Comprehensive evaluation of the quality of Houttuynia cordata from different producing areas / 中国药房

OBJECTIVE To evaluate the comprehensive quality of Houttuynia cordata from different producing areas. METHODS Using total flavonoids， water-soluble extract， moisture， total ash and acid-insoluble ash as indicators， the entropy weight method was used to objectively weigh each indicator， and the relative correlation degree （r）i calculated by grey correlation method was used as a measure to comprehensively evaluate the quality of H. cordata. RESULTS The weights of total flavonoids， total ash， moisture， acid-insoluble ash， and water-soluble extract were 0.295 5， 0.227 3， 0.188 7， 0.145 1， and 0.143 4， respectively. The weights of total flavonoids and total ash were relatively large. The ri of 30 batches of H. cordata ranged from 0.233 2 to 0.673 9； the average ri of samples from Quanzhou County and Ziyuan County of Guangxi Zhuang Autonomous Region were the highest， which were 0.638 3 and 0.598 7， respectively， followed by samples from Lingchuan County of Guangxi Zhuang Autonomous Region （0.556 1） and Jianshui County of Yunnan Province （0.452 8）. The quality of medicinal materials produced in the above producing areas was generally good and stable. CONCLUSIONS Entropy weight method combined with the grey correlation method can be used to comprehensively evaluate the quality of H. cordata. The overall quality of H. cordata produced in Quanzhou County of Guangxi Zhuang Autonomous Region is the best.

Systems Pharmacology-based Analysis of Anti-tumor Mechanism of Houttuynia cordata / 中国实验方剂学杂志

ObjectiveTo explore the effective components， targets， and mechanism of Houttuynia cordata against lung cancer by means of systems pharmacology and further to provide a reference for the further development and clinical application of this medicinal. MethodChemical components of H. cordata were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform （TCMSP） and the active components were screened based on oral bioavailability （OB） and drug-likeness （DL）. Then the potential targets were predicted， followed by enrichment analysis. Finally， sodium houttuyfonate （SH） was selected for verifying the anti-tumor mechanism. Cell counting kit-8 （CCK-8） assay was used to evaluate the effect of SH on the in vitro proliferation of two lung cancer cell lines： A549 and LLC， and the regulation of tumor-related proteins by SH was verified by Western blot. ResultA total of 7 active compounds and 352 targets of the active components were screened out. According to the enrichment analysis of targets， H. cordata had potential therapeutic effects on cancer. SH had inhibitory effect on both A549 and LLC. Western blot results showed that G1/S-specific Cyclin D1， E1 and cyclin-dependent kinase （CDK）2， CDK4 all tended to be down-regulated， and Janus kinase 2 （JAK2）/signal transducer and activator of transcription 3 （STAT3） also changed significantly. ConclusionH. cordata has the potential anti-tumor effects by arresting the tumor cells in the G1 phase through the JAK2/STAT3 pathway.

Study on the fingerprint establishment ，chemometrics analysis and content determination of dried Houttuynia cordata and its decoction pieces / 中国药房

