Identification of SARS-CoV-2 inhibitors from extracts of Houttuynia cordata Thunb

The antiviral effect and potential mechanism of Houttuynia cordata thunb. (HC) against coxsackievirus A4

ETHNOPHARMACOLOGICAL RELEVANCE

Hand, foot, and mouth disease (HFMD) is mainly caused by various of enteroviruses such as enterovirus 71 (EVA71), coxsackievirus A16 (CVA16), CVA6, and CVA10 in infants and children under 5 years old. During the past 5 years, CVA4 has become the dominant pathogen resulting in HFMD in China. However, there are no effective vaccines and antiviral drugs available. Houttuynia cordata Thunb (HC). is a Chinese herbal medicine eaten as vegetables for treating viral infection diseases, but whether HC has anti-CVA4 effect remains unclear.

AIM OF THE STUDY

In this study, we want to investigate the antiviral activity of HC against CVA4 in vitro and in vivo and elucidate the potential mechanism of HC against CVA4.

MATERIALS AND METHODS

MTT assay were used to evaluate the cytotoxicity of HC. Virus titers assay, CPE assay, violet staining and immunofluorescence were used to investigate the antiviral effect of HC against CVA4. A 13-day-old suckling mice model was established to evaluate the therapeutic efficacy of HC against CVA4 infection. Western blot, qRT-PCR and time-of-drug addition assay were performed to elucidate the potential mechanism of HC against CVA4 infection.

RESULTS

MTT assay indicated the cytotoxicity concentration of HC on Vero cells and RD cells were more than 1 mg/ml, suggesting that the low cytotoxicity of HC. In vitro antiviral assay revealed that HC could dose-dependently prevent the CPE, suppress the release of newborn virus, and inhibit the replication of CVA4 by decreasing viral RNA transcription and protein expression with IC50 of 88.96 μg/mL. A time-of-addition assay showed that HC mainly exerted anti-CVA4 effect by inhibiting virus replication at the post-entry stage. In vivo results further demonstrated that HC could effectively prevent the lethal infection of CVA4 by promoting survival, improving clinical symptoms, prolonging the survival time, inhibiting excessive inflammatory responses, and reducing pathological injury in vivo. Mechanistic studies revealed inhibition of p38 MAPK and JNK pathway over-activation may be the primary mechanism of HC against CVA4 infection.

CONCLUSION

In summary, our results for the first time demonstrated that HC not only effectively inhibited CVA4 replication, but also partially protected the lethal infection of CVA4 in vivo. Furthermore, pharmacological mechanism studies revealed that the primary mechanism of HC against CVA4 infection may be associated with its effect of inhibiting over-activation of p38 MAPK and JNK signaling pathways caused by enteroviruses. Our finding indicated that HC might be a potential innovative medicine for treating HFMD.

A near-complete assembly of the Houttuynia cordata genome provides insights into the regulatory mechanism of flavonoid biosynthesis in Yuxingcao

Houttuynia cordata, also known as Yuxingcao in Chinese, is a perennial herb in the Saururaceae family. It is highly regarded for its medicinal properties, particularly in treating respiratory infections and inflammatory conditions, as well as boosting the human immune system. However, a lack of genomic information has hindered research on the functional genomics and potential improvements of H. cordata. In this study, we present a near-complete assembly of H. cordata genome and investigate the biosynthetic pathway of flavonoids, specifically quercetin, using genomics, transcriptomics, and metabolomics analyses. The genome of H. cordata diverged from that of Saururus chinensis around 33.4 million years ago; it consists of 2.24 Gb with 76 chromosomes (4n = 76) and has undergone three whole-genome duplication (WGD) events. These WGDs played a crucial role in shaping the H. cordata genome and influencing the gene families associated with its medicinal properties. Through metabolomics and transcriptomics analyses, we identified key genes involved in the β-oxidation process for biosynthesis of houttuynin, one of the volatile oils responsible for the plant's fishy smell. In addition, using the reference genome, we identified genes involved in flavonoid biosynthesis, particularly quercetin metabolism, in H. cordata. This discovery has important implications for understanding the regulatory mechanisms that underlie production of active pharmaceutical ingredients in traditional Chinese medicine. Overall, the high-quality genome assembly of H. cordata serves as a valuable resource for future functional genomics research and provides a solid foundation for genetic improvement of H. cordata for the benefit of human health.

