Study on the Chemical Composition and Anti Plant Pathogen Activity of Ethyl Acetate Extract from Houttuynia cordata
Houttuynia cordata Thunb belongs to the family Trifolium, and its roots, stems, and leaves can all be used as medicine. It has the effects of clearing heat and detoxifying, and can enhance the body’s immune function. It is a dual-use plant for medicine and food, with the most significant effects being anti allergy, asthma relief, and cough relief. Therefore, it is commonly used in clinical practice to treat diseases such as phlegm, heat, wheezing, and cough. In 2003, it was selected by the country as one of the eight drugs for treating acute respiratory syndrome (SARS). In clinical practice, the active ingredient of its volatile oil, decanoyl acetaldehyde, which is also known as houttuynia cordata, is mainly used. The sodium bisulfite adduct of decanoyl acetaldehyde is commonly referred to as houttuynia cordata sodium. Houttuyfonate sodium can be used to treat chronic bronchitis and other upper respiratory infectious diseases, etc. At the same time, the flavonoids contained in Houttuyfonate, such as quercetin and quercetin, have good bactericidal, expectorant and antipruritic effects. At present, a novel structural new skeleton flavonoid has been discovered in Houttuynia cordata, which belongs to the new skeleton flavonoid composed of Houttuynia cordata extract and flavonoids. It has good anti herpes simplex virus activity and can be used as a characteristic component for quality control of Houttuynia cordata. According to authoritative natural product magazines, the most abundant chemical components in Houttuynia cordata are flavonoids, with over 100 of them; Next are alkaloids and polyphenolic compounds; There are over 70 compounds of alkaloids, mainly exhibiting biological activities such as antiviral and anti-inflammatory effects; Less reported are phenylpropanoids, coumarins, triterpenoids, and sesquiterpenes. The medicinal ingredients isolated and extracted from the natural plant Houttuynia cordata have low toxicity to the human body and good therapeutic effects, and have attracted much attention from researchers.
Agricultural products and other resources are becoming increasingly scarce in the world, and they will become important weapons for competition and limiting China’s rise among major powers. Agriculture holds significant political and strategic value for China. However, diseases and pests caused by plant pathogenic fungi are a major reason for the decline in global food and crop yields. At present, research has reported that secondary metabolites produced by endophytic fungi in Houttuynia cordata plants have antibacterial activity. Liu Zhengqiong from Sichuan Agricultural University also found that endophytic fungi isolated from Houttuynia cordata, such as Pestalotiopsis microspora, Chaetomium globorum, and Fusarium nemetophilum, have inhibition rates of over 40% against plant pathogens such as wheat Fusarium head blight, potato blast disease, pepper blight, watermelon wilt, and nuclear disc fungus. However, there are few reports on the anti plant pathogenic fungal activity of the chemical components of Houttuynia cordata. Therefore, this article continues to search for structurally diverse drug lead compounds with anti plant pathogenic fungi from Houttuynia cordata, in order to provide alternative compounds for the development and creation of new pesticides.

This paper isolated and identified 10 compounds, including 4 carbon reducing sesquiterpenes, 3 flavonoids, and 3 polyphenols, from the ethyl acetate extract of the 95% dried part of Houttuynia cordata. Compounds 1-4 are the first carbon reducing sesquiterpenes isolated from Houttuynia cordata in Qinling Mountains. There have been no reports of carbon reducing sesquiterpenes in the secondary metabolites of Houttuynia cordata. This article reports for the first time the carbon reducing sesquiterpenes in Houttuynia cordata, increasing the number of chemical components in Houttuynia cordata and enriching the structural types of its compounds. Compounds 1-4 of carbon reducing sesquiterpenes have weak antibacterial activity against Fusarium graminearum, Fusarium oxysporum, Botrytis cinerea, Fusarium oxysporum, and Fusarium oxysporum; Flavonoids 5-7 have moderate antibacterial activity against Fusarium graminearum, Fusarium oxysporum, Botrytis cinerea, Fusarium oxysporum, and Fusarium oxysporum; Polyphenolic compounds 8-10 have weak antibacterial activity against the five plant pathogens mentioned above, which provides a research basis for the subsequent study of the chemical composition and pharmacological effects of Houttuynia cordata.