, translation, stabilization and decay. Growing number of studies have indicated that natural products have outstanding anti-cancer effects of their unique advantages of high efficiency and minimal side effects. However, at present, there are very few research articles to study and explore the relationship between natural products and m6A RNA modification in tumorigenesis. m6A is dynamically deposited, removed, and recognized by m6A methyltransferases (METTL3/14, METTL16, WTAP, RBM15/15B, VIRMA, CBLL1, and ZC3H13, called as “writers”), demethylases (FTO and ALKBH5, called as “erasers”), and m6A-specific binding proteins (YTHDF1/2/3, YTHDC1/2, IGH2BP1/2/3, hnRNPs, eIF3, and FMR1, called as “readers”), respectively. In this review, we summarize the biological function of m6A modification, the role of m6A and the related signaling pathway in cancer, such as AKT, NF-kB, MAPK, ERK, Wnt/β-catenin, STAT, p53, Notch signaling pathway, and so on. Furthermore, we reviewed the current research on nature products in anti-tumor, and further to get a better understanding of the anti-tumor mechanism, thus provide an implication for nature products with anti-cancer research by regulating m6A modification in the future.

Application of the anthraquinone drug rhein as an axial ligand in bifunctional Pt(IV) complexes to obtain antiproliferative agents against human glioblastoma cells

Octahedral Pt(IV) prodrugs are an effective way to combine cisplatin-like moieties and a second drug to obtain selective and stimuli responsive bifunctional antiproliferative compounds. Recently, two bifunctional Pt(IV) complexes have shown interesting in vitro and in vivo effects in glioblastoma, the most aggressive primary brain tumor. An interesting observation indicates that 4,5-dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-carboxylic acid (rhein) can inhibit in vivo glioma tumor progression. Furthermore, a prodrug in which cisplatin was combined with two molecules of rhein showed a potency higher than that of cisplatin toward cisplatin-resistant lung carcinoma cells. However, the high lipophilicity of this type of complex affects their solubility and bioavailability. To overcome these limits, in the present work, three Pt(IV) derivatives were obtained by differently linking one molecule of rhein and one acetato ligand at the axial position to a cisplatin core. The complexes proved to be similar to or more potent than the parent cisplatin and rhein, and the reference drug temozolomide on two human glioblastoma cell lines (U87-MG and T98G). They retained their activity under hypoxia and caused a significant reduction in the motility of both cell lines, which can be related to their ability to inhibit MMP2 and MMP9 matrix metalloproteinases. Finally, physicochemical and computational studies indicated that these Pt(IV) derivatives are more prone than rhein to cross the blood-brain barrier.

Role of Induced Programmed Cell Death in the Chemopreventive Potential of Apigenin

The flavonoid apigenin (4′,5,7-trihydroxyflavone), which is one of the most widely distributed phytochemicals in the plant kingdom, is one of the most thoroughly investigated phenolic components. Previous studies have attributed the physiological effects of apigenin to its anti-allergic, antibacterial, antidiabetic, anti-inflammatory, antioxidant, antiviral, and blood-pressure-lowering properties, and its documented anticancer properties have been attributed to the induction of apoptosis and autophagy, the inhibition of inflammation, angiogenesis, and cell proliferation, and the regulation of cellular responses to oxidative stress and DNA damage. The most well-known mechanism for the compound’s anticancer effects in human cancer cell lines is apoptosis, followed by autophagy, and studies have also reported that apigenin induces novel cell death mechanisms, such as necroptosis and ferroptosis. Therefore, the aim of this paper is to review the therapeutic potential of apigenin as a chemopreventive agent, as well as the roles of programmed cell death mechanisms in the compound’s chemopreventive properties.

The influence of rhein on the absorption of rehmaionoside D: In vivo, in situ, in vitro, and in silico studies

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese Medicine, Rehmannia glutinosa (Gaertn.) DC., as the principle herb of ShengDiHuang Decotion (SDHD), has the effect of cooling blood and hemostasis, and tonifying the yin and kidney. Rheum L., as adjuvant herbs, assist Rehmannia glutinosa (Gaertn.) DC. to promote blood circulation to remove blood stasis.

AIM OF STUDY

To study the mechanism of Rhein (RH) involved in the promotion of Rehmannioside D (RD) absorption by pharmacokinetic studies, single-pass intestinal perfusion, Caco-2 cell models, molecular docking technique and western blotting.

MATERIALS AND METHODS

Initially, the intestinal absorption of RD in the presence or absence of RH was conducted through pharmacokinetic studies. Thereafter, the intestinal absorption of RD and RH was studied using the single-pass intestinal perfusion and Caco-2 cell models. Finally, using molecular docking technique and western blotting.

RESULTS

We found that the promotion of RD absorption by RH was mediated by breast cancer resistance and multidrug resistance-associated protein 2, thereby affecting the permeability of the intestinal epithelium. Additionally, RH and RD can competitively bind to breast cancer resistance and multidrug resistance-associated protein 2, and that RH inhibits the expression of breast cancer resistance and multidrug resistance-associated protein 2 in the ileum to promote the intestinal absorption of RD.

CONCLUSION

This study reveals the mechanisms associated with the RH-mediated promotion of RD absorption and provides a basis for further exploring the synergistic effect of Rehmannia glutinosa (Gaertn.) DC and rhubarb.

