Anti-influenza effect of the major flavonoids from Salvia plebeia R.Br. via inhibition of influenza H1N1 virus neuraminidase

Pharmacological mechanisms of Ma Xing Shi Gan Decoction in treating influenza virus-induced pneumonia: intestinal microbiota and pulmonary glycolysis

Background

Influenza virus is one of the most common pathogens that cause viral pneumonia. During pneumonia, host immune inflammation regulation involves microbiota in the intestine and glycolysis in the lung tissues. In the clinical guidelines for pneumonia treatment in China, Ma Xing Shi Gan Decoction (MXSG) is a commonly prescribed traditional Chinese medicine formulation with significant efficacy, however, it remains unclear whether its specific mechanism of action is related to the regulation of intestinal microbiota structure and lung tissue glycolysis.

Objective

This study aimed to investigate the mechanism of action of MXSG in an animal model of influenza virus-induced pneumonia. Specifically, we aimed to elucidate how MXSG modulates intestinal microbiota structure and lung tissue glycolysis to exert its therapeutic effects on pneumonia.

Methods

We established a mouse model of influenza virus-induced pneumoni, and treated with MXSG. We observed changes in inflammatory cytokine levels and conducted 16S rRNA gene sequencing to assess the intestinal microbiota structure and function. Additionally, targeted metabolomics was performed to analyze lung tissue glycolytic metabolites, and Western blot and enzyme-linked immunosorbent assays were performed to assess glycolysis-related enzymes, lipopolysaccharides (LPSs), HIF-1a, and macrophage surface markers. Correlation analysis was conducted between the LPS and omics results to elucidate the relationship between intestinal microbiota and lung tissue glycolysis in pneumonia animals under the intervention of Ma Xing Shi Gan Decoction.

Results

MXSG reduced the abundance of Gram-negative bacteria in the intestines, such as Proteobacteria and Helicobacter, leading to reduced LPS content in the serum and lungs. This intervention also suppressed HIF-1a activity and lung tissue glycolysis metabolism, decreased the number of M1-type macrophages, and increased the number of M2-type macrophages, effectively alleviating lung damage caused by influenza virus-induced pneumonia.

Conclusion

MXSG can alleviate glycolysis in lung tissue, suppress M1-type macrophage activation, promote M2-type macrophage activation, and mitigate inflammation in lung tissue. This therapeutic effect appears to be mediated by modulating gut microbiota and reducing endogenous LPS production in the intestines. This study demonstrates the therapeutic effects of MXSG on pneumonia and explores its potential mechanism, thus providing data support for the use of traditional Chinese medicine in the treatment of respiratory infectious diseases.

Selaginella tamariscina Ethanol Extract Attenuates Influenza A Virus Infection by Inhibiting Hemagglutinin and Neuraminidase

Selaginella tamariscina is a perennial plant that is used for diverse diseases. This study investigated whether Selaginella tamariscina has an antiviral effect against influenza A virus (IAV) infection. We used green fluorescent protein (GFP)-tagged influenza A virus (IAV) to examine the effect of Selaginella tamariscina ethanol extract (STE) on influenza viral infection. Fluorescence microscopy and flow cytometry showed that STE potently represses GFP expression by the virus, dose-dependently. STE significantly inhibited the expression of the IAV M2, NP, HA, NA, NS1, and PB2 proteins. Time-of-addition and hemagglutination inhibition assays showed that STE has an inhibitory effect on hemagglutinin and viral binding on the cells at an early infection time. In addition, STE exerted a suppressive effect on the neuraminidase activity of the H1N1 and H3N2 IAVs. Furthermore, dose-dependently, STE inhibited the cytopathic effect induced by H3N2, as well as by H1N1 IAV. Especially in the presence of 200 µg/mL STE, the cytopathic effect was completely blocked. Our findings suggest that STE has antiviral efficacy against IAV infection; thus, it could be developed as a natural IAV inhibitor.

