Chemical composition and biological activity of Houttuynia cordata

Houttuynia cordata is an important traditional Chinese medicine.It is widely used for clearing heat and detoxification,reducing swelling and treating sores,diuresis and dehumidification.It is also used to treat lung carbuncles,ulcers,hemorrhoids,rectal bleeding,spleen and stomach heat,which are caused by excess heat,heat toxicity,dampness,and disease heat.Modern pharmacological experiments have shown that H.cordata has antibacterial,antiviral,immune enhancing,diuretic and other effects.This article reviews the chemical components and biological activities of H.cordata to provide reference for clinical application.

Isolation and Identification of Houttuynia cordata Endophytic Bacteria and Study of Antibiotic Activity

[Objectives]To further explore the resources of biocontrol strains and provide new options for the control of pathogenic bacteria.[Methods]Houttuynia cordata endophytic bacteria were isolated and identified,and the antibiotic activity was explored.[Results]There are 8 strains(H1-H8)of endophytic bacteria isolated from the healthy plants of H.cordata,which had an antagonistic effect on the pathogenic bacteria.According to the gene sequence,the 8 strains were identified as Stenotrophomonas,Pseudomonas,and Bacillus,which strongly inhibited Colletotrichum(HC1),Fusarium(HC2),and Rhizoctonia(HC5)of H.cordata.On the PDA culture dish,the inhibition diameter of the 8 strains on Colletotrichum,Fusarium,and Rhizoctonia was 6,8,and 5 mm,respectively.[Conclusions]Pathogenic bacteria and endophytic bacteria inoculated with H.cordata seedlings showed that endophytic bacteria have certain antagonistic activity,and have the potential for development and application.

Expression of Exogenous Antimicrobial Peptide and Resistance to Stem Rot Disease of Houttuynia cordata Thunb.

[Objective] This study was to identify the expression of exogenous antimicrobial peptide in transgenic Houttuynia cordata Thunb. plants,and analyze their resistance to stem rot disease. [Methods] SDS-PAGE and Western blot analysis were employed to detect expression of exogenous antimicrobial peptide in transgenic H. cordata plants. Both wild type and transgenic H. cordata plants were inoculated with different concentrations of Rhizoctonia solani spores for detecting their resistance. [Results] The exogenous antimicrobial peptide was detected at translation level. The optimal parameters for detecting the resistance of transgenic H. cordata plants to R. solani was inoculation of spores at a concentration of 3×105 ind./ml and cultured for three days. The results showed that resistance of transgenic H. cordata plants to R. solani was enhanced in comparison with CKs. [Conclusion] Expression of exogenous antimicrobial peptide can enhance the resistance of transgenic H. cordata plants to stem rot disease.

Standard Operating Procedure of Houttuynia cordata Thunb.Plastic Greenhouse Cultivation

This standard operating procedure stipulated the natural condition of pro- ducing area, cultivation technique, disease and pest control, harvest, quality stan- dard, packaging, transportation and storage of H. cordata, in order to provide a ba- sis for the standard cultivation of H. cordata.

Systematic analysis of components and contents in Houttuynia cordata Thunb

Objective:This study aims to provide the material basis for the molecular mechanism of Yuxingcao(Houttuynia cordata Thunb,HCT)through the method of evidence-based study to summarize the natural constituents isolated from HCT.Methods:We searched CNKI,Wanfang,VIP,Pubmed and relevant conference compilations.The keywords were'Yuxingcao or Houttuynia cordata Thunb'and'components'or'ingredients'or'constituent'or'volatile oil'or'flavonoids'or'terpene'or'content',both in Chinese and English.According to the inclusion and exclusion criteria,the reported compositions and contents have been summarized,and SPSS software was used to draw the boxplot of contents.Results:A total of 603 natural compounds in 11 categories were obtained from pooled articles.In the diverse components,the number of aliphatic compounds(n=259)and terpenoids(n=158)are more than those of flavonoids(n=26),alkaloids(n=42)and aromatics(n=42).While,in the part of volatile oils of HCT,the largest components are aliphatic compounds(mainly distributed on the ground)and terpenoids(mainly distributed in the underground).Although,methyl n-nonylketone is distributed in the whole herb plant,a large proportion is present in the underground parts.As for non-volatiles,the flavonoid content(mainly distributed on the ground)was the highest,among which quercetin and its glycosyl derivatives were the prominent.Conclusion:The results of this study provide a more comprehensive material basis for the further study of HCT.It is also helpful to explain the mechanisms of anti-oxidant,anti-inflammatory,anti-bacterial,anti-viral and anti-cancer effects from the molecular target and molecular network levels.