OBJECTIVE To establish the fingerprints of dried Houttuynia cordata and its decoction pieces ，conduct chemometrics analysis and determine the contents of 5 flavonoids such as neochlorogenic acid. METHODS High performance liquid chromatography （HPLC）method was adopted. Using quercitrin as reference ，HPLC fingerprints of 10 batches of dried H. cordata and its decoction pieces were drawn. The similarity evaluation was conducted by Similarity Evaluation System of TCM Chromatographic Fingerprint （2012 edition），the common peaks were also confirmed. SIMCA-P 14.1 software was applied for principal component analysis （PCA）and partial least square-discriminant analysis （PLS-DA），and the variable importance in projection（VIP）value more than 1 was considered as a standard to screen the differential components affecting the quality of these two products ；meanwhile，the contents of 5 components such as neochlorogenic acid in both products were determined by the same HPLC method. RESULTS There were 20 common peaks in 10 batches of dried H. cordata and 10 batches of its decoction pieces with the similarity values more than 0.960. A total of 5 common peaks were identified ，which were neochlorogenic acid （peak 1）， chlorogenic acid （peak 3），cryptochlorogenic acid （peak 4），rutin（peak 7）and quercitrin （peak 11）. The results of PCA and PLS-DA showed that dried H. cordata could be distinguished from its decoction pieces obviously ；the common peaks with VIP value greater than 1 were as follows ：peak 7（rutin），peak 20，peak 5，peak 13，peak 2，peak 18，peak 3（chlorogenic acid ）， peak 14，peak 17 and peak 19. The linear range of neochlorogenic acid ，chlorogenic acid ，cryptochlorogenic acid ，rutin and quercitrin were 3.77-60.29 μg/mL（r＝0.999 7），1.40-22.42 μg/mL（r＝0.999 5），3.76-60.22 μg/mL（r＝0.999 9），2.19-35.06 μg/mL （r＝0.999 9）and 25.49-407.88 μg/mL（r＝0.999 7），respectively. RSDs of precision ，stability（24 h）and reproducibility E-mail：20190394@njucm.edu.cn tests were all lower than 3％. The average recoveries of the above components in these two products were 98.72％-101.12％ and 98.86％ -100.63％ with RSDs less than 3％（n＝9）. In dried H. cordata ，the average contents of 5 components were 0.87，0.33，0.59，0.61 and 6.17 mg/g，while the average contents were 0.42，0.11，0.26，0.23 and 3.16 mg/g in its decoction pieces ，respectively. CONCLUSIONS HPLC fingerprint and the method of content determination are stable and feasible ，which could be used for the quality control of dried H. cordata and its decoction pieces. Besides ，rutin and other components may be the differential components which could affect the quality of these two products ；the average contents of the 5 flavonoids such as neochlorogenic acid in dried H. cordata all decrease after processing.

Antimicrobial secondary metabolites obtained from endophytic fungi inhabiting healthy leaf tissues of Houttuynia cordata Thunb., an ethnomedicinal plant of Northeast India

Endophytic fungi from healthy leaf tissues of Houttuynia cordata Thunb., a widely used ethnomedicinal plant ofNortheast India, were investigated, and an attempt has been made to characterize the antimicrobial metabolites fromsome potent endophytic strains. Altogether, 56 endophytic fungal isolates were obtained from surface-sterilized leaffragments of H. cordata. The endophytes consisted of fungi belonging to genera Colletotrichum, Curvularia, Bipolaris,Corynespora, and Pseudozyma and non-sporulating fungi categorized as mycelia sterilia. Assay for antimicrobialactivity revealed that 73.07% of the isolates showed activity against the test pathogens in varying degrees, whereas92.32% of the isolates showed anticandida activity against Candida albicans. Among the isolates, two endophyticfungi identified as Colletotrichum coccodes and Phyllosticta capitalensis showed a significant antimicrobial activityagainst all the test pathogens. The metabolites obtained from C. coccodes revealed the presence of different functionalgroups and bioactive compounds such as geranylgeraniol, farnesol, hexacosanol, oleic acid, and squalene. Metabolitesobtained from P. capitalensis also showed various functional groups and the presence of bioactive compound,1-Octacosanol among several others. The study indicated that the ethnomedicinal plants are colonized by the richdiversity of endophytic fungi with antimicrobial activity. A further detailed investigation could practically lead to thedevelopment of pharmaceutical agents in the future.

Chemical constituents in chloroform fraction of Houttuynia cordata / 中国中药杂志

Nine compounds were isolated from chloroform fraction of Houttuynia cordata,and the isolates were identified as follows:( S)-5,6,6 a,7-tetrahydro-2,10-dimethoxy-4 H-dibenzo [DE,G] quinoline-1,9-diol( 1),( +)-isoboldine β-N-oxide( 2),liriotulipiferine( 3),telitoxinone( 4),isoboldine( 5),(-)-clovane-2β,9α-diol( 6),benzoic acid( 7),acantrifoside E( 8),and dibutyl phthalate( 9). Among them,compound 1 was new,and compounds 2-9 were reported from this species for the first time.