Three new nonenes from culture broth of marine-derived fungus Albifimbria verrucaria and their cytotoxic and anti-viral activities

Three new nonenes, verrucanonenes A‒C (1‒3), were isolated from culture broth of marine-derived fungus Albifimbria verrucaria. These compounds were isolated using silica gel column chromatography, reversed-phase medium pressure liquid chromatography, Sephadex LH-20 column chromatography, and preparative HPLC. Their structures were determined using a spectroscopic method. Cytotoxicities of these isolated compounds to A549, DU145, HCT116, and HT1080 cancer cell lines were assessed. Compounds 1‒3 exhibited cytotoxicities to DU145 cancer cell line, with IC50 values of 23.4, 28.6, and 20.1 µM, respectively. Compound 2 decreased H1N1-induced cytopathic effects on MDCK cells in a dose-dependent manner.

Protective effect of Salvia plebeia R. Br ethanol extract on UVB-induced skin photoaging in vitro and in vivo

BACKGROUND

UV exposure is one of the primary factors responsible for photoaging, causing the increase in matrix metalloproteinases (MMPs) and the reduction in collagen. Salvia plebeia R. Br (SP), as an herbaceous plant, contains abundant flavonoids and possesses excellent anti-inflammatory and antioxidant activities. This study aimed to investigate the photoprotective effects of SP on UVB-induced photodamage in immortalized human keratinocytes (HaCaTs) and Kunming mice, as well as its main active components such as homoplantaginin (HP).

METHODS

CCK-8 was applied to detect the cell viability in UVB-irradiated or non-irradiated HaCaTs. Commercial kits were used to evaluate the levels of ROS, MDA, SA-β-Gal, MMP-1, and IL-6. The expression of MAPK and TGF-β/Smad pathways was detected by western blot. HE and Masson's trichrome staining were performed to examine the epidermis thickness and collagen degradation of Kunming mice.

RESULTS

Our results found that SP and HP notably decreased UVB-induced ROS, MDA, and SA-β-Gal production, and inhibited MMP-1 and IL-6 secretion by inhibiting the MAPK signaling pathway. In addition, SP and HP significantly promoted type I procollagen synthesis by activation of TGF-β/Smad pathway. Consistently, the in vivo experiments also indicated that SP and HP had a photoprotective effect, which significantly reversed UVB-induced epidermis thickness and collagen degradation.

CONCLUSION

This study demonstrated that SP effectively could protect skin from UVB-induced photoaging, while HP acted as the active substance in SP. All these findings provided a new strategy for skin photoaging treatment.

Inhibiting virus replication and excessive inflammatory response: Mechanism of combined prescription of Ma-Xing-Shi-Gan decoction and Xiao-Chai-Hu decoction against influenza virus

ETHNOPHARMACOLOGICAL RELEVANCE

The combined prescription of two classical decoctions (Ma-Xing-Shi-Gan decoction with Xiao-Chai-Hu decoction), named as San-Yang-He-Zhi (SYHZ) decoction, has been widely used for the treatment of influenza virus (IFV) infections for decades.

AIM OF THE STUDY

This study aimed to evaluate the anti-influenza effect of SYHZ decoction and explore the underlying mechanism.

MATERIALS AND METHODS

The ingredients of SYHZ decoction were analyzed by mass spectrometry. An animal model of IFV infection was established by challenging C57BL/6J mice with PR8 virus. Three groups of mice were infected with lethal or non-lethal doses of IFV, then followed by oral administration of phosphate-buffered saline (PBS), or SYHZ, or oseltamir; blank control mice (without IFV infection) were treated with PBS. Survival rate, Lung index, colon length, body weight loss and IFV viral load were measured 7 days post infection; histology and electron-microscopy examinations of lung tissue were performed; cytokine and chemokine levels in lung and serum were measured; and the intestinal metagenome, the cecum metabolome, and the lung transcriptome were analyzed.

RESULTS

SYHZ treatment significantly improved survival rate compared with PBS (40% vs 0%); improved lung index, colon length, and body weight loss; and alleviated lung histological damage and viral load. SYHZ-treated mice had significantly lower levels of IL-1β, TNF-α, IL-6, CCL2, CXCL10 in lung and serum, and increased levels of multiple bioactive components in cecum. Pro-inflammatory cytokines, Toll- and NOD-like receptors, pro-apoptosis molecules, and lung-injury-related proteins were downregulated in SYHZ mice, whereas surfactant protein and mucin were upregulated. The NOD-like receptor pathway, Toll-like receptor pathway, and NF-κB pathway were downregulated by SYHZ treatment.

