In vitro effects of glycyrrhetinic acid on the growth of clinical isolates of Candida albicans

Nose-to-brain delivery of 18β-Glycyrrhetinic acid using optimized lipid nanocapsules: A novel alternative treatment for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder and the most relevant form of dementia affecting people worldwide. AD was reported to be associated with increased oxidative stress ending up with neuronal damage. 18β-Glycyrrhetinic acid (GA), triterpenoid aglycone of glycyrrhizin, was reported for its powerful antioxidant activities. However, its high molecular weight and lipophilicity are two major obstacles that limit its use and cause very low brain bioavailability. The aim of the present study was to formulate the GA in lipid nanocapsules (LNCs) for enhanced nose-to-brain delivery, as well as to elucidate its potential neuroprotective effect in AD. The optimized GA-loaded LNCs exhibited nanometric size range, good stability over 6 months, sustained drug release over 24 h and high steady state flux and permeability coefficient across nasal mucosa over 8 h. In-vivo studies were conducted on five groups; control, scopolamine (SCOP)-treated, SCOP + GA-LNCs, SCOP + oral GA suspension, and SCOP + intranasal GA suspension groups. Intranasal administration of GA-LNCs, at a reduced dose of 1 mg/kg, improved scopolamine-induced memory impairment in rats evidenced by behavioral testing, histological examination, and oxidative stress markers; catalase and superoxide dismutase. Collectively, GA-loaded LNCs (with 50 times lower dose) may provide a promising remedy for AD patients worldwide.

Microbiological Assessment of Glycyrrhizic Acid Effectiveness in Bacterial Vaginosis – A Comparative Study

Background. Bacterial vaginosis (BV) is one of the most common female diseases, which is currently characterized by an increasing rate of clinical sign reccurence, the appearance of asymptomatic carriers, and atypical forms. This study was aimed to evaluate the effectiveness of glycyrrhizic acid administration in the prevention of BV recurrence. Materials and Methods. The study involved 88 women after BV treatment (metronidazole per os for seven days). Participants were randomly divided into two groups: the main group included 46 patients who were administered 0.1% glycyrrhizic acid intravaginally for three months after the main treatment; the control group comprised 42 women who received no anti-recurrence BV course. The effectiveness was assessed three and six months after the beginning of treatment and included gynecological examination and laboratory assessments (pH, amine test, microbiological investigation). Results. After recommended BV treatment without anti-recurrence course, the recurrence of laboratory criteria for BV increased three months after the treatment, including the increase in vaginal pH to > 4.5 in all subjects, positive amine test in 35.7% of patients, the presence of Gardnerella vaginalis at a concentration of 104-105 CFU/ml in 31.0% of women, reduction in the frequency of Lactobacillus detection with worsening of the condition and the onset of clinical manifestations of the disease six months later. In the main group, after glycyrrhizic acid administration, laboratory criteria of BV recovery three months after the treatment, and clinical and laboratory markers of BV recovery six months after the treatment were lower as compared to the control group. Conclusions. The anti-recurrence course of BV (vaginal administration of 0.1% glycyrrhizic acid) demonstrated a decrease in the frequency of complaints, clinical and laboratory markers, stabilization of the species composition of Lactobacillus, and a decrease in facultative anaerobe concentration in the vaginal microbiome as compared to group without anti-recurrence treatment.