Virtual screening of antithrombotic alkaloids from Houttuynia cordata / 中国中药杂志

Antithrombus is one of the effective methods to prevent and treat cardiovascular diseases. Based on the theory of traditional Chinese medicine,the author's previous research and relevant literature,it was found that the alkaloids in Houttuynia cordata has potential antithrombotic effect. However,the pharmacological substance basis and antithrombotic mechanism of H. cordata have not been clarified. In this study,molecular docking was used for virtual screening of antithrombotic alkaloids from H. cordata. Seventy alkaloids selected from H. cordata were screened in the docking ligand data-base with teen thrombosis targets with known crystal structures as the receptors. In addition,the small-molecule approved or to be approved drugs of targets from Drug Bank database were set as a positive reference with minimum score(S value) of each target's approved or to be approved drugs as threshold. The Dock module in Molecular Operating Environment(Version 2016) software was applied to screen the potential active compounds which their scores(S value) were lower than the minimum score of reference. At last the mechanism of antithrombotic effect was preliminarily revealed by compared the main active sites of the test alkaloids with original ligands and references. This study provided some useful information to development of antithrombus drugs.

Anti-lipopolysaccharide effect of ultrafine granular powder of Houttuynia cordata / 中草药

Objective: To study the anti-lipopolysaccharide (LPS) effect of the ultrafine granular powder of Houttuynia cordata and the effects in comparison with traditional decoction pieces. Methods: BALB/c mice were injected with LPS through nose to establish lung inflammation model. The number of leukocytes in mice whole blood was examined, and the degree of the inflammation of lung tissue by pathology was observed. Rat inflammatory model was induced by injection of LPS into tail vein. The number of leukocytes in mice whole blood, content of LPS in plasma were examined, the content of IL-1β, IL-6, and TNF-α in serum were detected by enzyme-linked immunoadsordent assay (ELISA). The limulus test method was used to detect the anti- lipopolysaccharide effect of the ultrafine granular powder of H. cordata in vitro. Results: The ultrafine granular powder of H. cordata and traditional decoction pieces can reduce the level of leukocytes in mice whole blood in various degrees, and alleviated the infiltration of inflammatory cells in pathological lung tissue, and there was a positive dosage dependent relation. For the two decoction pieces, the number of leukocytes in rat whole blood, the content of LPS in plasma, the levels of IL-1β, IL-6, and TNF-α in serum decreased in different degrees were found. Compared with traditional decoction pieces group, the content of IL-1β and TNF-α of serum in ultrafine granular powder group were significant decreased. The ultrafine granular powder of H. cordata showed better anti-inflammatory activity than traditional decoction pieces in vitro at the same concentration and same dilution ratio. Conclusion: The ultrafine granular powder of H. cordata has satisfactory anti-lipopolysaccharide effect, and the effect is better than traditional decoction pieces in some extent.

Houttuynia cordata polysaccharide alleviated intestinal injury and modulated intestinal microbiota in H1N1 virus infected mice / 中国天然药物

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(d. 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.

Preparation of thermosensitive intestinal gels of Houttuynia cordata volatile oils HPCD inclusion compound / 中成药

AIM To prepare the thermosensitive intestinal gels of Houttuynia cordata Thunb volatile oils hydroxypropyl-β-cyclodextrin (HPCD) inclusion compound.METHODS For the gels prepared by cold dissolving method,poloxamer 407 consumption and poloxamer 188 consumption were taken as influencing factors,together with phase transition temperature as an evaluation index,central composite design-response surface method was applied to optimizing the formulation.With 2-undecanone as an index component,the gels' dissolution rate and in vitro release rate were investigated by non-membrane dissolution method and dialysis bag method respectively,whose stability was then evaluated by high temperature (40,60 ℃),low temperature (4 ℃),strong light [(4 500 ±500) 1x] and acceleration (three months) tests.RESULTS The optimal conditions were determined to be 20.61％ for P407 consumption and 3.03％ for P188 consumption,the phase transition temperature was 36.5 ℃.Within the time range of 30-150 min,the HPCD inclusion compound gels exhibited higher accumulative dissolution rate than the volatile oils gels,which tended to be consistent in 150-210 min,but the former exhibited higher accmulative release rate (0-50 h) than the latter all the time.The obtained gels showed good stability at low temperature,whose appearance,characteristic (except for high temperature) and pH were stable at high temperature,strong light and acceleration with obviously decreased 2-undecanone content.CONCLUSION The thermosensitive intestinal gels of Houttuynia cordata Thunb volatile oils HPCD inclusion compound should be stored at low temperature (4 ℃).

