Glycyrrhetinic Acid Mediated Drug Delivery Carriers for Hepatocellular Carcinoma Therapy

Thiolated polymer nanocarrier reinforced with glycyrrhetinic acid for targeted delivery of 5-fluorouracil in hepatocellular carcinoma

The present work investigates the targeting efficacy of a novel thiolated polymer-based nanocomposite reinforced with glycyrrhetinic acid (GA) and loaded with 5-fluorouracil in hepatocellular carcinoma (HCC). The thiolated polymers were synthesized by EDAC-mediated conjugation reactions and lyophilization. The nanoparticles were prepared by solvent diffusion and high-pressure homogenization method. The prepared nanocomposite was characterized by Fourier transform infrared (FTIR) radiation, x-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Pharmacological evaluation of the formulation was carried out on a rat model of diethylnitrosamine (DEN), and carbon tetrachloride (CCl₄)-induced HCC and MTT assay was carried out with HEP-G2 cell line. In silico studies were conducted to investigate the probable mechanistic pathway of the nanocomposite. FTIR and XRD analysis indicated the successful thiolation of the polymers and confirmed the formation of the nanocomposite without any incompatibilities. DLS, SEM/EDX and AFM characterization confirmed that the nanoparticles were within the nano-size range. MTT assay implied the cytotoxic nature of the nanocomposite against hepatic carcinoma cells. The in vivo study revealed that serum SGOT, SGPT, ALP, GGT and total bilirubin levels were significantly reduced, in comparison with disease control and the result was confirmed by histopathology studies. The results of the HPLC analysis of liver homogenate confirmed the liver targeting ability of the nanocomposite. In silico studies exhibited significant binding affinity of GA and thiolated Eudragit towards liver homolog receptor-1 (LRH-1) suggesting that the developed nanocomposite could be a potential material for the treatment of HCC.

Glycyrrhetinic Acid-Modified Silicon Phthalocyanine for Liver Cancer-Targeted Photodynamic Therapy

To supplement shortcomings of existing treatments and enhance the therapeutic effect for liver cancer, a novel photosensitizer is designed using silicon phthalocyanine (SiPC) and a unique targeting moiety, glycyrrhetinic acid (GA). The SiPC is modified with a hydrophilic polymer and finally bound with GA. The solubility, fluorescence, singlet oxygen generation, and UV-vis absorbance are analyzed, and receptor-dependent intracellular influx is estimated in various cell lines. Using flow cytometry and confocal microscopy, intracellular fluorescence was detected in liver cancer because of GA receptor overexpression. To prove in vitro photodynamic therapeutic effects, the sample treated cells are irradiated and viability of liver cancer cells decreases in proportion to laser power. Then, it is confirmed that GA-modified SiPC effectively accumulated in liver cancer of HepG2 tumor-bearing mouse. Additionally, the PDT-combined therapeutic effect of GA-modified SiPC is observed in the tumor model and shown to have a tumor growth inhibition effect (60.36 times higher than the control group) and supported by histological analyses. These results demonstrate that the newly modified SiPC can be applied to liver cancer-specific treatment with high therapeutic efficacy. Consequently, novel SiPC has the potential to alter conventional liver cancer-targeted therapy and chemotherapy in clinical use.

Glycyrrhizin mediated liver-targeted alginate nanogels delivers quercetin to relieve acute liver failure

Acute liver failure is an uncommon and dramatic clinical syndrome with a high risk of mortality. Previous treatments existed some limitations of poor bioavailability and targeting the efficiency of drugs. In this study, a novel glycyrrhizin mediated liver-targeted alginate nanogels, which can deliver the antioxidant quercetin to the liver for the treatment of acute liver injury. In vitro radical scavenging results showed that the antioxidant activity of quercetin was increased 81-fold. The tissue distribution results indicated that glycyrrhizin-mediated nanogels showed stronger fluorescence intensity in the liver, which improved liver targeting and therapeutic efficacy. Quercetin-glycyrrhizin nanogels were more effective at restoring liver injury as indicated on serum markers, including alanine transaminase, aspartate aminotransferase, and total bilirubin. The histopathology result showed that quercetin-glycyrrhizin nanogels reversed liver damage. Oxidative parameters of malondialdehyde and glutathione s-transferase were decreased, which provided supporting evidence of antioxidation. Moreover, quercetin-glycyrrhizin nanogels were more effective in down-regulating the inflammation-related gene expression of tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase and monocyte chemotactic protein-1. In conclusion, the novel glycyrrhizin mediated liver-targeted alginate nanogels might be a promising treatment for acute liver failure.

The Effect of PVP Molecular Weight on Dissolution Behavior and Physicochemical Characterization of Glycyrrhetinic Acid Solid Dispersions

The effect of polyvinylpyrrolidone (PVP) as glycyrrhetic acid (GA) solid dispersions carrier at different molecular weights on the dissolution behavior and physicochemical properties was investigated. PVP-GA-SDs prepared with all four molecular weight PVPs displayed good enhancement of dissolution rate and equilibrium solubility compared with pure drug and corresponding physical mixtures. The results showed that the enhancement effect of molecular weight on dissolution rate and equilibrium solubility follows $\text{PVP}\text{K}30>\text{PVP}\text{K}60>\text{PVP}\text{K}17>\text{PVP}\text{K}15$ . In addition, the dissolution rate and solubility of the SDs with a carrier-drug ratio of 8 : 1 were better than the samples of 4 : 1. The DSC and XRD patterns showed that the crystallization of GA in SDs prepared by PVP K30 and PVP K60 was significantly inhibited, and both were transformed to amorphous. Based on FTIR and Raman detection, a hydrogen-bond between PVP and drug molecules is formed. SEM results showed that there were no significant differences in the appearance of SDs prepared with four PVPs, and no crystalline morphology of GA was seen. In conclusion, the findings of this study demonstrated that the dissolution performance of the PVP-GA-SDs prepared by the solvent method is related to the molecular weight of PVP, and the change in the molecular weight of PVP does not cause a monotonic change in dissolution of GA. The samples with PVP K30 as the carrier have the best dissolution performance.

