18ß-glycyrrhetinic Acid Modulated Autophagy is Cytotoxic to Breast Cancer Cells.

The development of endocrine therapy resistance in the luminal A subtype of breast cancer is related to the appearance of protective autophagy. The bioactive component from the root of licorice, 18ß-glycyrrhetinic acid (18ß-GA), has many antitumor properties. Whether 18ß-GA can modulate autophagy to inhibit proliferation of the luminal A subtype is still unclear. The proportion of apoptosis caused by 18ß-GA in MCF-7 and T-47D cells was determined using flow cytometry. The autophagy marker, LC3-II conversion, was investigated using Western blotting, and a PremoTM Tandem Autophagy Sensor Kit. We found that the concentration (150-µM) of 18ß-GA caused caspase-dependent apoptosis and LC3-II accumulation or blocked autophagic flux. Moreover, 18ß-GA-mediated apoptosis was improved using rapamycin but reversed by 3-methyladenine (3-MA) addition. The phosphorylation level of Jun-amino-terminal kinase (JNK) was increased significantly in the 18ß-GA treatment and combined incubation using rapamycin. A JNK inhibitor (SP600125) significantly inhibited 18ß-GA-mediated apoptosis, LC3-II accumulation and rescued the numbers of MCF-7 and T-47D colony formation. Especially, 18ß-GA can inhibit xenograft tumor growth in BALB/c nude mice. These data indicate the combination of 18ß-GA with rapamycin or 3-MA can sensitize or decrease MCF-7 and T-47D cells to 18ß-GA-induced apoptosis, respectively. 18ß-GA modulated autophagy is cytotoxic to luminal A subtype breast cancer cells through apoptosis promotion and JNK activation.

Synthesis of glycyrrhetinic acid-modified liposomes to deliver Murrayafoline A for treatment of hepatocellular carcinoma.

Hepatocellular carcinoma is a common type of cancer associated with a high mortality rate. Among several bioactive compounds, Murrayafoline A (MuA) has been proved as a bio substance that exhibits great potentials in treating liver cancer. In order to overcome the high cytotoxicity and low solubility of MuA, a delivery system based on nanocarriers is necessary to deliver MuA towards the desired target. In the present study, 18ß-glycyrrhetinic acid (GA), which is known as a ligand for liver targeting, was used to construct the cholesterol-poly (ethylene glycol)-glycyrrhetinic acid (GA-PEG-Chol) conjugate and liposome for MuA administration. The compound was then examined for therapeutic efficacy and safety in HUVEC and HepG2 cells in 2D and 3D cell cultures. Results have shown that MuA-loaded liposomes had IC50 value of 2 µM in HepG2 and had the cytosolic absorption of 8.83 ± 0.97 ng/105 cells, while The IC50 value of MuA-loaded liposomes in HUVEC cell lines was 15 µM and the the cytosolic absorption was recorded as 3.62 ± 0.61 cells. The drug test on the 3D cancer sphere platform of the HepG2 cancer sphere showed that MuA-loaded GA liposomes had the highest efficacy at a concentration of 100 µg/mL. In short, these results suggest that MuA-loaded GA liposomes have the potential for maintenance drug delivery and liver targeting.

Transcriptional profile changes after treatment of ischemia reperfusion injury-induced kidney fibrosis with 18ß-glycyrrhetinic acid.

INTRODUCTION: Chronic kidney disease (CKD) is characterized by renal fibrosis without effective therapy. 18ß-Glycyrrhetinic acid (GA) is reported to have detoxification and anti-inflammatory functions and promotes tissue repair. However, the role of GA in CKD remains unclear. In this study, we investigated whether GA has a potential therapeutic effect in kidney fibrosis. METHODS: A renal fibrosis mouse model was established by ischemia/reperfusion (I/R) injury via clamping unilateral left renal pedicle for 45 min; then, the mice were treated with vehicle or GA. Kidney tissues and blood samples were extracted 14 days after reperfusion and renal function, histopathological staining, quantitative PCR, and western blotting were performed. RNA-seq was performed to explore the changes in the transcriptional profile after GA treatment. RESULTS: Renal function, pathological and molecular analysis displayed that fibrosis was successfully induced in the I/R model. In the GA treatment group, the severity of fibrosis gradually reduced with the best effect seen at a concentration of 25 mg kg -1. A total of 970 differentially expressed genes were identified. Pathway enrichment showed that reduced activation and migration of inflammatory cells and decreased chemokine interaction in significant pathways. Protein-protein interaction networks were constructed and 15 hub genes were selected by degree rank, including chemokines, such as C3, Ccl6, Ccr2, Ptafr, Timp1, and Pf4. CONCLUSIONS: GA may alleviate renal fibrosis by inhibiting the inflammatory response. GA is a promising therapy that may perhaps be used in treating renal fibrosis and CKD.

