Alkaloids from aerial parts of Houttuynia cordata and their anti-inflammatory activity

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.

Inhibition of LPS-Induced Skin Inflammatory Response and Barrier Damage via MAPK/NF-κB Signaling Pathway by Houttuynia cordata Thunb Fermentation Broth

Houttuynia cordata Thunb is rich in active substances and has excellent antioxidant and anti-inflammatory activity. Scanning electron microscopy and gel permeation chromatography were used to analyze the molecular characteristics of the fermentation broth of Houttuynia cordata Thunb obtained through fermentation with Clavispora lusitaniae (HCT-f). The molecular weight of HCT-f was 2.64265 × 105 Da, and the polydispersity coefficient was 183.10, which were higher than that of unfermented broth of Houttuynia cordata Thunb (HCT). By investigating the active substance content and in vitro antioxidant activity of HCT-f and HCT, the results indicated that HCT-f had a higher active substance content and exhibited a superior scavenging effect on 2,2-diphenyl-1-picrylhydrazyl radicals and hydroxyl radicals, with IC50 values of 11.85% and 9.01%, respectively. Our results showed that HCT-f could effectively alleviate the increase in the secretion of inflammatory factors and apoptotic factors caused by lipopolysaccharide (LPS) stimulation, and had a certain effect on repairing skin barrier damage. HCT-f could exert an anti-inflammatory effect by down-regulating signaling in the MAPK/NF-κB pathway. The results of erythrocyte hemolysis and chicken embryo experiments showed that HCT-f had a high safety profile. Therefore, this study provides a theoretical basis for the application of HCT-f as an effective ingredient in food and cosmetics.

Quality and production enhancement of fish mint, Houttuynia cordata Thunb., cultivated in a hydroponic planting system with designed plant growth-promoting additives

Fish mint, Houttuynia cordata Thunb. (HCT) is an edible vegetable that has also been used in traditional folk medicines. As both a medicinal herb and a dietary source, HCT has been clinically proven to be a pivotal ingredient in formulas administered to alleviate COVID-19 symptoms. With the increasing market demand for imported materials, ensuring the quality consistency of HCT becomes a significant concern. In this study, the growing time for hydroponically-cultivated HCT with seaweed extract and amino acids added (HCTW) reduced by half compared to conventional soil-cultivated HCT (HCTS). Key quantified components in HCTW, flavonoid glycosides and caffeoylquinic acid derivatives, exhibited a 143% increase over HCTS. These crucial constituents were responsible for possessing antioxidant activity (IC50 < 25 μg/mL) and anti-nitrite oxide production (IC50 < 20 μg/mL). An economically-designed hydroponic system with appropriate additives is proposed to replace HCTS with improvements of growth time, overall production yields, and bioactive qualities.

Toxicity Study on Crude Alkaloid Extracts of Houttuyniae herba Based on Zebrafish and Mice

Houttuyniae herba has a long history of medicinal and edible homology in China. It has the functions of clearing heat and detoxifying, reducing swelling and purulent discharge, diuresis, and relieving gonorrhea. It is mainly distributed in the central, southeastern, and southwestern provinces of China. Houttuyniae herba has been designated by the National Ministry of Health of China as a dual-use plant for both food and medicine. Comprising volatile oils, flavonoids, and alkaloids as its primary constituents, Houttuyniae herba harbors aristolactams, a prominent subclass of alkaloids. Notably, the structural affinity of aristolactams to aristolochic acids is discernible, the latter known for its explicit toxicological effects. Additionally, the safety study on Houttuyniae herba mainly focused on the ethanol, methanol, or aqueous extract. In this study, both zebrafish and mice were used to evaluate the acute toxicity of the total alkaloids extracts from Houttuyniae herba (HHTAE). The zebrafish experiment showed that a high concentration (0.1 mg/mL) of HHTAE had a lethal effect on zebrafish embryos. Furthermore, the mice experiment results showed that, even at a higher dose of 2000 mg/kg, HHTAE was not toxic. In conclusion, HHTAE was of low safety risk.

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.