SP94 peptide mediating highly specific and efficacious delivery of polymersomal doxorubicin hydrochloride to hepatocellular carcinoma in vivo

The effective treatment of hepatocellular carcinoma (HCC) requires development of novel drug formulations that selectively kill HCC cells while sparing healthy liver cells. Here, we designed and investigated HCC-specific peptide, SP94 (SFSIIHTPILPLGGC), decorated smart polymersomal doxorubicin hydrochloride (SP94-PS-DOX) for potent treatment of orthotopic human SMMC-7721 HCC xenografts. SP94-PS-DOX was fabricated by post ligand-modification, affording robust nano-formulations with a diameter of ∼ 76 nm and DOX content of 9.9 wt.%. The internalization of SP94-PS-DOX by SMMC-7721 cells showed a clear dependence on SP94 surface densities, in which 30 % SP94 resulted in ca. 3-fold better cellular uptake over non-targeted control (PS-DOX). In accordance, SP94-PS-DOX exhibited superior inhibition of SMMC-7721 cells to PS-DOX and clinical liposome injections (Lipo-DOX). Notably, a remarkable tumor deposition of 14.9 %ID/g and tumor-to-normal liver ratio of ca. 6.9 was observed for SP94-PS-DOX in subcutaneous SMMC-7721 HCC xenografts. More interestingly, SP94-PS-DOX under 10 mg DOX/kg induced far better therapeutic efficacy toward orthotopic SMMC-7721 HCC models than PS-DOX and Lipo-DOX controls giving substantial survival benefits and little adverse effects. The remarkable specificity and therapeutic outcomes lend SP94-PS-DOX promising for targeted HCC therapy.

Glycyrrhizic Acid Modulates Apoptosis through Extrinsic/Intrinsic Pathways and Inhibits Protein Kinase B- and Extracellular Signal-Regulated Kinase-Mediated Metastatic Potential in Hepatocellular Carcinoma In Vitro and In Vivo

A previous study presented that glycyrrhizic acid as the hepatoprotective agent inhibits total parenteral nutrition-associated acute liver injury in rats. However, the anticancer effect and mechanism of glycyrrhizic acid in human hepatocellular carcinoma (HCC) is ambiguous. The purpose of the present study was to investigate the effect of glycyrrhizic acid on apoptosis dysregulation and metastatic potential in HCC in vitro and in vivo. Both SK-Hep1 and Hep3B cells were treated with different concentrations of glycyrrhizic acid for 24 or 48h. SK-Hep1/luc2 tumor-bearing mice were treated with vehicle or glycyrrhizic acid (50mg/kg/day by intraperitoneal injection) for 7 days. Tumor cells growth, apoptotic, and metastatic signaling transduction were evaluated by using MTT assay, digital caliper, bioluminescence imaging (BLI), flow cytometry, western blotting assay, and immunohistochemistry (IHC) staining. The results demonstrated glycyrrhizic acid significantly inhibits tumor cell growth, cell invasion, and expression of AKT (Ser473), extracellular-signal-regulated kinase (ERK), epidermal growth factor receptor (EGFR) phosphorylation, anti-apoptotic and metastatic proteins in HCC in vitro and in vivo. Glycyrrhizic acid also significantly triggered apoptosis and extrinsic/intrinsic apoptotic signaling transduction. In addition, PD98059 (ERK inhibitor) and LY294002 (AKT inhibitor) obviously reduced cell invasion and expression of metastasis-associated proteins. Taken together, these results indicated that glycyrrhizic acid induces apoptosis through extrinsic/intrinsic apoptotic signaling pathways and diminishes EGFR/AKT/ERK-modulated metastatic potential in HCC in vitro and in vivo.

Glycyrrhetinic acid modified MOFs for the treatment of liver cancer

Liver cancer remains a major cause of cancer-related death across the globe. Nano medicines have emerged as promising candidates to improve liver cancer chemotherapy. In this study, a glycyrrhetinic acid (GA) modified metal-organic framework-based drug delivery system (GA-MOFs) was developed to enhance the liver targeting ability of 5-FU. The physicochemical properties of GA-MOFs regarding particle size, size distribution and morphology were evaluated. The results showed that the obtained 5-FU@GA-MOFs had an octahedral structure, a uniform particle size distribution, and a diameter of ∼200 nm. In vitro release experiments demonstrated that 5-FU@GA-MOFs exhibited a pH-dependent release pattern. MTT assays indicated that 5-FU-loaded GA-MOFs showed greater cytotoxicity towards HepG2 cells when compared to 5-FU alone at the same dose. In vivo tissue distribution demonstrated that the 5-FU@GA-MOFs significantly increased the accumulation of 5-FU in the liver. In vivo imaging analysis further manifested the liver targeting ability of GA-MOFs. Taken together, these results suggested that GA-modified MOFs showed promising potential as liver-targeting nanocarriers for the delivery of anti-tumor drugs.

Chitosan based pH-responsive polymeric prodrug vector for enhanced tumor targeted co-delivery of doxorubicin and siRNA

The co-delivery of chemotherapeutic drugs and siRNA has gained increasing attentions owing to the enhanced antitumor efficacy over single administration. In this work, a chitosan-based pH-responsive prodrug vector was developed for the co-delivery of doxorubicin (DOX) and Bcl-2 siRNA. The accumulation of fabricated nanoparticles in hepatoma cells was enhanced by glycyrrhetinic acid receptor-mediated endocytosis. The cumulative release amount of the encapsulated DOX and siRNA reached 90.2 % and 81.3 % in 10 h, respectively. More strikingly, this nanoplatform can efficiently integrate gene- and chemo-therapies with a dramatically enhanced tumor inhibitory rate (88.0 %) in vivo. This co-delivery system may provide the latest strategy to meet the needs of combination therapies for tumors, offering safe and efficient improvements to the synergistic antitumor efficacy of gene-chemotherapies.

Glycyrrhizin: An alternative drug for the treatment of COVID-19 infection and the associated respiratory syndrome?

Safe and efficient drugs to combat the current COVID-19 pandemic are urgently needed. In this context, we have analyzed the anti-coronavirus potential of the natural product glycyrrhizic acid (GLR), a drug used to treat liver diseases (including viral hepatitis) and specific cutaneous inflammation (such as atopic dermatitis) in some countries. The properties of GLR and its primary active metabolite glycyrrhetinic acid are presented and discussed. GLR has shown activities against different viruses, including SARS-associated Human and animal coronaviruses. GLR is a non-hemolytic saponin and a potent immuno-active anti-inflammatory agent which displays both cytoplasmic and membrane effects. At the membrane level, GLR induces cholesterol-dependent disorganization of lipid rafts which are important for the entry of coronavirus into cells. At the intracellular and circulating levels, GLR can trap the high mobility group box 1 protein and thus blocks the alarmin functions of HMGB1. We used molecular docking to characterize further and discuss both the cholesterol- and HMG box-binding functions of GLR. The membrane and cytoplasmic effects of GLR, coupled with its long-established medical use as a relatively safe drug, make GLR a good candidate to be tested against the SARS-CoV-2 coronavirus, alone and in combination with other drugs. The rational supporting combinations with (hydroxy)chloroquine and tenofovir (two drugs active against SARS-CoV-2) is also discussed. Based on this analysis, we conclude that GLR should be further considered and rapidly evaluated for the treatment of patients with COVID-19.