[Preparation of salvianolic acid B, tanshinone â ¡_A, and glycyrrhetinic acid lipid emulsion and its protective effect against acute liver injury induced by acetaminophen].

Salvianolic acid B(Sal B), tanshinone Ⅱ_A(TSN Ⅱ_A), and glycyrrhetinic acid(GA) lipid emulsion(GTS-LE) was prepared by the high-speed dispersion method combined with ultrasonic emulsification.The preparation process of the emulsion was optimized by single-factor method and D-optimal method with appearance, centrifugal stability, and particle size of the emulsion as evalua-tion indexes, followed by verification.In vitro release of Sal B, TSN Ⅱ_A, and GA in GTS-LE was performed by reverse dialysis.In vivo pharmacokinetic evaluation was carried out in mice.The acute liver injury model was induced by acetaminophen.The effect of oral GTS-LE on the acute liver injury was investigated by serum liver function indexes and pathological changes in liver tissues of mice.The results showed that under the optimal preparation process, the average particle size of GTS-LE was(145.4±9.25) nm and the Zeta potential was(-33.6±1.45) mV.The drug-loading efficiencies of Sal B, TSN Ⅱ_A, and GA in GTS-LE were above 95%, and the drug release in vitro conformed to the Higuchi equation.The pharmacokinetic results showed that the C_(max) of Sal B, TSN Ⅱ_A, and GA in GTS-LE was 3.128, 2.7, and 2.85 times that of the GTS-S group, and AUC_(0-t) of Sal B, TSN Ⅱ_A, and GA in GTS-LE was 3.09, 2.23, and 1.9 times that of the GTS-S group.After intragastric administration of GTS-LE, the activities of alanine aminotransferase and aspartate aminotransferase were significantly inhibited, the content of malondialdehyde was reduced, and the structure of hepatocytes recovered to normal.In conclusion, GTS-LE can delay the release of Sal B and promote the release of TSN Ⅱ_A and GA.The encapsulation of three drug components in the emulsion can improve the oral bioavailability to varying degrees and can effectively prevent the acute liver injury caused by acetaminophen.

Glycyrrhetinic acid remodels the tumor microenvironment and synergizes with doxorubicin for breast cancer treatment in a murine model.

We aimed to combine glycyrrhetinic acid with doxorubicin to prepare, characterize and evaluate a drug delivery nano-system with REDOX sensitivity for the treatment of breast cancer. M-DOX-GA NPs prepared by nano sedimentation were spherical, with a particle size of 181 nm. And the maximum encapsulation efficiency and drug loading in M-DOX-GA NPs were 89.28% and 18.22%, respectively. Cytotoxicity and cellular uptake experiments of nanoparticles to KC cells, Cal-27 cells and 4T1 cells were studied by the CCK-8 method. The result indicated that M-DOX-GA NPs could accurately release the drug into the tumor cells, thus achieving the targeted release of the drug. Comparing the survival rate of the above three cells, it was found that M-DOX-GA NPs had a good tumor selectivity and had a more significant therapeutic effect on breast cancer. A 4T1-bearing mouse model was established, and the tumor inhibition rate was 77.37% after injection of nanoparticle solution for 14 d. Normal tissue H&E stained sections and TUNEL assay were verified M-DOX-GA NPs have excellent tumor suppressive effect, and can efficiently reduce the toxic side effects on normal organisms, and effectively avoided 4T1 cells metastasis. Immunofluorescence detection and Western-blot analysis figured a decline in both CUGBP1 and α-SMA, which verifying the TME remodeling induced by glycyrrhetinic acid. Collectively, the combination of doxorubicin and glycyrrhetinic acid is an effective and safe strategy for remodeling fibrotic TME by improving the therapeutic outcome for breast cancer.