Deep integration of metabolome and transcriptome characterizes alkaloid metabolism in Houttuynia cordata

Alkaloids are the main medicinal components in Houttuynia cordata. In this study, two accessions 6# and 7# of H. cordata underwent thorough metabolomic analyses to identify and quantify alkaloid phytometabolites. It turned out that the alkaloid types were largely similar between 6# and 7#, and the identified 81 alkaloids could be divided into nine structural classes. However, the content of alkaloids in the two accessions was quite different. According to transcriptome data, a total of 114 differentially expressed genes related to alkaloid metabolism were screened. The alkaloid synthesis pathway of the two varieties was mainly different in the isoquinoline alkaloid biosynthesis and indole alkaloid biosynthesis; four genes A22110063c_transcript_59323, A22110063c_transcript_60118, A22110063c_transcript_51672 and A22110063c_transcript_48784 were highly expressed in 7#, which could be key candidate genes of alkaloid metabolism and warrant further analysis. These results provide a reference for the medicinal application of H. cordata and breeding alkaloid rich varieties.

Chinese Medicine for Treatment of COVID-19: A Review of Potential Pharmacological Components and Mechanisms

Coronavirus disease 2019 (COVID-19) is an acute infectious respiratory disease that has been prevalent since December 2019. Chinese medicine (CM) has demonstrated its unique advantages in the fight against COVID-19 in the areas of disease prevention, improvement of clinical symptoms, and control of disease progression. This review summarized the relevant material components of CM in the treatment of COVID-19 by searching the relevant literature and reports on CM in the treatment of COVID-19 and combining with the physiological and pathological characteristics of the novel coronavirus. On the basis of sorting out experimental methods in vivo and in vitro, the mechanism of herb action was further clarified in terms of inhibiting virus invasion and replication and improving related complications. The aim of the article is to explore the strengths and characteristics of CM in the treatment of COVID-19, and to provide a basis for the research and scientific, standardized treatment of COVID-19 with CM.

Houttuynia Cordata Thunb.: A comprehensive review of traditional applications, phytochemistry, pharmacology and safety

BACKGROUND

Houttuynia Cordata Thunb. (H. cordata; Saururaceae) is a medicine food homology plant that is grown in many Asian countries. Its main phytochemical constituents are volatile oils, flavonoids, polysaccharides and alkaloids. It has considerable clinical applications and health benefits.

PURPOSE

This paper reviews the existing literatures and patents, summarizes the phytochemistry, pharmacological activity, safety and economic botanical applications of H. cordata, and provides a reference for systematic study of the pharmacological effects of H. cordata, improvement of quality standards and further development of its medicinal resources.

METHODS

A comprehensive search of literature and patents on H. cordata and its active ingredients published before June 2023 was conducted using PubMed, Google Scholar, Web of Science, and China Knowledge Network.

RESULTS

H. cordata is not only edible and medicinal but also used in various aspects of daily life such as fermented beverages, nutraceuticals, feed and cosmetics. The main phytochemical constituents of H. cordata are volatile oils, flavonoids, organic acids and alkaloids. Several in vitro and in vivo studies and clinical trials have found that H. cordata extracts possess antioxidant, anti-inflammatory, antitumor, antibacterial, hepatoprotective and renal, immunomodulatory and potent antiviral effects. The mechanisms of expression of these pharmacological effects are related to the blood-brain barrier, lipophilicity, cAMP signaling and skin permeability, including blocking the MAPK signaling pathway, inhibiting the secretion of inflammatory factors such as TNF-α and IL-1β, and activating the AMPK pathway.

