- Houttuynia cordata is one of two species of the genus Houttuynia; the other, H. emeiensis, which is distributed in Sichuan, China.
The genus belongs to the Saururaceae family with 4 genera and a total of 6 species. (3)
- The genus is named after Martinus Houttuyn, a Dutch naturalist (1720-1798). (3)
- There are two chemotypes: the Japanese type with its orange scent and the Chinese type with a scent resembling coriander.
- In Japan, H. cordata name translates to poison-blocking herb. Ancient Japanese people use the herb to counteract the effects of poisoning.
- Although often referred to as "fish mint", it does not belong to the mint family of plants.
- As Chinese herbal medicine, it first appeared in "Mingyi Bie Lu" around 420-589 AD.
- Houttuynia cordata injection was recommended as an anti-SARS drug in 2003, The injection was suspended by the China National Drug Administration in 2006 due to side effects.
Houttuynia cordata is a herbaceous, perennial plant growing 0.6-1 m, spreading up to 1 m. Proximal part of the stem is trailing and producing adventitious roots. Distal part of the stem grows vertically. Leaves are alternate, broadly heart-shaped 4-9 cm long and 3-8 cm broad; often developing red and yellow splotches. Flowers are greenish-yellow, borne on a terminal spike 2-3 cm long with 4-6 large, white basal bracts.
- Cultivated as a leaf vegetable.
- Native to Japan, Korea, northern China.
- In many places, considered invasive.
- in most places, it is foraged rather than cultivated.
- The scent of H. cordata has been attributed to chemical compounds, including ß-myrcene and 2-undecanone.
- Three extracts of leaves, i.e. diethyl ether (DELE), ethanolic (ELE) and aqueous (ALE) extracts, were evaluated for polyphenol and flavonoid contents. Phytochemical screening yielded flavonoid, saponin, alkaloid, tannin, and steroid compounds. Quantitative study for total polyphenol content yielded 32.18, 97.98 and 22.22 mg of gallic acid equivalents/gm dry extract for DELE, ELE, and ALE, respectively; total flavonoid content was 31.65, 35.72, and 4.06 mg quercetin equivalents/gm dry extract, respectively. (6)
- Study of leaves for essential oil yielded major components of ß-myrcene (30.8%). 2-undecanone (19.7%), and (Z)-ß-ocimene (10.2%). (12)
- Study of fresh herb for flavonoids yielded five compounds: quercetin-3-O-beta-D-glucoside (1), kaempferol-3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (2), quercitrin (3), hyperin (4), quercetin-3-O-alpha-L-rhamnopyranosyl-7-O-beta-D-glucopyranoside (5). (22)
- Leaves impart a fishy taste, some of the common names relating to it: fish plant, fist mint, fishwort and, hence, limited used as a condiment.
- Studies have suggested antioxidant, anti-inflammatory, anti-Herpes simplex, anti-Dengue, iimmunomodulatory, antidiabetic, anticancer, hair growth-promoting properties.
- Cultivated as a leaf vegetable, used in salads, salsas, or as fresh herbal garnish.
- Roots are edible; eaten raw as salad or cooked in fish curry.
Tender roots ground into chutneys along with dry meat, fish, chilies and tamarind. (4)
- In Vietnamese cuisine, used as garnish in several dishes, such as goi cuon.
- In Japan the dokudami cha ( Houttuynia cordata tea) is made from leaves of H. cordata, Job's tears, and Oolong tea leaves. Leaves also used as tea in Korea.
- In Chinese medicine, Yu Xing Cao is used for diuresis, detoxification, malignancies, and lung afflictions such as bronchitis, bronchopneumonia, lung abscess, pertussis. Also used for treatment of keratitis, orchitis, pelvic inflammation. It is an ingredient in about 50 kinds of traditional Chinese prescriptions.
- In traditional Chinese medicine, used as injection for the treatment of SARS. (8)
- In Japan, used as an herbal tonic and for earaches.