Anticancer activities of phytoconstituents and their liposomal targeting strategies against tumor cells and the microenvironment

Various bioactive ingredients have been extracted from Chinese herbal medicines (CHMs) that affect tumor progression and metastasis. To further understand the mechanisms of CHMs in cancer therapy, this article summarizes the effects of five categories of CHMs and their active ingredients on tumor cells and the tumor microenvironment. Despite their treatment potential, the undesirable physicochemical properties (poor permeability, instability, high hydrophilicity or hydrophobicity, toxicity) and unwanted pharmacokinetic profiles (short half-life in blood and low bioavailability) restrict clinical studies of CHMs. Therefore, development of liposomes through relevant surface modifying techniques to achieve targeted CHM delivery for cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature, have been reviewed. Current challenges of liposomal targeting of these phytoconstituents and future perspective of CHM applications are discussed to provide an informative reference for interested readers.

Synthesis and anti-hepaticfibrosis of glycyrrhetinic acid derivatives with inhibiting COX-2

Many tests have shown cyclooxygenase-2 (COX-2) was closely related to the activation of hepatic stellate cells (HSCs), which further promoting the onset and development of hepatic fibrosis. According to these research findings, a series of glycyrrhetinic acid derivatives were designed and synthesized. Meanwhile, their anti-hepaticfibrotic activities were evaluated in vitro and in vivo. Firstly, in the tests of the cell models, all the compounds displayed anti-proliferative effect on the HSC-T6 activated by (transforming growth factor beta) TGF-β₁ (10 ng/mL). Among them, compounds 2 and 16 exhibited a stronger activity than the others, and their IC₅₀ values were 17.6 µM and 30.3 µM, respectively; both of them were low toxicity to normal HSC-T6 cells and WI38 cells, and they inhibited the activated HSC-T6 cells proliferation by promoting apoptosis and resting them at the G₀/G₁ phase. Secondly, compounds 2 and 16 displayed strong inhibitory effect on activation of HSCs; they not only inhibited the expression of α-SMA and Col1 in the activated HSC-T6 cells, but also decreased the levels of COX-2, TGF-β₁ and (reactive oxygen species) ROS in a concentration-dependent manner; they down-regulated the levels of three biomarkers in the process of test, but this decrease did not change linearly with the action time of compound. Thirdly, for the rats which induced with (carbontetrachloride) CCl₄, the symptoms of liver fibrosis in rats were significantly alleviated after successive administration the tested compound for 14d; the α-SMA level in liver tissue decreased in a concentration dependent manner; and the liver cell necrosis and the fat collagen fiber decreased significantly compared with the positive control group; furthermore, inflammatory infiltration was significantly lower than that of the control. This suggests the compounds possibly are candidates for hepatic fibrosis with promising application in clinic.

18-GA-Suc Modified Liposome Loading Cantharidin for Augmenting Hepatic Specificity: Preparation, Characterization, Antitumor Effects, and Liver-Targeting Efficiency

Cantharidin (CTD), a natural Chinese medicine constituent extracted from mylabris, is a potent drug against hepatocellular carcinoma. However, the clinical application of CTD was limited because of its toxicity and low solubility. In this work, a novel CTD-loaded liposome modified with 3-succinyl-30-stearyl glycyrrhetinic acid (18-GA-Suc-CTD-Lip) was prepared to enhance liver-targeting efficiency and antitumor activity. 18-GA-Suc-CTD-Lip and CTD-Lip were successfully prepared by film dispersion method and totally characterized. The antitumor effects in vitro were evaluated by cell proliferation inhibition assay, transwell assay, cell cycle analysis, and an apoptosis test. Pharmacokinetic and biodistribution were all investigated to precisely reveal liver-targeting efficiency of 18-GA-Suc-CTD-Lip in vivo. The IC₅₀ values of 18-GA-Suc-CTD-Lip in HepG2 (3.417 ± 0.165 nmol/L) and Huh-7 (4.478 ± 0.409 nmol/L) cells were much lower than that of CTD-Lip, indicating that antitumor effects of 18-GA-Suc-CTD-Lip were remarkable because of the modification of 18-GA-Suc. The maximum concentration in the liver of 18-GA-Suc-CTD-Lip (1.72 ± 0.14 μg/g) was more than twice CTD-Lip (0.75 ± 0.08 μg/g) at 30 min, illustrating that 18-GA-Suc-CTD-Lip possesses excellent liver-targeting efficiency. Conclusively, 18-GA-Suc-CTD-Lip could be a potential liver-targeting antitumor drug for hepatocellular carcinoma.

Molecular Dynamics Simulations of Glycyrrhizic Acid Aggregates as Drug-Carriers for Paclitaxel

BACKGROUND

Glycyrrhizic acid (GA) is a glycoside that has shown considerable promise as a penetration enhancer and drug carrier to improve the absorption of poorly water-soluble drugs. The aggregation behavior of GA and its ability to form large micelles at higher solution concentrations are thought to contribute to these bioavailability enhancing properties. The oral absorption of Paclitaxel (PTX) for example, an anti-cancer agent which exhibits poor oral bioavailability, has been found to significantly increase in the presence of GA.

METHODS

In an attempt to visualize the aggregation behavior of GA and its subsequent association with PTX, 100 ns molecular dynamics simulation of a 5 mM aqueous solution of GA with 10 molecules of PTX was conducted using GROMACS and an all-atom forcefield.

RESULTS

Aggregation of GA molecules was found to occur quickly at this level of saturation leading to two stable aggregates of 13 and 17 GA molecules with an effective radius of 10.17 nm to 10.92 nm. These aggregates form not in isolation, but together with PTX molecule embedded within the structures, which reduces the number of interactions and hydrogen-bonding with water.

CONCLUSION

GA aggregation occurs around PTX molecules in solution, forming co-joined GA-PTX cluster units at a ratio of 3:1. These clusters remain stable for the remainder of the 100ns simulation and serve to isolate and protect PTX from the aqueous environment.

Nanocarrier-mediated antioxidant delivery for liver diseases

Liver is the principal detoxifying organ and metabolizes various compounds that produce free radicals (FR) constantly. To maintain the oxidative/antioxidative balance in the liver, antioxidants would scavenge FR by preventing tissue damage through FR formation, scavenging, or by enhancing their decomposition. The disruption of this balance therefore leads to oxidative stress and in turn leads to the onset of various diseases. Supplying the liver with exogeneous antioxidants is an effective way to recreate the oxidative/antioxidative balance in the liver homeostasis. Nevertheless, due to the short half-life and instability of antioxidants in circulation, the methodology for delivering antioxidants to the liver needs to be improved. Nanocarrier mediated delivery of antioxidants proved to be an ingenious way to safely and efficiently deliver a high payload of antioxidants into the liver for circumventing liver diseases. The objective of this review is to provide an overview of the role of reactive oxygen species (oxidant) and ROS scavengers (antioxidant) in liver diseases. Subsequently, current nanocarrier mediated antioxidant delivery methods for liver diseases are discussed.

