Effects and cost of glycyrrhizin in the treatment of upper respiratory tract infections in members of the Japanese maritime self-defense force: Preliminary report of a prospective, randomized, double-blind, controlled, parallel-group, alternate-day treatment assignment clinical trial

Efficacy and safety of licorice (Glycyrrhiza glabra) in moderately ill patients with COVID-19: a randomized controlled trial

Licorice extract (glycyrrhizin), a potent antiviral, anti-inflammatory, and antioxidant remedy, is a potential therapeutic option for COVID-19. We evaluated the efficacy and safety of licorice in patients with moderate COVID-19. In this study, 60 patients with confirmed COVID-19 were randomly assigned in a 1:1 ratio to receive licorice (at a dose of 760 mg three times a day for seven days) or control groups. The primary outcomes were SPO2, body temperature, and respiratory rate (RR) after the end of the intervention. The findings indicated that SPO2, body temperature, and RR had no significant difference between the groups at the end of the intervention. However, CRP and ALT improved in the licorice group toward the baseline. The number of patients with worse prognoses, LOS, mortality, and the incidence of adverse events were not different between the groups at the end of the study. Licorice had no beneficial effect on the clinical symptoms of COVID-19. Moreover, this intervention demonstrated a safe profile of adverse events. The confirmation of the results of this preparatory trial requires more detailed multiple-center trials with a larger sample size.

Non-pharmacological remedies for the common cold

Acute rhinopharyngitis, usually called common cold, is a widespread disease, mainly in childhood and adolescence. The use of common cold relievers is, therefore, prevalent as documented by the market data. A well-established tradition considers natural remedies an effective and safe way to relieve the common cold. Hundreds of products for treating the common cold contain non-pharmacological components. Nevertheless, a few studies investigated the role of non-pharmacologic remedies for the common cold. The current study reported the most common non-pharmacological remedies for the common cold, including herbal medicines and other substances. As ancient people used traditional herbs to treat and prevent the common cold, various herbs are widely used to clear viral infections. The herbal agents include polyphenols, flavonoids, saponins, glucosides, and alkaloids. Moreover, other non-pharmacological agents are widely used in real-life. Many multi- or monocomponent dietary supplements or medical devices contain these substances and are available in the market as tablets, syrups, drops, nasal or oral sprays, and nebulization solutions. Many products are available in the market. However, there is some evidence only for some substances. Consequently, further rigorous studies should confirm natural products' efficacy and safety to relieve the common cold.

Glycyrrhizin for treatment of CRS caused by CAR T-cell therapy: A pharmacological perspective

Chimeric antigen receptor T (CAR T)-cell therapy promises to revolutionize the management of hematologic malignancies and possibly other tumors. However, the main side effect of cytokine release syndrome (CRS) is a great challenge for its clinical application. Currently, treatment of CRS caused by CAR T-cell therapy is limited to tocilizumab (TCZ) and corticosteroids in clinical guidelines. However, the theoretical risks of these two agents may curb clinicians' enthusiasm for their application, and the optimal treatment is still debated. CAR T-cell therapy induced-CRS treatment is a current research focus. Glycyrrhizin, which has diverse pharmacological effects, good tolerance, and affordability, is an ideal therapeutic alternative for CRS. It can also overcome the shortcoming of TCZ and corticosteroids. In this brief article, we discuss the therapeutic potential of glycyrrhizin for treating CRS caused by CAR T-cell therapy from the perspective of its pharmacological action.

Glycyrrhizin through liquorice intake modulates ACE2 and HMGB1 levels-A pilot study in healthy individuals with implications for COVID-19 and ARDS

Background

Glycyrrhizin, an active component of liquorice root extract, exhibits antiviral and immunomodulatory properties by direct inhibition of the pro-inflammatory alarmin HMGB1 (High-mobility group box 1).

Objective

The aim of this study was to explore the role of liquorice intake on the viral entry receptor ACE2 (angiotensin-converting enzyme 2) and the immunoregulatory HMGB1 in healthy individuals and to explore HMGB1 expression in coronavirus disease 2019 (COVID-19) or non-COVID-19 in ARDS (acute respiratory distress syndrome patients).