- Leaves used for treatment of measles, gonorrhea, skin diseases, fever, hemorrhoids.
- In India, whole plant is eaten raw to lower blood sugar. Leaf juice used for treatment of cholera, dysentery, blood purification, and as antidote.
- In Asia, used for treatment of alopecia in combination with P. frutescens and green tea. (see study below) (24)
- A good ground cover plant.
- Cosmetics: H. cordata extract is a common ingredient in high-end facial creams and lotions.
• Antihyperglycemic: Study evaluated the mechanism of antidiabetic activity of H. cordata extract in streptozotocin-induced diabetic rats. Oral administration of extract at dose of 200 and 400 mg/kbw daily resulted in a significant decrease (p<0.05) in fasting plasma glucose and elevated insulin level. It also reversed alterations in biochemical parameters i.e., lipid profile, BUN, creatinine, protein, antioxidant enzymes. Study suggests the antidiabetic effect is attributable to an upregulation of GLUT-4 and potential antioxidant activity, which may play a beneficial role in resolving complications associated with diabetes. (5)
• Immunomodulatory / Anti-SARS Activity: Severe acute respiratory syndrome (SARS) is a life-threatening pneumonia caused by SARS coronavirus (SARS-CoV). Study evaluated the SARS-preventing mechanisms of HC in immunological and anti-viral aspects. Results showed a water extract could significantly and dose-dependently stimulate proliferation of mouse splenic lymphocytes. It increased the proportion of CD4 and CD8 T cells and caused a significant increase in secretion of IL-2 and IL-10 by mouse splenic lymphocytes. The HC exhibited significant inhibitory effects on SARS-CoV 3C-like protease and DRA-dependent RNA polymerase. Results provide scientific data to support its efficient and safe use to combat SARS. (7)
• Anti-Inflammatory / HC Injection: Study evaluated the plausible anti-inflammatory property of H. cordata injection. GC-MS analysis yielded 22 components. Anti-inflammatory activity was studied by inflammation induced by carrageenan in the rat pleurisy model. HC injection attenuated the inflammatory parameters. It was also effective in inhibiting xylene induced ear edema. Results clearly indicated HCI anti-inflammatory activity. (8)
• Comparative Antioxidant Study / Acidic Polysaccharide: : Study compared the antioxidant potential of a water-soluble polysaccharide (HCP) with various solvent extracts from H. cordata. Results showed polar water extract exhibited highest reducing power and scavenging activity against DPPH radical, superoxide radical, and hydroxyl radical. The active HCP, identified as an acid hetero-polysaccharide, is one of the main active ingredients responsible for the antioxidant effect of H. cordata. H/ cordata has potential as natural antioxidant source in the medicine and food industry. (9)
• Anaphylactic Inhibitory Study: Oral administration of H. cordata water extract inhibited compound 48/80-induced systemic anaphylaxis in mice. Study suggested water extracts may be beneficial in the treatment of mast cell-mediated anaphylactic responses. (10)
• Anti-Inflammatory / Novel and Selective COXC-2 Inhibitory: Studies have implicated inducible cyclooxygenase-2 (COX-2) as a key regulator of the inflammatory process. This study evaluated the effect of HC on lipopolysaccharide (LPS)-induced prostaglandin (PG) E2 production and COX-2 gene and protein expression in mouse peritoneal macrophages. Results showed HC inhibited the release of LPS-induced PGE2 from mouse peritoneal macrophages with IC50 of 44.8 µg/mL. Also, HC essential oil elicited a dose-dependent inhibition of COX-2 enzyme activity with IC50 of 30.9 µg/mL. HC also caused reduction in LPS-induced COX-2 mRNA and protein expression. Results suggest HC mediates inhibition of COX-2 enzyme activity and can affect related gene and protein expression. It works via a mechanism of action similar to NSAIDs. (11)
