What is Houttuynia?
Houttuynia is a Southeast Asian herb that’s spread all over the world as an invasive species. It’s common name “fish mint” refers to the strong fish-like aroma of the essential oil content. This characteristic flavor makes the herb useful as a flavoring in various dishes.
The fishy roots of the herb are also eaten as a vegetable in some Asian dishes.
Houttuynia is one of the most relevant herbs at the moment in the search for potential sources of medicine against the COVID-19 virus.
This herb has potent antiviral activity — shown to be active against SARS, as well as other coronaviruses, influenza, herpes type I and II, HIV, Dengue, and Chikungunya virus.
What is Houttuynia Used For?
Houttuynia is primarily used for bacterial and viral infections of the respiratory tract. It’s considered most effective if taken prophylactically, but may provide use during infection as well to slow the spread of the disease.
Other applications of the herb are for its diuretic effects, anti-allergic effects, anti-inflammatory actions, and for diabetes.
Traditional Uses of Houttuynia
In Southeast Asia, where houttuynia thrives, the leaves are used in a lot of local culinary dishes. The leaves have a characteristic “fishy” flavor and aroma that lend itself to some dishes as a garnish or spice. In parts of China, the roots are eaten in a dish called Zhé'ěrgēn.
Medicinally, fish mint has had a long history of use in Japan, Korea, China, and Vietnam for a wide range of conditions.
The leaves of the fish mint plant were traditionally used for the following:
Digestive issues
Insect bites
Hypertension
Constipation
Hyperglycemia
Influenza or other viral infections
Pneumonia
Kidney disorders
Inflammation of the urinary tract
Cough
Insect repellant
Topically, the herb was used for sores, carbuncles, and inflammation.
In traditional Chinese medicine the herb was used to reduce heat.
Herb Details: Houttuynia
Herbal Actions:
- Antiviral
- Diuretic
- Antibacterial
- Anti-Anaphylactic
- Anti-Allergy
- Antinflammatory
- Febrifuge
Weekly Dose
- (1:30 Decoction)
15 – 30 Grams - View Dosage Chart
Part Used
Aerial Parts
Roots Are Eaten as a Vegetable
Family Name
Saururaceae
Distribution
Southeast Asia
Constituents of Interest
- β-myrcene
- 2-undecanone
Common Names
- Fish Mint
- Chameleon Plant
- Houttuynia
- Chinese Lizard Tail
- Bishop's Weed
- Diếp cá (Vietnam)
- Yu Xing Cao (China)
CYP450
- Unknown
Quality
- Cold
Pregnancy
- Avoid houttuynia if pregnant or breastfeeding
Taste
- Pungent
Duration of Use
- Long-term use should be avoided (more than 2 months)
Botanical Information
Houttuynia is a member of the Saururaceae family of plants — which is often referred to as the lizards table family because of the characteristic tail-like appearance of the flower spikes.
There are only two members of the Houttuynia genus — Houttuynia cordata and Houttuynia emeiensis.
Despite the common name “fish mint” houttuynia has no relation to the mint family of plants.
All parts of the plant posess a unique flavor and aroma — which is best described as having a raw fish aroma, with some hints of citrus, lemon, sandalwood, or coriander.
There are reportedly two varieties of fish mint:
Japanese Fish Mint — has more of a citrus aroma & flavor
Chinese Fish Mint — has a fishy and coriander aroma & flavor
The leaves of the fish mint plant are heart-shaped, which can range from being dark green to light pink. The underside of the leaves has a purple hue. Some of the ornamental cultivars come in a wide variety of different color combinations.
Cultivation, Harvesting & Preparation
Houttuynia prefers growing in shady, moist environments and can even grow while slightly submerged in water. You can often find this herb growing nearby streams, and in deep forests. This herb is very resourceful and can be very difficult to get rid of.
Once houttuynia finds an area it likes it will take over completely — causing many regions to classify it as a potential threat to the environment.
It’s considered an invasive weed in places such as the United States, Australia, various pacific islands, and South America. It reportedly thrives in USDA Zones 5a to 9b.
In Asia, the herb can be found growing anywhere from sea level to around 2500 meters in altitude.