Effects of Houttuynia Cordata Thumb on Expression of BMP-7 and TGF-β_1 in the Renal Tissues of Diabetic Rats

Objective： To explore the effects of Houttuynia Cordata Thumb （HCT 鱼腥草 Yu Xing Cao） on expression of transforming growth factor-β1 （TGF-β1） and bone morphogenetic protein-7 （BMP-7） in the renal tissues of diabetic rats. Methods： The diabetic rats induced by intravenous injection of streptozotocin（STZ） were randomly divided into a model group, a HCT group and a lotensin group, with normal rats designated as the controls. 8 weeks later, the ratio of kidney weight to body weight, the glomerular area, the excretion of β 2-microglobin （β2-MG） in 24-hr urine, the albumin excretion in 24-hr urine, and creatinine clearance rate （CCR） were investigated. The expression of TGF- β 1, BMP-7 and collagen I in the renal tissues was observed with the immunohistochemical method and by the semi-quantitative assay. Results： The overgrowth of glomerulus, the excretion of β 2-MG in 24-hr urine, the albumin excretion rate in 24-hr urine and CCR in the HCT group significantly reduced （P〈0.05）, and the expression of TGF-β1 and collagen I significantly decreased （P〈0.05）, but BMP-7 significantly increased （P〈0.05） in the HCT group as compared with those in the model group, with no significant difference as compared with the lotensin group （P〉0.05）. Conclusion： HCT has a protective effect on the renal tissues in diabetic rats, which is probably correlated with the decrease of the expression of TGF-β1 and collagen I and with the increase of the expression of BMP-7 in the renal tissues.

Effects of frying oil and Houttuynia cordata thunb on xenobiotic-metabolizing enzyme system of rodents

AIM: To evaluate the effects of frying oil and Houttuynia cordata Thunb (H. cordata), a vegetable traditionally consumed in Taiwan, on the xenobiotic-metabolizing enzyme system of rodents. METHODS: Forty-eight Sprague-Dawley rats were fed with a diet containing 0%, 2% or 5% H. cordata powder and 15% fresh soybean oil or 24-h oxidized frying oil (OFO) for 28 d respectively. The level of microsomal protein, total cytochrome 450 content (CYP450) and enzyme activities including NADPH reductase, ethoxyresorufin 0-deethylase (EROD), pentoxyresorufin 0-dealkylase (PROD), aniline hydroxylase (ANH), aminopyrine demethylase (AMD), and quinone reductase (QR) were determined. QR represented phase Ⅱ enzymes, the rest of the enzymes tested represented phase Ⅰ enzymes. RESULTS: The oxidized frying oil feeding produced a significant increase in phase Ⅰ and Ⅱ enzyme systems, including the content of CYP450 and microsomal protein, and the activities of NADPH reductase, EROD, PROD, ANH, AMD and QR in rats (P<0.05). In addition, the activities of EROD, ANH and AMD decreased and QR increased after feeding with H. cordata in OFO-fed group (P<0.05). The feeding with 2% H. cordata diet showed the most significant effect. CONCLUSION: The OFO diet induces phases I and II enzyme activity, and the 2% H. cordata diet resulted in a better regulation of the xenobiotic-metabolizing enzyme system.

Houttuynia cordata Thunb rescues retinal ganglion cells through inhibiting microglia activation in a rat model of retinal ischemia-reperfusion

AIM:To determine whether Houttuynia cordata Thunb(HCT)can increase the survival of the retinal ganglion cells(RGCs)and inhibit microglia activation following retinal ischemia-reperfusion(RIR)injury.METHODS:Rat model of RIR was induced by transient elevation of the intraocular pressure(IOP).HCT was orally administered for 2 d before the performance of retinal RIR model and once a day for the next 14 d.After 14 d of RIR injury,the rats were sacrificed for further analysis.Survival RGCs were stained with haematoxylin and eosin(H&E).Apoptosis of RGCs was detected by TUNEL staining.Retinal function was examined by flash-electroretinography(F-ERG).Retinal microglia were labeled using Iba-1,one specific marker for microglia.The m RNA expression levels of inducible nitric oxide synthase(i NOS),tumor necrosis factor alpha(TNF-α),and interleukin 1 beta(IL-1β)were assessed by quantitative real time reverse transcription polymerase chain reaction(q RT-PCR).RESULTS:Systemic HCT treatment significantly reduced RGCs death by H&E staining and exhibited an anti-apoptotic effect as assessed by TUNEL staining at day 14 after RIR injury.HCT greatly improved the retinal function as examined by F-ERG.The number of activated microglia significantly increased after RIR injury,which was significantly attenuated by HCT treatment.Besides,RIR injury induced a strong upregulation of pro-inflammatory genes TNF-α,i NOS and IL-1βm RNAs at day 14 post injury,which was suppressed by HCT.CONCLUSION:Neuroprotective effects of HCT encourage the survival of RGCs through inhibiting microglia activation due to RIR injury.Together these results support the use of HCT as promising therapy for the ischemic events of the retina diseases.

