Honokiol: A Novel Natural Agent for Cancer Prevention and Therapy

Honokiol Is More Potent than Magnolol in Reducing Head and Neck Cancer Cell Growth

The efficacy of treatment of head and neck squamous cell carcinoma (HNSCC) patients is still unsatisfactory, and there is an ongoing search for novel therapies. Locoregionally advanced HNSCC cases, which frequently require combined surgery and chemoradiotherapy, are especially difficult to treat. Natural compounds, like Magnolia-derived lignans-honokiol (HON) and magnolol (MAG)-can reduce cancer cell growth but retain a good safety profile and thus may show benefit as adjuvant therapeutics. The aim of this study was to evaluate the anti-cancer effects of HON and MAG in HNSCC cell lines and compare their effects between cisplatin-sensitive and cisplatin-tolerant cells. Cell viability was evaluated in FaDu and SCC-040 cells growing as monolayers and as spheroids. The effect of HON and MAG on the cell cycle, apoptosis, and gene expression was compared between wild-type FaDu cells and cisplatin persister FaDu cells. We observed that HON and MAG were more potent in reducing cell viability in cisplatin persister FaDu cells, although this effect was not directly followed by increased rates of apoptosis. Thus, HON's and MAG's capacity to affect cisplatin persister cells needs further studies. In general, we observed that HON exerted stronger cytotoxic effects than MAG in HNSCC cells, and the difference in their anti-cancer activity was especially pronounced in cells cultured in 3D.

Overcoming drug resistance of cancer cells by targeting the FGF1/FGFR1 axis with honokiol or FGF ligand trap

Background

Chemoresistance of cancer cells, resulting from various mechanisms, is a significant obstacle to the effectiveness of modern cancer therapies. Targeting fibroblast growth factors (FGFs) and their receptors (FGFRs) is becoming crucial, as their high activity significantly contributes to cancer development and progression by driving cell proliferation and activating signaling pathways that enhance drug resistance.

Methods

We investigated the potential of honokiol and FGF ligand trap in blocking the FGF1/FGFR1 axis to counteract drug resistance. Using PEAQ-ITC, we verified direct interaction of honokiol with the FGFR1 kinase domain. We then demonstrated the effect of FGF1/FGFR1 inhibition on taltobulin resistance in cells expressing FGFR1. Finally, we generated drug-resistant clones by prolonged exposure of cells with negligible FGFR levels to taltobulin alone, taltobulin and honokiol, or taltobulin and FGF ligand trap.

Results

We demonstrated for the first time a direct interaction of honokiol with the FGFR1 kinase domain, resulting in inhibition of downstream signaling pathways. We revealed that both honokiol and FGF ligand trap prevent FGF1-dependent protection against taltobulin in cancer cells expressing FGFR1. In addition, we showed that cells obtained by long-term exposure to taltobulin are resistant to both taltobulin and other microtubule-targeting drugs, and exhibit elevated levels of FGFR1 and cyclin D. We also found that the presence of FGF-ligand trap prevents the development of long-term resistance to taltobulin.

Conclusion

Our results shed light on how blocking the FGF1/FGFR1 axis by honokiol and FGF ligand trap could help develop more effective cancer therapies, potentially preventing the emergence of drug-resistant relapses.

Synergistic Strategies for Castration-Resistant Prostate Cancer: Targeting AR-V7, Exploring Natural Compounds, and Optimizing FDA-Approved Therapies

Castration-resistant prostate cancer (CRPC) remains a significant therapeutic challenge due to its resistance to standard androgen deprivation therapy (ADT). The emergence of androgen receptor splice variant 7 (AR-V7) has been implicated in CRPC progression, contributing to treatment resistance. Current treatments, including first-generation chemotherapy, androgen receptor blockers, radiation therapy, immune therapy, and PARP inhibitors, often come with substantial side effects and limited efficacy. Natural compounds, particularly those derived from herbal medicine, have garnered increasing interest as adjunctive therapeutic agents against CRPC. This review explores the role of AR-V7 in CRPC and highlights the promising benefits of natural compounds as complementary treatments to conventional drugs in reducing CRPC and overcoming therapeutic resistance. We delve into the mechanisms of action underlying the anti-CRPC effects of natural compounds, showcasing their potential to enhance therapeutic outcomes while mitigating the side effects associated with conventional therapies. The exploration of natural compounds offers promising avenues for developing novel treatment strategies that enhance therapeutic outcomes and reduce the adverse effects of conventional CRPC therapies. These compounds provide a safer, more effective approach to managing CRPC, representing a significant advancement in improving patient care.

Delivery Strategies, Structural Modification, and Pharmacological Mechanisms of Honokiol: A Comprehensive Review

Honokiol (HK) is a traditional Chinese herbal bioactive compound that originates mainly from the Magnolia species, traditionally used to treat anxiety and stroke, as well as alleviation of flu symptoms. This natural product and its derivatives displayed diverse biological activities, including anticancer, antioxidant, anti-inflammatory, neuroprotective, and antimicrobial activities. However, its poor bioavailability and pharmacological activity require primary consideration in the development of HK-based drugs. Recent innovative HK formulations based on the nanotechnology approach allowed for improvement in both bioavailability and therapeutic efficacy. Chemical derivation and drug combination are also effective strategies to ameliorate the drawbacks of HK. In recent years, studies on HK derivatives and compositions have made great progress in the treatment of cancer, inflammation, bacterial infection, cardiovascular, and cerebrovascular diseases, demonstrating better activity than HK. The objective of this review is an examination of the recent developments in the field of pharmacological activity of HK and its drug-related issues, and approaches to improve its physicochemical and biological properties, including solubility, stability, and bioavailability. Recent patents and the ongoing clinical trials in HK are also summarized.

Phosphate Prodrugs: An Approach to Improve the Bioavailability of Clinically Approved Drugs

The phosphate prodrug approach has emerged as a viable option for increasing the bioavailability of a drug candidate with low hydrophilicity and poor cell membrane permeability. When a phosphoric acid moiety is attached to the parent drug, it results in a several-fold elevation in aqueous solubility which helps to achieve desired bioavailability of the pharmaceutically active parental molecule. The neutral phosphate prodrugs have rapid diffusion ability through the plasma membrane as compared to their charged counterpart. The presence of phosphate mono ester breaking alkaline phosphatase (ALP) enzyme throughout the whole human body, is the main consideration behind the development of phosphate prodrug strategy. The popularity of this phosphate prodrug strategy is increasing nowadays due to the fulfillment of different desired pharmacokinetic characteristics required to get pharmaceutical and therapeutic responses without showing any serious adverse drug reactions (ADR). This review article mainly focuses on various phosphate prodrugs synthesized within the last decade to get an improved pharmacological response of the parent moiety along with various preclinical and clinical challenges associated with this approach. Emphasis is also given to the chemical mechanism to release the parent moiety from the prodrug.

Honokiol and its analogues as anticancer compounds: Current mechanistic insights and structure-activity relationship

Lignans are plant-derived polyphenolic compounds with a plethora of biological applications. Also, regarded as phytoestrogens, the lignans offer a variety of health benefits of which the anti-cancer effects are the most attractive. Honokiol is a lignan isolated from various parts of trees belonging to the genus Magnolia. The bioactivity of honokiol is attributed to its characteristic physical properties, which include small size and the presence of two phenolic groups that may interact with proteins in cell membranes via hydrophobic interactions, aromatic pi orbital co-valency, and hydrogen bonding. The hydrophobicity of honokiol enables its rapid dissolution in lipids and the crossing of physiological barriers, including the blood-brain barrier and cerebrospinal fluid. These factors contribute towards the high bioavailability of honokiol which further support its candidature in medicinal research. Therefore, the anticancer properties of honokiol are of particular interest as many of the contemporary anticancer drugs suffer from bioavailability drawbacks, which necessitates the identification and development of novel candidate molecules directed as anticancer chemotherapeutics. The antioncogenic profile of honokiol also arises from the regulation of various signalling pathways associated with oncogenesis, arresting of the cell cycle by regulation of cyclic proteins, upregulation of epithelial markers and downregulation of mesenchymal markers leading to the inhibition of epithelial-mesenchymal transition, and preventing the metastasis by restricting cell migration and invasion due to the downregulation of matrix-metalloproteinases. In this review, we discuss the anticancer properties of honokiol.