• Anti-Herpes Simplex Virus Activity: Study compared the antiviral activity of B. pilosa and Houttuynia cordata against cells infected with Herpes simplex virus (HSV). H. cordata extract significantly inhibited the replication of HSV at concentration of of 250 µg/mL (10.2% for HSV-1, p<0.05, 32.9% for HSV-2, p<0.005). The ED50 was 822.4 µg/mL and 362.5 µg/mL for HSV-1 and HSV2, respectively. Results showed H. cordata had better effect against HSV2 than HSV1, and had a low ED50 against HSV2. Results suggest a potentially useful plant against HSV2 infection. (13)
• In Vitro Glucose Utilization Capacity: Previous studies of whole plant have reported potent antihyperglycemic activity. This study investigated the glucose utilization capacity of bioactive fractions of ethanol extract of H. cordata in isolated rat hemidiaphragm. Aqueous and ethyl acetate extract significantly increase glucose uptake by isolated rat hemidiaphragm, The AQ fractions enhanced glucose uptake significantly (P<0.05) and was found more effective than insulin. Activity was attributed to presence of quercetin, which was found to be 7.1 and 3.2% w/w in the AQ and EA fractions, respectively. (14)
• Combination of H. cordata and Metformin / Modulation of Gut Micobiota: Study evaluated the therapeutic effects of H. cordata extract and metformin combination in a dysmetabolic mouse model. Results showed significantly lowering of body weight, abdominal fat, perirenal fat, liver and kidney weights, with no change in epididymal fat in HFD-fed animals. The combination markedly attenuated the elevated levels of TC, TG, AST, ALT, and endotoxin and restored depleted HDL level. The combination also dramatically suppressed inflammation in HFD-fed animals via inhibition of proinflammatory cytokines and LPS receptor. Histopathological study showed amelioration of fatty liver, shrinkage of intestinal villi and adipocytes enlargement. It also modulated the abundance of gut gram-negative bacteria, including E. coli and B. fragilis. Results suggest the combination exert its therapeutic effect via modulation of gut microbiota, especially reduction of gram-negative bacteria, resulting in alleviation of endotoxemia. (15)
• Anti-Inflammatory / Antioxidative: Study evaluated the efficacy of H. cordata extracts and its bioactive compounds in-vivo and in-vitro against oxidative stress and inflammation. Phytoconstituents afzelin, hyperoside and quercitrin were shown to reduced inflammation in both in-vitro and in-vivo models. The molecules showed strong antioxidant properties in both models. (16)
• Virucidal on HSV1, Influenza Virus and HIV / Essential Oils: Steam distillate of Houttuynia cordata fresh plants was found to have direct inhibitory activity against herpes simplex virus type 1, influenza virus, and human immunodeficiency virus type 1 without showing cytotoxicity. Three major components of the distillate, methyl n-nonyl ketone, lauryl aldehyde, and capryl aldehyde, also inactivated HSV2, influenza virus and HIV-1. Results suggest the essential oils provide in vitro virucidal activity against enveloped viruses by interfering with the function of virus envelope. (17)
• Inhibitory Effect on Anaphylactic Reaction and Mast Cell Activation: Study evaluated the effect of H. cordata water extract on mast cell-mediated anaphylactic reactions. Oral administration of the water extract inhibited compound 48/80-induced systemic anaphylaxis in mice. It also inhibited the local allergic reaction, passive cutaneous anaphylaxis (PCA) activated by anti-dinitrophenyl (DNP) IgE antibody in rats. The extract also inhibited histamine release, increased the level of intracellular cAMP and significantly inhibited the compound 48/80 induced cAMP reduction in RPMC. Results suggest HCWE may be beneficial in the treatment of mast cell-mediated anaphylactic responses. (18)
• Amelioration of Loperamide-Induced Constipation / Leaves: Study evaluated the efficacy of H. cordata leaf extract against loperamide-induced constipation in Wistar rats. Results showed the water content of fecal pellets and body weight gain of constipation rats changed significantly (p<0.05). Results suggest H. cordata leaf may be beneficial as a traditional herbal medicine for management of constipation. (19)