Structure-based design of glycyrrhetinic acid derivatives as potent anti-sepsis agents targeting high-mobility group box-1.

Novel Glycyrrhetinic Acid (GA) derivatives with fused heterocycles on A ring were structure-based designed and synthesized. Their potential anti-inflammatory effects were investigated by a classical LPS stimulated macrophage model. Surface plasmon resonance (SPR) was used to verify the binding of GA analogues with HMGB1. A preliminary structure-activity relationship was summarized and an analogue GA-60 with ortho-methoxybenzyl pyrozole showed stronger anti-inflammatory effect and higher affinity for HMGB1 with a Kd value of 12.5 µM. In addition, this compound exhibited excellent inhibitory functions on NO (96%), TNF-α (94%), and IL-6 (100%), by interfering with phosphorylation of p38, ERK, JNK MAPKs, as well as that of NF-κB p65 and IKKα/ß. Moreover, GA-60 extended the survival of either the classic CLP-induced or LPS-induced sepsis mouse models. Molecular modeling predictions further supported these findings, clearly indicating that inhibiting HMGB1 release, using fused heterocyclic GA derivatives, is a promising strategy for treatment of sepsis.

Research progress on the protective effects of licorice-derived 18ß-glycyrrhetinic acid against liver injury.

The first description of the medical use of licorice appeared in "Shennong Bencao Jing", one of the well-known Chinese herbal medicine classic books dated back to 220-280 AD. As one of the most commonly prescribed Chinese herbal medicine, licorice is known as "Guo Lao", meaning "a national treasure" in China. Modern pharmacological investigations have confirmed that licorice possesses a number of biological activities, such as antioxidation, anti-inflammatory, antiviral, immune regulation, and liver protection. 18ß-glycyrrhetinic acid is one of the most extensively studied active integrants of licorice. Here, we provide an overview of the protective effects of 18ß-glycyrrhetinic acid against various acute and chronic liver diseases observed in experimental models, and summarize its pharmacological effects and potential toxic/side effects at higher doses. We also make additional comments on the important areas that may warrant further research to support appropriate clinical applications of 18ß-glycyrrhetinic acid and avoid potential risks.

Administration of glycyrrhetinic acid reinforces therapeutic effects of mesenchymal stem cell-derived exosome against acute liver ischemia-reperfusion injury.

Recent studies have shown that mesenchymal stem cell-derived exosome could attenuate ischaemia-reperfusion (I/R) injury by suppressing inflammatory response in the liver. Glycyrrhetinic acid was also shown to be capable of repressing the TLR4 signalling pathway. However, it remains to be explored as whether the combined administration of mesenchyma stem cell (MSC)-derived exosome and glycyrrhetinic acid (GA) could increase their therapeutic effects on I/R injury. Western blot was performed to evaluate the expression of proteins associated with inflammatory response in THP-1 cells and I/R rat models treated under different conditions. Flow cytometry was carried out to analyse the proportions of different subtypes of peripheral blood cells in I/R rats. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured to assess the liver injury in I/R rats. Combined treatment with MSC-derived exosome and GA effectively maintained the expression of key proteins involved in inflammatory response in LPS stimulated THP-1 cells and THP-1 cells treated under hypoxia conditions. In the established of I/R rat models, GA administration reinforced the therapeutic efficiency of MSC-derived exosomes by maintaining the proportion of different subgroups of peripheral blood cells, decreasing the concentration of ALT and AST, and restoring the expression of dysregulated proteins associated with inflammation. Our results demonstrated that treatment with exosomes derived from mesenchymal stem cells (MSCs) attenuated liver I/R injury, while the pre-treatment with GA may further promote the therapeutic effect of mesenchymal stem cell-derived exosome against acute liver ischaemia-reperfusion injury.

Glycyrrhetinic acid alleviates acute lung injury by PI3K/AKT suppressing macrophagic Nlrp3 inflammasome activation.