CONCLUSIONS

SYHZ decoction alleviated IFV infection in a mouse model. Multiple bioactive ingredients of SYHZ may inhibit replication of IFV and suppress excessive immune response.

An Insight into Diverse Activities and Targets of Flavonoids

BACKGROUND

Flavonoids belong to the chemical class of polyphenols and are in the category of secondary metabolites imparting a wide protective effect against acute and chronic diseases.

OBJECTIVE

The study aims to investigate and summarize the information of various flavonoids extracted, isolated from various sources, and possess different pharmacological properties by acting on multiple targets.

METHODS

This comprehensive review summarizes the research information related to flavonoids and their pharmacological action targets from various sources like PubMed, Google Scholar and Google websites.

RESULTS

Extracted information in the paper discusses various therapeutic effects of flavonoids isolated from medicinal plant sources, which have the property to inhibit several enzymes, which finally results in health benefits like anti-cancer, anti-bacterial, antioxidant, anti-allergic, and anti-viral effects. This study also showed the different solvents and methods involved in the extraction and characterization of the isolated phytochemical constituents.

CONCLUSION

The findings showed the contribution of several flavonoids in the management and inhibition of various acute and chronic sicknesses by acting on different sites in the body. This study may lead to gaining interest for more research on the bioactives of different medicinal plants for the discovery of new lead compounds or further improvement of the efficacy of the existing compound.

Qingfeiyin Decoction Inhibits H1N1 Virus Infection via Modulation of Gut Microbiota and Inflammatory Pathways in a Murine Model

Influenza virus-caused lung infection and its pandemic outbreaks are a persistent public health challenge. The H1N1 subtype is the most common type of influenza infection observed in humans. Maxingshigantang decoction, a classic formula of Chinese herbal medicine, has been used for the prevention and treatment of respiratory infection for many centuries. Qingfeiyin decoction, based on Maxingshigantang, has been used in the clinic for decades. To explore the underlying mechanisms, according to the traditional Chinese medicine theory “the lung and the large intestine are interior–exterior,” which can be translated to the “gut–lung axis” in a contemporary term, the composition of gut microbiota was determined using 16S rRNA and the transcriptome of the colon was determined by RNA sequencing. The results showed that Qingfeiyin decoction decreased the viral load, alleviated the lung injury, increased the survival rate, partly restored the shortening of the colon caused by the H1N1 virus, and downregulated inflammatory pathways including MAPK, TNFα, and JAK-STAT signaling pathways. Qingfeiyin decoction increased the relative abundance of the genera of Coprococcus, Ruminococcus, Lactobacillus, and Prevotella and prevented the H1N1 virus-induced decrease in the abundance of the genera of Escherichia, Parabacteroides, Butyricimonas, and Anacrotruncus. These results will help better understand the mechanisms for Qingfeiyin decoction’s protective effect against influenza virus infection.

Plant-Derived Natural Products as Lead Agents against Common Respiratory Diseases

Never has the world been more challenged by respiratory diseases (RDs) than it has witnessed in the last few decades. This is evident in the plethora of acute and chronic respiratory conditions, ranging from asthma and chronic obstructive pulmonary disease (COPD) to multidrug-resistant tuberculosis, pneumonia, influenza, and more recently, the novel coronavirus (COVID-19) disease. Unfortunately, the emergence of drug-resistant strains of pathogens, drug toxicity and side effects are drawbacks to effective chemotherapeutic management of RDs; hence, our focus on natural sources because of their unique chemical diversities and novel therapeutic applications. This review provides a summary on some common RDs, their management strategies, and the prospect of plant-derived natural products in the search for new drugs against common respiratory diseases.

Computational screening of natural compounds from Salvia plebeia R. Br. for inhibition of SARS-CoV-2 main protease