Material and methods

This study enrolled 43 individuals, including hospitalised patients with i) acute respiratory distress syndrome (ARDS) due to COVID-19 (n = 7) or other underlying causes (n = 12), ii) mild COVID-19 (n = 4) and iii) healthy volunteers (n = 20). Healthy individuals took 50 g of liquorice (containing 3% liquorice root extract) daily for 7 days, while blood samples were collected at baseline and on day 3 and 7. Changes in ACE2 and HMGB1 levels were determined by Western blot analysis and enzyme-linked immunosorbent assay, respectively. Additionally, HMGB1 levels were measured in hospitalised COVID-19 patients with mild disease or COVID-19 associated acute respiratory distress syndrome (ARDS) and compared with a non-COVID-19-ARDS group.

Results

Liquorice intake significantly reduced after 7 days both cellular membranous ACE2 expression (-51% compared to baseline levels, p = 0.008) and plasma HMGB1 levels (-17% compared to baseline levels, p<0.001) in healthy individuals. Half of the individuals had a reduction in ACE2 levels of at least 30%. HMGB1 levels in patients with mild COVID-19 and ARDS patients with and without COVID-19 were significantly higher compared with those of healthy individuals (+317%, p = 0.002), but they were not different between COVID-19 and non-COVID-19 ARDS.

Conclusions

Liquorice intake modulates ACE2 and HMGB1 levels in healthy individuals. HMGB1 is enhanced in mild COVID-19 and in ARDS with and without COVID-19, warranting evaluation of HMGB1 as a potential treatment target and glycyrrhizin, which is an active component of liquorice root extract, as a potential treatment in COVID-19 and non-COVID-19 respiratory disease.

Recent advances in glycyrrhizin metabolism, health benefits, clinical effects and drug delivery systems for efficacy improvement; a comprehensive review

BACKGROUND

Glycyrrhizin (GL) is a major active constituent of licorice root (Glycyrrhiza glabra) that is considered one of the oldest and most frequently employed botanicals in Chinese medicine and worldwide, with most effects attributed to its rich GL content. Structurally, GL a triterpene saponin that is widely used as a flavoring agent in foodstuffs and cosmetics, and also proposed for various clinical applications with a myriad of health benefits. Pharmacological and biological activities of GL include antiviral, anti-inflammatory, antioxidant, and anticancer activities (in vitro and in vivo). Currently, there is no comprehensive review on GL biological effects and its action mechanisms.

PURPOSE

This review summarizes GL pharmacological actions from a molecular biology perception, presented on its metabolism and side effects based on in vitro, in vitro and clinical studies. Moreover, the potential of GL as a nanomedicine delivery system is also summarized. The progress in drug delivery research using GL presented herein is expected to provide a theoretical basis for developing other novel drugs formulations.

METHODS

A systematic review was carried out in several electronic databases (Science Direct, SpringerLink, CNKI, PubMed, Web of Science, Elsevier, and Scopus), using the following key words: glycyrrhizin "AND" bioactivity "OR" clinic "OR" therapeutic "OR" drug delivery. This search included manuscripts published between 1989 and 2021.

RESULTS

126 researches were selected and summarized in this review. The analysis of these studies indicated that GL has antiviral activity against different viruses. Further, GL efficiently suppressed the respiratory manifestations associated with COVID-19 by reducing the expression of angiotensin converting enzyme 2 (ACE2) that employed by the virus as an entry point. Otherwise, GL was found to induce antioxidant, anti-inflammatory, immune-modulatory, and anticancer activity. Besides, diminution the particle size of GL to nanometer size significantly augments their action and biodistribution.

CONCLUSION

This article summarizes the pharmacological actions of GL. The potential of GL as a nanomedicine delivery system is also presented. Nevertheless, most studies reported provide no deep insight of GL health effects warranting for more future studies to elucidate its action mechanism and potential therapeutic benefits through preclinical and clinical trials.