Glycyrrhetinic acid (GA), a triterpene saponins, has been widely proven to have multiple medicinal properties. Our study aimed to figure out the protective effect of GA on acute lung injury (ALI) and the underlying mechanism. The LPS-induced ALI model mice were intratracheally administrated with 10 mg/kg LPS. Pretreatment with GA (10, 20, 40 mg/kg, i.g.) ameliorated acute lung injury pathological damage, macrophage infiltration and lung edema. In the lung tissue, immunofluorescence (IF) and Immunohistochemistry (IHC) were performed to detect macrophage Nod-like receptor 3 (Nlrp3) inflammasome activation and interleukin-1ß (IL-1ß) protein expression. In macrophages, the co-localization of Nlrp3 with caspase-1 and Nlrp3 with ASC were assessed by IF. The translational and transcriptional level of Nlrp3, cle-caspase-1 and apoptosis-associated speck-like protein containing CARD (ASC), were examined by Western blot and Real time PCR (RT-PCR). The protein expression of Cle-caspase-1 was remarkably suppressed via sh-Nlrp3 transfection compared with LPS groups. GA notably attenuated ALI by inhibiting Nlrp3 formation and activation. Furthermore, GA downregulated the production of reactive oxygen species (ROS) and the phosphorylation level of PI3K and AKT in macrophages. These findings indicate that GA ameliorated ALI in mice by suppressing the activation of Nlrp3 inflammasome which may be mediated by ROS-PI3K/AKT pathway. GA may serve as a promising agent for the attenuation of ALI-related inflammation and pathology.

Glycyrrhetinic acid and its derivatives as potential alternative medicine to relieve symptoms in nonhospitalized COVID-19 patients.

SARS-CoV-2 is highly infectious, and infection by this virus results in COVID-19, manifesting predominantly symptoms in the lower respiratory system. Detection of viral genomic materials by RT-PCR is the gold standard for diagnosis. Suspected COVID-19 patients who had a documented history of exposure and exhibited symptoms, but did not have positive PCR test results, were generally self-quarantined with prescriptions aiming to help attenuate their symptoms. These prescriptions are however neither specific nor highly effective for COVID-19 treatment. Given the rapidly growing pandemic and the overwhelmed medical system, the number of self-quarantined patients is increasing. There is an urgent need of alternative medicine to help patients relieve symptoms during self-quarantine, and to potentially help increase their chances of survival and recovery from the infection. We report here a case of severe COVID-19 that never had a positive PCR test result during disease progression but was confirmed with antibody test post recovery. This patient was self-quarantined and received diammonium glycyrrhizinate (DG), a steroid-like molecule, in combination with vitamin C as alternative medicine. This patient went through severe COVID-19 but eventually recovered upon the implementation of this treatment regimen, suggesting potential therapeutic effects of DG as alternative medicine to help relieve COVID-19 symptoms.

A Previously Unknown Drug-Drug Interaction Is Suspected in Delayed Elimination of Plasma Methotrexate in High-Dose Methotrexate Therapy.

Background: High-dose methotrexate (HD-MTX) therapy is widely implemented for leukemia, osteosarcoma, and lymphoma. Although various measures have been taken to avoid toxicity from high serum MTX concentrations, there are many cases of delayed elimination of MTX. Objective: We suspected that delayed elimination of serum MTX was caused by unknown interactions between MTX and concomitant drugs. Methods: Concerning concomitant drugs in the case of delayed elimination of MTX, we performed screening tests in 35 patients who had undergone HD-MTX therapy. We then investigated the risk factors for delayed MTX elimination in 94 patients with leukemia, lymphoma, or osteosarcoma retrospectively. Results: The percentages of concomitant use of Stronger Neo-Minophagen C (SNMC), a glycyrrhizin preparation, and vincristine were higher in the delayed group. The percentage of delayed MTX elimination in patients receiving HD-MTX therapy was 41%. Multiple logistic regression analysis revealed that the concomitant use of SNMC solely was a significant risk factor for delayed MTX (odds ratio = 12.20; 95% CI = 1.06-139.84). Conclusion and Relevance: Concomitant use of SNMC was shown to be related to delayed elimination of serum MTX, and our results suggested a previously unknown drug-drug interaction between MTX and SNMC.

Synthesis, anti-microbial and anti-inflammatory activities of 18ß-glycyrrhetinic acid derivatives.