• Anti-Neuroinflammatory / LPS-Stimulated Microglia / Antioxidant: Study evaluated the anti-neuroinflammatory effects of H. cordata extract in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. The ethyl acetate extract significantly scavenged DPPH free radicals in a concentration dependent manner. The increased levels of NO, iNOS, and IL-6 in LPS-stimulated BV-2 microglial cells were also suppressed in a concentration-dependent manner. Results suggest strong antioxidant properties and inhibition of excessive production of pro-inflammatory mediators. The antioxidant phenolic compounds could have played an important role in ameliorating the neuroinflammatory processes in the microglial cells. (20)
• Antiviral Activities Against Murine Coronavirus and Dengue Virus / Toxicity Study: Study evaluated the antiviral activities of an EA fraction of H. cordata and flavonoids using virus neutralization tests against mouse hepatitis virus (MHV) and DENV type-2 (DENC-2). Mice fed with the EA fraction up to 2,000 mg/kg did not show signs of acute toxicity nor histopathologic changes in major organs. Certain flavonoids exhibited comparatively weaker antiviral activity, notably quercetin, which would inhibit both MHV and DWNV-2. Results suggest the compounds in H. cordata contribute to superior antiviral efficacy of the EA fraction, which lacked cytotoxicity in vitro and acute toxicity in vivo. Results suggest potential for the development of antiviral agents against coronavirus and dengue infections. (21)
• Anti-HSV Infection Via Inhibition of NF-kB Activation: Studies have reported H. cordata activity against herpes simplex virus (HSV) and virus of severe acute respiratory syndrome (SARS)/ This study showed a hot water extract inhibition of HSV-2 infection through inhibition of NF-kB activation. Also, treatment with quercetin, quercitrin or isoquercitrin, major water extractable flavonoids from H. cordata, significantly blocked HSV-2 infection. (23)
• Hair Growth Promoting Effect / Herbal Mix with P. frutescens and Green Tea: Study evaluated the hair growth promoting effect of the herbal complex of Houttuynia cordata, Perilla frutescens var. acuta, and green tea in C57BL/6 mice. Hair growth was evaluated visually and microscopically, along with Western blot analysis for insulin-like growth factor (IGF)-1 and transforming growth factor (TGF)-ß1. Results showed hair growth-promoting activity. (24)
• Upregulation of Fillagrin Expression / ROS-Related Photoaging: Study evaluated the effects of H. cordata extract on human keratinocytes. HCE activated aryl hydrocarbon receptor (AHR) and nuclear factor E2-related factor-2, with subsequent induction of antioxidative enzyme NAD(P)H: quinone oxidoreductase 1 gene. HCE inhibited the generation of ROS in keratinocytes stimulated with TNF-a or benzo(a)pyrene. HCE upregulated the gene expression of filaggrin, an essential skin barrier protein, in an AHR-dependent manner. Results suggest HCE may be beneficial for treating ROS-related photoaging and barrier-disrupted skin conditions. (26)
• Inhibition of Cell Growth and Induction of Apoptosis in Colorectal Cancer Cells: Study evaluated the molecular mechanism of cytotoxicity and apoptosis in human primary colorectal cancer cell. Results indicated H, cordata inhibited growth of cancer cells in a dose-dependent manner. It increased ROS production and decreased mitochondrial membrane potential in examined cells. H. cordata induced apoptotic ell death in primary colorectal cancer cells through a mitochondria=dependent signaling pathway. (26)
• Inhibitory Actions on Dengue Virus and Dengue-Infected Cells: Study evaluated the antiviral activities of H. cordata aqueous extract against dengue virus serotype 2 (DEN-2) strain 16681. Results showed pre- and post-incubation of H. cordata extract with HepG2 cells significantly reduced intracellular DEN-2 RNA production correlating with the decrease in dengue protein expression. In direct blocking mode, the extract bound with DEN-2 and strongly inhibited the intracellular viral RNA replication. The extract also exhibited protective effect on virion release from infected LLC-MK2 cells. HPLC indicated hyperoside was the dominant bioactive compound, and likely play a role in inhibition. The extract showed no genotoxic effect on human blood cells. (27)