Identification, Formation, and Occurrence of Perlolyrine: A β-Carboline Alkaloid with a Furan Moiety in Foods

β-Carbolines are naturally occurring bioactive alkaloids found in foods and in vivo. This research reports the identification, characterization, mechanism of formation, and occurrence of perlolyrine (1-(5-(hydroxymethyl)furan-2-yl)-9H-pyrido[3,4-b]indole), a β-carboline with a furan moiety. Perlolyrine did not arise from l-tryptophan and hydroxymethylfurfural but from the reaction of l-tryptophan with 3-deoxyglucosone, an intermediate of carbohydrate degradation. The mechanism of formation occurs through 3,4-dihydro-β-carboline-3-carboxylic acid intermediates (imines), followed by the oxidation of C1'-OH to ketoimine and oxidative decarboxylation at C-3, along with dehydration and cyclization to afford the β-carboline with a furan moiety. The formation of perlolyrine was favored in acidic conditions and temperatures in the range of 70-110 °C. Perlolyrine occurred in the reactions of tryptophan with carbohydrates. The formation rate from fructose was much higher than from glucose. Sucrose also gave perlolyrine under acidic conditions and heating. Perlolyrine was identified in many foods by HPLC-MS and analyzed by HPLC-fluorescence. It occurred in many processed foods such as tomato products including tomato puree, fried tomato, ketchups, tomato juices, and jams but also in soy sauce, beer, balsamic vinegar, fruit juices, dried fruits, fried onion, and honey. The concentrations ranged from an undetected amount to 3.5 μg/g with the highest average levels found in tomato concentrate (1.9 μg/g) and soy sauce (1.5 μg/mL). The results show that perlolyrine formed during the heating process of foods. It is concluded that perlolyrine is widely present in foods and it is daily ingested in the diet.

Effects of dietary pretreated Chinese herbal medicine supplementation on production performance, egg quality, uterine histopathological changes, and antioxidant capacity in late-phase laying hens

Aims: The study aimed to evaluate the effects of pretreated Chinese herbal medicine (PCHM) on egg quality, production performance, histopathological changes in the uterus, antiox idant capacity, and antioxidant gene expression in late-phase layers. Methods: Jinghong No.1 layers (n = 360, 68 weeks old) were assigned randomly to one of f our dietary interventions. Each treatment was replicated six times. Repeat 15 chickens per g roup. All birds were fed a diet composed of a corn-soybean meal-based diet supplemented with 0, 0.2, 0.4, or 0.8% PCHM for 6 weeks. Results: Dietary PCHM supplementation had no significant effects on laying rate, feed con sumption, yolk color, and shape index. With increasing PCHM level the Haugh unit linearly increased (P < 0.05). Supplementation of 0.8% PCHM increased egg weight, compared with the control (P < 0.05). PCHM can effectively alleviated the pathological changes caused by aging in the uterus including hemorrhage, and many inflammatory cell infiltrations. Supplementation of 0.4% PCHM increased glutathione peroxidase (GSHPx) in liver, magnum, and plasm considerably, compared with the control (P < 0.05). Supplementation of PCHM decr ease in the liver, magnum, and uterus on malondialdehyde (MDA) content, compared with the control (P < 0.05). Compared with the control group, mRNA expressions of glutathione peroxidase 1 (GPX1), peroxidase 4 (GPX4), catalase (CAT), and nuclear factor E2-related factor 2 (Nrf2) in the magnum, liver, and uterus were dramatically rose in the 0.4% PCHM supplementation group (P < 0.05). In summary, dietary supplementation after PCHM increased egg weight and quality in late-phase laying hens. Conclusion: Dietary PCHM increased the antioxidative capacity of late-phase laying hens, which could be associated with increased mRNA expression of antioxidant enzymes and Nrf2. These findings provide potential for using PCHM to increase the production performance in late-phase laying hens.