The novel Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) has emerged to be the reason behind the COVID-19 pandemic. It was discovered in Wuhan, China and then began spreading around the world, impacting the health of millions. Efforts for treatment have been hampered as there are no antiviral drugs that are effective against this virus. In the present study, we have explored the phytochemical constituents of Salvia plebeia R. Br., in terms of its binding affinity by targeting COVID-19 main protease (M^pro) using computational analysis. Molecular docking analysis was performed using PyRx software. The ADMET and drug-likeness properties of the top 10 compounds showing binding affinity greater than or equal to - 8.0 kcal/mol were analysed using pkCSM and DruLiTo, respectively. Based on the docking studies, it was confirmed that Rutin and Plebeiosides B were the most potent inhibitors of the main protease of SARS-CoV-2 with the best binding affinities of - 9.1 kcal/mol and - 8.9 kcal/mol, respectively. Further, the two compounds were analysed by studying their biological activity using the PASS webserver. Molecular dynamics simulation analysis was performed for the selected protein-ligand complexes to confirm their stability at 300 ns. MM-PBSA provided the basis for analyzing the affinity of the phytochemicals towards M^pro by calculating the binding energy, and secondary structure analysis indicated the stability of protease structure when it is bound to Rutin and Plebeiosides B. Altogether, the study identifies Rutin and Plebeiosides B to be potent M^pro inhibitors of SARS-CoV-2.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s42535-021-00304-z.

Therapeutic benefits of Salvia species: A focus on cancer and viral infection

Man is increasingly being faced with many health conditions, including viral infection, some of which increases the risk to cancer. These infectious agents contribute to the large number of persons with cancer and the worrisome number that die from the diseases. A good range of drugs are currently in place for treating patients infected with viruses, however, some of the drugs' effectiveness are limited by the emergence of drug-resistant strains of the viruses, as well as adverse effects of the drugs. Similarly, the inability of many anticancer drugs to selectively kill cancer cells while sparing hosts' normal cells limit their use. This warrants more research for newer drugs, especially from chemicals naturally encrypted in plants with anticancer and antiviral activities. In response to infection with cancer-inducing viruses, plants such as Salvia species synthesize and store secondary metabolites to protect themselves and kill these viruses as well as inhibit their ability to induce carcinogenesis. Hence, this review presented a discussion on the potential application of Salvia species in the prevention and management of cancer and viral infection. The study also discusses the cellular mechanisms of action of these herbal products against cancer cells and viruses, where available and provided suggestions on future research directions. The study is believed to spur more research on how to exploit Salvia phytochemicals as candidates for the development of nutraceuticals and drugs for managing cancers and viral infection.

Modulation of Hair Growth Promoting Effect by Natural Products

A large number of people suffer from alopecia or hair loss worldwide. Drug-based therapies using minoxidil and finasteride for the treatment of alopecia are available, but they have shown various side effects in patients. Thus, the use of new therapeutic approaches using bioactive products to reduce the risk of anti-hair-loss medications has been emphasized. Natural products have been used since ancient times and have been proven safe, with few side effects. Several studies have demonstrated the use of plants and their extracts to promote hair growth. Moreover, commercial products based on these natural ingredients have been developed for the treatment of alopecia. Several clinical, animal, and cell-based studies have been conducted to determine the anti-alopecia effects of plant-derived biochemicals. This review is a collective study of phytochemicals with anti-alopecia effects, focusing mainly on the mechanisms underlying their hair-growth-promoting effects.

Natural Compounds With Antimicrobial and Antiviral Effect and Nanocarriers Used for Their Transportation

Due to the increasing prevalence of life-threatening bacterial, fungal and viral infections and the ability of these human pathogens to develop resistance to current treatment strategies, there is a great need to find and develop new compunds to combat them. These molecules must have low toxicity, specific activity and high bioavailability. The most suitable compounds for this task are usually derived from natural sources (animal, plant or even microbial). In this review article, the latest and most promising natural compounds used to combat bacteria, filamentous fungi and viruses are presented and evaluated. These include plant extracts, essential oils, small antimicrobial peptides of animal origin, bacteriocins and various groups of plant compounds (triterpenoids; alkaloids; phenols; flavonoids) with antimicrobial and antiviral activity. Data are presented on the inhibitory activity of each natural antimicrobial substance and on the putative mechanism of action against bacterial and fungal strains. The results show that among the bioactive compounds studied, triterpenoids have significant inhibitory activity against coronaviruses, but flavonoids have also been shown to inhibit SARS-COV-2. The last chapter is devoted to nanocarriers used to improve stability, bioavailability, cellular uptake/internalization, pharmacokinetic profile and reduce toxicity of natural compunds. There are a number of nanocarriers such as liposomes, drug delivery microemulsion systems, nanocapsules, solid lipid nanoparticles, polymeric micelles, dendrimers, etc. However, some of the recent studies have focused on the incorporation of natural substances with antimicrobial/antiviral activity into polymeric nanoparticles, niosomes and silver nanoparticles (which have been shown to have intrinsic antimicrobial activity). The natural antimicrobials isolated from animals and microorganisms have been shown to have good inhibitory effect on a range of pathogens, however the plants remain the most prolific source. Even if the majority of the studies for the biological activity evaluation are in silico or in vitro, their internalization in the optimum nanocarriers represents the future of “green therapeutics” as shown by some of the recent work in the field.