Synergistic Effects of Licorice Root and Walnut Leaf Extracts on Gastrointestinal Candidiasis, Inflammation and Gut Microbiota Composition in Mice

Candida albicans is an opportunistic pathogen that causes gastrointestinal (GI) candidiasis closely associated with intestinal inflammation and dysbiosis. Drug resistance, side effects of available antifungal agents, and the high recurrence of candidiasis highlight the need for new treatments. We investigated the effects of hydroethanolic extracts of licorice root (LRE) and walnut leaf (WLE) on GI colonization by C. albicans, colon inflammation, and gut microbiota composition in C57BL/6 female mice. Oral administration of LRE and WLE alone or in combination once daily for 12 days before C. albicans infection and then for 5 days after infection significantly reduced the level of C. albicans in the feces of gastrointestinal infected mice as well as colonization of the GI tract, both extracts showing robust antifungal activity. Although total bacterial content was unaffected by the extracts (individually or combined), the abundance of protective bacteria, such as Bifidobacterium spp. and Faecalibacterium prausnitzii, increased with the combination, in contrast to that of certain pathobiont bacteria, which decreased. Interestingly, the combination induced a more robust decrease in the expression of proinflammatory genes than either extract alone. The anti-inflammatory activity of the combination was further supported by the reciprocal increase in the expression of anti-inflammatory cytokines and the significant decrease in enzymes involved in the synthesis of proinflammatory eicosanoids and oxidative stress. These findings suggest that LRE and WLE have synergistic effects and that the LRE/WLE combination could be a good candidate for limiting GI candidiasis and associated inflammation, likely by modulating the composition of the gut microbiota. IMPORTANCE The adverse effects and emergence of resistance of currently available antifungals and the high recurrence of candidiasis prompt the need for alternative and complementary strategies. We demonstrated that oral administration of hydroethanolic extracts of licorice root (LRE) and walnut leaf (WLE) separately or in combination significantly reduced the colonization of the gastrointestinal (GI) tract by C. albicans, highlighting a robust antifungal activity of these plant extracts. Interestingly, our data indicate a correlation between LRE and WLE consumption, in particular the combination, and a shift within the gut microbiome toward a protective profile, a decrease in colonic inflammation and prooxidant enzymes, suggesting a synergistic effect. This study highlights the significant prebiotic potential of the LRE/WLE combination and suggests that the health benefits are due, at least in part, to their ability to modulate the gut microbiota, reduce inflammation and oxidative stress, and protect against opportunistic infection.

Glycyrrhiza Genus: Enlightening Phytochemical Components for Pharmacological and Health-Promoting Abilities

The Glycyrrhiza genus, generally well-known as licorice, is broadly used for food and medicinal purposes around the globe. The genus encompasses a rich pool of bioactive molecules including triterpene saponins (e.g., glycyrrhizin) and flavonoids (e.g., liquiritigenin, liquiritin). This genus is being increasingly exploited for its biological effects such as antioxidant, antibacterial, antifungal, anti-inflammatory, antiproliferative, and cytotoxic activities. The species Glycyrrhiza glabra L. and the compound glycyrrhizin (glycyrrhizic acid) have been studied immensely for their effect on humans. The efficacy of the compound has been reported to be significantly higher on viral hepatitis and immune deficiency syndrome. This review provides up-to-date data on the most widely investigated Glycyrrhiza species for food and medicinal purposes, with special emphasis on secondary metabolites' composition and bioactive effects.

Development of sodium carboxymethyl cellulose based polymeric microparticles for in situ hydrogel wound dressing formation

18β-glycyrrhetinic acid (Gly), a natural compound obtained from licorice, is known both for the anti-inflammatory and antioxidant activities and for this reason useful for wound treatment. Due to its poor solubility, Gly is not suitable for formulations used in conventional topical products such as gels, foams and creams. Polymeric bioadhesive microparticles (MP), loaded with Gly, were developed to be introduced in the wound bed and swell, once in contact with the exudate, to form a hydrogel in situ able to close the wound. The MP were prepared by spray drying method from the polymeric solution of polysaccharide sodium carboxymethyl cellulose (CMC) and copolymer Soluplus® (SL). Soluplus® introduction in MP composition, using a 3:1 ratio (CMC/SL wt./wt.), allowed to stabilize Gly in non-crystalline form, favoring the improvement of water solubility, and to obtain a spherical with rugged surface MP morphology. Ex vivo studies showed these MP maintain high swelling capability and are able to form in situ a hydrogel for wound repair. The controlled release of Gly from the hydrogel stimulates keratinocyte growth, potentially supporting the physiological healing processes.