Protective Effects of Fermented Houttuynia cordata Against UVA and H2O2-Induced Oxidative Stress in Human Skin Keratinocytes

The biological activities of Houttuynia cordata (H. cordata) fermented with Aureobasidium pullulans (A. pullulans) was investigated for human skin keratinocyte-induced chemical and photo oxidations. In this research, H₂O₂/UVA-induced HaCaT cell lines were treated with H. cordata water/ethanol extracts (HCW/HCE) and fermented with A. pullulans water/ethanol extracts (HCFW/HCFE). A. pullulans fermented with H. cordata (HCFW) increased in 5.4-folds of total polyphenol (HCFW 46.89 mg GAE/extract g), and 2.3-folds in flavonoids (HCFW 53.80 mg GAE/extract g) compared with water extracts of H. cordata (HCW). Further, no significant cytotoxicity for HaCaT cells showed by all the extracts of H. cordata fermented with A. pullulans. HCFW extracts have significantly lowered inflammation factors such as COX-2 and Hsp70 proteins in oxidative stressed HaCaT cells induced by H₂O₂ and UVA treatments. All H. cordata extracts significantly downregulated gene expression involved in oxidative stress and inflammation factors, including IL-1β, IL-6, COX-2, TNF-α, NF-κB, and MMP-1 in the H₂O₂/UVA-treated HaCaT cells. However, keratin-1 gene expression in the UVA-treated HaCaT cells was increased in twofolds by HCFW extracts. Further, A. pullulans fermented H. cordata extracts (HCFW/HCFE) reduced the genes involved in oxidative stresses more effectively than those of H. cordata extract only. Overall, the polyphenol-rich extracts of H. cordata fermented with A. pullulans showed synergistic protective effects for human epidermal keratinocytes to prevent photoaging and intrinsic aging by anti-oxidation and anti-inflammatory functions.

Pharmacological Effects of Houttuynia cordata Thunb (H. cordata): A Comprehensive Review

Houttuynia cordata Thunb (H. cordata) is a rhizomatous, herbaceous, and perennial plant widely distributed in Asia. It has multiple chemical constituents, such as alkaloids, essential oils, phenolic acids, and flavonoids used against various health problems. The essential oils and flavonoids are the main components of H. cordata that play an essential role in disease treatment and traditional health care. Moreover, the leaves and stems of H. cordata have a long medicinal history in China. In addition, H. cordata is used against several health issues, such as cold, cough, fever, pneumonia, mumps, and tumors, due to its anti-inflammatory, anti-bacterial, anti-viral, anti-oxidant, and anti-tumor effects. It protects organs due to its anti-inflammatory activity. H. cordata regulates immunity by enhancing immune barriers of the oral cavity, vagina, and gastrointestinal tract, and shows broad-spectrum activity against liver, lung, breast, and colon tumors. However, there are some gaps to be filled to understand its pathways and mechanisms. Mechanisms such as its interaction with cells, cell membranes, and various drugs are important. Studies in relation to the blood–brain barrier, lipophilicity, cAMP signaling, and skin permeability, including pharmaceutical effects, will be very useful. This review includes the biological and pharmacological activities of H. cordata based on up-to-date research.

Predicting for anti-(mutant) SARS-CoV-2 and anti-inflammation compounds of Lianhua Qingwen Capsules in treating COVID-19

BACKGROUND

Lianhua Qingwen Capsules (LHQW) is a traditional Chinese medicine prescription commonly used to treat viral influenza in China. There has been sufficient evidence that LHQW could effectively treat COVID-19. Nevertheless, the potential anti-(mutant) SARS-CoV-2 and anti-inflammation compounds in LHQW are still vague.

METHODS

The compounds of LHQW and targets were collected from TCMSP, TCMID, Shanghai Institute of Organic Chemistry of CAS database, and relevant literature. Autodock Vina was used to carry out molecular docking. The pkCSM platform to predict the relevant parameters of compound absorption in vivo. The protein-protein interaction (PPI) network was constructed by the STRING database. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was carried out by Database for Annotation, Visualization, and Integrated Discovery (DAVID). The anti-(mutant) SARS-CoV-2 and anti-inflammation networks were constructed on the Cytoscape platform.

RESULTS

280 compounds, 16 targets related to SARS-CoV-2, and 54 targets related to cytokine storm were obtained by screening. The key pathways Toll-like receptor signaling, NOD-like receptor signal pathway, and Jak-STAT signaling pathway, and the core targets IL6 were obtained by PPI network and KEGG pathway enrichment analysis. The network analysis predicted and discussed the 16 main anti-SARS-CoV-2 active compounds and 12 main anti-inflammation active compounds. Ochnaflavone and Hypericin are potential anti-mutant virus compounds in LHQW.