Flavonoids as Promising Antiviral Agents against SARS-CoV-2 Infection: A Mechanistic Review

A newly diagnosed coronavirus in 2019 (COVID-19) has affected all human activities since its discovery. Flavonoids commonly found in the human diet have attracted a lot of attention due to their remarkable biological activities. This paper provides a comprehensive review of the benefits of flavonoids in COVID-19 disease. Previously-reported effects of flavonoids on five RNA viruses with similar clinical manifestations and/or pharmacological treatments, including influenza, human immunodeficiency virus (HIV), severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Ebola, were considered. Flavonoids act via direct antiviral properties, where they inhibit different stages of the virus infective cycle and indirect effects when they modulate host responses to viral infection and subsequent complications. Flavonoids have shown antiviral activity via inhibition of viral protease, RNA polymerase, and mRNA, virus replication, and infectivity. The compounds were also effective for the regulation of interferons, pro-inflammatory cytokines, and sub-cellular inflammatory pathways such as nuclear factor-κB and Jun N-terminal kinases. Baicalin, quercetin and its derivatives, hesperidin, and catechins are the most studied flavonoids in this regard. In conclusion, dietary flavonoids are promising treatment options against COVID-19 infection; however, future investigations are recommended to assess the antiviral properties of these compounds on this disease.

Sesquiterpenoids from the Aerial Parts of Salvia plebeia with Inhibitory Activities on Proprotein Convertase Subtilisin/Kexin Type 9 Expression

Phytochemical investigation of the methanol extract of the aerial parts of Salvia plebeia aided by a proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA expression screening assay in HepG2 cells led to the identification of 19 compounds including one new norsesquiterpene (1), six new eudesmane sesquiterpenoids (2-5, 8, and 11), and 12 known compounds. The structures of all compounds were elucidated by interpretation of their 1D and 2D NMR spectroscopic and MS data. Furthermore, computational prediction of ECD or chemical shifts was used to propose the absolute configurations of the new structures. All isolates were assessed for their inhibitory activities against PCSK9 mRNA expression and PCSK9-low-density lipoprotein receptor (LDLR) interactions. None of the isolated compounds inhibited PCSK9 and LDLR interactions. However, compounds 1, 9, and 10 downregulated PCSK9 mRNA expression.

Potential Natural Products Against Respiratory Viruses: A Perspective to Develop Anti-COVID-19 Medicines

The emergence of viral pneumonia caused by a novel coronavirus (CoV), known as the 2019 novel coronavirus (2019-nCoV), resulted in a contagious acute respiratory infectious disease in December 2019 in Wuhan, Hubei Province, China. Its alarmingly quick transmission to many countries across the world and a considerable percentage of morbidity and mortality made the World Health Organization recognize it as a pandemic on March 11, 2020. The perceived risk of infection has led many research groups to study COVID-19 from different aspects. In this literature review, the phylogenetics and taxonomy of COVID-19 coronavirus, epidemiology, and respiratory viruses similar to COVID-19 and their mode of action are documented in an approach to understand the behavior of the current virus. Moreover, we suggest targeting the receptors of SARS-CoV and SARS-CoV-2 such as ACE2 and other proteins including 3CLpro and PLpro for improving antiviral activity and immune response against COVID-19 disease. Additionally, since phytochemicals play an essential role in complementary therapies for viral infections, we summarized different bioactive natural products against the mentioned respiratory viruses with a focus on influenza A, SARS-CoV, MERS, and COVID-19.Based on current literature, 130 compounds have antiviral potential, and of these, 94 metabolites demonstrated bioactivity against coronaviruses. Interestingly, these are classified in different groups of natural products, including alkaloids, flavonoids, terpenoids, and others. Most of these compounds comprise flavonoid skeletons. Based on our survey, xanthoangelol E (88), isolated from Angelica keiskei (Miq.) Koidz showed inhibitory activity against SARS-CoV PLpro with the best IC50 value of 1.2 μM. Additionally, hispidulin (3), quercetin (6), rutin (8), saikosaponin D (36), glycyrrhizin (47), and hesperetin (55) had remarkable antiviral potential against different viral infections. Among these compounds, quercetin (6) exhibited antiviral activities against influenza A, SARS-CoV, and COVID-19 and this seems to be a highly promising compound. In addition, our report discusses the obstacles and future perspectives to highlight the importance of developing screening programs to investigate potential natural medicines against COVID-19.