New Technological Approach for Glycyrrethic Acid Oral and Topical Administration

Background:

18β- glycyrrhetinic acid (Gly) is the major bioactive component of licorice roots and rhizomes of the Glycyrrhiza glabra species. It shows many activities such as antiviral, anti-inflammatory, antioxidant, antimicrobial, and antifungal, however, its use in the health field is very limited due to the low water solubility.

Methods:

This paper deals with the development of a new technological approach for Gly dissolution rate enhancement. It consists of Gly intercalation (guest) in the interlamellar spaces between the inorganic spaces (host) of the anionic clays “hydrotalcites” (HTlc) to obtain hybrids MgAl-HTlc-Gly and ZnAl-HTlc-Gly. Gly can find applications in both systemic and local therapies, thus advantages of the use of the hybrids in these two fields were investigated.

Results:

Gly dissolution rate from hybrids in the intestinal environment, site in which it is preferentially absorbed, resulted enhanced (ZnAl-HTlc-Gly > MgAl-HTlc-Gly) compared to the crystalline form, thereby, making them suitable for oral administration as dry powder in hard capsules.

:

For a local therapy, bioadhesive, vaginal emulgels loaded with the hybrids were developed. These showed suitable mucoadhesive property to the vaginal mucosa, necessary to prolong the residence time in the application site. The emulgel containing ZnAl-HTlc-Gly showed a faster and higher release profile than that containing MgAl- HTlc-Gly.

Conclusions:

The obtained results suggest that Gly intercalation into HTlc, especially in ZnAl-HTlc, allows to enhance Gly dissolution when the hybrids are formulated both as oral or topical products.

Glycyrrhiza glabra L. (Fabaceae/Leguminosae)

Liquorice is a perennial, temperate-zone herb or subshrub, native of India, Pakistan and southern Europe; also cultivated in England, Belgium, France, Germany, Spain, Italy, Greece, Turkey, Russia, South Africa, Egypt, Syria and Iraq. It has also been grown experimentally in the United States. Ancient historical manuscripts from China, India and Greece mention its use for symptoms of viral respiratory tract infections and hepatitis. The plant has also been described by Theophrastus. Licorice from Egypt has been described to be the best, followed by from Iraq and Syria; the root should be decorticated before use. It concocts viscid humours in diseases of liver, bladder and lungs, and expectorates them. It has been used in Iranian herbal medicine for skin eruptions, including dermatitis, eczema, pruritus and cysts, and for treatment of stomach disorders including peptic ulcers. The herb extract inhibits gastric motility in vivo, which is regarded to be an important aspect for its antiulcer activity. Licorice possesses both anti-inflammatory and antiulcer activities; whereas most anti-inflammatory agents are ulcerogenic. Former German Commission E believed it to be effective in the treatment of atopic dermatitis. Licorice root has been used for years to regulate gastrointestinal function in TCM, has been used for generations as an antidote, demulcent, and elixir in folk medicine of China, and is the most commonly used crude drug in Kampo Medicines, the Japanese form of modified TCM, for the treatment of peptic ulcer. Roots contain glycyrrhizin, the main water-soluble constituent that is 50× sweeter than sugar, 2-β-glucuronosyl glucuronic acid, and isoliquiritigenin-4-glucoside. Glycyrrhizin is a nonhemolytic saponin with foaming property, and one of the most potent hydroxyl radical scavengers. No significant effect of deglycyrrhizinised liquorice was observed on gastric ulcer in an RCT of British patients. Treatment of healthy men with licorice for one-week decreased salivary testosterone values by 26% but no significant decrease in free testosterone, and nine healthy women treated with licorice daily for two cycles, had their mean total serum testosterone decreased by 37% at the end of 2nd month. This property could be useful as an adjunct therapy of hirsutism and PCOS.