CONCLUSIONS

In summary, this study explored the potential anti-(mutant) SARS-CoV-2 and anti-inflammation compounds of LHQW against COVID-19, which can provide new ideas and valuable references for discovering active compounds in the treatment of COVID-19.

Structural characterization and anti-inflammatory activity of a pectin polysaccharide HBHP-3 from Houttuynia cordata

In this study, a hot buffer soluble Houttuynia cordata polysaccharide (HBHP-3) with a molecular weight of 397.4 kDa was isolated from H. cordata. HBHP-3 was composed of rhamnose, arabinose, glucose, galactose and galacturonic acid with molar ratio of 16.0:12.6:4.6:18.1:15.6. Structural analysis showed that the main chain of HBHP-3 was composed of →2)-α-L-Rhap-(1→, →4)-α-D-GalpA-(1→ and →4)-β-D-Galp-(1→. There were branched chains of α-L-Araf-(1→, →5)-α-L-Araf-(1→, →4)-α-D-Glcp-(1→, →6)-β-D-Galp-(1→, β-D-Galp-(1→ connected to the O-4 positions of →2)-α-L-Rhap-(1→. HBHP-3 effectively inhibited the secretion of NO and the mRNA expression of pro-inflammatory cytokines in a dose-dependent manner in macrophages. HBHP-3 inhibited the phosphorylation of p65 and IκBα proteins as well, illustrating that HBHP-3 exerted its anti-inflammatory activity by inhibiting the activation of NF-κB pathway.

Ingredients with anti-inflammatory effect from medicine food homology plants

Inflammation occurs when the immune system responses to external harmful stimuli and infection. Chronic inflammation induces various diseases. A variety of foods are prescribed in the traditional medicines of many countries all over the world, which gave birth to the concept of medicine food homology. Over the past few decades, a number of secondary metabolites from medicine food homology plants have been demonstrated to have anti-inflammatory effects. In the present review, the effects and mechanisms of the medicine food homology plants-derived active components on relieving inflammation and inflammation-mediated diseases were summarized and discussed. The information provided in this review is valuable to future studies on anti-inflammatory ingredients derived from medicine food homology plants as drugs or food supplements.

Houttuynia cordata Thunb: An Ethnopharmacological Review

Houttuynia cordata Thunb (H. cordata; Saururaceae) is widely distributed in Asian regions. It plays an important role in traditional health care and disease treatment, as its aboveground stems and leaves have a long medicinal history in China and are used in the treatment of pneumonia and lung abscess. In clinical treatment, it can usually be combined with other drugs to treat dysentery, cold, fever, and mumps; additionally, H. cordata is an edible plant. This review summarizes detailed information on the phytochemistry and pharmacological effects of H. cordata. By searching the keywords “H. cordata and lung”, “H. cordata and heart”, “H. cordata and liver”, and “H. cordata and inflammation” in PubMed, Web of Science and ScienceDirect, we screened out articles with high correlation in the past ten years, sorted out the research contents, disease models and research methods of the articles, and provided a new perspective on the therapeutic effects of H. cordata. A variety of its chemical constituents are characteristic of medicinal plants, the chemical constituents were isolated from H. cordata, including volatile oils, alkaloids, flavonoids, and phenolic acids. Flavonoids and volatile oils are the main active components. In pharmacological studies, H. cordata showed organ protective activity, such as reducing the release of inflammatory factors to alleviate lung injury. Moreover, H. cordata regulates immunity, enhances the immune barriers of the vagina, oral cavity, and intestinal tract, and combined with the antibacterial and antiviral activity of its extract, effectively reduces pathogen infection. Furthermore, experiments in vivo and in vitro showed significant anti-inflammatory activity, and its chemical derivatives exert potential therapeutic activity against rheumatoid arthritis. Antitumour action is also an important pharmacological activity of H. cordata, and studies have shown that H. cordata has a notable effect on lung tumour, liver tumour, colon tumour, and breast tumour. This review categorizes the biological activities of H. cordata according to modern research papers, and provides insights into disease prevention and treatment of H. cordata.