Neuropharmacological potential of honokiol and its derivatives from Chinese herb Magnolia species: understandings from therapeutic viewpoint

Honokiol is a neolignan biphenol found in aerial parts of the Magnolia plant species. The Magnolia plant species traditionally belong to China and have been used for centuries to treat many pathological conditions. Honokiol mitigates the severity of several pathological conditions and has the potential to work as an anti-inflammatory, anti-angiogenic, anticancer, antioxidant, and neurotherapeutic agent. It has a long history of being employed in the healthcare practices of Southeast Asia, but in recent years, a greater scope of research has been conducted on it. Plenty of experimental evidence suggests it could be beneficial as a neuroprotective bioactive molecule. Honokiol has several pharmacological effects, leading to its exploration as a potential therapy for neurological diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), cerebral ischemia, anxiety, depression, spinal cord injury, and so on. So, based on the previous experimentation reports, our goal is to discuss the neuroprotective properties of honokiol. Besides, honokiol derivatives have been highlighted recently as possible therapeutic options for NDs. So, this review focuses on honokiol's neurotherapeutic actions and toxicological profile to determine their safety and potential use in neurotherapeutics.

Nanotechnology-Based Drug Delivery Systems for Honokiol: Enhancing Therapeutic Potential and Overcoming Limitations

Honokiol (HNK) is a small-molecule polyphenol that has garnered considerable attention due to its diverse pharmacological properties, including antitumor, anti-inflammatory, anti-bacterial, and anti-obesity effects. However, its clinical application is restricted by challenges such as low solubility, poor bioavailability, and rapid metabolism. To overcome these limitations, researchers have developed a variety of nano-formulations for HNK delivery. These nano-formulations offer advantages such as enhanced solubility, improved bioavailability, extended circulation time, and targeted drug delivery. However, existing reviews of HNK primarily focus on its clinical and pharmacological features, leaving a gap in the comprehensive evaluation of HNK delivery systems based on nanotechnology. This paper aims to bridge this gap by comprehensively reviewing different types of nanomaterials used for HNK delivery over the past 15 years. These materials encompass vesicle delivery systems, nanoparticles, polymer micelles, nanogels, and various other nanocarriers. The paper details various HNK nano-delivery strategies and summarizes their latest applications, development prospects, and future challenges. To compile this review, we conducted an extensive search using keywords such as "honokiol", "nanotechnology", and "drug delivery system" on reputable databases, including PubMed, Scopus, and Web of Science, covering the period from 2008 to 2023. Through this search, we identified and selected approximately 90 articles that met our specific criteria.

Honokiol affects the composition of gut microbiota and the metabolism of lipid and bile acid in methionine-choline deficiency diet-induced NASH mice

Honokiol (HNK), one of the main active components of Magnolia officinalis, has a positive effect on non-alcoholic steatohepatitis (NASH). However, the effects of HNK on the composition of serum lipids and bile acids (BAs) and gut microbiota (GM) of NASH mice are still unknown.C57BL/6 mice were fed with methionine-choline deficiency (MCD) diet and gavaged with HNK (20 mg/kg/d) for 8 weeks, then the serum lipids and BAs were detected by LC-MS, the composition of ileum microflora and the mRNA expression of hepatic BAs homeostasis related genes were analyzed by 16S rDNA sequencing and RT-qPCR, respectively. HNK treatment decreased the degree of hepatic lipid drops, inflammatory cell infiltration and fibrosis. Meantime, the serum levels of 34 lipids and 4 BAs in MCD mice were significantly altered by HNK treatment, as well as the increased abundance of Ruminococcaceae, Caulobacteraceae and Brevundimonas, and the decreased abundance of Firmicutes and Dubosiella. Besides, HNK treatment increased the hepatic mRNA expression of Oatp1b2 in MCD mice. The ameliorating effect of HNK on NASH may be partly related to its correction on the disorders of GM, serum lipids and BAs of MCD mice.

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.

Pharmacological features, health benefits and clinical implications of honokiol

Honokiol (HNK) is a natural polyphenolic compound extracted from the bark and leaves of Magnolia grandiflora. It has been traditionally used as a medicinal compound to treat inflammatory diseases. HNK possesses numerous health benefits with a minimal level of toxicity. It can cross the blood-brain barrier and blood-cerebrospinal fluid, thus having significant bioavailability in the neurological tissues. HNK is a promising bioactive compound possesses neuroprotective, antimicrobial, anti-tumorigenic, anti-spasmodic, antidepressant, analgesic, and antithrombotic features . HNK can prevent the growth of several cancer types and haematological malignancies. Recent studies suggested its role in COVID-19 therapy. It binds effectively with several molecular targets, including apoptotic factors, chemokines, transcription factors, cell surface adhesion molecules, and kinases. HNK has excellent pharmacological features and a wide range of chemotherapeutic effects, and thus, researchers have increased interest in improving the therapeutic implications of HNK to the clinic as a novel agent. This review focused on the therapeutic implications of HNK, highlighting clinical and pharmacological features and the underlying mechanism of action.Communicated by Ramaswamy H. Sarma.

Effects of natural products on cisplatin ototoxicity and chemotherapeutic efficacy

INTRODUCTION

Cisplatin is a very effective chemotherapeutic agent against a variety of solid tumors. Unfortunately, cisplatin causes permanent sensorineural hearing loss in at least two-thirds of patients treated. There are no FDA approved drugs to prevent this serious side effect.

AREAS COVERED

This paper reviews various natural products that ameliorate cisplatin ototoxicity. These compounds are strong antioxidants and anti-inflammatory agents. This review includes mostly preclinical studies but also discusses a few small clinical trials with natural products to minimize hearing loss from cisplatin chemotherapy in patients. The interactions of natural products with cisplatin in tumor-bearing animal models are highlighted. A number of natural products did not interfere with cisplatin anti-tumor efficacy and some agents actually potentiated cisplatin anti-tumor activity.

EXPERT OPINION

There are a number of natural products or their derivatives that show excellent protection against cisplatin ototoxicity in preclinical studies. There is a need to insure uniform standards for purity of drugs derived from natural sources and to ensure adequate pharmacokinetics and safety of these products. Natural products that protect against cisplatin ototoxicity and augment cisplatin's anti-tumor effects in multiple studies of tumor-bearing animals are most promising for advancement to clinical trials. The most promising natural products include honokiol, sulforaphane, and thymoquinone.

Honokiol inhibits the growth of hormone-resistant breast cancer cells: its promising effect in combination with metformin

Background and purpose

Primary and metastatic breast cancers still represent an unmet clinical need for improved chemotherapy and hormone therapy. Considerable attention has been paid to natural anticancer compounds, especially lignans. The study aimed to evaluate the activity of several lignans against breast cancer cells and assess the effect of leading lignans on signaling pathways in combination with metformin.

Experimental approach

Human breast cancer cell lines MCF7 (hormone-dependent), MDA-MB-231, and SKBR3 (hormone-independent) were used. A hormone-resistant MCF7/hydroxytamoxifen (HT) subline was obtained by long-term cultivation of the MCF7 line with hydroxytamoxifen. Antiproliferative activity was assessed by the MTT test; the expression of signaling pathway proteins was evaluated by immunoblotting analysis.

Findings/Results

We evaluated the antiproliferative activity of lignans in breast cancer cells with different levels of hormone dependence and determined the relevant IC50 values. Honokiol was chosen as the leading compound, and its IC50 ranged from 12 to 20 μM, whereas for other tested lignans, the IC50 exceeded 50 μM. The accumulation of cleaved PARP and a decrease in the expression of Bcl-2 and ERα in MCF7/HT were induced following the combination of honokiol with metformin.

Conclusions and implications

Honokiol demonstrated significant antiproliferative activity against both hormone-dependent breast cancer cells and lines with primary and acquired hormone resistance. The combination of honokiol with metformin is considered an effective approach to induce death in hormone-resistant cells. Honokiol is of interest as a natural compound with antiproliferative activity against breast cancers, including resistant tumors.