A Mouse Model of Trichophyton Inflammation Based on Trichophytin-induced Contact Hypersensitivity

The prevalence of Trichophyton-induced superficial skin mycosis is very high among human patients. Dermatophytes generally infect the epidermis, especially the stratum corneum, forming scales, hyperkeratosis, and vesicles. The important roles played by the immune system in Trichophyton infection are detection of fungal invasion and elimination of fungi.These immune mechanisms are presumed to involve not only innate immunity but also acquired immunity. Therefore, there is a substantial need for studies on treatment methods based on new basic knowledge, and the elucidation of immunological mechanisms of Trichophyton-induced inflammatory reactions is especially important.However, since Trichophyton cannot colonize on the mouse skin, we tried to develop a model for Trichophyton inflammation induced by trichophytin extracted from Trichophyton mentagrophytes using a method based on contact hypersensitivity.Trichophytin is a crude extract that mainly contains fungal cell wall constituents including β-glucan and zymosan. In this model, TLR2, TLR4, and dectin-1 were highly expressed, and production of IL-17A and IL23 was observed. This indicates that we succeeded in inducing fungal-specific inflammation in the mice.In this review, we introduce a mouse Trichophyton inflammation model developed to investigate the immunological mechanisms of Trichophyton-induced inflammatory reactions. In addition, we report results of evaluation of anti-inflammatory and anti-itching effects of anti-fungal agents using the inflammation model.

Phytochemical Constituents and Pharmacological Effects of Licorice: A Review

Licorice (or “liquorice”) is one of most widely used in foods, herbal medicine, and extensively researched medicinal plants of the world. In traditional medicine licorice roots have been used against treating many ailments including lung diseases, arthritis, kidney diseases, eczema, heart diseases, gastric ulcer, low blood pressure, allergies, liver toxicity, and certain microbial infections. Licorice extract contains sugars, starch, bitters, resins, essential oils, tannins, inorganic salts, and low levels of nitrogenous constituents such as proteins, individual amino acids, and nucleic acids. A large number of biological active compounds have been isolated from Glycyrrhiza species, where triterpene saponins and flavonoids are the main constitutes which show broad biological activity. This review examines recent studies on the phytochemical and pharmacological data and describes some side effects and toxicity of licorice and its bioactive components.

Economic Importance

The beneficial effects of liquorice in treating chills, colds, and coughs have been fully discussed in Ayurveda, as well as in the texts of ancient Egyptians, Greeks, and Romans. The plant has been prescribed for dropsy during the period of famous Hippocrates. The reason being that it was quite helpful as thirst-quenching drugs (Biondi et al. in J Nat Prod 68:1099–1102, 2005; Mamedov and Egamberdieva in Herbals and human health-phytochemistry. Springer Nature Publishers, 41 pp, 2017). No doubt, the clinical use of liquorice in modern medicine started around 1930; Pedanios Dioscorides of Anazarba (Adana), first century AD-Father of Pharmacists, mentions that it is highly effective in the treatment of stomach and intestinal ulcers. In Ayurveda, people in ancient Hindu culture have used it for improving sexual vigor.

Glycyrrhetinic acid and its derivatives in infectious diseases

Introduction. Licorice or liquorice (Glycyrrhiza glabra, Leguminosae) is a perennial plant naturally occurring or cultivated in Europe and Asia. It was appreciated by many ancient cultures, and was employed within Arabic medicine and (beginning in the Middle Ages) in Europe folk medicine as a remedy for many diseases. Currently, the sweet flavoured root of this plant – Radix Glycyrrhizae (Liquirtiae), is widely taken for the treating of various upper respiratory tract diseases, as well as for gastric ulcer disease. It is also utilized as a sweetening and flavouring agent in the food, tobacco and pharmacy industries. The main active ingredient of liquorice is the triterpenoid saponin, glycyrrhizin, which is a mixture of calcium, magnesium and potassium salts of glycyrrhizic acid (GA). Glycyrrhizic acid is composed of an aglycone, that is 18β-glycyrrhetinic acid (GE), and a D-glucuronic acid dimer. The aim of this review is to discuss some aspects of the activity of glycyrrhetinic acid and its derivatives in infectious diseases.