CONCLUSION

This paper provides a comprehensive review of the progress of research on the traditional applications, botany, chemical composition, pharmacological effects and safety of H. cordata and discusses for the first time the economic botanical aspects, which were not explored in the previous reviews. H. cordata has a wide range of bioactive substances whose therapeutic potential has not been fully exploited, and it could provide a new non-toxic approach to many diseases. This traditional medicinal food plant should receive more attention and in-depth research in the future.

Scientific Insights for Drug Development Based on Normal Habitat of Tribal Population of Manipur: An Observational Study Regarding the Implication of "Houttuynia cordata"

The development of new and novel drugs starts following a path of targeting possible candidate drug, elucidation their mechanism of action, animal studies, and finally after the completion of phases I/II and III clinical trials. The fundamental raw materials of drugs may be synthetic substances or plants. Many plants are habitually used in many countries as food or for the remedy of diseases. We found that a tribal population of Bangladesh use an herbal plant regularly and this plant has been shown to have potential positive effect for management of coronavirus disease-2019 (COVID-19). The present observation assessed the incidence and fatality of this community inhabitants due to COVID-19. Although a conclusion cannot be reached due to small sample size, this approach and theological concept may be helpful for the development, discovery, and innovation of new drugs for different pathological conditions.

How to cite this article

Rahim MA, Singha SK, Foez SA, et al. Scientific Insights for Drug Development Based on Normal Habitat of Tribal Population of Manipur: An Observational Study Regarding the Implication of "Houttuynia cordata". Euroasian J Hepato-Gastroenterol 2023;13(2):142-144.

Potential herb‒drug interactions between anti-COVID-19 drugs and traditional Chinese medicine

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide. Effective treatments against COVID-19 remain urgently in need although vaccination significantly reduces the incidence, hospitalization, and mortality. At present, antiviral drugs including Nirmatrelvir/Ritonavir (PaxlovidTM), Remdesivir, and Molnupiravir have been authorized to treat COVID-19 and become more globally available. On the other hand, traditional Chinese medicine (TCM) has been used for the treatment of epidemic diseases for a long history. Currently, various TCM formulae against COVID-19 such as Qingfei Paidu decoction, Xuanfei Baidu granule, Huashi Baidu granule, Jinhua Qinggan granule, Lianhua Qingwen capsule, and Xuebijing injection have been widely used in clinical practice in China, which may cause potential herb-drug interactions (HDIs) in patients under treatment with antiviral drugs and affect the efficacy and safety of medicines. However, information on potential HDIs between the above anti-COVID-19 drugs and TCM formulae is lacking, and thus this work seeks to summarize and highlight potential HDIs between antiviral drugs and TCM formulae against COVID-19, and especially pharmacokinetic HDIs mediated by metabolizing enzymes and/or transporters. These well-characterized HDIs could provide useful information on clinical concomitant medicine use to maximize clinical outcomes and minimize adverse and toxic effects.

Recuperative herbal formula Jing Si maintains vasculature permeability balance, regulates inflammation and assuages concomitants of "Long-Covid"

Coronavirus disease 2019 (COVID-19) is a worldwide health threat that has long-term effects on the patients and there is currently no efficient cure prescribed for the treatment and the prolonging effects. Traditional Chinese medicines (TCMs) have been reported to exert therapeutic effect against COVID-19. In this study, the therapeutic effects of Jing Si herbal tea (JSHT) against COVID-19 infection and associated long-term effects were evaluated in different in vitro and in vivo models. The anti-inflammatory effects of JSHT were studied in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and in Omicron pseudotyped virus-induced acute lung injury model. The effect of JSHT on cellular stress was determined in HK-2 proximal tubular cells and H9c2 cardiomyoblasts. The therapeutic benefits of JSHT on anhedonia and depression symptoms associated with long COVID were evaluated in mice models for unpredictable chronic mild stress (UCMS). JSHT inhibited the NF-ƙB activities, and significantly reduced LPS-induced expression of TNFα, COX-2, NLRP3 inflammasome, and HMGB1. JSHT was also found to significantly suppress the production of NO by reducing iNOS expression in LPS-stimulated RAW 264.7 cells. Further, the protective effects of JSHT on lung tissue were confirmed based on mitigation of lung injury, repression in TMRRSS2 and HMGB-1 expression and reduction of cytokine storm in the Omicron pseudotyped virus-induced acute lung injury model. JSHT treatment in UCMS models also relieved chronic stress and combated depression symptoms. The results therefore show that JSHT attenuates the cytokine storm by repressing NF-κB cascades and provides the protective functions against symptoms associated with long COVID-19 infection.