Toxicity of traditional Chinese medicine herbal and mineral products

Traditional Chinese medicine (TCM) has been used to treat numerous kinds of diseases for more than 2000 years in eastern Asian countries. A portion of the TCM herbal and mineral products are believed to be toxic according to modern standards, and are still widely prescribed in the clinic. However, some TCM products considered to be non-toxic or low-toxic have been reported to possess significant toxicological effects on different organs in both animal and human models. In this review, we define the term "toxic" in TCM, and then we summarize the advances in pharmacology and toxicology research of Toxic Traditional Chinese Medicine (TTCM), including Chinese aconite (Fu Zi), Arsenic Trioxide, Tripterygium wilfordii Hook f. (Thunder God Vine), herbal drugs derived from plants in the Aristolochiaceae Juss. family (Ma Dou Ling), and other TCM products. Finally, the compatibility art of TCM and modern pharmaceutical approaches to manage undesired toxicity of TTCM is discussed. Promoting pharmacology and toxicology studies of TTCM and non-toxic TCM is critical for the further development and safety of TCM in clinical practice.

Glycyrrhizin Acid and Glycyrrhetinic Acid Modified Polyethyleneimine for Targeted DNA Delivery to Hepatocellular Carcinoma

In the last 2-3 decades, gene therapy represented a promising option for hepatocellular carcinoma (HCC) treatment. However, the design of safe and efficient gene delivery systems is still one of the major challenges that require solutions. In this study, we demonstrate a versatile method for covalent conjugation of glycyrrhizin acid (GL) or glycyrrhetinic acid (GA) to increase the transfection efficiency of Polyethyleneimine (PEI, Mw 1.8K) and improve their targeting abilities of hepatoma carcinoma cells. GA and GL targeting ligands were grafted to PEI via N-acylation, and we systematically investigated their biophysical properties, cytotoxicity, liver targeting and transfection efficiency, and endocytosis pathway trafficking. PEI-GA0.75, PEI-GL10.62 and PEI-GL20.65 conjugates caused significant increases in gene transfection efficiency and superior selectivity for HepG2 cells, with all three conjugates showing specific recognition of HepG2 cells by the free GA competition assay. The endocytosis inhibition and intracellular trafficking results indicated that PEI-GA0.75 and GL10.62 conjugates behaved similarly to SV40 virus, by proceeding via the caveolae- and clathrin-independent mediated endocytosis pathway and bypassing entry into lysosomes, with an energy independent manner, achieving their high transfection efficiencies. In the HepG2 intraperitoneal tumor model, PEI-GA0.75 and PEI-GL10.62 carrying the luciferase reporter gene gained high gene expression, suggesting potential use for in vivo application.

Influence of glycyrrhetinic acid on the pharmacokinetics of warfarin in rats

1. Combination of different drugs has been widely applied in clinics in China. Both glycyrrhetinic acid (GA) and warfarin possess various pharmacological activities, the co-administration of them is becoming popular. However, the herb-drug interaction between GA and warfarin is still unknown.2. The herb-drug interaction between GA and warfarin in vivo and in vitro was studied, to clarify the effect of GA on the pharmacokinetics of warfarin and its main mechanism.3. The pharmacokinetics of intragastric administered warfarin (0.5 mg/kg) with or without GA pretreatment (100 mg/kg/day, 7 days) were investigated. The rat liver microsomes incubation systems were used to study the effect of GA on the metabolic stability of warfarin and support the in vivo pharmacokinetic data.4. The pharmacokinetic results indicated that co-administration of GA could increase the systemic exposure of warfarin, including area under the curve (48.87 ± 2.89 µg·h·mL^-1 without GA versus 58.63 ± 1.90 µg·h·mL^-1 with GA), maximum plasma concentration and t_1/2. The metabolic stability of warfarin increased from 23.8 ± 5.9 to 41.4 ± 7.1 min with the pretreatment of GA.5. These results indicated that GA could change the pharmacokinetic profile of warfarin. The metabolism of warfarin was slowed down in rat liver and the systemic exposure increased by GA, via inhibiting the activity of CYP3A4.

Nanomedicine as a putative approach for active targeting of hepatocellular carcinoma

The effectiveness of chemotherapy in hepatocellular carcinoma (HCC) is restricted by chemo-resistance and systemic side effects. To improve the efficacy and safety of chemotherapeutics in HCC management, scientists have attempted to deliver these drugs to malignant tissues using targeted carriers as nanoparticles (NPs). Among the three types of NPs targeting (active, passive, and stimuli-responsive), active targeting is the most commonly investigated in HCC treatment. Despite the observed promising results so far, clinical research on nanomedicine targeting for HCC treatment still faces many challenges.These include batch-to-batch physicochemical properties' variations, limiting large scale production and insufficient data on human and environmental toxicities. This review summarized the characteristics of different nanocarriers, ligands, targeted receptors on HCC cells and provided recommendations to overcome the challenges, facing this novel line of treatment for HCC.

Nanoconjugation and Encapsulation Strategies for Improving Drug Delivery and Therapeutic Efficacy of Poorly Water-Soluble Drugs

Nanoconjugations have been demonstrated to be a dominant strategy for drug delivery and biomedical applications. In this review, we intend to describe several strategies for drug formulation, especially to improve the bioavailability of poorly water-soluble molecules for future application in the therapy of numerous diseases. The context of current studies will give readers an overview of the conjugation strategies for fabricating nanoparticles, which have expanded from conjugated materials to the surface conjugation of nanovehicles. Moreover, nanoconjugates for theranostics are also discussed and highlighted. Overall, these state-of-the-art conjugation methods and these techniques and applications for nanoparticulate systems of poorly water-soluble drugs will inspire scientists to explore and discover more productive techniques and methodologies for drug development.

Enhanced Allicin Cytotoxicity on HEPG-2 Cells Using Glycyrrhetinic Acid Surface-Decorated Gelatin Nanoparticles

The cytotoxic potential of allicin was evaluated on different cancer cell lines, particularly, hepatic (HepG-2), breast (MCF-7), lung (A-549), and prostatic (PC-3), where allicin scored an IC₅₀ score of 19.26 μM on HepG-2. In order to increase the cell uptake, optimized allicin-loaded gelatin nanoparticles (GNPs) were prepared where the optimum formulation was surface-conjugated to glycyrrhetinic acid. GNPs were optimized using a D-optimal design. The optimum formulation had a particle size of 370.7 ± 6.78 nm and polydispersity index of 0.0363 ± 0.009 and 39.13 ± 2.38% of drug entrapment. The conjugation of the ligand, glycyrrhetinic acid with allicin-loaded GNPs, was confirmed utilizing ¹H NMR. Drug release profiles in the presence/absence of collagenase were obtained. Finally, a cytotoxicity study on HepG-2 was performed for the unconjugated and conjugated allicin-loaded GNPs scoring IC₅₀ of 10.95 and 5.046 μM, revealing two- and fourfold enhancements in allicin cytotoxicity, respectively. To our knowledge, the ligand-carrier pair, glycyrrhetinic acid-gelatin, was not explored before, and the developed system poses a successful liver cancer therapy.