Thirteen 18ß-glycyrrhetinic acid (GA) derivatives were obtained by reduction at C-11 position, oxidation at C-3 position and condensation at C-2 position of GA. Anti-microbial activity evaluation indicated that compounds 04, 05, 10, 13 and 14 showed more potent inhibitory activity against Staphylococcus aureus subsp. aureus, Staphylococcus epidermidis, Staphylococcus aureus than GA, especially compound 10, the inhibitory activity against Staphylococcus epidermidis was equaled with Ampicillin. Moreover, in vivo experiments exhibited that compound 10 also has anti-inflammatory effect, which could decrease about 59.69% TPA-induced ear edema of mice with the gavage treatment of 40.0 mg/mL. Immunohistochemistry results revealed that the effect of inhibition was related to inhibition of TPA-induced upregulation of the pro-inflammatory cytokines TNF-α and IL-1ß. Furthermore, compound 10 also significantly decreased the expression level of p65 in NF-κB signaling pathway. In general, compound 10, both with antibacterial and anti-inflammatory activities, was expected to become a promising bio-functional agent.

Synthesis and antitumor effects of novel 18ß-glycyrrhetinic acid derivatives featuring an exocyclic α,ß-unsaturated carbonyl moiety in ring A.

A series of novel 18ß-glycyrrhetinic acid (GA) derivatives featuring an exocyclic α,ß-unsaturated carbonyl moiety in ring A were synthesized and evaluated for their antitumor activities. Compounds 5c and 5l showed stronger cytotoxicity than other compounds and reported GA analogue CDODA-Me (methyl 2-cyano-3,11-dioxo-18ß-olean-1,12-dien-30-oate). 5c and 5l induced apoptosis in cancer cells accompanying with c-Flip reduction and Noxa induction, associated with decreased HDAC3 expression and increased acetylation of H3. 5l displayed better stability properties than 5c and CDODA-Me in microsomes and plasma, 5l also showed favorable pharmacokinetic profiles and inhibited tumor growth in mice. Compound 5l represents a new type of GA derivatives with improved antitumor activity.

Clinical and noninvasive instrumental evaluation of the efficacy of a nonsteroidal anti-inflammatory 8-beta glycyrrhetinic acid cream for the treatment of erythema in rosacea.

Rosacea is a very common chronic facial dermatosis characterized by a multiphase evolution. Inflammation is an important reaction in rosacea not only due to inflammatory reactions to cutaneous microorganisms, such as Demodex follicolorum, but also to ultraviolet damage that generates reactive oxygen species. This study evaluated the efficacy and tolerability of a nonsteroidal anti-inflammatory 18-beta glycyrrhetinic acid cream for the treatment of mild rosacea by means of noninvasive methods. A total of 24 subjects suffering from erythemato-telangiectatic or mild papulo-pustular rosacea were recruited in the trial. Twelve patients applied an anti-inflammatory cream with 18-beta glycyrrhetinic acid twice daily for 20 days and 12 patients, recruited as control, applied the same formulation without 18-beta glycyrrhetinic acid. After 10 days of treatment, a significant reduction of erythema was recorded in the patient sample who applied the 18-beta glycyrrhetinic acid cream, the mean change from baseline showed an increase in hydration level of the skin surface but it was not statistically significant. The use of 18-beta glycyrrhetinic acid cream can be helpful in managing symptoms and condition of rosacea skin, especially in the management of erythema.

What's new in atopic eczema? An analysis of systematic reviews published in 2016. Part 1: treatment and prevention.

This review is part of a series of annual updates summarizing the evidence base for atopic eczema (AE). It provides a summary of key findings from 28 systematic reviews that were published or indexed during 2016 with a focus on treatment and prevention of AE. There is reasonable evidence of benefit for topical corticosteroids, calcineurin inhibitors, a glycyrrhetinic acid-containing preparation (Atopiclair® ), oral ciclosporin, oral azathioprine, narrowband ultraviolet B radiation and education programmes. Overall, there is evidence that topical corticosteroids and calcineurin inhibitors have similar efficacy and that both can prevent AE flares when used twice weekly as maintenance therapy. However, topical calcineurin inhibitors are costlier and have more adverse reactions, thus topical corticosteroids should remain the standard of care for patients with AE. There is no evidence that multiple applications are better than once-daily application of topical corticosteroid. There is inconsistent evidence to support omalizumab and specific allergen immunotherapy use in AE. There is some evidence that vitamin D supplementation and synbiotics reduce AE severity, although the margin of improvement may not be clinically meaningful. There is little evidence to support the use of wet wraps or of complementary/alternative medicine (including Chinese herbal medicine). There is some evidence to suggest that a diet high in fish in infancy may be preventative for AE, but other dietary interventions for the prevention of AE show little promise. This review provides a succinct guide for clinicians and patients wishing to remain up to date with the latest evidence for the treatment and prevention of AE.