Honokiol Inhibits SARS-CoV-2 Replication in Cell Culture at a Post-Entry Step

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019, and the resulting pandemic has already caused the death of over 6 million people. There are currently few antivirals approved for treatment of the 2019 coronavirus disease (COVID-19), and more options would be beneficial, not only now but also to increase our preparedness for future coronavirus outbreaks. Honokiol is a small molecule from magnolia trees for which several biological effects have been reported, including anticancer and anti-inflammatory activities. Honokiol has also been shown to inhibit several viruses in cell culture. In this study, we determined that honokiol protected Vero E6 cells from SARS-CoV-2-mediated cytopathic effect, with a 50% effective concentration of 7.8 μM. In viral load reduction assays, honokiol decreased viral RNA copies as well as viral infectious progeny titers. The compound also inhibited SARS-CoV-2 replication in the more relevant human A549 cells expressing angiotensin converting enzyme 2 and transmembrane protease serine 2. Time-of-addition and other assays showed that honokiol inhibited virus replication at a post-entry step of the replication cycle. Honokiol was also effective against more recent variants of SARS-CoV-2, including Omicron, and it inhibited other human coronaviruses as well. Our study suggests that honokiol is an interesting molecule to be evaluated further in animal studies and, when successful, maybe even in clinical trials to investigate its effect on virus replication and pathogenic (inflammatory) host responses. IMPORTANCE Honokiol is a compound that shows both anti-inflammatory and antiviral effects, and therefore its effect on SARS-CoV-2 infection was assessed. This small molecule inhibited SARS-CoV-2 replication in various cell-based infection systems, with up to an ~1,000-fold reduction in virus titer. In contrast to earlier reports, our study clearly showed that honokiol acts on a postentry step of the replication cycle. Honokiol also inhibited different recent SARS-CoV-2 variants and other human coronaviruses (Middle East respiratory syndrome CoV and SARS-CoV), demonstrating its broad spectrum of antiviral activity. The anticoronavirus effect, combined with its anti-inflammatory properties, make honokiol an interesting compound to be further explored in animal coronavirus infection models.

Honokiol reduces cadmium-induced oxidative injury and endosomal/lysosomal vacuolation via protecting mitochondrial function in quail (Coturnix japonica) liver tissues

Cadmium (Cd) pollution in environment is toxic to birds. This study aimed to assess antagonistic effect of honokiol (HNK) on Cd-induced quail (Coturnix japonica) liver tissue damage and Cd-induced vacuolation in hepatocytes. We found that HNK alleviated Cd-induced liver pathological damage marked by elevated serum liver biochemical indicators, disordered antioxidant levels and trace elements in quails. HNK reduced Cd-induced liver cell apoptosis as assessed by western blotting and TUNEL staining. The ultrastructure of hepatocytes under transmission electron microscope revealed that Cd induced mitochondrial damage in addition to abnormal enlargement and increased vacuolar structure of cells. Mitochondrial damage and vacuolization were reduced in the HNK + Cd group. Cd induced an increase in the levels of endosomal/lysosomal-related genes, while HNK treatment reversed this effect. Finally, we demonstrated that vacuolation in buffalo rat liver 3A (BRL 3A) cells occurred primarily due to Cd-induced oxidative stress damage that reduces mitochondrial ATP content and indirectly led to dysfunction of ATP-dependent lipid kinase PIKfyve complex. In summary, we are the first to report that Cd induces abnormal enlargement of endosome/lysosomes in quail liver cells and HNK alleviated this phenomenon by reducing mitochondrial damage and increasing intracellular ATP level. This study demonstrated the toxic effect of Cd pollution on birds and how HNK mitigated these effect at the cellular level. Overall, more research on Cd pollution and HNK use in animal husbandry is warranted.

Honokiol Microemulsion Causes Stage-Dependent Toxicity Via Dual Roles in Oxidation-Reduction and Apoptosis through FoxO Signaling Pathway

Honokiol, the main bioactive extract of Magnolia officinalis, exhibits extensive therapeutic actions. Its treatment for advanced non-small cell lung cancer is undergoing clinical trials in China. However, the published safety evaluation studies have focused on extract mixtures of Magnolia officinalis in which the honokiol content was well below the reported clinical dose of the honokiol monomer. Therefore, safety assessment of the honokiol monomer is urgently needed. Our previous studies have already demonstrated that a high dose of the honokiol microemulsion (0.6 μg/mL) induces developmental toxicity in rats and zebrafish by inducing oxidative stress. By exploring the relationship between time and toxicity, we found that developmental toxic responses were stage-dependent. They mainly occurred within the first 24 h post fertilization (hpf) especially the first 12 hpf. In zebrafish, low doses of honokiol microemulsion (0.15, 0.21 μg/mL) significantly decreased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and increased the mRNA expression of bcl-2. In contrast, high dose (0.6 μg/mL) increased the levels of ROS and MDA, decreased activities and mRNA expression of superoxide dismutase (SOD) and catalase (CAT), and increased mRNA expression of bax, c-jnk, p53 and bim. By acridine orange staining, we found that a high dose of honokiol microemulsion induced apoptosis mainly in zebrafish brain. In rat pheochromocytoma cells (PC12 cells), low doses of the honokiol microemulsion (1, 5, 10 µM) exerted a protective effect against H₂O₂-induced oxidative damage while high doses (≥20 µM) induced oxidative stress, which further confirms the dual effects of honokiol microemulsion on nerve cells. These dual roles of the honokiol microemulsion in oxidation-reduction reactions and apoptosis may be regulated by the forkhead box class O (FoxO) signaling pathway. Due to the potential of developmental toxicity, we recommend that the administration of high dose honokiol microemulsion in pregnant women should be considered with caution.

Sequential Delivery of Novel Triple Drug Combination via Crosslinked Alginate/Lactoferrin Nanohybrids for Enhanced Breast Cancer Treatment

While breast cancer remains a global health concern, the elaboration of rationally designed drug combinations coupled with advanced biocompatible delivery systems offers new promising treatment venues. Herein, we repurposed rosuvastatin (RST) based on its selective tumor apoptotic effect and combined it with the antimetabolite pemetrexed (PMT) and the tumor-sensitizing polyphenol honokiol (HK). This synergistic three-drug combination was incorporated into protein polysaccharide nanohybrids fabricated by utilizing sodium alginate (ALG) and lactoferrin (LF), inspired by the stealth property of the former and the cancer cell targeting capability of the latter. ALG was conjugated to PMT and then coupled with LF which was conjugated to RST, forming core shell nanohybrids into which HK was physically loaded, followed by cross linking using genipin. The crosslinked HK-loaded PMT-ALG/LF-RST nanohybrids exhibited a fair drug loading of 7.86, 5.24 and 6.11% for RST, PMT and HK, respectively. It demonstrated an eight-fold decrease in the IC50 compared to the free drug combination, in addition to showing an enhanced cellular uptake by MCF-7 cells. The in vivo antitumor efficacy in a breast cancer-bearing mouse model confirmed the superiority of the triple cocktail-loaded nanohybrids. Conclusively, our rationally designed triple drug-loaded protein/polysaccharide nanohybrids offer a promising, biocompatible approach for an effective breast tumor suppression.

Magnolol as a Potential Anticancer Agent: A Proposed Mechanistic Insight

Cancer is a serious disease with high mortality and morbidity worldwide. Natural products have served as a major source for developing new anticancer drugs during recent decades. Magnolol, a representative natural phenolic lignan isolated from Magnolia officinali, has attracted considerable attention for its anticancer properties in recent years. Accumulating preclinical studies have demonstrated the tremendous therapeutic potential of magnolol via a wide range of pharmacological mechanisms against cancer. In this review, we summarized the latest advances in preclinical studies investigating anticancer properties of magnolol and described the important signaling pathways explaining its underlying mechanisms. Magnolol was capable of inhibiting cancer growth and metastasis against various cancer types. Magnolol exerted anticancer effects through inhibiting proliferation, inducing cell cycle arrest, provoking apoptosis, restraining migration and invasion, and suppressing angiogenesis. Multiple signaling pathways were also involved in the pharmacological actions of magnolol against cancer, such as PI3K/Akt/mTOR signaling, MAPK signaling and NF-κB signaling. Based on this existing evidence summarized in the review, we have conclusively confirmed magnolol had a multi-target anticancer effect against heterogeneous cancer disease. It is promising to develop magnolol as a drug candidate for cancer therapy in the future.

Effects of non-covalent binding of lignans with rice starch driven by high-pressure homogenization on the starch structure and in vitro nutritional characteristics

As a type of phytoestrogen, lignans have attracted attention in recent years for their nutritional functions. To investigate the effects of lignans on the structural and nutritional functions of starch, honokiol (HK) and arctiin (AC) were complexed with rice starch respectively under high-pressure homogenization (UHPH) (UHPHRS/HK and UHPHRS/AC). The results showed that both HK and AC could form inclusive complexes with rice starch via non-covalent bonding (hydrophobic interaction and hydrogen bonds), and these complexes could further form V-type crystals and aggregates, which reduced the starch digestibility as well as endowing them with the ability to retard glucose release and bind sodium cholate. Interestingly, due to its smaller molecular size, HK could induce starch to form a more compact structure than AC, leading to better nutritional functions. When the addition of HK/AC reached 8%, the resistant starch content could reach 26% and 19.8%, respectively. Meanwhile, the glucose dialysis retardation index could increase to 17.2% and 14.8%, respectively, and the sodium cholate-binding capacity could increase to 33.1 mg g^-1 and 21.8 mg g^-1, respectively. These results demonstrated that UHPH with lignans' molecular interaction could be beneficial for controlling the nutritional functions of starch products with the desired digestibility.