Determination of Total Flavonoids and Its Antioxidant Ability in Houttuynia cordata

The total flavonoids of Houttuynia cordata are determined by UV-Vis spectrophotometry. The ex-traction condition of flavonoids from Houttuynia cordata includes: the extraction temperature is 70℃, solid-liquid ratio is 1:20, solvent is 80% ethanol, extraction time is 65 min. We studied the antioxidation of flavonoids in Houttuynia cordata, and results showed that flavonoids had strong reducing capacity, hydroxyl free radical scavenging activity and the superoxide anion radical scavenging ability, thus can provide a basis for the development of natural antioxidants.

Network pharmacology-based analysis on three amicoumacin-type isocoumarin compounds from an endophytic bacterium in Houttuynia cordata

Amicoumacin isocoumarin-type compounds are mainly derived from the secondary metabolites of Bacillus bacteria,and have potential biological activities such as antibacterial,anti-tumor,anti-inflammatory,and anti-ulcer.In our previous research,three amicoumacin-type isocoumarin compounds,Paenicoumacin A,Paenicoumacin B,and Paenicoumacin C(B and C are novel),were isolated from an endophytic bacterium in Houttuynia cordata.In this study,network pharmacology and bioinformatics techniques were used to analyze the potential activities of amicoumacin compounds in the treatment of liver cancer.These compounds were found to mainly regulate cellular oxidative stress,cancer process,nucleic acid metabolism,nutritional metabolism and other pathways.The findings provide useful information for subsequent experimental verification.

Responses of Houttuynia cordata Thunb.to Tetracycline Stress

[Objectives]To study responses of Houttuynia cordata Thunb.to tetracycline(TC)stress in a sterile environment.[Methods]Aseptic H.cordata seedlings were cultured in the medium which added the different concentrations of TC,and then the contents of chlorophyll and malondialdehyde(MDA),and activity of catalase(CAT),peroxidase(POD)and superoxide dismutase(SOD)of H.cordata leaves were measured.[Results]Compared with the CK,the contents of chlorophyll of H.cordata leaves decreased,and the accumulation of MDA,and the activity of CAT,POD and SOD in H.cordata leaves increased when H.cordata was stressed by different concentration of TC.[Conclusions]The growth,metabolism and physiology of H.cordata were affected by the stress of TC.More importantly,this proved an insight into the effect or harm of undegraded antibiotics in the soil and water in the natural environment to plant growth all the time.

Study on the Effect of Aqueous Extract of Houttuynia cordata on Serum TNF-αand IL-6 Content in Mice Infected with Five Common Pathogenic Bacteria

[Objectives]To observe the effect of aqueous extract of Houttuynia cordata on the content of serum TNF-αand IL-6 in mice with abdominal infection caused by Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa,Proteus vulgaris and Klebsiella pneumoniae,so as to investigate the antibacterial effect of aqueous extract of Houttuynia cordata in vivo.[Methods]A total of 72 KM mice were randomly divided into six groups:model group,blank group,cefdinir dispersible tablet group(0.25 g/kg),high,medium and low dose groups of aqueous extract of Houttuynia cordata(40,20,10 g/kg crude drug).There were 12 mice in each group,half male and half female,continuously given intragastric administration for three days,once a day.The blank group and the model group were intragastrically infused with normal saline,and the other groups were given corresponding drugs with a volume of 0.02 mL/g.After 30 min of administration on the third day,the mice were injected intraperitoneally with 0.5 mL of bacterial suspension to make bacterial infection.The mice in the blank group were intraperitoneally injected with the same amount of normal saline,followed by intragastric administration 6 h after intraperitoneal injection and intragastric administration again after 24 h.The mice were observed for three days,and the changes of body weight before and after infection were recorded.On the fourth day of infection,eyeball blood was taken,serum was separated,and the concentration of inflammatory factors TNF-αand IL-6 in serum was determined.[Results]Compared with the model group,the high,medium and low dose groups of H.cordata aqueous extract had protective effects on mice with abdominal infection caused by S.aureus,E.coli,P.aeruginosa,P.vulgaris and K.pneumoniae,and decreased the content of TNF-αand IL-6 in serum.[Conclusions]The aqueous extract of H.cordata had a certain antibacterial effect on acute abdominal infection caused by S.aureus,E.coli,P.aeruginosa,P.vulgaris and K.pneumoniae,and its mechanism was related to TNF-αand IL-6.