Computational and Biological Comparisons of Plant Steroids as Modulators of Inflammation through Interacting with Glucocorticoid Receptor.

Despite the usefulness of glucocorticoids, they may cause hazardous side effects that limit their use. Searching for compounds that are as equally efficient as glucocorticoids, but with less side effects, the current study compared plant steroids, namely, glycyrrhetinic acid, guggulsterone, boswellic acid, withaferin A, and diosgenin with the classical glucocorticoid, fluticasone. This was approached both in silico using molecular docking against glucocorticoid receptor (GR) and in vivo in two different animal models. All tested compounds interacted with GR, but only boswellic acid and withaferin A showed docking results comparable to fluticasone, as well as similar in vivo anti-inflammatory effects, by significantly decreasing serum levels of interleukin-6 and tumor necrosis factor-α in cotton pellet-induced granuloma in rats. In addition, both compounds significantly decreased the percent of change in ear weight in croton oil-induced ear edema in mice and the granuloma weight in cotton pellet-induced granuloma in rats, to levels comparable to that of fluticasone. Both boswellic acid and withaferin A had no effect on adrenal index, but only withaferin A significantly increased the thymus index. In conclusion, boswellic acid may have comparable anti-inflammatory effects to fluticasone with fewer side effects.

18ß-Glycyrrhetinic acid: its core biological properties and dermatological applications.

Recently, attention has been focused on identifying natural herbal compounds with high biological activity, especially antioxidative, anti-inflammatory and antimicrobial properties, for preventing and controlling various skin conditions, including inflammation-related diseases such as atopic dermatitis and UV-induced skin photoaging. One key active plant ingredient is 18ß-glycyrrhetinic acid (GA), the main metabolite of glycyrrhizin (GL), obtained from licorice root. The review examines the valuable biological properties of GA, particularly those playing key roles in the treatment of various dermatological disorders in humans. The review highlights the key anti-inflammatory, antioxidant and antimicrobial properties of GA and its toxicity towards normal cells lines. It also examines the physicochemical properties of GA and presents methods of increasing its penetration through the stratum corneum and bioaccumulation with the use of modern delivery systems such as liposomes and nanoemulsions.

Récemment, l'attention s'est concentrée sur l'identification de composés naturels à base de plantes ayant une activité biologique élevée, en particulier des propriétés antioxydantes, anti-inflammatoires et antimicrobiennes, pour prévenir et contrôler diverses affections cutanées, y compris les maladies liées à l'inflammation telles que la dermatite atopique et le photovieillissement induit par les UV. Un ingrédient actif végétal clé est l'acide 18ß-glycyrrhétinique (GA), le principal métabolite de la glycyrrhizine (GL), obtenu à partir de la racine de réglisse. La revue examine les propriétés biologiques précieuses de l'AG, en particulier celles qui jouent un rôle clé dans le traitement de divers troubles dermatologiques chez l'homme. La revue met en évidence les propriétés anti-inflammatoires, anti-oxydantes et antimicrobiennes essentielles de l'AG et sa toxicité vis-à-vis des lignées cellulaires normales. Il examine également les propriétés physicochimiques de l'AG et présente des méthodes pour augmenter sa pénétration dans la couche cornée et sa bioaccumulation grâce à l'utilisation de systèmes d'administration modernes tels que les liposomes et les nanoémulsions.

Liver-Targeted Co-delivery of Entecavir and Glycyrrhetinic Acid Based on Albumin Nanoparticle To Enhance the Accumulation of Entecavir.

Hepatitis B, one of the most common contagious viral hepatitis with high infection rate, is challenging to treat. Although the treatment for hepatitis B has been improved over the years, many therapeutic drugs still have either severe adverse effects or insufficient effectiveness via systemic administration. In this study, we confirmed that glycyrrhetinic acid can enhance the accumulation of entecavir in HepaRG cell and liver. Then we constructed a novel albumin nanoparticle co-loading entecavir and glycyrrhetinic acid (ETV-GA-AN) to improve liver accumulation of entecavir and investigated its ability to deliver both drugs to liver. In vitro cellular uptake study and in vivo tissue distribution experiment showed that these negatively charged ETV-GA-AN (112 ± 2 nm in diameter) can increase the accumulation of entecavir in hepatic HepaRG cells and improve entecavir distribution in liver. We also revealed the mechanism that glycyrrhetinic acid enhances intracellular accumulation of entecavir by inhibiting the activity of specific efflux transporters. Our delivery system is the first liver-targeted albumin nanoparticle that utilizes the site-specific co-delivery strategy to delivery entecavir and glycyrrhetinic acid. As it combines high efficiency and low toxicity, it possess great potential for treating hepatitis B.