Preparation of a Self-Assembled Rhein-Doxorubicin Nanogel Targeting Mitochondria and Investigation on Its Antihepatoma Activity

Mitochondria are involved in the regulation of apoptosis, making them a promising target for the development of new anticancer drugs. Doxorubicin (DOX), a chemotherapeutic drug, can induce reactive oxygen species (ROS)-mediated apoptosis, improving its anticancer effects. Herein, Rhein, an active ingredient in rhubarb, with the capability of self-assembly and mitochondrial targeting, was used in conjunction with DOX to form efficient nanomaterials (Rhein-DOX nanogel) capable of sustained drug release. It was self-assembled with a hydrogen bond, π-π stacking interactions, and hydrophobic interactions as the main driving force, and its loading efficiency was up to 100%. Based on its self-assembly characteristics, we evaluated the mechanism of this material to target mitochondria, induce ROS production, and promote apoptosis. The IC₅₀ of the Rhein-DOX nanogel (3.74 μM) was only 46.3% of that of DOX (11.89 μM), and the tumor inhibition rate of the Rhein-DOX nanogel was 79.4% in vivo, 2.3 times that of DOX. This study not only addresses the disadvantages of high toxicity of DOX and low bioavailability of Rhein, when DOX and Rhein are combined for the treatment of hepatoma, but it also significantly improved the synergistic antihepatoma efficacy of Rhein and DOX, which provides a new idea for the development of long-term antihepatoma agents with low toxicity.

Reiterating the Emergence of Noncoding RNAs as Regulators of the Critical Hallmarks of Gall Bladder Cancer

Gall bladder cancer (GBC) is a rare and one of the most aggressive types of malignancies, often associated with a poor prognosis and survival. It is a highly metastatic cancer and is often not diagnosed at the initial stages, which contributes to a poor survival rate of patients. The poor diagnosis and chemoresistance associated with the disease limit the scope of the currently available surgical and nonsurgical treatment modalities. Thus, there is a need to explore novel therapeutic targets and biomarkers that will help relieve the severity of the disease and lead to advanced therapeutic strategies. Accumulating evidence has correlated the atypical expression of various noncoding RNAs (ncRNAs), including circular RNAs (circRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and small nucleolar RNAs (snoRNA) with the increased cell proliferation, epithelial-mesenchymal transition (EMT), invasion, migration, metastasis, chemoresistance, and decreased apoptosis in GBC. Numerous reports have indicated that the dysregulated expression of ncRNAs is associated with poor prognosis and lower disease-free and overall survival in GBC patients. These reports suggest that ncRNAs might be considered novel diagnostic and prognostic markers for the management of GBC. The present review recapitulates the association of various ncRNAs in the initiation and progression of GBC and the development of novel therapeutic strategies by exploring their functional and regulatory role.

Embelin: A novel XIAP inhibitor for the prevention and treatment of chronic diseases

Chronic diseases are a serious health concern worldwide, especially in the elderly population. Most chronic diseases like cancer, cardiovascular ailments, neurodegenerative disorders, and autoimmune diseases are caused due to the abnormal functioning of multiple signaling pathways that give rise to critical anomalies in the body. Although a lot of advanced therapies are available, these have failed to entirely cure the disease due to their less efficacy. Apart from this, they have been shown to manifest disturbing side effects which hamper the patient's quality of life to the extreme. Since the last few decades, extensive studies have been done on natural herbs due to their excellent medicinal benefits. Components present in natural herbs target multiple signaling pathways involved in diseases and therefore hold high potential in the prevention and treatment of various chronic diseases. Embelin, a benzoquinone, is one such agent isolated from Embelia ribes, which has shown excellent biological activities toward several chronic ailments by upregulating a number of antioxidant enzymes (e.g., SOD, CAT, GSH, etc.), inhibiting anti-apoptotic genes (e.g., TRAIL, XIAP, survivin, etc.), modulating transcription factors (e.g., NF-κB, STAT3, etc.) blocking inflammatory biomarkers (e.g., NO, IL-1β, IL-6, TNF-α, etc.), monitoring cell cycle synchronizing genes (e.g., p53, cyclins, CDKs, etc.), and so forth. Several preclinical studies have confirmed its excellent therapeutic activities against malicious diseases like cancer, obesity, heart diseases, Alzheimer's, and so forth. This review presents an overview of embelin, its therapeutic prospective, and the molecular targets in different chronic diseases.

An updated review on the potential antineoplastic actions of oleuropein

Oleuropein is an ester of elenolic acid and hydroxytyrosol (3, 4-dihydroxyphenylethanol). It is a phenolic compound and the most luxuriant in olives. The detailed information related to the anticancer effects of oleuropein was collected from the internet database PubMed/Medline, ResearchGate, Web of Science, Wiley Online Library, and Cnki using appropriate keywords until the end of October 2021. Oleuropein has been shown to have antioxidant, anticancer, antiinflammatory, cardioprotective, neuroprotective, and hepatoprotective effects. Previous studies also revealed that oleuropein could effectively inhibit the malignant progression of esophageal cancer, gastric cancer, breast cancer, lung cancer, liver cancer, pancreatic cancer, ovarian cancer, prostate cancer, and cervical cancer. Recently, the role of oleuropein in inhibiting tumor cell proliferation, invasion, and migration and inducing tumor cell apoptosis has gained extensive attention. In this review, we have summarized the latest research progress related to the antioncogenic mechanisms and the potential role of oleuropein in targeting different human malignancies. Based on these findings, it can be concluded that oleuropein can function as a promising chemopreventive and chemotherapeutic agent against cancer, but its more detailed anticancer effects and underlying mechanisms need to be further validated in future preclinical as well as clinical studies.