Anticancer Effect of Salvia plebeia and Its Active Compound by Improving T-Cell Activity via Blockade of PD-1/PD-L1 Interaction in Humanized PD-1 Mouse Model

Immune checkpoint inhibitors, increasingly used to treat malignant tumors, are revolutionizing cancer treatment by improving the patient survival expectations. Despite the high antitumor efficacy of antibody therapeutics that bind to PD-1/PD-L1, study on small molecule-based PD-1/PD-L1 inhibitors is required to overcome the side effects of antibody therapeutics caused by their size and affinity. Herein, we investigated antitumor potential of Salvia plebeia R. Br. extract (SPE), which has been used as a traditional oriental medicine and food in many countries, and its components by the blockade of PD-1/PD-L1 interaction. SPE and its component cosmosiin effectively blocked the molecular interaction between PD-1 and PD-L1. SPE also inhibited tumor growth by increasing CD8+ T-cells in the tumor through the activation of tumor-specific T-cells in a humanized PD-1 mouse model bearing hPD-L1 knock-in MC38 colon adenocarcinoma tumor. This finding presents a preclinical strategy to develop small molecule-based anticancer drugs targeting the PD-1/PD-L1 immune checkpoint pathway.

An Ethnobotanical Study on Qīng-Căo-Chá Tea in Taiwan

Herbal tea, a beverage prepared from a variety of plant materials excluding the leaves of the tea plant Camellia sinensis (L.) Kuntze of the family Theaceae, for a long time, has been consumed by most Chinese people for preventive and/or therapeutic health care. Usually, it is brewed or prepared as a decoction of local plants in water. The qīng-căo-chá tea, a commercial herbal tea, is the most common among many differently formulated herbal teas in Taiwan. For hundreds of years, qīng-căo-chá tea has played an important role in the prevention and treatment of diseases associated with the environmental conditions in Taiwan. However, research studies in this field have been insufficient. The raw material formulas of qīng-căo-chá tea have always been passed down from “masters” to “apprentices.” Hence, there is no systematic collation or record, and, therefore, there is a need to assess and confirm the composition, safety, and effectiveness of the raw materials. This study aimed to document the uses of Taiwan's qīng-căo-chá tea through a semi-structured interview survey and investigate the background of traditional practitioners, tea compositions, and plant origins and uses. This will improve our understanding of the knowledge inherited by the practitioners and the theoretical basis of the medicinal uses of these teas. In our field investigation, we visited 86 shops and assessed 71 raw ingredients of qīng-căo-chá tea. A semi-structured questionnaire was used to conduct the interviews. During the interviews, in addition to written records, audio and video recordings were made, and photographs were taken with the permission of the interviewees. The qīng-căo-chá raw materials have long been used as herbal teas, although more research should clarify their efficacy and safety. Traditional sellers of qīng-căo-chá tea were mainly males, and most shops have been in operation for more than 71 years. Some of the raw materials were derived from multiple sources, including different plants, and were often mixed without any safety concerns. To our knowledge, this is the first systematic ethnobotanical study on qīng-căo-chá tea that assesses and confirms its herbal ingredients. Our study represents a reference for herbal teas in Taiwan that can be used by the public and regulatory agencies.