Efficacy of Persian medicine herbal formulations (capsules and decoction) compared to standard care in patients with COVID-19, a multicenter open-labeled, randomized, controlled clinical trial

Persian medicine has recommended clinical experiences and proper herbal remedies for prevention and treatment of microbial infections and respiratory diseases. An open‐label, randomized, controlled, multicenter trial was conducted at five hospitals in Tehran and Isfahan provinces of Iran on 358 hospitalized adult patients. A total of 174 patients received standard care and 184 received herbal remedies (polyherbal decoction every 8 hr and two herbal capsules every 12 hr) plus standard care for 7 days. The primary clinical endpoint was the duration of hospital stay, and secondary outcomes were clinical improvement of symptoms based on self‐assessment questionnaire. Results demonstrated that these natural decoction and capsules treatment plus routine care significantly decreased duration of hospital dyspnea (3.291 day vs. 6.468 days), accelerated clinical improvement, and decreased symptoms such as dry cough, dyspnea, muscle pain, headache, fatigue, anorexia, chills, runny nose, sputum cough, and vertigo in the treatment group compared with standard‐care group. Significant effects of these polyherbal formulations on improving the symptoms of COVID‐19 could be incredibly promising for managing this pandemic with acceptable tolerability.

Effectiveness of Natural Antioxidants against SARS-CoV-2? Insights from the In-Silico World

The SARS CoV-2 pandemic has affected millions of people around the globe. Despite many efforts to find some effective medicines against SARS CoV-2, no established therapeutics are available yet. The use of phytochemicals as antiviral agents provides hope against the proliferation of SARS-CoV-2. Several natural compounds were analyzed by virtual screening against six SARS CoV-2 protein targets using molecular docking simulations in the present study. More than a hundred plant-derived secondary metabolites have been docked, including alkaloids, flavonoids, coumarins, and steroids. SARS CoV-2 protein targets include Main protease (MPro), Papain-like protease (PLpro), RNA-dependent RNA polymerase (RdRp), Spike glycoprotein (S), Helicase (Nsp13), and E-Channel protein. Phytochemicals were evaluated by molecular docking, and MD simulations were performed using the YASARA structure using a modified genetic algorithm and AMBER03 force field. Binding energies and dissociation constants allowed the identification of potentially active compounds. Ligand-protein interactions provide an insight into the mechanism and potential of identified compounds. Glycyrrhizin and its metabolite 18-β-glycyrrhetinic acid have shown a strong binding affinity for MPro, helicase, RdRp, spike, and E-channel proteins, while a flavonoid Baicalin also strongly binds against PLpro and RdRp. The use of identified phytochemicals may help to speed up the drug development and provide natural protection against SARS-CoV-2.

Non-pharmacological remedies for post-viral acute cough

The post-viral acute cough (PAC) is a widespread symptom, mainly in childhood and adolescence, and is usually associated with an acute upper respiratory infection, namely the common cold. The use of cough relievers is, therefore, impressive, as documented by the market data. There are many medical devices and dietary supplements for treating PAC, which contain non-pharmacological components. Ancient people used traditional herbs to treat PAC. Thus, a well-established tradition considers natural remedies as an effective and safe way to relieve PAC. The herbal agents include polyphenols, flavonoids, saponins, glucosides, and alkaloids. Also, the European Medicine Agency has recognized the value of plant extracts and other natural substances to treat PAC. Nevertheless, a few studies investigated the role of non-pharmacologic remedies for PAC. There is some evidence for honey, glycerol, Althea officinalis, Drosera rotundifolia, Grindelia, Hedera helix, Pelargonium sidoides, Sambucus nigra, Thymus vulgaris, hyaluronic acid, and saline solutions. However, further rigorous studies should confirm natural products' efficacy and safety to relieve PAC.

Nature-derived hit, lead, and drug-like small molecules: Current status and future aspects against key target proteins of Coronaviruses

BACKGROUND

COVID-19 pandemic, the most unprecedented event of the year 2020, has brought millions of scientists worldwide in a single platform to fight against it. Though several drugs are now in the clinical trial, few vaccines available on the market already but the lack of an effect of those is making the situation worse.