Acute and subacute toxicity evaluation of Houttuynia cordata ethanol extract and plasma metabolic profiling analysis in both male and female rats

Houttuynia cordata has been used as a traditional medicine for more than 1500 years. It has aroused wide public concern about its safety in the past few years, for it contains various aristolactams. However, the safety of H. cordata extract remains unclear. In the present study, single dose (2000 mg/kg) and subacute (250, 500, and 1000 mg/kg/day for 28 days) oral toxicity studies of the 95% ethanol extract of H. cordata (HCE) were performed in both male and female Sprague-Dawley (SD) rats. Hematological, biochemical, histopathological parameters, and plasma metabolic profiling were assessed. The single-dose toxicity of HCE was more than 2000 mg/kg. The subacute toxicity results showed that no significant adverse effect of HCE was observed at 250 mg/kg/day. However, five rats died in 500 and 1000 mg/kg/day groups and exhibited toxicities to liver and kidney. Plasma metabolic profiling analysis suggested that a number of metabolic disturbances were induced by oral administration of HCE, focusing on energy metabolism, amino acid metabolism, and lipids metabolism. Moreover, it appeared that male rats were more susceptible to the toxic effects of HCE than female rats. Therefore, in this preliminary study, oral administration of HCE 250 mg/kg/day can be regarded as the no observed adverse effect level in rats over 28 days. However, long-term use of HCE with large doses exhibited some hepatotoxicity and nephrotoxicity in rats.

Discovery of natural anti-inflammatory alkaloids: Potential leads for the drug discovery for the treatment of inflammation

Inflammation is an adaptive response of the immune system to tissue malfunction or homeostatic imbalance. Corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs) are frequently applied to treat varieties of inflammatory diseases but are associated with gastrointestinal, cardiovascular, and kidney side effects. Developing more effective and less toxic agents remain a challenge for pharmaceutical chemist due to the complexity of the different inflammatory processes. Alkaloids are widely distributed in plants with diverse anti-inflammatory activities, providing various potential lead compounds or candidates for the design and discovery of new anti-inflammatory drug candidates. Therefore, re-examining the anti-inflammatory alkaloid natural products is advisable, bringing more opportunities. In this review, we summarized and described the recent advances of natural alkaloids with anti-inflammatory activities and possible mechanisms in the period from 2009 to 2020. It is hoped that this review of anti-inflammatory alkaloids can provide new ideas for researchers engaged in the related fields and potential lead compounds for the discovery of anti-inflammatory drugs.

Indole alkaloids: 2012 until now, highlighting the new chemical structures and biological activities

Indole alkaloids have attracted attention because of their therapeutic properties, being anti-inflammatory, antinociceptive, antitumoural, antioxidant and antimicrobial. These compounds present a wide structural diversity, which is directly related to the genera of the producing plants, as well as the biological activities. Indole alkaloids have attracted attention over the last decade because of this combination of bioactivity and structural diversity. Therefore, this review presented recent (2012-2018) advances in alkaloids, focusing on new compounds, extraction methods and biological activities. As such, approximately 70 articles were identified, which showed 261 new compounds produced by plants of the families Apocynaceae, Rubiaceae, Annonaceae and Loganiaceae. In addition, different extraction methods were identified, and the structures of the new compounds were analysed. In addition to indole molecules, there were mono-indole-, di-indole-, vinblastine-, vimblastine-, gelsedine-, geissospermidine-, koumine-, geissospermidine-, iboga-, perakine-, corynanthe-, vincamine-, ajmaline-, aspidorpema-, strychnos-type, β-carboline alkaloids and indole alkaloid glucosides. The reported biological activities are mainly anticancer, antibacterial, antimalarial, antifungal, antiparasitic, and antiviral, as well as anti-acetylcholinesterase and anti-butyrylcolinesterase properties. This review serves as a guide for those wishing to find the most recently identified alkaloid structures and their associated activities.