Recent Findings on Nanotechnology-based Therapeutic Strategies Against Hepatocellular Carcinoma

Background:

Nanotechnology-based therapies are emerging as a promising new anticancer approach. Early clinical studies suggest that nanoparticle-based therapeutics can show enhanced efficacy while reducing side effects minimal, owing to targeted delivery and active intracellular uptake.

Methods:

To overcome the problems of gene and drug delivery, nanotechnology based delivery system gained interest in the last two decades. Encouraging results from Nano formulation based drug delivery systems revealed that these emerging restoratives can efficiently lead to more effective, targeted, selective and efficacious delivery of chemotherapeutic agents to the affected target cells.

Results:

Nanotechnology not only inhibits targeted gene products in patients with cancer, but also taught us valuable lessons regarding appropriate dosages and route of administrations. Besides, nanotechnology based therapeutics holds remarkable potential as an effective drug delivery system. We critically highlight the recent findings on nanotechnology mediated therapeutics strategies to combat hepatocellular carcinoma and discuss how nanotechnology platform can have enhanced anticancer effects compared with the parent therapeutic agents they contain.

Conclusion:

In this review, we discussed the key challenges, recent findings and future perspective in the development of effective nanotechnology-based cancer therapeutics. The emphasis here is focused on nanotechnology-based therapies that are likely to affect clinical investigations and their implications for advancing the treatment of patients with hepatocellular carcinoma.

Natural products in licorice for the therapy of liver diseases: Progress and future opportunities

Liver diseases related complications represent a significant source of morbidity and mortality worldwide, creating a substantial economic burden. Oxidative stress, excessive inflammation, and dysregulated energy metabolism significantly contributed to liver diseases. Therefore, discovery of novel therapeutic drugs for the treatment of liver diseases are urgently required. Licorice is one of the most commonly used herbal drugs in Traditional Chinese Medicine for the treatment of liver diseases and drug-induced liver injury (DILI). Various bioactive components have been isolated and identified from the licorice, including glycyrrhizin, glycyrrhetinic acid, liquiritigenin, Isoliquiritigenin, licochalcone A, and glycycoumarin. Emerging evidence suggested that these natural products relieved liver diseases and prevented DILI through multi-targeting therapeutic mechanisms, including anti-steatosis, anti-oxidative stress, anti-inflammation, immunoregulation, anti-fibrosis, anti-cancer, and drug-drug interactions. In the current review, we summarized the recent progress in the research of hepatoprotective and toxic effects of different licorice-derived bioactive ingredients and also highlighted the potency of these compounds as promising therapeutic options for the treatment of liver diseases and DILI. We also outlined the networks of underlying molecular signaling pathways. Further pharmacology and toxicology research will contribute to the development of natural products in licorice and their derivatives as medicines with alluring prospect in the clinical application.

2D- and 3D-QSAR modelling, molecular docking and in vitro evaluation studies on 18β-glycyrrhetinic acid derivatives against triple-negative breast cancer cell line

Triple-negative breast cancers (TNBCs) are one of the most aggressive and complex forms of cancers in women. TNBCs are commonly known for their complex heterogeneity and poor prognosis. The present work aimed to develop a predictive 2D and 3D quantitative structure-activity relationship (QSAR) models against metastatic TNBC cell line. The 2D-QSAR was based on multiple linear regression analysis and validated by Leave-One-Out (LOO) and external test set prediction approach. QSAR model presented regression coefficient values for training set (r²), LOO-based internal regression (q²) and external test set regression (pred_r²) which are 0.84, 0.82 and 0.75, respectively. Five properties, Epsilon4 (electronegativity), ChiV3cluster (valence molecular connectivity index), chi3chain (retention index for three-membered ring), TNN5 (nitrogen atoms separated through 5 bond distance) and nitrogen counts, were identified as important structural features responsible for anticancer activity of MDA-MB-231 inhibitors. Five novel derivatives of glycyrrhetinic acid (GA) named GA-1, GA-2, GA-3, GA-4 and GA-5 were semi-synthesised and screened through the QSAR model. Further, in vitro activities of the derivatives were analysed against human TNBC cell line, MDA-MB-231. The result showed that GA-1 exhibits improved cytotoxic activity to that of parent compound (GA). Further, atomic property field (APF)-based 3D-QSAR and scoring recognise C-30 carboxylic group of GA-1 as major influential factor for its anticancer activity. The significance of C-30 carboxylic group in GA derivatives was also confirmed by molecular docking study against cancer target glyoxalase-I. Finally, the oral bioavailability and toxicity of GA-1 were assessed by computational ADMET studies.Communicated by Ramaswamy H. Sarma.

Glycyrrhizic acid as a multifunctional drug carrier - From physicochemical properties to biomedical applications: A modern insight on the ancient drug

•

Glycyrrhizic acid (GA), saponin of licorice shows wide range of biological activity.

•

Mechanism of GA activity on the cell and molecular level is rarely discussed.

•

GA activity could be caused by the cell membrane modification.

Glycyrrhizic acid is the main active component of Licorice root which has been known in traditional Chinese and Japanese medicine since ancient times. In these cultures glycyrrhizic acid (GA) is one of the most frequently used drugs. However, only in 21-st century a novel unusual property of the GA to enhance the activity of other drugs has been discovered. The review describes briefly the experimental evidences of wide spectrum of own biological activities of glycyrrhizic acid as well as discusses the possible mechanisms of the ability of GA to enhance the activity of other drugs. We have shown that due to its amphiphilic nature GA is able to form self-associates in aqueous and non-aqueous media, as well as water soluble complexes with a wide range of lipophilic drugs. The main purpose of our review is to focus reader's attention on physicochemical studies of the molecular mechanisms of GA activity as a drug delivery system (DDS). In our opinion, the most intriguing feature of glycyrrhizic acid which might be the key factor in its therapeutic activity is the ability of GA to incorporate into the lipid bilayer and to increase the membrane fluidity and permeability. The ability of biomolecules and their aggregates to change the properties of cell membranes is of great significance, from both fundamental and practical points of view.