Quercetin Blocks Ebola Virus Infection by Counteracting the VP24 Interferon-Inhibitory Function

Ebola virus (EBOV) is among the most devastating pathogens causing fatal hemorrhagic fever in humans. The epidemics from 2013 to 2016 resulted in more than 11,000 deaths, and another outbreak is currently ongoing. Since there is no FDA-approved drug so far to fight EBOV infection, there is an urgent need to focus on drug discovery. Considering the tight correlation between the high EBOV virulence and its ability to suppress the type I interferon (IFN-I) system, identifying molecules targeting viral protein VP24, one of the main virulence determinants blocking the IFN response, is a promising novel anti-EBOV therapy approach. Hence, in the effort to find novel EBOV inhibitors, a screening of a small set of flavonoids was performed; it showed that quercetin and wogonin can suppress the VP24 effect on IFN-I signaling inhibition. The mechanism of action of the most active compound, quercetin, showing a half-maximal inhibitory concentration (IC₅₀) of 7.4 μM, was characterized to significantly restore the IFN-I signaling cascade, blocked by VP24, by directly interfering with the VP24 binding to karyopherin-α and thus restoring P-STAT1 nuclear transport and IFN gene transcription. Quercetin significantly blocked viral infection, specifically targeting EBOV VP24 anti-IFN-I function. Overall, quercetin is the first identified inhibitor of the EBOV VP24 anti-IFN function, representing a molecule interacting with a viral binding site that is very promising for further drug development aiming to block EBOV infection at the early steps.

The hepatoprotective effects of Salvia plebeia R. Br. extract in zebrafish (Danio rerio)

Salvia plebeia R. Br. is a traditional Chinese medicinal herb that has been widely used for the treatment of many inflammatory diseases such as hepatitis. However, the underlying molecular mechanism about the hepatoprotective effects of S. plebeia remains largely unknown. Here, we investigated the antioxidant activities and anti-inflammatory effects of ethanol extracts of S. plebeia (SPEE) in the zebrafish model. Firstly, we determined the chemical compositions of SPEE and identified three major constituents by using GC-MS analysis. After that, SPEE exhibited significantly antioxidant properties in the LPS-induced zebrafish embryos, and the enzyme activities of ROS, CAT and SOD were obviously inhibited in a dose-dependent manner. Secondly, SPEE greatly reduced fat vacuoles (HE staining), lipid accumulation (Oil O staining) and hepatocyte fibrosis (Gemori staining) in the thioacetamide (TAA)-induced hepatocyte injury of adult zebrafish. Meanwhile, the NO contents and lipid metabolism-related genes were substantially down-regulated after SPEE exposure. Thirdly, we used RNA-Seq analysis to identify the differentially expressed genes (DEGs) after SPEE exposure in adult zebrafish liver. The results showed that 1289 DEGs including 558 up-regulated and 731 down-regulated were identified between the TAA + SPEE and TAA groups. KEGG pathway and GO functional analysis revealed that steroid biosynthesis, oxidation-reduction and innate immunity were significantly enriched. Mechanistically, SPEE can considerably reduce the cell apoptosis of hepatocytes and promote the translocation of Nrf2 protein from the nucleus to the cytoplasm in TAA-induced zebrafish. Moreover, SPEE can modulate various inflammatory cytokines and immune genes both in the control and H₂O₂-stimulated conditions. The pro-inflammatory cytokines such as IL-1β and TNF-α was markedly up-regulated but the anti-inflammatory cytokines such as TGF-β was greatly down-regulated after SPEE treatment. In addition, some key genes in the TLR signaling were also activated in the H₂O₂-stimulated conditions. In summary, our results suggested that SPEE had an important role in the antioxidant and anti-inflammatory effects in zebrafish in the near future. Some of the components identified in this study may be served as potential sources of new hepatoprotective compounds for the treatment of inflammatory diseases.

Salvia plebeia R. Br. : an overview about its traditional uses, chemical constituents, pharmacology and modern applications

Salvia plebeia R. Br. (SP), has been widely used in traditional Chinese medicine (TCM). It contains a number of chemical components and reported to possess a variety of pharmacological activities. SP is distributed in many countries such as China, Korea, Japan, Afghanistan and India. SP was first described in Compendium of Materia Medica in the Ming dynasty. The aim of this review is to compile all the information reported in the literature on SP. This review covers traditional uses, including 16 TCM classics and 21 traditional prescriptions; a total of 93 compounds from SP have been reported, including flavonoids, monoterpenoids, sesquiterpenoids, diterpenoids, triterpenes, phenolic acids etc; biological actives such as antioxidant, antimicrobial, hypoglycaemic, anti-inflammatory, analgesic, sedative, antiasthmatic, antiviral, antitumour, hepatoprotective effects etc. In addition, this paper also compiled the quality control studies and clinical applications. The future prospects and the existing problems of SP were also discussed. Overall, we believe this review will be a comprehensive record of SP for researchers to refer for carrying out for further research.