The effect of fishwort (Houttuynia cordata) on skin mucosal, serum immunities, and growth performance of Nile tilapia

The present study addressed the possible effects of fishwort (Houttuynia cordata) powder (FWP) on Nile tilapia's skin mucus parameter, serum immune response, and growth performance. Three hundred twenty tilapia fingerlings (average weight of 39.06 ± 0.16 g) were divided into four treatments and fed four levels of FWP; 0, 5, 10, and 20 g kg^-1 for 72 days. Completed randomised design of the four replications was applied and revealed that fish fed FWP significantly improved skin mucus lysozyme activity (SMLA). The highest value (P < 0.05) was recorded in fish fed 10 g kg^-1 FWP. However, no significant difference in SMLA was observed by feeding the fish 5 and 20 g kg^-1 FWP. Significant (P < 0.05) enhanced skin mucus peroxidase activity (SMPA) was observed in fish fed 10 g kg^-1 FWP, but no significant difference in SMPA was detected between FWP supplemented diets (5 and 20 g kg^-1 FWP) and the control group. Regarding serum immunity, dietary administration of FWP showed significantly (P < 0.05) improved serum lysozyme, peroxidase, alternative complement (ACH50), and phagocytosis vs. the control. The highest values of serum immunity (P < 0.05) were recorded in fish fed 10 g kg^-1 FWP. However, no significance in respiratory burst activity was observed. Similarly, no significant difference in growth performance, feed conversion ratio, and survival rate was observed in fish fed FWP compared to the control. In summary, diets supplemented with FWP (10 g kg^-1) increased the serum and mucosal immunity; however, no FWP supplementations had effects on Nile tilapia growth and survival rate.

Flavonoids from Houttuynia cordata attenuate H1N1-induced acute lung injury in mice via inhibition of influenza virus and Toll-like receptor signalling

BACKGROUND

Influenza virus is one of the most important human pathogens, causing substantial seasonal and pandemic morbidity and mortality. Houttuynia cordata is a traditionally used medicinal plant for the treatment of pneumonia. Flavonoids are one of the major bioactive constituents of Houttuynia cordata.

PURPOSE

This study was designed to investigate the therapeutic effect and mechanism of flavonoid glycosides from H. cordata on influenza A virus (IAV)-induced acute lung injury (ALI) in mice.

METHODS

Flavonoids from H. cordata (HCF) were extracted from H. cordata and identified by high-performance liquid chromatography. Mice were infected intranasally with influenza virus H1N1 (A/FM/1/47). HCF (50, 100, or 200 mg/kg) or Ribavirin (100 mg/kg, the positive control) were administered intragastrically. Survival rates, life spans, weight losses, lung indexes, histological changes, inflammatory infiltration, and inflammatory markers in the lungs were measured. Lung virus titers and neuraminidase (NA) activities were detected. The expression of Toll-like receptors (TLRs) and levels of NF-κB p65 phosphorylation (NF-κB p65(p)) in the lungs were analysed. The effects of HCF on viral replication and TLR signalling were further evaluated in cells.

RESULTS

HCF contained 78.5% flavonoid glycosides. The contents of rutin, hyperin, isoquercitrin, and quercitrin in HCF were 8.8%, 26.7%, 9.9% and 31.7%. HCF (50, 100 and 200 mg/kg) increased the survival rate and life span of mice infected with the lethal H1N1 virus. In H1N1-induced ALI, mice treated with HCF (50, 100 and 200 mg/kg) showed lesser weight loss and lower lung index than the model group. The lungs of HCF-treated ALI mice presented more intact lung microstructural morphology, milder inflammatory infiltration, and lower levels of monocyte chemotactic protein 1 (MCP-1), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α) and malondialdehyde (MDA) than in the model group. Further investigation revealed that HCF exerted antiviral and TLR-inhibitory effects in vivo and in vitro. HCF (50, 100 and 200 mg/kg) reduced lung H1N1 virus titers and inhibited viral NA activity in mice. HCF (100 and 200 mg/kg) elevated the levels of interferon-β in lungs. HCF also decreased the expression of TLR3/4/7 and level of NF-κB p65(p) in lung tissues. In vitro experiments showed that HCF (50, 100 and 200 μg/ml) significantly inhibited viral proliferation and suppressed NA activity. In RAW 264.7 cells, TLR3, TLR4, and TLR7 agonist-stimulated cytokine secretion, NF-κB p65 phosphorylation, and nuclear translocation were constrained by HCF treatment. Furthermore, among the four major flavonoid glycosides in HCF, hyperin and quercitrin inhibited both viral replication and TLR signalling in cells.