Liver-Targeted Combination Therapy Basing on Glycyrrhizic Acid-Modified DSPE-PEG-PEI Nanoparticles for Co-delivery of Doxorubicin and Bcl-2 siRNA

Combination therapy based on nano-sized drug delivery system has been developed as a promising strategy by combining two or more anti-tumor mechanisms. Here, we prepared liver-targeted nanoparticles (GH-DPP) composed of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-polyetherimide (DSPE-PEG-PEI) with Glycyrrhetinic acid-modified hyaluronic acid (GA-HA) for co-delivery of doxorubicin (DOX) and Bcl-2 siRNA. Particles size, zeta potential and morphology were determined for the drug-loaded GH-DPP nanoparticles (siRNA/DOX/GH-DPP). Cellular uptake and in vitro cytotoxicity were analyzed against HepG2 cells. In vivo bio-distribution and anti-tumor therapeutic effects of siRNA/DOX/GH-DPP were evaluated in H22-bearing mice. The results showed that siRNA/DOX/GH-DPP nanoparticles were nearly spherical and showed dose-dependent cytotoxicity against HepG2 cells. Compared to Glycyrrhetinic acid-free co-delivery system (siRNA/DOX/DPP) and GH-DPP nanoparticles for delivery of DOX or Bcl-2 siRNA alone, siRNA/DOX/GH-DPP nanoparticles could induce more cellular apoptosis, and showed higher anti-tumor effect. Herein GH-DPP nanoparticles could simultaneously deliver both chemotherapy drugs and siRNA into the tumor region, exhibiting great potential in anti-tumor therapy.

Diammonium Glycyrrhizinate Protects against Nonalcoholic Fatty Liver Disease in Mice through Modulation of Gut Microbiota and Restoration of Intestinal Barrier

Nonalcoholic fatty liver disease (NAFLD), as a common chronic liver disorder, is prevalent in the world. Recent evidence demonstrates that the "gut-liver axis" is related well to the progression of NAFLD, which regards gut microbiota and the intestinal barrier as two critical factors correlated with NAFLD. Diammonium glycyrrhizinate (DG), a compound of the natural bioactive pentacyclic triterpenoid glycoside, is the main component of licorice root extracts. The anti-inflammatory and liver protection effects of DG have already been reported, but to date, the mechanism has not been fully elucidated. In this research, we observed that DG reduced body weight, liver steatosis, as well as hepatic inflammation in NAFLD model mice induced by a high-fat diet. Illumina sequencing of the 16S rRNA revealed that DG intervention notably altered the composition of the gut microbiota in NAFLD mice. The richness of gut microbiota was significantly increased by DG. Specifically, DG reduced the Firmicutes-to- Bacteroidetes ratio and the endotoxin-producing bacteria such as Desulfovibrio and elevated the abundance of probiotics such as Proteobacteria and Lactobacillus. DG could augment the levels of short-chain fatty acid (SCFA)-producing bacteria such as Ruminococcaceae and Lachnospiraceae and promote SCFA production. In addition, DG supplementation dramatically alleviated the intestinal low-grade inflammation. Meanwhile, DG improved the expression of tight junction proteins, the goblet cell number, and mucin secretion and sequentially enhanced the function of intestinal barrier. Collectively, the prevention of NAFLD by DG might be mediated by modulating gut microbiota and restoring the intestinal barrier.

Preparation and Optimization Lipid Nanocapsules to Enhance the Antitumor Efficacy of Cisplatin in Hepatocellular Carcinoma HepG2 Cells

This work aimed to develop and optimize several lipid nanocapsule formulations (LNCs) to encapsulate cisplatin (CDDP) for treatment of hepatocellular carcinoma. By comparing the effect of oil/surfactant ratio, lecithin content, and oil/surfactant type on LNC characteristics, two LNCs were selected as optimal formulations: HS15-LNC (Solutol HS 15/MCT/lecithin, 54.5:42.5:3%, w/w) and EL-LNC (Cremophor EL/MCT/lecithin, 54.5:42.5:3%, w/w). Both LNCs could effectively encapsulate CDDP with the encapsulation efficiency of 73.48 and 78.84%. In vitro release study showed that both LNCs could sustain the release CDDP. Moreover, cellular uptake study showed that C6-labeled LNCs could be effectively internalized by HepG2 cells. Cellular cytotoxicity study revealed that both LNCs showed negligible cellular toxicity when their concentrations were below 313 μg/mL. Importantly, CDDP-loaded LNCs exhibited much stronger cell killing potency than free CDDP, with the IC50 values decreased from 17.93 to 3.53 and 5.16 μM after 72-h incubation. In addition, flow cytometric analysis showed that the percentage of apoptotic cells was significantly increased after treatment with LNCs. Therefore, the prepared LNC formulations exhibited promising anti-hepatocarcinoma effect, which could be beneficial to hepatocellular carcinoma therapy.

Synthesis, characterization and in vitro/in vivo evaluation of novel reduction-sensitive hybrid nano-echinus-like nanomedicine

To remedy the problems resulting from the usage of anti-cancer drugs in cancer chemotherapy, such as deficient drug concentration in tumour cells, low water-solubility and non-specific distribution of antitumour drugs, a kind of reduction-sensitive polymer prodrug of curcumin (Cur) containing in the nano-echinus was synthesized and designed. The nano-echinus-like nanomedicine presented synergistic effect with glycyrrhetic acid (GA) and oligomeric hyaluronic (HA) for targeting and combating HepG2 human liver cancer cell. Firstly, a kind of small molecular prodrug of Cur, dithiodipropionic acid-Cur (-SS-Cur), was chemically conjugated onto the side chain of the conjugated glycyrrhetic acid- oligomeric hyaluronic (GA-HA) to generate an amphiphilic polymeric prodrug of Cur, GA-HA-SS-Cur. The obtained GA-HA-SS-Cur prodrug and subsidiary material mPEG-DSPE could self-assemble into a sea urchin-like micelles in aqueous media and release Cur rapidly in response to glutathion (GSH). Then, Cur was loaded into the nano-echinus with a particle size of (118.1 ± 0.2 nm) and drug-loading efficiency of (8.03 ± 2.1%). The structure of GA-HA-SS-Cur was characterized by ¹H-NMR in this report. The morphology of micelles was observed with a transmission electron microscope (TEM). Subsequently, the reduction-sensitivity of the nano-echinus was confirmed by the changes in in-vitro drug release after different concentrations of GSH treatment. Besides, the cellular uptake behaviour and MTT assays of the nano-echinus were investigated, suggesting that the nano-echinus was of desirable safety and could be taken into HepG2 cells in a time-dependent manner. Later, anti-tumour efficacy in vivo revealed the effective inhibition of tumour growth.