Effects of Climate Factors in Greenhouses on the Growth Development and Quality of Houttuynia cordata Thunb.

[Objectives]This study was conducted to demonstrate whether greenhouse planting can solve the problem of insufficient supply of fresh H.cordata Thunb.in winter and spring.[Methods]The effects of meteorological factors on the growth and quality of H.cordata Thunb.were analyzed.[Results]The highest temperature and lowest temperature in greenhouses were 6-12℃and 5-10℃higher than those in the open fields,respectively,and the average temperature difference between the greenhouses and the open fields was large in the early stage,but small in the late stage.The effective accumulated temperature≥10℃was 3463℃in the greenhouses and 2046℃in the open fields.Although the humidity in the open fields was higher than that in the greenhouses,the humidity in the greenhouses was relatively stable and that in the open field changed greatly.The light intensity of the greenhouses was lower than that of the open fields.In terms of the periods from film covering day to seedling emergence,seedling emergence to full emergence,and full emergence to crop closure,greenhouse planting was shortened by 47,11,and 5 d,respectively,compared with open field planting,but the period from crop closure to flowering was extended by 40 d.The plant height of the plants planted in the greenhouses reached 0.1 cm on January 7,while those planted in the open fields did not have seedlings until February 25,and the plant height,daily growth rate,yield and effective components in volatile oil of the plants planted in the greenhouses were significantly higher than those planted in the open fields.The growth,development and quality of H.cordata Thunb.reached the extremely significant or significant level with temperature,but had no significant correlation with humidity and light intensity,indicating that temperature had the greatest impact on the growth,development and quality of H.cordata Thunb.when planted in the greenhouses.[Conclusions]This study provides a theoretical basis for protected cultivation and explores new planting methods for the further development of its industry.

Effects and safety of Chinese herbals containing Houttuynia cordata Thunb in the treatment of lung cancer:a systematic review

Objective:This study systematically evaluates the efficacy and safety of Houttuynia cordata in the treatment of lung cancer in order to provide clinical data support for better application of Houttuynia cordata.Methods:PubMed,EMbase,Web of Science,ScienceDirect,Scopus,CNKI,WanFang Data,VIP and SinoMed were used to retrieve clinical observations and clinical controlled studies of Houttuynia cordata in the treatment of lung cancer.The retrieval time ranges from database building to January 2019.Two researchers independently screened literature,extracted data and conducted computational analysis.Result:In the clinical observational study,12 literatures of pure Chinese medicine treatment(1473 patients)and 4 literatures of combined Chinese and Western medicine treatment(193 patients)were compared.The total effective rate and total stable rate of combined Chinese and Western medicine treatment for tumour control were better,but the total improvement rate of quality of life of combined Chinese and Western medicine treatment was lower than that of pure Chinese medicine,and the incidence of adverse reactions such as bone marrow suppression and gastrointestinal tract reaction was also higher than that of pure Chinese medicine.Chinese medicine In the clinical control study,8 articles(567 patients)in the treatment group were treated by Chinese medicine and 9 articles in the treatment group(530 patients)were treated by combination of Chinese and Western medicine.Compared with Chinese medicine group,the total effective rate and total stability rate in the control of tumor size were higher in the combination of Chinese and Western medicine;The survival rate of 0.5~2 years was higher,and the total effective rate of body weight gain was slightly higher in the combination of Chinese and Western medicine.At the same time,the incidence of side effects was significantly higher than that of pure Chinese medicine treatment group.In addition,compared with the control group,the incidence of all side effects in the pure Chinese medicine group was lower.Compared with the control group,besides"bleeding","oral reaction"and"skin reaction",the probability interval of side effects in the treatment group was less than that in the control group,and the degree of side effects was also less than that in the chemotherapy group.Conclusion:In the treatment of lung cancer,the use of herbs containing Houttuynia cordata combined with western medicine or radiotherapy and chemotherapy not only has good curative effect,but also reduces toxicity and side effects.Therefore,the combination of herbs with western medicine has unique advantages,which deserves further in-depth research and development.