Therapeutic efficacy of Nano-formulation of lactoperoxidase and lactoferrin via promoting immunomodulatory and apoptotic effects

This study identifies promising potential of a novel and safer nanocombination of bovine milk lactoperoxidase (LPO) and lactoferrin (LF) to target breast cancer in vitro and in adult female albino rat model. Favorable selective anticancer effects of the prepared nanocombination were observed, in a dose-dependent manner, against both MCF-7 and MDA cell lines, sparing normal HFB-4 cells. The administration of LPO + LFNPs markedly improved the induced-breast cancer disorders, prolonged survival and reduced the values of serum TNF-α, IL1β, CD4⁺, ALAT, ASAT, urea, creatinine, cholesterol and triglycerides with remarkable elevation in mammary SOD and GPx activity and GSH level. Moreover, the histopathological findings showed that LPO + LFNPs succeeded in prevention of mammary gland tumorigenesis. Superior efficacy of LPO + LFNPs was observed against pro-inflammatory cytokines through their anti-inflammatory and immunomodulatory properties. The treatment of LPO + LFNPs more significantly modulated the apoptosis and enhanced the expression of cell cycle regulator genes, which demonstrates a successful tumor therapy in vitro and in vivo. Therefore, this study provided evidence that the chemo-preventive feature of LPO + LFNPs may offer a novel alternative therapy for the treatment of breast cancer through enhances apoptosis pathway, improvement of immune response, reduction of inflammation and restoration of the impaired oxidative stress.

Honokiol alleviates ulcerative colitis by targeting PPAR-γ-TLR4-NF-κB signaling and suppressing gasdermin-D-mediated pyroptosis in vivo and in vitro

Ulcerative colitis (UC) is a chronic, idiopathic relapsing inflammatory bowel disease. Honokiol is a major active component of the traditional Chinese medicinal herb Magnolia officinalis, which has been widely used in traditional prescriptions to treat tumors, inflammation, and gastrointestinal disorders. In this study, we investigated the ability of this polyphenolic compound to suppress UC in mice and the possible regulatory mechanism. A mouse model of UC induced with dextran sulfate sodium (DSS) in 40 male C57BL/6J mice was used for the in vivo study, and in vitro experiments were performed in mouse RAW264.7 macrophages. Lipopolysaccharide was used to induce the inflammatory response. The mouse bodyweights, stool consistency, and bleeding were determined and the disease activity indices calculated. RAW264.7 macrophages were cultured with or without either honokiol or lipopolysaccharide. Gene and protein expression was analyzed with RT-PCR and western blotting, respectively. GW6471 and GW9662 were used to interrupt the transcription of peroxisome proliferator activated receptor alpha (PPAR-α) and peroxisome proliferator activated receptor gamma (PPAR-γ). Both the in vivo and in vitro experimental results showed that the oral administration of honokiol markedly attenuated the severity of UC by reducing the inflammatory signals and restoring the integrity of the colon. Honokiol dramatically reduced the proinflammatory cytokines TNF-α, IL6, IL1β, and IFN-γ in mice with DSS-induced UC. It also upregulated PPAR-γ expression, and downregulated the TLR4-NF-κB signaling pathway. Moreover, honokiol inhibited gasdermin-D-mediated cell pyroptosis. These findings demonstrate for the first time that honokiol exerts a strong anti-inflammatory effect in a mouse model of UC, and that its underlying mechanism is associated with the activation of the PPAR-γ-TLR4-NF-κB signaling pathway and gasdermin-D-mediated macrophage pyroptosis. Therefore, honokiol may be a promising new drug for the clinical management of UC.

Improved Pharmaceutical Properties of Honokiol via Salification with Meglumine: an Exception to Oft-quoted ∆pKa Rule

Honokiol (HK), a BCS class II drug with a wide range of pharmacological activities, has poor solubility and low oral bioavailability, severely limiting its clinical application. In the current study, incorporating a water-soluble meglumine (MEG) into the crystal lattice of HK molecule was performed to improve its physicochemical properties. The binary mixture of HK and MEG was obtained by anti-solvent method and characterized by TGA, DSC, FTIR, and PXRD. The SCXRD analysis showed that two HK^- molecules and two MEG⁺ molecules were coupled in each unit cell via the ionic interaction along with intermolecular hydrogen bonds, suggesting the formation of a salt, which was further confirmed by the XPS measurements. However, the ∆pK_a value between HK and MEG was found to be less than 1, which did not follow the oft-quoted ∆pK_a rule for salt formation. After salification with MEG, the solubility and dissolution rate of HK exhibited 3.50 and 25.33 times improvement than crystalline HK, respectively. Simultaneously, the powder flowability, tabletability and stability of HK-MEG salt was also significantly enhanced, and the salt was not more hygroscopic, and that salt formation did not compromise processability in that regard. Further, in vivo pharmacokinetic study showed that C_max and AUC_0-t of HK-MEG salt were enhanced by 2.92-fold and 2.01-fold compared to those of HK, respectively, indicating a considerable improvement in HK oral bioavailability.

Comprehensive Computational Analysis of Honokiol Targets for Cell Cycle Inhibition and Immunotherapy in Metastatic Breast Cancer Stem Cells

Breast cancer stem cells (BCSCs) play a critical role in chemoresistance, metastasis, and poor prognosis of breast cancer. BCSCs are mostly dormant, and therefore, activating them and modulating the cell cycle are important for successful therapy against BCSCs. The tumor microenvironment (TME) promotes BCSC survival and cancer progression, and targeting the TME can aid in successful immunotherapy. Honokiol (HNK), a bioactive polyphenol isolated from the bark and seed pods of Magnolia spp., is known to exert anticancer effects, such as inducing cell cycle arrest, inhibiting metastasis, and overcoming immunotherapy resistance in breast cancer cells. However, the molecular mechanisms of action of HNK in BCSCs, as well as its effects on the cell cycle, remain unclear. This study aimed to explore the potential targets and molecular mechanisms of HNK on metastatic BCSC (mBCSC)-cell cycle arrest and the impact of the TME. Using bioinformatics analyses, we predicted HNK protein targets from several databases and retrieved the genes differentially expressed in mBCSCs from the GEO database. The intersection between the differentially expressed genes (DEGs) and the HNK-targets was determined using a Venn diagram, and the results were analyzed using a protein-protein interaction network, hub gene selection, gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, genetic alteration analysis, survival rate, and immune cell infiltration levels. Finally, the interaction between HNK and two HNK-targets regulating the cell cycle was analyzed using molecular docking analysis. The identified potential therapeutic targets of HNK (PTTH) included CCND1, SIRT2, AURKB, VEGFA, HDAC1, CASP9, HSP90AA1, and HSP90AB1, which can potentially inhibit the cell cycle of mBCSCs. Moreover, our results showed that PTTH could modulate the PI3K/Akt/mTOR and HIF1/NFkB/pathways. Overall, these findings highlight the potential of HNK as an immunotherapeutic agent for mBCSCs by modulating the tumor immune environment.

Targeting cancer signaling pathways by natural products: Exploring promising anti-cancer agents

Cancer is one of the leading causes of death and significantly burdens the healthcare system. Due to its prevalence, there is undoubtedly an unmet need to discover novel anticancer drugs. The use of natural products as anticancer agents is an acceptable therapeutic approach due to accessibility, applicability, and reduced cytotoxicity. Natural products have been an incomparable source of anticancer drugs in the modern era of drug discovery. Along with their derivatives and analogs, natural products play a major role in cancer treatment by modulating the cancer microenvironment and different signaling pathways. These compounds are effective against several signaling pathways, mainly cell death pathways (apoptosis and autophagy) and embryonic developmental pathways (Notch pathway, Wnt pathway, and Hedgehog pathway). The historical record of natural products is strong, but there is a need to investigate the current role of natural products in the discovery and development of cancer drugs and determine the possibility of natural products being an important source of future therapeutic agents. Many target-specific anticancer drugs failed to provide successful results, which accounts for a need to investigate natural products with multi-target characteristics to achieve better outcomes. The potential of natural products to be promising novel compounds for cancer treatment makes them an important area of research. This review explores the significance of natural products in inhibiting the various signaling pathways that serve as drivers of carcinogenesis and thus pave the way for developing and discovering anticancer drugs.