Enhanced delivery of doxorubicin to the liver through self-assembled nanoparticles formed via conjugation of glycyrrhetinic acid to the hydroxyl group of hyaluronic acid

Liver-targeted nanoparticles is highly desired for better therapy of liver cancer. In this study, enhanced delivery of doxorubicin (DOX) to the liver cells through self-assembled nanoparticles formed via conjugation of glycyrrhetinic acid (GA) to the hydroxyl group of hyaluronic acid (HA) was investigated. The DOX loaded hyaluronic acid-glycyrrhetinic acid succinate (HSG) conjugates based nanoparticles (HSG/DOX nanoparticles) were sub-spherical in shape with particle size in the range of 180-280 nm, the drug loading was drug-to-carrier ratio and GA graft ratio dependent. In vitro release study suggested that the release of DOX from HSG nanoparticles was sustained and the release rate was pH and GA graft ratio dependent. MTT assay indicated the HSG/DOX nanoparticles presented a GA-dependent cytotoxicity to HepG2 cells. Pharmacokinetics study demonstrated the HSG/DOX nanoparticles could prolong blood circulation time of DOX and had a higher AUC value than that of DOX solution. Furthermore, tissue distribution study revealed the HSG/DOX nanoparticles significantly increased the accumulation of DOX in the liver and meanwhile decreased the cardiotoxicity and nephrotoxicity of DOX. Moreover, the liver targeting enhancing capacity was HSG conjugate structure dependent. The accumulation of HSG-20/DOX, HSG-12/DOX, and HSG-6/DOX nanoparticles in the liver was 4.0-, 3.1-, and 2.6-fold higher than that of DOX solution. In vivo imaging analysis further demonstrated HSG nanoparticles not only had better liver targeting effect, but also presented superior tumor targeting efficiency, and the tumor targeting capacity was also GA-dependent. These results indicated that HSG conjugates prepared via modifying the hydroxyl groups of HA have promising potential as a liver-targeting nanocarrier for the delivery of hydrophobic anti-tumor drugs.

Convenient synthesis of 6-alkyl phenanthridines and 1-alkyl isoquinolines via silver-catalyzed oxidative radical decarboxylation

A convenient and efficient protocol for the synthesis of 6-alkyl phenanthridines and 1-alkyl isoquinolines has been developed. The reaction relies on the coupling of 2-isocyanobiphenyls and vinyl isonitriles with alkyl radicals formed by the silver-catalyzed decarboxylation of stoichiometric aliphatic carboxylic acids, and affords diverse phenanthridine and isoquinoline derivatives under mild reaction conditions. The experiment of β-scission of cyclobutylcarbinyl radicals is used to shed light on the reaction mechanism.

Surface Engineering of Nanoparticles for Targeted Delivery to Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated deaths worldwide. There is a lack of efficient therapy for HCC; the only available first-line systemic drug, sorafenib, can merely improve the average survival by two months. Among the efforts to develop an efficient therapy for HCC, nanomedicine has drawn the most attention, owing to its unique features such as high drug-loading capacity, intrinsic anticancer activities, integrated diagnostic and therapeutic functionalities, and easy surface engineering with targeting ligands. Despite its tremendous advantages, no nanomedicine can be effective unless it successfully targets the tumor site, which is a challenging task. In this review, the features of HCC are described, and the physiological hurdles that prevent nanoparticles from targeting HCC are discussed. Then, the surface physicochemical factors of nanoparticles that can influence targeting efficiency are discussed. Finally, a thorough description of the physiological barriers that nanomedicine must conquer before uptake by HCC cells if possible is provided, as well as the surface engineering approaches to nanomedicine to achieve targeted delivery to HCC cells. The physiological hurdles and corresponding solutions summarized in this review provide a general guide for the rational design of HCC targeting nanomedicine systems.

Nanoparticles based on glycyrrhetinic acid modified porphyrin for photodynamic therapy of cancer

Nanoparticles were prepared from amphiphilic glycyrrhetinic acid–porphyrin conjugates (TPP–GA) and applied for the photodynamic therapy of cancer.

Modifying glycyrrhetinic acid liposomes with liver-targeting ligand of galactosylated derivative: preparation and evaluations

In this study, novel glycyrrhetinic acid (GA) liposomes modified with a liver-targeting galactosylated derivative ligand (Gal) were prepared using a film-dispersion method. To characterize the samples, particle size, zeta potential, drug loading, and encapsulation efficiency were performed. Moreover, plasma and tissues were pre-treated by liquid-liquid extraction and analyzed by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that the mean residence times (MRTs) and the area under the curve (AUC) of GA liposomes with Gal (Gal-GA-LP), and GA liposomes (GA-LP) were higher than the GA solution (GA-S) in plasma. The tissue (liver) distribution of Gal-GA-LP was significantly different in contrast to GA-LP. The relative intake rate (Re) of Gal-GA-LP and GA-LP in the liver was 4.752 and 2.196, respectively. The peak concentration ratio (Ce) of Gal-GA-LP and GA-LP in the liver was 2.796 and 1.083, respectively. The targeting efficiency (Te) of Gal-GA-LP and GA-LP in the liver was 48.193% and 34.718%, respectively. Taken together, the results indicate that Gal-GA-LP is an ideal complex for liver-targeting, and has great potential application in the clinical treatment of hepatic diseases. Drug loading and releasing experiments also indicated that most liposomes are spherical structures and have good dispersity under physiologic conditions, which could prolong GA release efficiency in vitro.

Glycyrrhetinic Acid Liposomes Containing Mannose-Diester Lauric Diacid-Cholesterol Conjugate Synthesized by Lipase-Catalytic Acylation for Liver-Specific Delivery

Mannose-diester lauric diacid-cholesterol (Man-DLD-Chol), as a liposomal target ligand, was synthesized by lipase catalyzed in a non-aqueous medium. Its chemical structure was confirmed by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Glycyrrhetinic acid (GA) liposomes containing Man-DLD-Chol (Man-DLD-Chol-GA-Lp) were prepared by the film-dispersion method. We evaluated the characterizations of liposomes, drug-release in vitro, the hemolytic test, cellular uptake, pharmacokinetics, and the tissue distributions. The cellular uptake in vitro suggested that the uptake of Man-DLD-Chol-modified liposomes was significantly higher than that of unmodified liposomes in HepG2 cells. Pharmacokinetic parameters indicated that Man-DLD-Chol-GA-Lp was eliminated more rapidly than GA-Lp. In tissue distributions, the targeting efficiency (Te) of Man-DLD-Chol-GA-Lp on liver was 54.67%, relative targeting efficiency (R_Te) was 3.39, relative uptake rate (Re) was 4.78, and peak concentration ratio (Ce) was 3.46. All these results supported the hypothesis that Man-DLD-Chol would be an efficient liposomal carrier, and demonstrated that Man-DLD-Chol-GA-Lp has potential as a drug delivery for liver-targeting therapy.