Design, synthesis, and evaluation of curcumin analogues as potential inhibitors of bacterial sialidase

Sialidases are key virulence factors that remove sialic acid from the host cell surface glycan, unmasking receptors that facilitate bacterial adherence and colonisation. In this study, we developed potential agents for treating bacterial infections caused by Streptococcus pneumoniae Nan A that inhibit bacterial sialidase using Turmeric and curcumin analogues. Design, synthesis, and structure analysis relationship (SAR) studies have been also described. Evaluation of the synthesised derivatives demonstrated that compound 5e was the most potent inhibitor of S. pneumoniae sialidase (IC50 = 0.2 ± 0.1 µM). This compound exhibited a 3.0-fold improvement in inhibitory activity over that of curcumin and displayed competitive inhibition. These results warrant further studies confirming the antipneumococcal activity 5e and indicated that curcumin derivatives could be potentially used to treat sepsis by bacterial infections.

Salviachinensines A-F, Antiproliferative Phenolic Derivatives from the Chinese Medicinal Plant Salvia chinensis

Six new phenolic acid derivatives, salviachinensines A-F (1-6), together with 14 known compounds (7-20) were isolated from the Chinese medicinal plant Salvia chinensis. The structures of salviachinensines A-F (1-6) were elucidated by NMR spectroscopy, bioinspired chemical synthesis, ECD analysis, and quantum chemical calculation methods. Compounds 2 and 3 are a pair of cis- trans isomers, and compounds 5 and 6 a pair of epimers. The solvent-induced isomerization of compounds 5 and 6 and the hypothetical biogenetic pathway of compounds 1-6, as well as the antiproliferative property and the ability of 1 to induce apoptosis and arrest cell cycle progression of MOLM-13 cells, were also investigated.

Computational screening of known broad-spectrum antiviral small organic molecules for potential influenza HA stem inhibitors

Background

With the emergence of new influenza virus strains that are resistant to current inhibitors such as oseltamivir (anti-neuraminidase (NA)) and amantadine (anti-M2 proton channel), influenza A viruses continue to be a serious threat to the public health worldwide. With this in view, there is a persistent need for the development of broader and more effective vaccines and therapeutics. Identification of broadly neutralizing antibodies (bNAbs) that recognize relatively invariant structures ‎on influenza haemagglutinin (HA) stem has invigorated efforts to develop universal influenza vaccines.

Aim

The current computational study is designed to identify potential flavonoid inhibitors that bind to the contact epitopes of HA stem that are targeted by broadly neutralizing antibodies (bNAb).

Method

In this study, we utilized the three-dimensional crystallographic structure of different HA subtypes (H1, H2, H5, H3, and H7) in complex with bNAb to screen for potential broadly reactive influenza inhibitors. We performed Quantitative Structure-Activity and Relationship (QSAR) for 100 natural compounds known for their antiviral activity and performed molecular docking using AutoDock 4.2 suite. Furthermore, we conducted virtual screening of 1413 bioassay hit compounds by using virtual lab bench CLC Drug Discovery.

Results

The results showed 18 lead flavonoids with strong binding abilities to bNAb epitopes of various HA subtypes. These 18 broadly reactive compounds exhibited significant interactions with an average of seven Hbonds, docking energy of -22.43 kcal·mol⁻¹, and minimum interaction ‎ energy of -4.65 kcal·mol⁻¹, with functional contact residues. Procyanidin depicted strong interactions with group 1 HAs, whereas both sorbitol and procyanidin exhibited significant interactions with group 2 HAs.

Conclusion

Using in silico docking analysis, we identified 18 bioactive flavonoids with potential strong binding cababilities to influenza HA-stems of various subtypes, which are the target for bNAb. The virtual screened bioassay hit compounds depicted a high number of Hbonds but low interaction and docking values compared to antiviral flavonoids. Using structure-based design and nanotechnology-based approaches, identified molecules could be modified to generate next generation anti-influenza drugs.