CONCLUSION

HCF significantly alleviated H1N1-induced ALI in mice, which were associated with its dual antiviral and anti-inflammatory effects via inhibiting influenzal NA activity and TLR signalling. among the four major flavonoid glycosides in HCF, hyperin and quercitrin played key roles in the therapeutic effect of HCF.

Houttuynia cordata polysaccharide alleviated intestinal injury and modulated intestinal microbiota in H1N1 virus infected mice

Houttuynia cordata polysaccharide (HCP) is extracted from Houttuynia cordata, a key traditional Chinese medicine. The study was to investigate the effects of HCP on intestinal barrier and microbiota in H1N1 virus infected mice. Mice were infected with H1N1 virus and orally administrated HCP at a dosage of 40 mg(kg⁻¹(d⁻¹. H1N1 infection caused pulmonary and intestinal injury and gut microbiota imbalance. HCP significantly suppressed the expression of hypoxia inducible factor-1α and decreased mucosubstances in goblet cells, but restored the level of zonula occludens-1 in intestine. HCP also reversed the composition change of intestinal microbiota caused by H1N1 infection, with significantly reduced relative abundances of Vibrio and Bacillus, the pathogenic bacterial genera. Furthermore, HCP rebalanced the gut microbiota and restored the intestinal homeostasis to some degree. The inhibition of inflammation was associated with the reduced level of Toll-like receptors and interleukin-1β in intestine, as well as the increased production of interleukin-10. Oral administration of HCP alleviated lung injury and intestinal dysfunction caused by H1N1 infection. HCP may gain systemic treatment by local acting on intestine and microbiota. This study proved the high-value application of HCP.

Efficacy of Houttuynia eye drops for the treatment of vernal keratoconjunctivitis: A systemic review and meta-analysis protocol

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a common eye disease and can result in permanent decrease or loss of vision. Houttuynia eye drops (HED) is used for the treatment of VKC. However, the clinical evidence of HED has not been well concluded. Herein, we described a proposed systemic review and meta-analysis to evaluate the clinical efficacy of HED for the treatment of VKC.

METHODS

Six electronic databases (Medline, Embase, the Cochrane database, Chinese National Knowledge Infrastructure, Wanfang database, and Chinese Biology and Medicine database) will be searched for randomized controlled trials (RCTs) which evaluating the clinical efficacy of HED for the treatment of VKC. Studies meet the eligibility criteria will be included. Data of the included studies will be extracted and the quality will also be evaluated. Data synthesis will be performed using RevMan software. Sensitivity analysis and publication bias will also be investigated.

RESULTS

This study will provide high-quality systemic review and synthesis of RCTs on efficacy of HED for the treatment of VKC.

CONCLUSION

This systemic review and meta-analysis will conclude the efficacy of HED for the treatment of VKC.

REGISTRATION

PROSPERO CRD42019124737.

Traditional Chinese Medicine as a Potential Source for HSV-1 Therapy by Acting on Virus or the Susceptibility of Host

Herpes simplex virus type 1 (HSV-1) is the most common virus, with an estimated infection rate of 60–95% among the adult population. Once infected, HSV-1 can remain latent in the host for a lifetime and be reactivated in patients with a compromised immune system. Reactivation of latent HSV-1 can also be achieved by other stimuli. Though acyclovir (ACV) is a classic drug for HSV-1 infection, ACV-resistant strains have been found in immune-compromised patients and drug toxicity has also been commonly reported. Therefore, there is an urge to search for new anti-HSV-1 agents. Natural products with potential anti-HSV-1 activity have the advantages of minimal side effects, reduced toxicity, and they exert their effect by various mechanisms. This paper will not only provide a reference for the safe dose of these agents if they are to be used in humans, referring to the interrelated data obtained from in vitro experiments, but also introduce the main pharmacodynamic mechanisms of traditional Chinese medicine (TCM) against HSV-1. Taken together, TCM functions as a potential source for HSV-1 therapy by direct (blocking viral attachment/absorption/penetration/replication) or indirect (reducing the susceptibility to HSV-1 or regulating autophagy) antiviral activities. The potential of these active components in the development of anti-HSV-1 drugs will also be described.