Honokiol Induces Ferroptosis by Upregulating HMOX1 in Acute Myeloid Leukemia Cells

Acute myeloid leukemia (AML) is one of the malignant hematological cancers with high mortality. Finding a more effective and readily available treatment is of the utmost importance. Here, we aimed to identify the anti-leukemia effect of a natural small molecule compound honokiol on a panel of AML cell lines, including THP-1, U-937, and SKM-1, and explored honokiol’s potential biological pathways and mechanisms. The results showed that honokiol decreased the viability of the targeted AML cells, induced their cell cycle arrest at G0/G1 phase, and inhibited their colony-formation capacity. Honokiol also triggers a noncanonical ferroptosis pathway in THP-1 and U-937 cells by upregulating the level of intracellular lipid peroxide and HMOX1 significantly. Subsequent studies verified that HMOX1 was a critical target in honokiol-induced ferroptosis. These results reveal that honokiol is an effective anti-leukemia agent in AML cell lines and may be a potential ferroptosis activator in AML.

Anisi Stellati Fructus, a Significant Traditional Chinese Medicine (TCM) Herb and Its Bioactivity against Gastric Cancer

Anisi stellati fructus (ASF) is the fruit of Illicium verum Hook F. (Chinese star anise), which is native to many countries, and is a significant Chinese medicinal herb. Gastric cancer (GC) is one of the major fatal types of cancers with multiple stages and a poor prognosis. The present review aims to discuss the bioactive properties of ASF and its phytocompounds against GC, with a particular insight into the molecular mechanisms and signaling pathways involved in its anti-GC mechanism. Furthermore, it highlights the potential mechanism of action of major phytocompounds of ASF against GC. Clinical studies (in vitro and in vivo) regarding the action of ASF and its major bioactive compounds such as quercetin, luteolin, kaempferol, d-limonene, and honokiol against GC were reviewed. For this review, search of literature was performed in Science, PubMed, Google Scholar, Web of Science, and Scopus related to ASF and its phytocompounds, from which only relevant studies were chosen. Major bioactive compounds of ASF and their extracts have proven to be effective against GC due to the mechanistic action of these compounds involving signaling pathways that target cancer cell apoptosis, proliferation, and tumor metastasis in GC cells. Existing reports of these compounds and their combinatory effects with other modern anticancer agents have also been reviewed. From its traditional use to its role as an anticancer agent, ASF and its bioactive phytocompounds have been observed to be effective in modern research, specifically against GC. However, further studies are required for the identification of molecular targets and pharmacokinetic potential and for the formulation of anti-GC drugs.

Potential Therapeutic Targets and Promising Agents for Combating NAFLD

Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), is a growing cause of liver cirrhosis and liver cancer worldwide because of the global increases in obesity, dyslipidemia, hypertension, and type 2 diabetes mellitus. Contrary to the advancements in therapies for viral hepatitis, effective treatments remain unestablished for patients with NAFLD. NAFLD, including NASH, is characterized by steatosis, inflammation, hepatic necrosis, and fibrosis. Despite our understanding of its pathophysiology, there are currently no effective treatments for NAFLD. In this review, we provide an update on the known pathophysiological mechanisms involved in the development of NAFLD and the role of hepatic stellate cells, and summarize the potential therapeutic agents, including natural products, for NAFLD.

Honokiol Provides Cardioprotection from Myocardial Ischemia/Reperfusion Injury (MI/RI) by Inhibiting Mitochondrial Apoptosis via the PI3K/AKT Signaling Pathway

Background

Myocardial injury refers to a major complication that occurs in myocardial ischemia/reperfusion injury (MI/RI). Honokiol is a well-recognized active compound extracted from the traditional Chinese herb known as Magnolia officinalis and is utilized in treating different vascular diseases. This research is aimed at examining whether Honokiol might alleviate myocardial injury in an MI/RI model.

Methods

Seventy-eight male C57BL/6 mice were categorized randomly into three cohorts including the Sham operation (Sham) cohort, the MI/RI cohort (Con), and the Honokiol cohort (n = 26 for each cohort). The mice in the Honokiol cohort were treated with Honokiol before MI/RI surgery (0.2 mg/kg/day for 14 days, intraperitoneal), while the mice in the Con cohort were given an intraperitoneal injection with an equivalent volume of vehicle (DMSO) daily in 14 days prior to exposure to MI/RI. After the surgery, creatine kinase- (CK-) MB and cardiac troponin T (cTnT) levels, as well as the infarct area, were measured to assess the degree of myocardial damage. Apoptotic levels were detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. Electron microscopy was utilized to identify mitochondrial damage. Lastly, the expression levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cleaved caspase-9, cytochrome C (Cyt-C), B cell lymphoma/leukemia-2 (Bcl-2), B cell lymphoma/leukemia-2 associated X (Bax), AKT, p-AKT, PI3K, and p-PI3K were analyzed utilizing western blotting.

Results

Honokiol can reduce the MI/RI-induced cTnT and CK-MB levels, apoptosis index, and mitochondrial swelling in cardiomyocytes via activating the PI3K/AKT signaling pathway.

Conclusion

Honokiol provides cardiac protection from MI/RI by suppressing mitochondrial apoptosis through the PI3K/AKT signaling pathway.

Natural Kinase Inhibitors for the Treatment and Management of Endometrial/Uterine Cancer: Preclinical to Clinical Studies

Endometrial cancer (EC) is the sixth most prevalent type of cancer among women. Kinases, enzymes mediating the transfer of adenosine triphosphate (ATP) in several signaling pathways, play a significant role in carcinogenesis and cancer cells’ survival and proliferation. Cyclin-dependent kinases (CDKs) are involved in EC pathogenesis; therefore, CDK inhibitors (CDKin) have a noteworthy therapeutic potential in this type of cancer, particularly in EC type 1. Natural compounds have been used for decades in the treatment of cancer serving as a source of anticancer bioactive molecules. Many phenolic and non-phenolic natural compounds covering flavonoids, stilbenoids, coumarins, biphenyl compounds, alkaloids, glycosides, terpenes, and terpenoids have shown moderate to high effectiveness against CDKin-mediated carcinogenic signaling pathways (PI3K, ERK1/2, Akt, ATM, mTOR, TP53). Pharmaceutical regimens based on two natural compounds, trabectedin and ixabepilone, have been investigated in humans showing short and midterm efficacy as second-line treatments in phase II clinical trials. The purpose of this review is twofold: the authors first provide an overview of the involvement of kinases and kinase inhibitors in the pathogenesis and treatment of EC and then discuss the existing evidence about natural products’ derived kinase inhibitors in the management of the disease and outline relevant future research.

New and Emerging Targeted Therapies for Advanced Breast Cancer

In the United States, breast cancer is among the most frequently diagnosed cancers in women. Breast cancer is classified into four major subtypes: human epidermal growth factor receptor 2 (HER2), Luminal-A, Luminal-B, and Basal-like or triple-negative, based on histopathological criteria including the expression of hormone receptors (estrogen receptor and/or progesterone receptor) and/or HER2. Primary breast cancer treatments can include surgery, radiation therapy, systemic chemotherapy, endocrine therapy, and/or targeted therapy. Endocrine therapy has been shown to be effective in hormone receptor-positive breast cancers and is a common choice for adjuvant therapy. However, due to the aggressive nature of triple-negative breast cancer, targeted therapy is becoming a noteworthy area of research in the search for non-endocrine-targets in breast cancer. In addition to HER2-targeted therapy, other emerging therapies include immunotherapy and targeted therapy against critical checkpoints and/or pathways in cell growth. This review summarizes novel targeted breast cancer treatments and explores the possible implications of combination therapy.

Tumor-targeted delivery of honokiol via polysialic acid modified zein nanoparticles prevents breast cancer progression and metastasis

In this work, we developed polysialic acid (PSA) modified zein nanoparticles for targeted delivery of honokiol (HNK) to enhance drug delivery efficiency and specific biodistribution at tumor sites. The antisolvent precipitation and electrostatic interaction methods were employed to fabricate the PSA-Zein-HNK nanoparticles, which exhibited mean size of 107.2 ± 10.1 nm and HNK encapsulation efficiency of 79.2 ± 2.3%. The PSA-Zein-HNK maintained a uniform dispersion in serum for 48 h, implying the improved colloid stability of zein nanoparticles via PSA coating. The cellular uptake of PSA-Zein-Cou6 nanoparticles in 4 T1 cells was 2.58-fold higher than non-targeting Zein-Cou6. In addition, the IC₅₀ value at 48 h for PSA-Zein-HNK (4.37 μg/mL) was significantly higher than the Zein-HNK (7.74 μg/mL). Enhanced tumor accumulation of the PSA-Zein-HNK was confirmed in 4 T1 breast cancer-bearing mice by near-infrared fluorescence imaging, resulting in desirable antitumor efficacy and favorable biosafety. Besides, compared with non-targeting zein nanoparticles, the PSA-Zein-HNK achieved a higher tumor growth inhibition rate of 52.3%. In particular, the metastasis of breast cancer to the lung or liver was remarkably suppressed by PSA-Zein-HNK. Together, our results demonstrated that the PSA-Zein-HNK could be a potential tumor-targeted drug delivery strategy for efficient treatment of breast cancer.