Beneficial effects of polysaccharides on "two-hit" acute lung injury and endotoxic fever in rats associated with anti-complementary activities

Thunb. is a traditional herb used for clearing heat and eliminating toxins, and has also been used for the treatment of severe acute respiratory syndrome (SARS). the crude polysaccharides (CHCP) exhibited potent anti-complementary activity through both the classical and alternative pathways by acting on components C3 and C4 of the complement system without interfering with the coagulation system. This study was to investigate the preventive effects of CHCP on acute lung injury (ALI) induced by hemorrhagic shock plus lipopolysaccharide (LPS) instillation (two-hit) and LPS-induced fever in rats. CHCP significantly attenuated pulmonary injury in the "two-hit" ALI model by reducing pulmonary edema and protein exudation in bronchoalveolar lavage fluid (BALF). In addition, it reduced the deposit of complement activation products in the lung and improved oxidant-antioxidant imbalance. Moreover, CHCP administration inhibited fever in rats, reduced the number of leukocytes and restored serum complement levels. The inhibition on the inappropriate activation of complement system by CHCP may play an important role in its beneficial effects on inflammatory diseases. The anti-complementary polysaccharides are likely to be among the key substances for the heat-clearing function of .

Molecular cloning, sequence identification, and expression analysis of HMGR gene in Houttuynia cordata / 中草药

Objective To clone and analyze the expression difference sequence of 3-hydroxy-3-methylglutaryl coenzyme A redutase (HMGR) gene from Houttuynia cordata. Methods The sequence of HMGR was cloned from H. cordata by RT-PCR strategy. The physical and chemical properties, secondary structure, and three-dimensional structure of the HMGR protein were forecasted and analyzed, and its structure and function were predicted. And the different expression of HMGR gene in rhizome, stems, leaves, and flowers were analyzed by fluorescent quantitative PCR. Results The cDNA contained a 1 626 bp open reading frame and encoded a predicted protein of 541 amino acids. Two transmembrane regions and no signal peptide were present in HMGR. Relative real-time PCR analysis indicated that HMGR showed the highest transcript abundance in the flowers, and the lowest levels in the rhizomes. Conclusion This study cloned and expression analyzed HMGR gene from H. cordata for the first time. The result will provide a foundation for exploring the mechanism of terpenoid biosynthesis in H. cordata.

Endophytic fungus strain 28 isolated from Houttuynia cordata possesses wide-spectrum antifungal activity

Abstract The aim of this paper is to identify and investigate an endophytic fungus (strain 28) that was isolated from Houttuynia cordata Thunb, a famous and widely-used Traditional Chinese Medicine. Based on morphological methods and a phylogenetic analysis of ITS sequences, this strain was identified as Chaetomium globosum. An antifungal activity bioassay demonstrated that the crude ethyl acetate (EtOAc) extracts of strain 28 had a wide antifungal spectrum and strong antimicrobial activity, particularly against Exserohilum turcicum (Pass.) Leonard et Suggs, Botrytis cinerea persoon and Botrytis cinerea Pers. ex Fr. Furthermore, the fermentation conditions, extraction method and the heat stability of antifungal substances from strain 28 were also studied. The results showed that optimal antifungal activity can be obtained with the following parameters: using potato dextrose broth (PDB) as the base culture medium, fermentation for 4–8 d (initial pH: 7.5), followed by extraction with EtOAc. The extract was stable at temperatures up to 80 °C. This is the first report on the isolation of endophytic C. globosum from H. cordata to identify potential alternative biocontrol agents that could provide new opportunities for practical applications involving H. cordata.

Analysis on SSR loci information in transcriptome of Houttuynia cordata and its polymorphism / 中草药

Objective: Simple sequence repeats (SSR) loci information in the transcriptome of Houttuynia cordata was analyzed in this study and the more powerful tools were provided for molecular marker-assisted breeding in this plant. Methods: SSR loci were searched in all 63 954 unigenes by using MISA. SSR loci information was analyzed and SSR primers were designed by Primer 3. Furthermore, 50 pairs of primers were randomly selected for the polymorphic analysis on 16 H. cordata plants collected from different habitats. Results: A total of 4 800 SSRs were found in the transcriptome of H. cordata, which distributed in 4 413 unigenes with the distribution frequency of 7.51%. Tri-nucleotide repeat was the main type, accounted for as much as 41.54% of all SSRs, followed by mono-nucleotide repeat motif (27.35%). The mononucleotide repeat motifs of A/T were the predominant repeat type (27.0%). A total of 3068 pairs of SSR primers were designed by using Primer 3. For validating the availability of those SSR primers, 50 pairs of primers were randomly selected for PCR amplification. Among them, 43 pairs of primers (86.0%) produced clear and reproductive bands, which showed polymorphism, and 16 H. cordata plants collected from different places were divided into two groups by UPGMA. Conclusion: There are numerous SSRs in H. cordata transcriptome with high frequency and various types, this will provide the basis for study on genetic diversity and genetic map for H. cordata.