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 b-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.

鱼腥草地上部分和根部提取物抑制尖吻蝮蛇毒的比较

研究鱼腥草Houttuynia cordata Thunb地上部分提取物和根部提取物对尖吻蝮Deinagkistrodon acutus蛇毒抑制作用。采用体外实验检测两种提取物对尖吻蝮蛇毒中主要酶类(蛋白水解酶、磷脂酶A2(PLA 2)、透明质酸酶等)的抑制作用;采用体内实验检测其对尖吻蝮蛇毒诱导体内毒性(出血、水肿、组织坏死和致死毒性)的抑制作用。鱼腥草地上部分提取物对尖吻蝮蛇毒蛋白水解酶、磷脂酶A2和透明质酸酶活性具有显著的抑制作用,同时能有效抑制促凝活性和纤维蛋白原水解活性;在体内,能够使尖吻蝮蛇毒引起的出血、水肿、组织坏死和致死毒性明显减弱。相比之下,鱼腥草根部提取物也表现出类似的抑制模式,但在相同浓度下其抑制效果均低于地上部分提取物。植物化学成分分析表明,两种提取物中均含有生物碱、蒽醌类物质和蛋白质;地上部分提取物中含有黄酮、多酚、单宁、三萜、甾醇和皂苷类物质,而根部提取物中缺少这些物质。实验结果首次验证了鱼腥草地上部分及根部对尖吻蝮蛇毒的抑制作用,并证实地上部分比根部在抑制毒液的主要酶类和体内毒性方面更为有效,表明鱼腥草地上部分可以作为一种潜在资源用于开发治疗毒蛇咬伤的解毒剂。

不同肥料配施对鱼腥草产量及品质的影响

为了优化当阳市鱼腥草(Houttuynia cordata Thunb.)田间施肥管理,开展了不减少钾肥施用量,分别减少不同氮磷肥施用量及增施生物菌肥等不同肥料配施对鱼腥草产量及品质影响的研究。结果表明,在降低化肥施用量13.7%的同时增施生物菌肥,鱼腥草地下茎的可溶性蛋白质比常规施肥(CK)增加44.2%,维生素C含量比常规施肥(CK)增加33.6%,对生长期的株高和茎粗影响不显著,产量较对照高2.3%。仅减少化肥施用量不增施生物菌肥时,鱼腥草生长指标及产量均有不同程度的降低。因此,不减少钾肥的情况下,减施氮磷肥13.7%、增施生物菌肥更适合目前当阳市鱼腥草种植中对肥料的需求,可促进鱼腥草高效绿色生产。

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

Houttuynia cordata 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). In vitro, the crude H. cordata 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 oxidantantioxidant 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 heatclearing function of H. cordata.

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.

Structures,Components and Functions of Secretory Tissues in Houttuynia cordata

Houttuynia cordata Thunb., traditionally used as a therapeutic plant in folk medicine, has shown antioxidant and anticancer activities. The species, as a core component of paleoherbs, is normally characterized based on the presence of different types of secretory tissue： oil cells, three types of secretory cells and glandular hairs. The aim of this work was to study the structural, componential, and the functional characteristics of the secretory tissues in both the floral and vegetative parts. The results indicate that oil cells and secretory cells are distributed in all organs of the plant, while glandular hairs are situated on the aerial stems and leaves. Both oil cells and glandular hairs initiate from the protoderm, but their developmental processes are different. Although three types of secretory cells initiate from different primary meristems, the developmental patterns of different secretory cells are the same. Also, although the origins of secretory cells are different from oil cells, their early developmental processes are the same. Histochemical results show that oil cells, secretory cells and glandular hairs produce flavonoids, phenolic compounds, tannins, lipids, aldehyde and ketone-compounds. In addition, there are terpenoids and pectic-like substances in oil cells, alkaloids in secretory cells of aerial stems, and terpenoids and alkaloids in glandular hairs. These compounds play very important roles in protecting plants from being eaten by herbivores （herbivory） and infected by microbial pathogens. The oil cell and secretory cell, as unicellular secretory tissues, are intermediates between the primitive surface glandular and secretory cavity and canal during the evolution of secretory structures.