The much-despised "Houttuynia cordata" is actually a natural anti-inflammatory drug?

Audit expert: Shi Jun

PhD in Botany

Speaking of Houttuynia cordata , also known as Houttuynia cordata, it is well-known in central and southern China. During the Wuhan epidemic in 2020, Sichuan donated 3 tons of Houttuynia cordata to Wuhan. This made many netizens and friends in Wuhan confused: What exactly can this thing do?

Sichuan once donated Houttuynia cordata to Wuhan

Source: Weibo screenshot

A Wuhan netizen said that he didn’t need this.

Source: Weibo screenshot

Some netizens even got inspiration from this during the Shanghai epidemic

Source: Weibo screenshot

So who is Zhe Er Gen? How could it be so powerful?

Houttuynia cordata, or fish mint, is also known as Cen grass, Houttuynia cordata, Jiujielian, Lung-shaped grass, etc. It generally refers to the fresh whole grass or dried above-ground parts of Houttuynia cordata, a plant of the Saururaceae family . It is widely distributed in the Yangtze River Basin and areas to the south. It is a common dish on the tables of local residents. Yunnan, Guizhou, Sichuan and Chongqing are its main production areas.

When a traveler returns home from a foreign land and sees Houttuynia cordata on the menu of a roadside restaurant, he knows that he has arrived home. After all, this special taste is often accompanied by deep memories (whether good or bad).

The above-ground part of Houttuynia cordata is surprisingly beautiful

Source: Wikipedia

Because the stems and leaves have a characteristic fishy smell when crushed , it has a polarized reputation among diners. Some love it for its freshness, while others are terrified of it.

The most common way to cook it is to make a cold dish of Houttuynia cordata. Wash and cut the Houttuynia cordata into small pieces, add freshly poured chili oil, coriander, soy sauce and a little MSG, and it will become a delicious dish on the table of many families.

Cold mixed Houttuynia cordata

Source: Wikipedia

The culprit of fishy smell

Houttuynia cordata is not a food that looks delicious. It is quite long (up to 1 meter long). As a vegetable, it only has a thin root with soil and roots. It does not have large fruits or fresh leaves like other vegetables, and it does not even have round and plump rhizomes like potatoes and sweet potatoes.

However, the chemical composition of Houttuynia cordata is very complex. In addition to volatile oils, flavonoids, alkaloids, and sterols, it also contains a variety of amino acids, proteins, vitamins, etc. It has a variety of pharmacological activities such as bactericidal, anti-inflammatory, analgesic, and antiviral. As early as 2002, it was officially identified as a plant with both medicinal and edible properties by the Ministry of Health. Today, as people pay more and more attention to health, Houttuynia cordata can be said to have a bright future.

Appearance of Houttuynia cordata

Source: zhanjo-com

Houttuynia cordata contains about 0.05% volatile oil, the main component of which is decanoyl acetaldehyde , also known as houttuynia cordata. In fact, as a readily available volatile substance, aldehydes have a good reputation in the world of odors. For example, trace amounts of many aldehydes are found in plant essential oils, which usually help them emit pleasant smells, such as cinnamaldehyde, coriander and vanillin, and in perfumes, aldehydes often play an indispensable role.

Back to our protagonist, the fishy smell in Houttuynia cordata is caused by this aldehyde substance, which is a relative of 2,4-decadienal, one of the fishy smell components (it is the main oxidation product of linoleic acid, which is produced during the heating process of most vegetable oils and is found in French fries).

Decanoyl acetaldehyde

Source: pubchem

The characteristic volatile substance of decanoyl acetaldehyde means deliciousness for those who love to eat. On the other hand, it also has both internal and external benefits. It is the main antibacterial ingredient in Houttuynia cordata, and has obvious inhibitory effects on catarrhalis, influenza bacteria (not the pathogen of influenza, but it causes secondary respiratory infections when infected by influenza virus), pneumococcus, Staphylococcus aureus (the common culprit of acne), etc.

Bacteria killer or cancer killer?

Houttuynia cordata has long been proven to be antibacterial and anti-inflammatory . With the in-depth study of Houttuynia cordata, the aristolochic acid substances in its alkaloid components have attracted attention. There are also reports that Houttuynia cordata contains aristolochic acid substances, which may have kidney and liver toxicity and carcinogenic effects, causing the public to pay attention to the safety of Houttuynia cordata as a vegetable, causing anxiety.

Aristolochic acid substances are mainly found in plants of the Aristolochiaceae family. They can be divided into two categories: aristolochic acid and aristolochic acid lactones. There are more than 80 species in total, some of which are toxic. Aristolochic acid is a type of organic acid. Some species have been found to be anti-tumor, but their use is restricted because they can damage the kidneys. They are mainly divided into categories A, B, C, and D. Aristolochic acid lactones have two sources: one is directly derived from plants, and the other is obtained by enzyme processing after aristolochic acid enters the body.

Aristolochic acid mainly includes aristolochic acid Ⅰ, Ⅱ, A, B, F, etc. Studies have shown that aristolochic acid AⅠ, BⅡ and its metabolites aristolochic acid Ⅰ and Ⅱ have clear renal toxicity, which can cause aristolochic acid kidney damage and liver damage. At the same time, aristolochic acid may also be related to the occurrence of liver cancer.

Houttuynia cordata contains aristolochic acid lactam B, FⅡ, and AⅡ, mainly AⅡ. There is no report that aristolochic acid lactam AⅡ can cause kidney disease, and there is not enough evidence to show that this substance can damage the kidneys. However, it is still unclear whether Houttuynia cordata is non-nephrotoxic.

Classification of Aristolochic Acid

Source丨Author

So, can you eat Houttuynia cordata freely? A safer option is to pay attention to the amount you eat.

Although the several types of aristolochic acid lactones contained in Houttuynia cordata are not the most toxic, the entire class of aristolochic acid lactones has a similar structure, among which IV shows cytotoxicity, while IVa, I and II have also been shown to inhibit cell growth in the laboratory. Therefore, although many friends still regard Houttuynia cordata as one of the delicacies, it is okay to try it occasionally, but it is better to be cautious when eating it for a long time.