Rapid PCR identification of Houttuynia cordata and Gymnotheca chinensis / 中草药

Objective: For rapid identification of Houttuynia cordata and Gymnotheca chinensis, the specific PCR for mutual authentication of them was established based on the SNPs in matK sequence. Methods: H. cordata and G. chinensis samples from different origins were collected, total DNA of all samples was extracted, and the matK gene was seqenced. SNPs in the matK sequences of all the samples were found by ClustulX 2.1 program. Primers for identifying H. cordata and G. chinens were designed according to the SNP site, and specific PCR method was established to identify them, for rapid detection by addition of SYBR Green I dye. In addition, constructing a multi-PCR reaction system, and then the PCR reaction system was optimized. Results: The band special for H. cordata (185 bp) and band special for G. chinensis (389 bp) were found using specific PCR reaction and multi-PCR reaction, and SYBR Green I dye can be used for rapid detection. Conclusion: The multi-PCR reaction system could be used to identify H. cordata and G. chinensis.

Isolation and identification of anti-inflammatory constituents from Houttuynia cordata / 中国药科大学学报

@#Ten compounds were isolated and purified from the ethyl acetate fraction of Houttuynia cordata by silica gel and ODS column chromatographies. The chemical structures of the compounds were identified on the basis of physicochemical properties as well as spectral data. These isolated compounds were elucidated as sequinoside L(1), a new phenolic glycoside, together with nine known compounds, including sequinoside K(2), methyl chlorogenate(3), chlorogenic acid(4), hydroquinone(5), vanillic acid(6), hyperin(7), isoquercitrin(8), quercetin(9), and quercitrin(10). In addition, the anti-inflammatory activities of compounds 1-10 were evaluated in LPS-induced RAW264. 7 macrophages. Among them, compounds 1, 2, 6 and 9 showed potent anti-inflammatory activity which was similar to that of positive control dexamethasone.

Evaluation of antiviral activities of Houttuynia cordata Thunb. extract, quercetin, quercetrin and cinanserin on murine coronavirus and dengue virus infection

Objective: To evaluate the in vitro activities of the ethyl acetate (EA) fraction of Houttuynia cordata (H. cordata) Thunb. (Saururaceae) and three of its constituent flavonoids (quercetin, quercitrin and rutin) against murine coronavirus and dengue virus (DENV). Methods: The antiviral activities of various concentrations of the EA fraction of H. cordata and flavonoids were assessed using virus neutralization tests against mouse hepatitis virus (MHV) and DENV type 2 (DENV-2). Cinanserin hydrochloride was also tested against MHV. The EA fraction of H. cordata was tested for acute oral toxicity in C57BL/6 mice. Results: The EA fraction of H. cordata inhibited viral infectivity up to 6 d. Cinanserin hydrochloride was able to inhibit MHV for only 2 d. The 50% inhibitory concentrations (IC

Clinical Observation of Houttuynia cordata Eye Drops Combined with Olopatadine Eye Drops in the Treat-ment of Allergic Conjunctivitis / 中国药房

OBJECTIVE:To observe clinical efficacy and ADR of Houttuynia cordata eye drops combined with Olopatadine eye drops in the treatment of allergic conjunctivitis. METHODS:160 eyes with allergic conjunctivitis were randomly divided into observation group and control group,with 80 eyes in each group. The control group was given olopatadine eye drops,and observa-tion group was additionally given H. cordata eye drops(medication interval>10 min)on the basis of control group. Both groups were treated for 14 days. Symptoms and signs of 2 groups were observed and scored before treatment and 14 d after treatment. Ef-fective rates of 2 groups were calculated,and the occurrance of ADR was observed. RESULTS:Compared with before treatment, symptoms and sings score of 2 groups were decreased,with statistical significance (P<0.01 or P<0.05);the decrease of two score in observation group were more significant than in control group,with statistical significance (P<0.05);effective rates of control group and observation group were 37.50%and 77.50%,with statistical significance(P<0.05). CONCLUSIONS:H. corda-ta eye drops combined with olopatadine eye drops can ameliorate clinical symptoms and signs of allergic conjunctivitis patients sig-nificantly,and improve therapeutic efficacies without obvious ADR.