AIM OF THE STUDY

In this review, we demonstrated comprehensive data of natural antiviral products showing activities against different proteins of Human Coronaviruses (HCoV) that are responsible for its pathogenesis. Furthermore, we categorized the compounds into the hit, lead, and drug based on the IC50/EC50 value, drug-likeness, and lead-likeness test to portray their potentiality to be a drug. We also demonstrated the present status of our screened antiviral compounds with respect to clinical trials and reported the lead compounds that can be promoted to clinical trial against COVID-19.

METHODS

A systematic search strategy was employed focusing on Natural Products (NPs) with proven activity (in vitro, in vivo, or in silico) against human coronaviruses, in general, and data were gathered from databases like PubMed, Web of Science, Google Scholar, SciVerse, and Scopus. Information regarding clinical trials retrieved from the Clinical Trial database.

RESULTS

Total "245" natural compounds were identified initially from the literature study. Among them, Glycyrrhizin, Caffeic acid, Curcumin is in phase 3, and Tetrandrine, Cyclosporine, Tacrolimus, Everolimus are in phase 4 clinical trial. Except for Glycyrrhizin, all compounds showed activity against COVID-19.

CONCLUSIONS

In summary, our demonstrated specific small molecules with lead and drug-like capabilities clarified their position in the drug discovery pipeline and proposed their future research against COVID-19.

Can Antiviral Activity of Licorice Help Fight COVID-19 Infection?

The phytotherapeutic properties of Glycyrrhiza glabra (licorice) extract are mainly attributed to glycyrrhizin (GR) and glycyrrhetinic acid (GA). Among their possible pharmacological actions, the ability to act against viruses belonging to different families, including SARS coronavirus, is particularly important. With the COVID-19 emergency and the urgent need for compounds to counteract the pandemic, the antiviral properties of GR and GA, as pure substances or as components of licorice extract, attracted attention in the last year and supported the launch of two clinical trials. In silico docking studies reported that GR and GA may directly interact with the key players in viral internalization and replication such as angiotensin-converting enzyme 2 (ACE2), spike protein, the host transmembrane serine protease 2, and 3-chymotrypsin-like cysteine protease. In vitro data indicated that GR can interfere with virus entry by directly interacting with ACE2 and spike, with a nonspecific effect on cell and viral membranes. Additional anti-inflammatory and antioxidant effects of GR cannot be excluded. These multiple activities of GR and licorice extract are critically re-assessed in this review, and their possible role against the spread of the SARS-CoV-2 and the features of COVID-19 disease is discussed.

Medicinal plants from the 14th edition of the Russian Pharmacopoeia, recent updates

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicine in Russia has a long history starting with handwritten herbalist manuscripts from the Middle Ages to the officinal Pharmacopoeia of the 21st century. The "herbophilious" Russian population has accumulated a lot of knowledge about the beneficial effects of local medicinal plants. Yet, for a long time, Russian traditional and officinal herbal medicine was not well known to the international audience. In our previous comprehensive review, we discussed the pharmacological effects of specific plants included in the 11^th edition of the Pharmacopoeia of the USSR, which was also for a while used in Russia. The 14^th edition of the Russian Federation's State Pharmacopoeia was implemented in 2018.

AIM OF THE REVIEW

The aims of the present review are: (i) to trace the evolution of medicinal plant handling from handwritten herbalist manuscripts to Pharmacopoeias; (ii) to describe the modern situation with regulatory documents for herbal medicinal products and their updated classification; (iii) to summarize and discuss the pharmacology, safety, and clinical data for new plants, which are included in the new edition of the Pharmacopoeia.

METHODS

New medicinal plants included in the 14th edition of the Russian Federation's State Pharmacopoeia were selected. We carefully searched the scientific literature for data related to traditional use, pharmacological, clinical application, and safety. The information was collected from local libraries in Saint-Petersburg, the online databases E-library.ru, Scopus, Web of Science, and the search engine Google scholar.