Fish mint loves water, so make sure to keep this one wet at all times. As long as the leaves remain above the water-level the plant will continue to thrive.
This herb is a perennial, growing up to 1 meter in height and spreading out in a 1 meter radius. It primarily spreads with the help of adventitious roots that creep along the moist soil of the rainforest bottom.
propagating the plant is best done from cuttings. The seeds of the plant are usually sterile.
Pharmacology & Medical Research
+ SARS-CoV 1 & 2
SARS (Severe Acute Respiratory Syndrome) is a life-threatening form of pneumonia caused by the SARS-CoV-1 virus. It began spreadin in late 2002 to 2003 from patient 0 in China. The disease eventually spread to over 8000 people around the world. As the world scrambled to find treatment, houttynia was shortlisted by Chinese researchers.
During this research, houttuynia was found to increase the proportion of CD4+ and CD8+ T cells [5].
CD4+ T-helper cells play a critical role in the adaptive immune system when dealing with bacterial or viral infections. These cells then pass along information to CD8 cytotoxic cells that can use three separate mechanisms to attack and kill the infection once identified.
The same study also showed houttuynia extract increased IL-2 and IL-10 activity — both of which are critical components in the adaptive immune response necessary to fight viral infection.
This study also looked at the direct effects of houttuynia extract on the SARS virus. The study found the extract had an inhibitory effect on SARS-CoV 3C-like protease (3CLpro) and RNA-dependent RNA polymerase (RdRp).
3C-like protease and SARS-CoV are both critically important for the life-cycle of the virus. These are two areas deemed critically important target in the search for potential prevention or treatment of the virus.
Now, in 2020, another closely related virus is currently causing a pandemic around the globe — SARS-CoV-2 (AKA COVID-19). As a result, houttuynia is being re-investigated as the world seeks to find a potential cure for the new and deadly virus.
+ Other Antiviral Activity
Houttuynia has been the subject of study for dozens of human and animal viruses — many of which the herb has shown primising inhibitory effects:
- Chikungunya virus [9]
- Human Immunodeficiency virus type 1 (HIV-1) [10]
- Herpes Simplex Virus type 1 (HSV-1) [10]
- Herpes Simplex Virus Type 2 (HSV-2)
- Influenza Virus [10]
- Enterovirus-71 [11]
- Dengue Virus Type 2 [12]
+ Antibacterial Activity
Houttuynia has a long history of use for treating respiratory tract infections of both viral and bacterial causes. This has prompted a lot of researcher to look at the effects of the herb on bacterial infections — particularily those developing resistance to antibiotics such as multi-drug resistant staphylococcus aureaus (MRSA).
One study found houttuynia posessed anti-bacterial effects against MRSA through direct bacteriocidal activity (inhibition of biofilm formation) and an induction of IL-8 [6] — which is one of the first responses triggered by the body during bacterial infection.
+ Cytotoxic Effects
There are five bioactive alkaloids isolated from houttuynia that have been shown to have cytotoxic effects agains human cancer cell lines (in vitro) [1]. This was only a preliminary study but offers evidence for further investigation.
The alkaloids used in the study included:
- A-549
- SK-OV-3
- SK-MEL-2
- XF-498
- HCT-15
+ Anti-Allergic Effects
A mice study investigated the anti-allergic effects of houttuynia by exploring the potential effects of the herb to prevent anaphylaxis — a severe allergic reaction [2].
The study found hoouttuynia water extract was able to inhibit induced systemic anaphylaxis in mice, as well as local allergic reactions by reducing the degranulation of mast cells, histamine release, and calcium uptake.
The study concluded by stating that "[houttuynia] may be beneficial in the treatment of mast cell-mediated anaphylactic responses.
Another animal study showed a houttuynia water-extract had an inhibitory effect on inhibited IgE-mediated systemic passive cutaneous anaphylaxis (in mice) [4].
+ Anti-Inflammatory Effects
An animal study exploring the anti-inflammatory effects of houttuynia found the volotile oil extract of the plant had an inhibitory effect on PGE2 — a potent inflammatory cytokine produced via the COX-2 enzyme [3]. This is the main inflammatory mediator inhibited by such medications as acetyl-salycilic-acid (Aspirin).