Protective Effects of Herba Houttuyniae Aqueous Extract against OVA-Induced Airway Hyperresponsiveness and Inflammation in Asthmatic Mice

Herba Houttuyniae is the well-knownfood-medicine herb with the special taste and smell. It is also widely used in south China for prevention of various chronic pulmonary inflammatory diseases including asthma. However, the active ingredients and therapeutic mechanism of this herb remain obscure. In this study, network pharmacology technology was employed to investigate the effects of Herba Houttuyniae aqueous extract (HHAE) on OVA-induced airway hyperresponsiveness and inflammation. The results showed that six compounds (isoramanone, kaempferol, 1-methyl-2-nonacosyl-4-quinolone, C09747, spinasterol, and quercetin) were found to be mainly responsible for the therapeutic effects of the herb, which totally regulated the expressions of 168 asthma-related proteins. All those targets involved in the signal transduction of the prolactin signaling pathway, central carbon metabolism in cancer, EGFR tyrosine kinase inhibitor resistance, endocrine resistance, and VEGF signaling pathway. The in vivo experiment also revealed that orally administrated with HHAE alleviated airway hyperresponsiveness and inflammation in OVA-induced asthmatic mice. It significantly decreased the counts of neutrophils, eosinophils, and lymphocytes as well as the levels of IL-1β, IL-4, IL-6, and IL-13 in BALF of asthmatic mice. Mechanically, HHAE downregulated both the mRNA and protein expressions of p38 MAPK, PI3K, AKT, and VEGF in the lung tissues of asthmatic mice. Therefore, HHAE improved OVA-induced airway hyperresponsiveness and inflammation in mice and could be a potential supplement for asthma treatment.

The Traditional Chinese Medicine Houttuynia cordata Thunb decoction alters intestinal barrier function via an EGFR dependent MAPK (ERK1/2) signalling pathway

BACKGROUND

A traditionally prepared aqueous extract (= decoction) of Houttuynia cordata Thunb (Yu xing cao) (HC) is widely used in Traditional Chinese Medicine (TCM) to treat inflammatory disease. Previous chemical and biological studies on HC have mainly focused on organic extracts rather than the aqueous decoction, which is the traditional formulation.

PURPOSE

The study aimed to investigate whether the chemical composition of HC aqueous decoction (HCD) varies with geographical sourcing, to investigate the mechanism of action of HCD, and to determine if chemical variation impacts on HCDs anti-inflammatory activity.

METHOD

Sixteen samples of HC were purchased from Sichuan, Hubei and Anhui provinces in the People's Republic of China (PRC) and were prepared by the traditional decoction method to yield their corresponding HCDs. A Quality Control (QC) sample was prepared by combining individual HCD extracts. HCDs were analysed by Nuclear Magnetic Resonance (NMR) and High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS). The anti-inflammatory activities associated with intestinal barrier function of HCD were studied by tumor necrosis factor-α (TNF-α) activated Caco-2 monolayers in vitro and in vivo using Dextran Sulfate Sodium (DSS)-induced murine colitis. Proteins involved in inflammation, mRNA levels, disease severity scores, and histology involved in intestinal inflammation were analysed.

RESULTS

HCD samples exhibited different chemical fingerprints and three regional outliers were identified by Principal Component Analysis (PCA). Fifteen phytochemical metabolites were identified and quantified. HCD showed in vitro anti-inflammatory activity, enhancing zonula occludens-1 (ZO-1), occludin, interleukin (IL)-10 and decreasing IL-1β, IL-6 and epidermal growth factor receptor (EGFR) via an EGFR-dependent mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase 1/2 (ERK 1/2) signaling pathway. This beneficial effect on intestinal inflammation was also seen in the in vivo colitis model at a molecular level in colonic tissues.