Ethnopharmacological Approaches for Therapy of Jaundice: Part II. Highly Used Plant Species from Acanthaceae, Euphorbiaceae, Asteraceae, Combretaceae, and Fabaceae Families

In many developing countries, jaundice is the common symptom of hepatic diseases which are a major cause of mortality. The use of natural product-based therapies is very popular for such hepatic disorders. A great number of medicinal plants have been utilized for this purpose and some facilitated the discovery of active compounds which helped the development of new synthetic drugs against jaundice. However, more epidemiological studies and clinical trials are required for the practical implementation of the plant pharmacotherapy of jaundice. The focus of this second part of our review is on several of the most prominent plants used against jaundice identified in the analysis performed in the first part of the review viz. Andrographis paniculata (Burm.f.) Nees, Silybum marianum (L.) Gaertn., Terminalia chebula Retz., Glycyrrhiza glabra L. and some species of genus Phyllanthus. Furthermore, we discuss their physiological effects, biologically active ingredients, and the potential mechanisms of action. Some of the most important active ingredients were silybin (also recommended by German commission), phyllanthin and andrographolide, whose action leads to bilirubin reduction and normalization of the levels of relevant serum enzymes indicative for the pathophysiological status of the liver.

Cellular uptake mechanism and clearance kinetics of fluorescence-labeled glycyrrhetinic acid and glycyrrhetinic acid-modified liposome in hepatocellular carcinoma cells

Glycyrrhetinic acid (GA) is a natural pentacyclic triterpene derivative that exerts significant effects in the suppression of liver cancer. The receptors of GA on liver cells and hepatocellular carcinoma (HCC) cells have drawn broad attention. The effects of GA might depend on its transport into and out of cells. However, the question has not been previously addressed despite its obvious and fundamental importance. In this paper, GA and GA-modified liposome (GA-Lip) were labeled with fluorescein isothiocyanate (FITC) or coumarin 6 (Cou6) using chemical or pharmaceutical techniques. The transport courses of FITC-GA and GA-Cou6-Lip were studied in HepG2 cells in vitro. We found that the fluorescence labeled GA and GA-Lip uptake and clearance were time-dependent. FITC-GA uptake involved passive diffusion and active transport, and the receptors were in the cytomembrane proteins. GA-Cou6-Lip uptake was mediated by caveolae-dependent endocytosis. In addition, FITC-GA and GA-Cou6-Lip clearance of the HCC cells fitted exponential decay and second-order processes, respectively. These findings provide new insights into the anti-HCC actions of GA.

Glycyrrhetic acid, but not glycyrrhizic acid, strengthened entecavir activity by promoting its subcellular distribution in the liver via efflux inhibition

Entecavir (ETV) is a superior nucleoside analogue used to treat hepatitis B virus (HBV) infection. Although its advantages over other agents include low viral resistance and the elicitation of a sharp decrease in HBV DNA, adverse effects such as hepatic steatosis, hepatic damage and lactic acidosis have also been reported. Glycyrrhizin has long been used as hepato-protective medicine. The clinical combination of ETV plus glycyrrhizin in China displays better therapeutic effects and lower rates of liver damage. However, there is little evidence explaining the probable synergistic mechanism that exists between these two drugs from a pharmacokinetics view. Here, alterations in the plasma pharmacokinetics, tissue distribution, subcellular distribution, and in vitro and in vivo antiviral activity of ETV after combination with glycyrrhizic acid (GL) were analysed to determine the synergistic mechanisms of these two drugs. Specific efflux transporter membrane vesicles were also used to elucidate their interactions. The primary active GL metabolite, glycyrrhetic acid (GA), did not affect the plasma pharmacokinetics of ETV but promoted its accumulation in hepatocytes, increasing its distribution in the cytoplasm and nucleus and augmenting the antiviral efficiency of ETV. These synergistic actions were primarily due to the inhibitory effect of GA on MRP4 and BCRP, which transport ETV out of hepatocytes. In conclusion, GA interacted with ETV at cellular and subcellular levels in the liver through MRP4 and BCRP inhibition, which enhanced the antiviral activity of ETV. Our results partially explain the synergistic mechanism of ETV and GL from a pharmacokinetics view, providing more data to support the use of these compounds together in clinical HBV treatment.

Recent advances in hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC), also called malignant hepatoma, is one of the deadliest cancers due to its complexities, reoccurrence after surgical resection, metastasis and heterogeneity. Incidence and mortality of HCC are increasing in Western countries and are expected to rise as a consequence of the obesity epidemic. Multiple factors trigger the initiation and progression of HCC including chronic alcohol consumption, viral hepatitis B and C infection, metabolic disorders and age. Although Sorafenib is the only FDA approved drug for the treatment of HCC, numerous treatment modalities such as transcatheter arterial chemoembolization/transarterial chemoembolization (TACE), radiotherapy, locoregional therapy and chemotherapy have been tested in the clinics. Polymeric nanoparticles, liposomes, and micelles carrying small molecules, proteins, peptides and nucleic acids have attracted great attention for the treatment of various cancers including HCC. Herein, we discuss the pathogenesis of HCC in relation to its various recent treatment methodologies using nanodelivery of monoclonal antibodies (mAbs), small molecules, miRNAs and peptides. Synopsis of recent clinical trials of mAbs and peptide drugs has been presented with a broad overview of the pathogenesis of the disease and treatment efficacy.

Preparation and evaluation of glycyrrhetinic acid-modified and honokiol-loaded acoustic nanodroplets for targeted tumor imaging and therapy with low-boiling-point phase-change perfluorocarbon

Glycyrrhetinic acid-modified and honokiol-loaded acoustic nanodroplets for targeted tumor imaging and therapy with low-boiling-point phase-change perfluorocarbon.

Ligand-based targeted therapy: a novel strategy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with high morbidity and mortality worldwide. Chemotherapy is recommended to patients with intermediate or advanced stage cancer. However, the conventional chemotherapy yields low desired response rates due to multidrug resistance, fast clearance rate, nonspecific delivery, severe side effects, low drug concentration in cancer cells, and so on. Nanoparticle-mediated targeted drug delivery system can surmount the aforementioned obstacles through enhanced permeability and retention effect and active targeting as a novel approach of therapeutics for HCC in recent years. The active targeting is triggered by ligands on the delivery system, which recognize with and internalize into hepatoma cells with high specificity and efficiency. This review focuses on the latest targeted delivery systems for HCC and summarizes the ligands that can enhance the capacity of active targeting, to provide some insight into future research in nanomedicine for HCC.

Self-assembly modes of glycyrrhetinic acid esters in view of the crystal packing of related triterpene molecules

The crystal structures of three ester derivatives of glycyrrhetinic acid (GE) are reported. X-ray crystallography revealed that despite differences in the size of the ester substituents (ethyl, isopropyl and 2-morpholinoethyl) the scheme of molecular self-assembly is similar in all three cases but differs significantly from that observed in other known GE esters. According to our analysis, the two basic patterns of self-assembly of GE esters observed in their unsolvated crystals correspond to two distinct orientations of the ester groups relative to the triterpene backbone. Moreover, comparison of the self-assembly modes of GE esters in their unsolvated forms with the supramolecular organization of GE and carbenoxolone in their solvated crystals revealed that ester substituents replace solvent molecules hydrogen bonded to the COOH group at the triterpene skeleton, resulting in similar packing arrangements of these compounds.