A Combination therapy using an mTOR inhibitor and Honokiol effectively induces autophagy through the modulation of AXL and Rubicon in renal cancer cells and restricts renal tumor growth following organ transplantation

Development of cancer, including renal cancer, is a major problem in immunosuppressed patients. The mTOR inhibitor Rapamycin (RAPA) is used as an immunosuppressive agent in patients with organ transplants and other immunological disorders; and it also has antitumorigenic potential. However, long-term use of RAPA causes reactivation of Akt, and ultimately leads to enhanced tumor growth. Honokiol (HNK) is a natural compound, which possesses both anti-inflammatory and antitumorigenic properties. In this study, we investigated the effect of a novel combination therapy using RAPA + HNK on allograft survival and post-transplantation renal tumor growth. We observed that it effectively modulated the expression of some key regulatory molecules (like Carabin, an endogenous Ras inhibitor; and Rubicon, a negative regulator of autophagy) that play important roles in tumor cell growth and survival. This combination induced toxic autophagy and apoptosis to promote cancer cell death; and was associated with a reduced expression of the tumor-promoting receptor tyrosine kinase AXL. Finally, we utilized a novel murine model to examine the effect of RAPA + HNK on post-transplantation renal tumor growth. The combination treatment prolonged the allograft survival and significantly inhibited post-transplantation tumor growth. It was associated with reduced tumor expression of Rubicon and the cytoprotective/antioxidant heme oxygenase-1 to overcome therapeutic resistance. It also downregulated the coinhibitory programmed death-1 ligand, which plays major role(s) in the immune escape of tumor cells. Together, this combination treatment has a great potential to restrict renal tumor growth in transplant recipients as well as other immunosuppressed patients.

Receptor tyrosine kinases as a therapeutic target by natural compounds in cancer treatment

Background

Receptor tyrosine kinases (RTKs) are single-pass transmembrane proteins that play significant roles in regulating cellular processes, including cell division and growth. Overexpression and mutations of RTKs have been found in clinical manifestations of different forms of cancer. Therefore, RTKs have received considerable interest as a therapeutic biomarker in the treatment of cancer cells.

Main body of the abstract

Comprehensive data on RTKs, pharmacological and biological properties of natural compounds were systematically searched up to 2021 using relevant keywords from various databases, such as Google Scholar, PubMed, Web of Science, and Scopus. The scientific search by various standard electronic resources and databases unveils the effectiveness of medicinal plants in the treatment of various cancers. In vitro and in vivo studies suggested that bioactive compounds such as flavonoids, phenols, alkaloids, and many others can be used pharmacologically as RTKs inhibitors (RTKI) either by competing with ATP at the ATP binding site of the tyrosine kinase domain or competing for the receptor extracellular domain. Additionally, studies conducted on animal models indicated that inhibition of RTKs catalytic activity by natural compounds is one of the most effective ways to block the activation of RTKs signaling cascades, thereby hampering the proliferation of cancer cells. Furthermore, various pharmacological experiments, transcriptomic, and proteomic data also reported that cancer cells treated with different plants extracts or isolated phytochemicals exhibited better anticancer properties with minimal side effects than synthetic drugs. Clinically, natural compounds have demonstrated significant anti-proliferative effect via induction of cell apoptosis in cancer cell lines.

Short conclusion

An in-depth knowledge of the mechanism of inhibition and structural characterization of RTKs is important to the design of novel and selective RTKIs. This review focuses on the molecular mechanisms and structures of natural compounds RTKI targeting vascular endothelial growth factor, epidermal growth factor receptor, insulin receptor, and platelet-derived growth factor while also giving future directions to ameliorate the scientific burden of cancer.

Graphic abstract

The modulation of SIRT1 and SIRT3 by natural compounds as a therapeutic target in doxorubicin-induced cardiotoxicity: A review

Doxorubicin (DOX) is a potent antitumor agent with a broad spectrum of activity; however, irreversible cardiotoxicity resulting from DOX treatment is a major issue that limits its therapeutic use. Sirtuins (SIRTs) play an essential role in several physiological and pathological processes including oxidative stress, apoptosis, and inflammation. It has been reported that SIRT1 and SIRT3 can act as a protective molecular against DOX-induced myocardial injury through targeting numerous signaling pathways. Several natural compounds (NCs), such as resveratrol, sesamin, and berberine, with antioxidative, anti-inflammation, and antiapoptotic effects were evaluated for their potential to suppress the cardiotoxicity induced by DOX via targeting SIRT1 and SIRT3. Numerous NCs exerted their therapeutic effects on DOX-mediated cardiac damage via targeting different signaling pathways, including SIRT1/LKB1/AMPK, SIRT1/PGC-1α, SIRT1/NLRP3, and SIRT3/FoxO. SIRT3 also ameliorates cardiotoxicity by enhancing mitochondrial fusion.

Novel doxorubicin / folate-targeted trans-ferulic acid-loaded PLGA nanoparticles combination: In-vivo superiority over standard chemotherapeutic regimen for breast cancer treatment

AIM

Doxorubicin/Cyclophosphamide (AC) is one of the standard adjuvant anthracycline-containing regimens that is still in use for breast cancer treatment. Cancer cell resistance and AC-induced side effects make treatment suboptimal and worsen patients' quality of life. This study aimed to improve trans-ferulic acid's (TFA) efficiency via loading into folate-receptor-targeted-poly lactic-co-glycolic acid nanoparticles (FA-PLGA-TFA NPs). Also, investigating both the antitumor efficacy of Doxorubicin (Dox)/FA-PLGA-TFA NPs combination against dimethylbenz[a]anthracene (DMBA)-induced breast cancer and its safety profile.

METHODS

FA-PLGA-TFA NPs were optimally fabricated and characterized. Levels of Notch1, Hes1, Wnt-3a, β-catenin, MMP-9, cyclin D1, Permeability-Glycoprotein (P-gp), ERα, PR, and HER2 were assessed as a measure of the antitumor efficacy of different treatment protocols. Histopathological examination of heart and bone, levels of ALT, AST, ALP, CK-MB, and WBCs count were evaluated to ensure the combination's safety profile.

KEY FINDINGS

Dox/FA-PLGA-TFA NPs not only inhibited Notch signaling but also suppressed Notch synergy with Wnt, estrogen, progesterone, and HER2 pathways. Interestingly, Dox/FA-PLGA-TFA NPs decreased P-gp level and preserved heart, bone, and liver health as well as WBCs count.

SIGNIFICANCE

Dox/FA-PLGA-TFA NPs reduced the side-effects of each single drug, and at the same time exerted excellent antitumor activity that surpass the AC regimen in evading cancer cell resistance and having a superior safety profile.

Novel Delivery Systems of Polyphenols and Their Potential Health Benefits

Liposome-based delivery systems have been studied and used more frequently in recent years due to their advantages, such as low toxicity, specificity, and the ability to protect the encapsulated substance from environmental factors, which could otherwise degrade the active compound and reduce its effectiveness. Given these benefits, many researchers have encapsulated polyphenols in liposomes, thus increasing their bioavailability and stability. Similarly, polyphenols encapsulated in liposomes are known to produce more substantial effects on targeted cells than unencapsulated polyphenols, while having minimal cytotoxicity in healthy cells. Although polyphenols play a role in preventing many types of disease and generally have beneficial effects on health, we solely focused on their chemopreventive effects on cancer through liposomes in this review. Our goal was to summarize the applicability and efficacy of liposomes encapsulated with different classes of polyphenols on several types of cancer, thus opening the opportunity for future studies based on these drug delivery systems.