State of knowledge. The pentacyclic system of glycyrrhetinic acid consists of condensed six-membered rings with a hydroxyl group at C-3, a carboxyl moiety at C-30 and a ketone functional group at C-11. Considering the presence of the above mentioned functional groups, many structural transformations have been proposed, including those by way of esterification, alkylation and reduction reactions. The introduction of various chemical residues into its structure, as well as the modification of the glycyrrhetinic acid in its pentacyclic triterpene skeleton, has led to the generation of compounds with many valuable antimicrobial, anti-parasitic, antiviral properties and modified lipophilic parameters.

Summary. In summary, glycyrrhetinic acid derivatives appear to have promise as active pharmaceutical ingredients that contain a wide range of biological and pharmacological properties.

Glycyrrhetinic acid inhibits contact hypersensitivity induced by trichophytin via dectin-1

Trichophyton infection is highly prevalent and tends to be recurrent. Therefore, it is important to develop new therapeutic agents. Previously, we established a mouse model of Trichophyton-induced contact hypersensitivity (CHS) and demonstrated that dectin-1 was involved in inflammation induced by trichophytin, the Trichophyton antigen. Here, we used that model to investigate glycyrrhetinic acid (GA) from plants of the genus Glycyrrhiza as a potential anti-inflammatory agent against superficial mycoses. GA suppressed swelling and the expression of inflammatory cytokines, including macrophage inflammatory protein (MIP)-2, interleukin (IL)-6, tumor necrosis factor (TNF)-α and interferon (IFN)-γ mRNA. Anti-MIP-2 antibody suppressed trichophytin-induced inflammation, and antidectin-1 antibody suppressed zymosan-induced MIP-2 production in keratinocyte cells. These results suggest that MIP-2 is produced by dectin-1 activation and is involved in inflammation associated with CHS to trichophytin. GA also suppressed zymosan-induced MIP-2 and interleukin (IL)-8, production in mouse and human macrophages and keratinocytes. Furthermore, GA suppressed the phosphorylation of spleen tyrosine kinase (Syk) and inhibitor of nuclear factor-kappa B (IκBα) and the degradation of IκBα in zymosan-simulated RAW264.7 cells. The results of this study suggest that GA suppresses inflammation induced by trichophytin, partly by the downregulation of Syk phosphorylation.

Glycyrrhiza glabra

Liquorice foliage

Pharmacological Effects of Glycyrrhiza spp. and Its Bioactive Constituents: Update and Review

The roots and rhizomes of various species of the perennial herb licorice (Glycyrrhiza) are used in traditional medicine for the treatment of several diseases. In experimental and clinical studies, licorice has been shown to have several pharmacological properties including antiinflammatory, antiviral, antimicrobial, antioxidative, antidiabetic, antiasthma, and anticancer activities as well as immunomodulatory, gastroprotective, hepatoprotective, neuroprotective, and cardioprotective effects. In recent years, several of the biochemical, molecular, and cellular mechanisms of licorice and its active components have also been demonstrated in experimental studies. In this review, we summarized the new phytochemical, pharmacological, and toxicological data from recent experimental and clinical studies of licorice and its bioactive constituents after our previous published review.

In Vitro Antifungal Activity of Ankaferd Blood Stopper Against Candida albicans

BACKGROUND

Candida albicans is a memeber of the oral flora that can lead to various complications in immunosupresive patients after oral surgery processes. Ankaferd Blood Stopper® (ABS) is a medical plant extract that is safe to use in patients with dental surgery bleedings in Turkey.