Controlled release of 18-ß-glycyrrhetic acid by nanodelivery systems increases cytotoxicity on oral carcinoma cell line.

The topical treatment for oral mucosal diseases is often based on products optimized for dermatologic applications; consequently, a lower therapeutic effect may be present. 18-ß-glycyrrhetic acid (GA) is extracted from Glycirrhiza glabra. The first aim of this study was to test the cytotoxicity of GA on PE/CA-PJ15 cells. The second aim was to propose and test two different delivery systems, i.e. nanoparticles and fibers, to guarantee a controlled release of GA in vitro. We used chitosan and poly(lactic-co-glycolic) acid based nanoparticles and polylactic acid fibers. We tested both delivery systems in vitro on PE/CA-PJ15 cells and on normal human gingival fibroblasts (HGFs). The morphology of GA-loaded nanoparticles (GA-NPs) and fibers (GA-FBs) was investigated by electron microscopy and dynamic light scattering; GA release kinetics was studied spectrophotometrically. MTT test was used to assess GA cytotoxicity on both cancer and normal cells. Cells were exposed to different concentrations of GA (20-500 µmol l-1) administered as free GA (GA-f), and to GA-NPs or GA-FBs. ROS production was evaluated using dichlorodihydrofluorescein as a fluorescent probe. Regarding the cytotoxic effect of GA on PE/CA-PJ15 cells, the lowest TC50 value was 200 µmol l-1 when GA was added as GA-NPs. No cytotoxic effects were observed when GA was administered to HGFs. N-acetyl Cysteine reduced mortality induced by GA-f in PE/CA-PJ15 cells. The specific effect of GA on PE/CA-PJ15 cells is mainly due to the different sensitivity of cancer cells to ROS over-production; GA-NPs and GA-FBs formulations increase, in vitro, this toxic effect on oral cancer cells.

Topical application of glycyrrhetinic acid in the gingival sulcus inhibits attachment loss in lipopolysaccharide-induced experimental periodontitis in rats.

BACKGROUND AND OBJECTIVE: Attachment loss of the junctional epithelium and alveolar bone destruction are signs of periodontitis, which is mainly caused by an inflammatory response to dental plaque. Glycyrrhetinic acid (GA), a component of the licorice herb, has been shown to have important anti-inflammatory activities; however, there are no previous reports on the ability of its inhibitory effects to prevent periodontal diseases. Hence, in this study, using our experimental periodontitis model, we attempted to evaluate whether GA had an effect on the prevention of attachment loss and alveolar bone loss. MATERIAL AND METHODS: Rats were intraperitoneally immunized with Escherichia coli lipopolysaccharide (LPS). The LPS group (n = 5) received 3 topical applications of 50 µg/µL of LPS followed by one application of the vehicle (propylene glycol:ethyl alcohol:phosphate-buffered saline [PBS] = 8:1:1) into the gingival sulcus. This protocol was repeated twice per day for 10 days. The low (n = 5) and high (n = 5) groups received topical application of LPS and 0.03% or 0.3% GA, respectively. The control group received topical application of PBS and vehicle. The rats were killed on the 10th day. Attachment loss, alveolar bone level and inflammatory cell infiltration were investigated histometrically. The formation of immune complexes and infiltration of LPS were evaluated immunohistologically. RESULTS: Attachment loss, formation of immune complexes and infiltration of inflammatory cells were increased in the LPS group compared with the control group, and were completely inhibited in the low and high groups compared with the LPS group. The LPS group showed greater alveolar bone destruction compared with the control group and GA-treated groups. In addition, invasion of LPS was detected in the LPS group, was absent in the control group and was weaker in the GA-treated groups than in the LPS group. CONCLUSION: In the present study, we showed that GA inhibits periodontal destruction in the rat experimental periodontitis model.