Novel 1,3,4-thiadiazole/oxadiazole-linked honokiol derivatives suppress cancer via inducing PI3K/Akt/mTOR-dependent autophagy

Honokiol is a bioactive biphenolic component derived from Magnoliae officinalis Cortex (known as "Hou Po" in Chinese), a traditional Chinese herbal medicine. A series of novel 1,3,4-thiadiazole/oxadiazole-linked honokiol derivatives were synthesized and tested for anticancer activity against seven human cancer cell lines in this study. Among all derivatives, 8a had the most potent cytotoxic effect on all tested cancer cells, with IC₅₀ values ranging from 1.62 ± 0.19 to 4.61 ± 0.51 µM, which were 10.38-34.36 folds more potent than the parental honokiol (IC₅₀ values of 30.96 ± 1.81-55.67 ± 0.31 µM). On A549, HCT116, and MDA-MB-231 cell lines, 8a demonstrated 5.69-fold, 5.65-fold, and 4.83-fold greater cytotoxicity than cisplatin, respectively. Compound 8a also had higher selectivity (SI values of 8.41-49.38) towards seven cancer cell lines over the normal cell lines than cisplatin (SI values of 1.24-2.52). The analysis of structure-activity relationships (SARs) revealed that honokiol derivatives bearing 1,3,4-thiadiazoles (8a-j) possessed stronger anticancer activity than those containing 1,3,4-oxadiazoles. Further mechanistic investigation indicated that 8a induced cytotoxic autophagy in cancer cells in a time- and dose-independent manner via suppressing the PI3K/Akt/mTOR pathway. Molecular docking suggested that 8a could bind to the PI3Kα active sites. Additionally, 8a inhibited the migration and invasion of A549 and MDA-MB-231 cancer cells.

Green Synthesized Honokiol Transfersomes Relieve the Immunosuppressive and Stem-Like Cell Characteristics of the Aggressive B16F10 Melanoma

BACKGROUND

Honokiol (HK) is a natural bioactive compound with proven antineoplastic properties against melanoma. However, it shows very low bioavailability when administered orally. Alternatively, topical administration may offer a promising route. The objective of the current study was to fabricate HK transfersomes (HKTs) for topical treatment of melanoma. As an ultradeformable carrier system, transfersomes can overcome the physiological barriers to topical treatment of melanoma: the stratum corneum and the anomalous tumor microenvironment. Moreover, the immunomodulatory and stemness-regulation roles of HKTs were the main interest of this study.

METHODS

TFs were prepared using the modified scalable heating method. A three-factor, three-level Box-Behnken design was utilized for the optimization of the process and formulation variables. Intracellular uptake and cytotoxicity of HKTs were evaluated in nonactivated and stromal cell-activated B16F10 melanoma cells to investigate the influence of the complex tumor microenvironment on the efficacy of HK. Finally, ELISA and Western blot were performed to evaluate the expression levels of TGF-β and clusters of differentiation (CD47 and CD133, respectively).

RESULTS

The optimized formula exhibited a mean size of 190 nm, highly negative surface charge, high entrapment efficiency, and sustained release profile. HKTs showed potential to alleviate the immunosuppressive characteristics of B16F10 melanoma in vitro via downregulation of TGF-β signaling. In addition, HKTs reduced expression of the "do not eat me" signal - CD47. Moreover, HKTs possessed additional interesting potential to reduce the expression of the stem-like cell marker CD133. These outcomes were boosted upon combination with metformin, an antihyperglycemic drug recently reported to possess different functions in cancer, while combination with collagenase, an extracellular matrix-depleting enzyme, produced detrimental effects.

CONCLUSION

HKTs represent a promising scalable formulation for treatment of the aggressive B16F10 melanoma, which is jam-packed with immunosuppressive and stem-like cell markers.

Honokiol Alleviates High-Fat Diet-Induced Obesity of Mice by Inhibiting Adipogenesis and Promoting White Adipose Tissue Browning

Honokiol (HON) is one of the main biological active components of the traditional Chinese medicine Magnolia officinalis and has many health benefits. The aim of this study was to investigate whether HON could alleviate obesity in mice by inhibiting adipogenesis and promoting the browning of white adipose tissue (WAT). C57BL/6 mice were divided into five groups and fed with a normal diet (ND), high-fat diet (HFD), or HFD supplemented with 200 (H200), 400 (H400), or 800 (H800) mg/kg BW HON for 8 weeks. The results showed that the mice fed HFD plus HON had lower body fat ratios (BFRs) and smaller adipocyte diameters in the epididymal WAT compared with those of the HFD group. With a proteomics analysis, the HON group upregulated 30 proteins and downregulated 98 proteins in the epididymal WAT of mice, and the steroid O-acyltransferase 1 (SOAT1) was screened as a key protein. The HON supplement prevented HFD-induced adipogenesis by reduced the mRNA and protein expression of SOAT1 and CCAAT/enhancer-binding protein-α (C/EBPα), suggesting that SOAT1 might play an important role in regulating adipogenesis. Moreover, HON treatment increased the expression of proteins related to the classical pathways of energy and lipid metabolism, such as AMP-activated kinase (AMPK) and acetyl-CoA carboxylase (ACC), and promoted the browning of epididymal WAT by upregulation of the protein expression of uncoupling protein 1 (UCP1) in the HFD mice. In conclusion, these results suggest that HON supplements could prevent increases in body fat for HFD mice by suppressing adipogenesis and promoting WAT browning.

Honokiol inhibits hepatoma carcinoma cell migration through downregulated Cyclophilin B expression

Hepatocellular carcinoma (HCC) is the fifth common types of cancer with poor prognosis in the world. Honokiol (HNK), a natural biphenyl compound derived from the magnolia plant, has been reported to exert anticancer effects, but its mechanism has not been elucidated exactly. In the present study, HNK treatment significantly suppressed the migration ability of HepG2 and Hep3B human hepatocellular carcinoma. The treatment reduced the expression levels of the genes associated with cell migration, such as S100A4, MMP-2, MMP-9 and Vimentin. Interestingly, treatment with HNK significantly reduced the expression level of Cyclophilin B (CypB) which stimulates cancer cell migration. However, overexpressed CypB abolished HNK-mediated suppression of cell migration, and reversed the apoptotic effects of HNK. Altogether, we concluded that the suppression of migration activities by HNK was through down-regulated CypB in HCC. These finding suggest that HNK may be a promising candidate for HCC treatment via regulation of CypB.

Honokiol induces paraptosis-like cell death of acute promyelocytic leukemia via mTOR & MAPK signaling pathways activation

Acute promyelocytic leukemia (APL) is a blood system disease caused by the accumulation of a large number of immature blood cells in bone marrow. Although the introduction of all-trans retinoic acid (ATRA) and arsenic has reached a high level of complete remission rate and 5-year disease-free survival rate, the occurrence of various adverse reactions still severely affects the quality of life of patients. As a natural product, honokiol (HNK) has the advantages of low toxicity and high efficiency, and it is a potential drug for the treatment of cancer. Since cancer cells can escape apoptotic cell death through multiple adaptive mechanisms, HNK, a drug that induces cancer cell death in a nonapoptotic way, has attracted much interest. We found that HNK reduced the viability of human APL cell line (NB4 cells) by inducing paraptosis-like cell death. The process was accompanied by excessive reactive oxygen species (ROS), mitochondrial damage, endoplasmic reticulum stress, and increased microtubule-associated protein 1 light chain 3 (LC3) processing. The inactivation of proteasome activity was the main cause of misfolded and unfolded protein accumulation in endoplasmic reticulum, such as LC3II/I and p62. This phenomenon could be alleviated by adding cycloheximide (CHX), a protein synthesis inhibitor. We found that mTOR signaling pathway participated in paraptosis-like cell death induced by HNK in an autophagy-independent process. Moreover, the mitogen-activated protein kinase (MAPK) signaling pathway induced paraptosis of NB4 cells by promoting endoplasmic reticulum stress. In summary, these findings indicate that paraptosis may be a new way to treat APL, and provide novel insights into the potential mechanism of paraptosis-like cell death.

Synergistic killing effect of paclitaxel and honokiol in non-small cell lung cancer cells through paraptosis induction

PURPOSE

Paclitaxel is an anticancer drug for the treatment of non-small cell lung cancer (NSCLC). However, drug-resistance remains a major problem. Honokiol is a natural component which has been found to exhibit anti-tumor activity. Paclitaxel and honokiol have been reported to be able to induce paraptosis. The aim of this study was to investigate whether honokiol can reverse paclitaxel resistance by inducing paraptosis in NSCLC cells.

METHODS

NSCLC cell lines H1650 (paclitaxel-sensitive), H1299 and H1650/PTX (intrinsic and acquired paclitaxel-resistant, respectively) were used to assess the cytotoxic effects of paclitaxel and honokiol. Light and transmission electron microscopy were performed to detect cytoplasmic vacuolation. In vitro cell viability and clonogenic survival assays, as well as in vivo xenograft assays were conducted to test synergistic killing effects of paclitaxel and honokiol on NSCLC cells. Western blotting, flow cytometry and immunofluorescence were performed to evaluate paraptosis-regulating mechanisms.