OBJECTIVE

The study evaluated the antifungal activity of ABS medicinal plant extract against C albicans using the agar diffusion and broth microdilution methods.

METHODS

The plant extract antifungal activity was assessed in vitro either by applying the ABS extract directly and by applying different concentrations of ABS onto Candida culture. For these experiments, an agar diffusion method was used. To determine the minimum inhibitory concentration (MIC), a broth microdilution method was used.

RESULTS

Different volumes of the active substance (10, 20, 30, and 40 μL) were applied onto Candida (0.5 McFarland solution) cultivated plate; Candida growth was inhibited in accordance with the volumes of ABS. However, when various dilutions of ABS (1:2, 1:20, 1:40, and 1:80) were added as drops containing 20 μL, no antifungal effects were found. No MIC values were identified using broth microdilution. When different dilutions of ABS containing 100 μL of 0.5 McFarland solution of C albicans were cultured depending on the time (10, 20, 30, and 40 minutes), the effect of the duration was not significant.

CONCLUSION

The various tests were carried out to investigate antifungal effects of ABS on Candida, but none were found.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry

Background

With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7).

Methods

Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA.

Results

In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL).

Conclusions

All plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic.

Isolation and characterization of three fungi with the potential of transforming glycyrrhizin

Three fungi with different types of transformation of glycyrrhizin (GL) were isolated from the soil samples of glycyrrhiza glabra planting area in China. According to their morphologies and 18 S rDNA gene sequence analysis, the three fungi were identified and named as Penicillium purpurogenum Li-3, Aspergillus terreus Li-20 and Aspergillus ustus Li-62. Transforming products analysis by TLC and HPLC-MS indicated that P. purpurogenum Li-3, A. terreus Li-20 and A. ustus Li-62 could stably transform GL into GAMG, GAMG and GA, and GA, respectively. P. purpurogenum Li-3 was especially valuable to directly prepare GAMG for applications in the pharmaceutical industry.

Potent Antifungal Activity of Pure Compounds from Traditional Chinese Medicine Extracts against Six Oral Candida Species and the Synergy with Fluconazole against Azole-Resistant Candida albicans

This study was designed to evaluate the in vitro antifungal activities of four traditional Chinese medicine (TCM) extracts. The inhibitory effects of pseudolaric acid B, gentiopicrin, rhein, and alion were assessed using standard disk diffusion and broth microdilution assays. They were tested against six oral Candida species, Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei, Candida dubliniensis, and Candida guilliermondii, including clinical isolates from HIV-negative, HIV-positive, and Sjögren's syndrome patients. It was found that pseudolaric acid B had the most potent antifungal effect and showed similar antifungal activity to all six Candida spp, and to isolates from HIV-negative, HIV-positive, and Sjögren's syndrome patients. The MIC values ranged from 16 to 128 μg/mL. More interestingly, a synergistic effect of pseudolaric acid B in combination with fluconazole was observed. We suggest that pseudolaric acid B might be a potential therapeutic fungicidal agent in treating oral candidiasis.

Licorice and its potential beneficial effects in common oro-dental diseases

Licorice, the name given to the roots and stolons of Glycyrrhiza species, has been used since ancient times as a traditional herbal remedy. Licorice contains several classes of secondary metabolites with which numerous human health benefits have been associated. Recent research suggests that licorice and its bioactive ingredients such as glycyrrhizin, glabridin, licochalcone A, licoricidin, and licorisoflavan A possess potential beneficial effects in oral diseases. This paper reviews the effects of licorice and licorice constituents on both the oral microbial pathogens and the host immune response involved in common ora-dental diseases (dental caries, periodontitis, candidiasis, and recurrent aphthous ulcers). It also summarizes results of clinical trials that investigated the potential beneficial effects of licorice and its constituents for preventing/treating oro-dental diseases.