• Hepatoprotective / CCl4-Toxicity / Polyphenol-Rich Extract / Tea: Study evaluated the antioxidant activity, hepatoprotective effect, and phenolic composition of EA fraction from H. cordata tea. The EAF showed strong ferric-reducing antioxidant power (FRAP) and scavenging activity against DPPH radical in-vitro. Hepatoprotective and antioxidant effects were verified by suppressing CCl4-induced oxidative stress in mouse liver. Pretreatment with the EAF significantly (p<0.001) decreased the CCl4-elevated levels of serum AST, ALT, AP, total bilirubin and hepatic MDA in mice and prevented increases in GSH, SOD, and CAT caused by CCl4. HPLC analysis revealed three polyphenolic compounds in the EAF i.e., quecitrin, quercetin, and hyperoside. The significant hepatoprotective effect may be due to strong antioxidant activity of the phenolic components. (28)
• Anticancer Activity of Fermentation Products of H. cordata: Study evaluated the phenolic acid composition and anticancer activity of two commercialized H. cordata fermentation products. Seven phenolic acids were detected i.e., protocatechuic, p-hydroxybenzoic, vanillic, syringic, p-coumaric, ferulic, and sinapinic acids. The growth inhibitory effects of both fermentation products in HeLa, HCT116, and HT29 cells included induction of apoptosis. Results suggest the fermentation products contain several anticancer phenolic acids, which may be beneficial in the treatment of human cancer. (29)
• Amelioration of Bladder Damage in Interstitial Cystitis: Study evaluated the efficacy and possible mechanisms of H. cordata extract in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) in adult female rats induced with cyclophosphamide intraperitoneally. Results showed HC extract can effectively inhibit mast cell proliferation and activation and downregulate proinflammatory cytokine in a rat model of IC/BPS induced with cyclophosphamide. (30)
• Anti-Inflammatory / Volatile Oil: Study evaluated the inhibitory effect of volatile oil from HC on animal models of inflammation and the production of inflammatory mediators in-vivo and in-vitro. In-vivo, xylene-induced mouse ear edema, formaldehyde induced paw edema, and carrageenan induced mice paw edema were significantly decreased by HC volatile oil. In-vitro exposure of mouse resident peritoneal macrophages to HC volatile oil significantly suppressed LPS-stimulated production of NO and tumor necrosis factor-a in a dose dependent manner. Western blot analysis showed the HCVO attenuated LPS-stimulated synthesis of iNOS and TNF-a protein in the macrophages. The study adds a novel aspect to the biological profile of HC and clarifies its anti-inflammatory mechanism. (31)
• HC Polysaccharide (HCP) Effect on Intestinal Barrier and Microbiota in H1N1 Infection: Study evaluated the effects of H. cordata polysaccharide (HCP) on intestinal barrier and microbiota in H1N1 infected mice. HCP significantly suppressed expression of hypoxia inducible factor-1a and decreased mucosubstances in goblet cells. It reversed composition change of intestinal microbiota caused by H1N1, with significantly reduced Vibrio and Bacillus, the pathogenic bacterial genera. HCP alleviated lung injury and intestinal dysfunction caused by H1N1 infection. (33)
• Facilitation of Metformin on Ameliorating Insulin Resistance: Study evaluated the synergistic anti-diabetic effect of H. cordata extract (HCE) and metformin combination in OLETF rats. The combination resulted in significantly ameliorated glucose tolerance (OGTT). Results of insulin tolerance test (ITT) showed the combination dramatically improved insulin sensitivity compared to metformin alone. Both fecal and serum endotoxin, along with TNF-a and IL-6 were significantly ameliorated by the combination. The combination also changed microbiota composition. The mechanisms are associated with alleviation of endotoxemia via regulation of gut microbiota. (34)
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