RESULTS

Investigating the evolution of all medicinal plants referred to in the Russian Pharmacopoeias led us to the identification of ten medicinal plants that were present in all editions of civilian Russian Pharmacopoeias starting from 1778. In the 14^th edition of the modern Russian Pharmacopoeia, medicinal plants are described in 107 monographs. Altogether, 25 new monographs were included in the 14^th edition, and one monograph was excluded in comparison to the 11^th edition. Some of the included plants are not endemic to Russia and do not have a history of traditional use, or on the other hand, are widely used in Western medicine. For 15 plants, we described the specificity of their application in Russian traditional medicine along with the claimed dosages and indications in officinal medicine. The pharmacology, safety, and clinical data are summarized and assessed for nine plants, underlining their therapeutic potential and significance for global phytopharmacotherapy.

CONCLUSIONS

In this review, we highlight the therapeutical potential of new plants included in the modern edition of the Russian Pharmacopoeia. We hope that these plants will play an imperative role in drug development and will have a priority for future detailed research.

Successful Treatment of Elderly Male With COVID-19 Infection With Severe Acute Respiratory Distress Syndrome Using Multimodal Therapy, Including Immune Modulation Therapy

A 78-year-old man fell from a ladder and suffered a right distal tibial fracture. On the seventh day after injury, he developed a low-grade fever and was isolated in a private room. Polymerase chain reaction for COVID-19 was positive (day 4 from the day of saliva sampling). On day 5, he required 1 liter per minute of oxygen and dexamethasone therapy was initiated. On day 6, his D-dimer level was 25.0 μg/mL, and continuous infusion of heparin was initiated. From day 7, he was administered remdesivir. On day 9, his oxygenation suddenly showed a remarkable deterioration. He received a tentative diagnosis of COVID-19-induced pneumonia accompanied by severe acute respiratory distress syndrome (ARDS) and underwent urgent tracheal intubation and mechanical ventilation. He also received intravenous immunoglobulin (IVIG) and was also administered glycyrrhizin. His oxygenation gradually improved and extubation was performed on day 15. Following rehabilitation, he did not require oxygen on day 19. On day 20, his D-dimer level was found to be increased and enhanced computed tomography revealed pulmonary embolism. He was prescribed a direct oral anticoagulant. On day 28 he was transferred to a general ward for rehabilitation. These unspecific antiviral therapies and immune modulation therapy may be useful treatments for the main cause of ARDS, which may explain the favorable outcome that was obtained in the present case.

Glycyrrhizin: An old weapon against a novel coronavirus

Currently, over 100 countries are fighting against a common enemy, the severe acute respiratory syndrome coronavirus (SARS-CoV)-2, which causes COVID-19. This has created a demand for a substance whose effectiveness has already been demonstrated in a similar scenario. Glycyrrhizin (GZ) is a promising agent against SARS-CoV-2 as its antiviral activity against SARS-CoV has already been confirmed. It is worthwhile to extrapolate from its proven therapeutic effects as there is a high similarity in the structure and genome of SARS-CoV and SARS-CoV-2. There are many possible mechanisms through which GZ acts against viruses: increasing nitrous oxide production in macrophages, affecting transcription factors and cellular signalling pathways, directly altering the viral lipid-bilayer membrane, and binding to the ACE2 receptor. In this review, we discuss the possible use of GZ in the COVID-19 setting, where topical administration appears to be promising, with the nasal and oral cavity notably being the potent location in terms of viral load. The most recently published papers on the distribution of ACE2 in the human body and documented binding of GZ to this receptor, as well as its antiviral activity, suggest that GZ can be used as a therapeutic for COVID-19 and as a preventive agent against SARS-CoV-2.

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.

Preparation of complex microcapsules of soluble polysaccharide from Glycyrrhiza uralensis and its application in wound repair and scar inhibition

The extraction process of Glycyrrhiza soluble polysaccharide (GP) was optimized by RSM, a rat trauma model was established via longitudinal incision on the back skin. The effects of GP combined with microcapsule collagen on the repair of rat injury model were discussed at different levels, Based on the content of hydroxyproline at the whole animal level, the proliferation of granulation tissue stained by HE, the number of microvessels labeled by CD34, the production of collagen fibers stained by Masson, the level of phosphorylation of STAT3 protein and that of VEGF at protein level were investigated. The results showed that after the administration of GP combined with microcapsules, the content of hydroxyproline in granulation tissue increased, the proliferation of capillaries and fibroblasts in granulation tissue became active, and the number of microvessels in wound increased. The formation density of collagen fibers was uniform and orderly. GP combined with microcapsules could activate the expression of p-STAT3 and VEGF proteins and up-regulate the transcription level of VEGF mRNA and miRNA-21 genes. Furthermore, GP combined with microcapsules could accelerate wound healing and promote neovascularization.