Cloning, expression, and bioinformatics analysis of acetyl-CoA C-acetyltransferase gene in Houttuynia cordata / 中草药

Objective: Acetyl-CoA C-acetyltransferase (AACT) is the initial enzyme in the terpenoid biosynthesis pathway of mevalonate (MVA), two units of acetyl-CoA were catalyzed to acetoacetyl-CoA. To clone the full length cDNA of AACT gene and carry out the bioinformatics analysis and expression analysis in order to provide the basis on resolving the mechanism of biosynthesis for terpenoid secondary metabolites from Houttuynia cordata. Methods: The cDNA sequence of AACT gene was obtained from H. cordata by using RT-PCR strategy. And the different expression of AACT gene in the rhizomes, stems, leaves, and flowers of H. cordata was analyzed by fluorescent quantitative PCR. Results: The cDNA contains a 1 218 bp open reading frame and encodes a predicted protein of 405 amino acids. No transmembrane region and signal peptide were present in AACT protein by bioinformatics prediction. Relative real-time PCR analysis indicated that AACT gene showed the highest transcript abundance in the stems and rhizomes of H. cordata lower levels in the flowers and leaves, the values of them were 1.49, 0.96, 0.20, and 0.10, respectively. Conclusion: This AACT gene is cloned from H. cordata for the first time. The results will provide a foundation for exploring the mechanism of the gene in terpenoid biosynthesis and metabolism in H. cordata.

Cloning and differential expression of 1-deoxy-D-xylulose-5-phosphate reductoisomerase gene in Houttuynia cordata / 中草药

Objective: To clone the 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) gene from Houttuynia cordata and analyze the differential expression. Methods: The cDNA sequence of DXR was cloned from H. cordata by using RT-PCR strategy. The physical and chemical properties, secondary structure, and three-dimensional structure of the DXR protein were forecasted and analyzed, and its function was predicted. The differential expression of DXR gene in rhizome, stems, leaves, and flowers was analyzed by fluorescent quantitative PCR. Results: The cDNA contained a 1 416 bp open reading frame and encoded a predicted protein of 471 amino acids. Bioinformatics predicted that no transmembrane region and signal peptide were present in DXR. Relative real-time PCR analysis indicated that DXR showed the highest transcript abundance in leaves, moderate level in rhizomes, lower level in stems, and the lowest level in flowers. Conclusion: This study clones DXR gene from H. cordata for the first time, and provides a foundation for exploring the mechanism of this gene for the terpenoid biosynthesis in H. cordata.

Cloning and expression analysis of 1-deoxy-D-xylulose-5-phosphate synthase 1 gene in Houttuynia cordata / 中草药

Objective: To clone the 1-deoxy-D-xylulose-5-phosphate synthase 1 (DXS1) gene from Houttuynia cordata and to analyze the expression difference. Methods: The cloning primers were designed based on the transcriptome dataset of H. cordata, one unique sequence encoding DXS1 was discovered. The sequence of DXS1 was cloned from H. cordata by RT-PCR. The physicochemical properties, secondary structure, and three-dimensional structure of the DXS1 protein were forecasted and analyzed, and its structure and function were predicted. And the different expression levels of DXS1 gene in rhizome, stems, leaves, and flowers were analyzed by fluorescent quantitative PCR. Results: The cDNA (named as DXS1) contains a 2 172 bp open reading frame and encodes a predicted protein of 723 amino acids. No transmembrane region and signal peptide were present in DXS1. The conserved domain of DXS was present in DXS1. Relative real-time PCR analysis indicated that DXS1 showed the highest transcript abundance in the flowers, moderate level in the leaves, lower level in the rhizomes, and the lowest level in the stems. Conclusion: This study cloned the DXS1 gene from H. cordata for the first time. The results will lay a foundation for exploring the mechanism of terpenoid biosynthesis in H. cordata plants.