The same study also found houttuynia volotile oil reduced other key inflammatory messengers including nitric oxide (NO) and TNF‐α.
+ Effects of Houttuynia on Diabetes
An animal study on diabetic rats given houttuynia found the herb had protective effects on the pancreatic beta-cells through an upregulation of GLUT-4 and potential antioxidant activity [7].
The beta-cells are tasked with producing the body's insulin supply. As blood glucose levels rise, the glucose can damage sensitive tissues such as the beta-cells in the pancrease — leading to a further reduction of insulin activity and worsening of hyperglycemia.
GLUT-4 is the insulin-mediated transporter on the surface of our cells. Insulin binds to GLUT-4 to pull glucose molecules inside where they're converted into energy.
Phytochemistry
+ Essential Oil Content
- 2-undecanone (methyl nonyl ketone)
- Myrcene
- Houttuynin (decanoyl acetaldehyde/3-oxo-dodecanal)
- Decanal
- (E)-caryophyllene
- Decanoic ac id
- Camphene
- β-pinene
- Lauraldehyde
- Bornyl acetate
- α-pinene
- Limonene
- 4-terpineol
- Caryophyllene oxide
- Nonanol
- linalool
Source: [8]
Cautions & Safety Information:
Houttuynia has been reported to cause severe allergic reactions in some people.
Avoid using this herb if pregnant or breastfeeding. There is not enough evidence to prove the herb is safe during pregnancy.
Recent Blog Posts:
References:
Kim, S. K., Ryu, S. Y., No, J., Choi, S. U., & Kim, Y. S. (2001). Cytotoxic alkaloids fromHouttuynia cordate. Archives of pharmacal research, 24(6), 518-521.
Li, G. Z., Chai, O. H., Lee, M. S., Han, E. H., Kim, H. T., & Song, C. H. (2005). Inhibitory effects of Houttuynia cordata water extracts on anaphylactic reaction and mast cell activation. Biological and Pharmaceutical Bulletin, 28(10), 1864-1868.
Li, W., Fan, T., Zhang, Y., Fan, T., Zhou, P., Niu, X., & He, L. (2013). Houttuynia cordata Thunb. Volatile Oil Exhibited Anti‐inflammatory Effects In Vivo and Inhibited Nitric Oxide and Tumor Necrosis Factor‐α Production in LPS‐stimulated Mouse Peritoneal Macrophages In Vitro. Phytotherapy Research, 27(11), 1629-1639.
Han, E. H., Park, J. H., Kim, J. Y., & Jeong, H. G. (2009). Houttuynia cordata water extract suppresses anaphylactic reaction and IgE-mediated allergic response by inhibiting multiple steps of FcεRI signaling in mast cells. Food and chemical toxicology, 47(7), 1659-1666.
Lau, K. M., Lee, K. M., Koon, C. M., Cheung, C. S. F., Lau, C. P., Ho, H. M., ... & Tsui, S. K. W. (2008). Immunomodulatory and anti-SARS activities of Houttuynia cordata. Journal of Ethnopharmacology, 118(1), 79-85.
Sekita, Y., Murakami, K., Yumoto, H., Mizuguchi, H., Amoh, T., Ogino, S., ... & Kashiwada, Y. (2016). Anti-bacterial and anti-inflammatory effects of ethanol extract from Houttuynia cordata poultice. Bioscience, biotechnology, and biochemistry, 80(6), 1205-1213.
Kumar, M., Prasad, S. K., Krishnamurthy, S., & Hemalatha, S. (2014). Antihyperglycemic activity of Houttuynia cordata Thunb. in streptozotocin-induced diabetic rats. Advances in pharmacological sciences, 2014.
Verma, R. S., Joshi, N., Padalia, R. C., Singh, V. R., Goswami, P., Kumar, A., ... & Saikia, D. (2017). Chemical Composition and Allelopathic, Antibacterial, Antifungal, and Antiacetylcholinesterase Activity of Fish‐mint (Houttuynia cordataThunb.) from India. Chemistry & biodiversity, 14(10), e1700189.
As COVID-19 continues to spread around the world, we’re getting a lot of questions on what the potential role of herbal medicine is during the outbreak. Learn how the virus works and how to limit your chances of transmission.