CONCLUSION

This study shows that the test HCDs were chemically different, resulting in different levels of activity on intestinal barrier function and inflammation. Moreover, a "Daodi" product showed the greatest biological activity in this study, thus validating the importance of the "Daodi" quality material in TCM and supporting the traditional used of HCD for the treatment of inflammation.

Prevention, treatment and potential mechanism of herbal medicine for Corona viruses: A review

The pandemic of coronavirus disease 2019 (COVID-19) caused by the SARS-coronavirus 2(SARS-CoV-2) virus has become the greatest global public health crisis in recent years,and the COVID-19 epidemic is still continuing. However, due to the lack of effectivetherapeutic drugs, the treatment of corona viruses is facing huge challenges. In thiscontext, countries with a tradition of using herbal medicine such as China have beenwidely using herbal medicine for prevention and nonspecific treatment of corona virusesand achieved good responses. In this review, we will introduce the application of herbalmedicine in the treatment of corona virus patients in China and other countries, andreview the progress of related molecular mechanisms and antiviral activity ingredients ofherbal medicine, in order to provide a reference for herbal medicine in the treatment ofcorona viruses. We found that herbal medicines are used in the prevention and fightagainst COVID-19 in countries on all continents. In China, herbal medicine has beenreported to relieve some of the clinical symptoms of mild patients and shorten the length of hospital stay. However, as most herbal medicines for the clinical treatment of COVID-19still lack rigorous clinical trials, the clinical and economic value of herbal medicines in theprevention and treatment of COVID-19 has not been fully evaluated. Future work basedon large-scale randomized, double-blind clinical trials to evaluate herbal medicines andtheir active ingredients in the treatment of new COVID-19 will be very meaningful.

Pharmacogenetics and Precision Medicine Approaches for the Improvement of COVID-19 Therapies

Many drugs are being administered to tackle coronavirus disease 2019 (COVID-19) pandemic situations without establishing clinical effectiveness or tailoring safety. A repurposing strategy might be more effective and successful if pharmacogenetic interventions are being considered in future clinical studies/trials. Although it is very unlikely that there are almost no pharmacogenetic data for COVID-19 drugs, however, from inferring the pharmacokinetic (PK)/pharmacodynamic(PD) properties and some pharmacogenetic evidence in other diseases/clinical conditions, it is highly likely that pharmacogenetic associations are also feasible in at least some COVID-19 drugs. We strongly mandate to undertake a pharmacogenetic assessment for at least these drug-gene pairs (atazanavir-UGT1A1, ABCB1, SLCO1B1, APOA5; efavirenz-CYP2B6; nevirapine-HLA, CYP2B6, ABCB1; lopinavir-SLCO1B3, ABCC2; ribavirin-SLC28A2; tocilizumab-FCGR3A; ivermectin-ABCB1; oseltamivir-CES1, ABCB1; clopidogrel-CYP2C19, ABCB1, warfarin-CYP2C9, VKORC1; non-steroidal anti-inflammatory drugs (NSAIDs)-CYP2C9) in COVID-19 patients for advancing precision medicine. Molecular docking and computational studies are promising to achieve new therapeutics against SARS-CoV-2 infection. The current situation in the discovery of anti-SARS-CoV-2 agents at four important targets from in silico studies has been described and summarized in this review. Although natural occurring compounds from different herbs against SARS-CoV-2 infection are favorable, however, accurate experimental investigation of these compounds is warranted to provide insightful information. Moreover, clinical considerations of drug-drug interactions (DDIs) and drug-herb interactions (DHIs) of the existing repurposed drugs along with pharmacogenetic (e.g., efavirenz and CYP2B6) and herbogenetic (e.g., andrographolide and CYP2C9) interventions, collectively called multifactorial drug-gene interactions (DGIs), may further accelerate the development of precision COVID-19 therapies in the real-world clinical settings.