RESULTS

We found that combination treatment with paclitaxel and honokiol synergistically killed H1650, H1299 and H1650/PTX cells by inducing paraptosis, which is characterized by cytoplasmic vacuolation. Moreover, paclitaxel/honokiol treatment resulted in a significant growth delay in H1299 xenograft tumors that showed extensive cytoplasmic vacuolation. Mechanistically, proteasomal inhibition-mediated endoplasmic reticulum (ER) stress and unfolded protein responses leading to ER dilation, and the disruption of intracellular Ca2+ homeostasis and mitochondrial Ca2+ overload resulting in mitochondrial disfunction, were found to be involved in paclitaxel/honokiol-induced paraptosis. Cellular protein light chain 3 (LC3) may play an important role in paclitaxel/honokiol induced cytoplasmic vacuolation and NSCLC cell death.

CONCLUSIONS

Combination of honokiol and paclitaxel may represent a novel strategy for the treatment of paclitaxel-resistant NSCLC.

Potential Effects of Nutraceuticals in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), the most common cause of childhood blindness, is a hypoxia-induced eye disease characterized by retinal neovascularization. In the normal retina, a well-organized vascular network provides oxygen and nutrients as energy sources to maintain a normal visual function; however, it is disrupted when pathological angiogenesis is induced in ROP patients. Under hypoxia, inadequate oxygen and energy supply lead to oxidative stress and stimulate neovasculature formation as well as affecting the function of photoreceptors. In order to meet the metabolic needs in the developing retina, protection against abnormal vascular formation is one way to manage ROP. Although current treatments provide beneficial effects in reducing the severity of ROP, these invasive therapies may also induce life-long consequences such as systemic structural and functional complications as well as neurodevelopment disruption in the developing infants. Nutritional supplements for the newborns are a novel concept for restoring energy supply by protecting the retinal vasculature and may lead to better ROP management. Nutraceuticals are provided in a non-invasive manner without the developmental side effects associated with current treatments. These nutraceuticals have been investigated through various in vitro and in vivo methods and are indicated to protect retinal vasculature. Here, we reviewed and discussed how the use of these nutraceuticals may be beneficial in ROP prevention and management.

Nutraceutical based SIRT3 activators as therapeutic targets in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, and its incidence is increasing worldwide with increased lifespan. Currently, there is no effective treatment to cure or prevent the progression of AD, which indicates the need to develop novel therapeutic targets and agents. Sirtuins, especially SIRT3, a mitochondrial deacetylase, are NAD-dependent histone deacetylases involved in aging and longevity. Accumulating evidence indicates that SIRT3 dysfunction is strongly associated with pathologies of AD, hence, therapeutic modulation of SIRT3 activity may be a novel application to ameliorate the pathologies of AD. Natural products commonly used in traditional medicine have wide utility and appear to have therapeutic benefits for the treatment of neurodegenerative diseases such as AD. The present review summarizes the currently available natural SIRT3 activators and their potentially neuroprotective molecular mechanisms of action that make them a promising agent in the treatment and management of neurodegenerative diseases such as AD.

Honokiol Alleviates Methionine-Choline Deficient Diet-Induced Hepatic Steatosis and Oxidative Stress in C57BL/6 Mice by Regulating CFLAR-JNK Pathway

Background

Honokiol (HNK) has been reported to possess various beneficial effects in the context of metabolic disorders, including fatty liver, insulin resistance, and oxidative stress which are closely related to nonalcoholic steatohepatitis (NASH), however with no particular reference to CFLAR or JNK.

Methods

C57BL/6 mice were fed methionine-choline-deficient (MCD) diet and administered simultaneously with HNK (10 and 20 mg/kg once a day, ig) for 6 weeks, and NCTC1469 cells were pretreated, respectively, by oleic acid (OA, 0.5 mmol/L) plus palmitic acid (PA, 0.25 mmol/L) for 24 h, and adenovirus-down Cflar for 24 h, then exposed to HNK (10 and 20 μmol/L) for 24 h. Commercial kits, H&E, MT, ORO staining, RT-qPCR, and Western blotting were used to detect the biomarkers, hepatic histological changes, and the expression of key genes involved in NASH.

Results

The in vivo results showed that HNK suppressed the phosphorylation of JNK (pJNK) by activating CFLAR; enhanced the mRNA expression of lipid metabolism-related genes Acox, Cpt1α, Fabp5, Gpat, Mttp, Pparα, and Scd-1; and decreased the levels of hepatic TG, TC, and MDA, as well as the levels of serum ALT and AST. Additionally, HNK enhanced the protein expression of oxidative stress-related key regulatory gene NRF2 and the activities of antioxidases HO-1, CAT, and GSH-Px and decreased the protein levels of prooxidases CYP4A and CYP2E1. The in vivo effects of HNK on the expression of CLFAR, pJNK, and NRF2 were proved by the in vitro experiments. Moreover, HNK promoted the phosphorylation of IRS1 (pIRS1) in both tested cells and increased the uptake of fluorescent glucose 2-NBDG in OA- and PA-pretreated cells.

Conclusions

HNK ameliorated NASH mainly by activating the CFLAR-JNK pathway, which not only alleviated fat deposition by promoting the efflux and β-oxidation of fatty acids in the liver but also attenuated hepatic oxidative damage and insulin resistance by upregulating the expression of NRF2 and pIRS1.

Mitochondria as a Novel Target for Cancer Chemoprevention: Emergence of Mitochondrial-targeting Agents

Cancer chemoprevention is the most effective approach to control cancer in the population. Despite significant progress, chemoprevention has not been widely adopted because agents that are safe tend to be less effective and those that are highly effective tend to be toxic. Thus, there is an urgent need to develop novel and effective chemopreventive agents, such as mitochondria-targeted agents, that can prevent cancer and prolong survival. Mitochondria, the central site for cellular energy production, have important functions in cell survival and death. Several studies have revealed a significant role for mitochondrial metabolism in promoting cancer development and progression, making mitochondria a promising new target for cancer prevention. Conjugating delocalized lipophilic cations, such as triphenylphosphonium cation (TPP+), to compounds of interest is an effective approach for mitochondrial targeting. The hyperpolarized tumor cell membrane and mitochondrial membrane potential allow for selective accumulation of TPP⁺ conjugates in tumor cell mitochondria versus those in normal cells. This could enhance direct killing of precancerous, dysplastic, and tumor cells while minimizing potential toxicities to normal cells.

Systemic application of honokiol prevents cisplatin ototoxicity without compromising its antitumor effect

Cisplatin is a potent drug used in about 40% of cancer treatment but also leads to severe deafness in 60-80% of the cases. Although the mechanism is known to be related to the accumulation of reactive oxygen species (ROS), no drug or FDA approved treatment is currently available to prevent cisplatin ototoxicity. With this study, we show for the first time that honokiol (HNK), a pleiotropic poly-phenol prevents cisplatin-induced hearing loss. HNK also improves the wellbeing of the mice during the treatment, determined by the increase in the number of surviving animals. In a transgenic tumor mouse model, HNK does not hinder cisplatin's antitumor effect. The mechanism is related to the activation of sirtuin 3, a deacetylase in mitochondria essential for ROS detoxification. We expect a paradigm shift in cisplatin chemotherapy based on the current study and future clinical trials, where honokiol is applied to reduce side effects including hearing loss.

Pharmaceutical Evaluation of Honokiol and Magnolol on Apoptosis and Migration Inhibition in Human Bladder Cancer Cells

Among herbal medicines, magnolia bark extract, particularly its components honokiol (Hono) and magnolol (Mag), has been widely documented to have antineoplastic properties. The present study aimed to evaluate the synergism of Hono and Mag in bladder cancer therapy both in vitro and in vivo. Treatment with Mag alone at concentrations up to 80 μM failed to have an antiproliferative effect. In contrast, the combination of Hono and Mag at 40 μM decreased viability, caused cell cycle arrest and enhanced the proportion of Annexin V/7AAD-positive cells. Moreover, Mag with Hono at 40 μM induced caspase 3-dependent apoptosis and autophagy. Neither Hono nor Mag alone had an anti-migratory effect on bladder cancer cells. In contrast, Hono and Mag at 20 μM inhibited the motility of TSGH8301 and T24 cells in wound-healing and Transwell assays. The above phenomena were further confirmed by decreased phosphorylated focal adhesion kinase (p-FAK), p-paxillin, integrin β1, and integrin β3 protein levels. In a nude mouse xenograft model, Mag/Hono administration preferentially retarded T24 tumor progression, which was consistent with the results of cellular experiments. Current findings suggest Hono and Mag treatment as a potential anticancer therapy for both low- and high-grade urothelial carcinoma.