Hyaluronan as a therapeutic target in human diseases

Accumulation and turnover of extracellular matrix is a hallmark of tissue injury, repair and remodeling in human diseases. Hyaluronan is a major component of the extracellular matrix and plays an important role in regulating tissue injury and repair, and controlling disease outcomes. The function of hyaluronan depends on its size, location, and interactions with binding partners. While fragmented hyaluronan stimulates the expression of an array of genes by a variety of cell types regulating inflammatory responses and tissue repair, cell surface hyaluronan provides protection against tissue damage from the environment and promotes regeneration and repair. The interactions of hyaluronan and its binding proteins participate in the pathogenesis of many human diseases. Thus, targeting hyaluronan and its interactions with cells and proteins may provide new approaches to developing therapeutics for inflammatory and fibrosing diseases. This review focuses on the role of hyaluronan in biological and pathological processes, and as a potential therapeutic target in human diseases.

One-step immunochromatographic separation and ELISA quantification of glycyrrhizin from traditional Chinese medicines

The bioactive constituent, glycyrrhizin or glycyrrhizic acid (GA), was purified from two traditional Chinese medicines (TCM), Shaoyao gancao tang and Dahuang gancao tang, and from crude extracts from licorice roots by means of immunoaffinity chromatography using anti-GA monoclonal antibody (MAb) and was quantified with an enzyme-linked immunosorbent assay (ELISA). Laboratory preparations included the synthesis of conjugate GA-human serum albumin (GA-HSA), the production of anti-GA-MAb, the optimization of the immunoaffinity column packed with the anti-GA-MAb coupled to hydrazide gel and the determination of the GA content in TCM and crude drugs from five different sources by ELISA and high performance liquid chromatography (HPLC). The experimental results reveal that the anti-GA-MAb coupled to Affi-Gel Hz gel results in a coupling efficiency of 95.2%, and the immunoaffinity chromatography gives a mean recovery of 97.6% of GA with a capacity of 33.5+/-2.40 microg/mL of immunoaffinity gel under the given conditions. The GA content of the crude extracts (ranging 74.8-114.6 microg/mg) from different sources by the ELISA method is much greater than that of the TCM (16.4-25.1 microg/mg) which is, in good agreement with the results of the HPLC method. Our report provides a rapid, reliable and sensitive approach for one-step separation and quantification of GA.

Development of antiviral therapy for severe acute respiratory syndrome

A new disease, the severe acute respiratory distress syndrome (SARS), caused by the SARS coronavirus (SARS-CoV), emerged at the beginning of 2003 and rapidly spread throughout the world. Although the disease had disappeared in June 2003 its re-emergence cannot be excluded. The development of vaccines against SARS-CoV may take years. Therefore, the availability of effective antiviral drugs against SARS-CoV may be crucial for the control of future SARS outbreaks. In this review, experimental and clinical data about potential anti-SARS drugs is summarised and discussed. Animal model studies will be needed to help to determine which interventions warrant controlled clinical testing.

Antiviral activity of glycyrrhizic acid derivatives against SARS-coronavirus

Glycyrrhizin (GL) was shown to inhibit SARS-coronavirus (SARS-CoV) replication in vitro. Here the anti-SARS-CoV activity of 15 GL derivatives was tested. The introduction of 2-acetamido-beta-d-glucopyranosylamine into the glycoside chain of GL resulted in 10-fold increased anti-SARS-CoV activity compared to GL. Amides of GL and conjugates of GL with two amino acid residues and a free 30-COOH function presented up to 70-fold increased activity against SARS-CoV but also increased cytotoxicity resulting in decreased selectivity index.