Study on the Chemical Composition and Anti Tobacco Mosaic Virus Activity of Qianli Guang
Plant viral diseases, also known as “plant cancers,” are the second largest plant diseases after fungal diseases. Due to the lack of ideal prevention and control measures, they cause huge losses to agricultural production, with economic losses caused by plant viruses exceeding $10 billion annually. Tobacco mosaic virus (TMV) is the earliest discovered single stranded RNA plant virus, with a wide host range involving 885 plant species from 65 families. After tobacco and other crops are infected with TMV, the chlorophyll in the leaves of the infected plants is destroyed, leading to reduced photosynthesis, growth difficulties, dwarfism, and even death. Tobacco is an important economic crop in China, and TMV causes serious losses in tobacco production and quality every year. According to relevant data statistics, the economic losses caused by tobacco mosaic virus reach 100 million US dollars every year, and controlling TMV is relatively difficult. Although several commercial antiviral agents against TMV have been put into use, there are few effective and practical varieties. Therefore, it is urgent to develop efficient and low toxicity new anti TMV drugs.
The Senecio genus, as the largest genus in the Asteraceae family, includes over 1500 species, with more than 160 distributed in China. Senecio scandens is a perennial plant of the Senecio genus. Its stems are often twisted and climbing, with multiple branches in the upper part. It has a head shaped inflorescence, yellow flowers, and leaves that are ovate triangular or elliptical lanceolate in shape. It is mainly distributed in eastern, central southern, and southwestern China, and is mostly found in hilly and mountainous forests, shrubs, grasslands, and roadside areas. Qianli Guang is a traditional Chinese medicinal herb with the effects of clearing heat and detoxifying, improving vision, and relieving dampness. It also has good anti-inflammatory, antibacterial, and antiviral effects.
The purpose of this study is to screen for anti TMV activity in Qianli Guang and investigate the chemical components with anti tobacco mosaic virus activity. Selecting the most active compounds from them provides a theoretical basis for the prevention and control of tobacco mosaic disease, as well as a scientific basis for the resource utilization of Senecio plants.

The plant kingdom produces over 400000 secondary metabolites, including active ingredients that can resist plant viruses, and the chemical defense substances produced by plants themselves have low self toxicity and are environmentally friendly. Therefore, searching for anti TMV active substances from plants is a very feasible route, and there have been many reports in recent years.
This study used modern and efficient phytochemical separation methods to isolate 13 monomeric compounds from the ethyl acetate extract of Senecio asiatica. Except for compounds 7 and 10, all other compounds were isolated from Senecio asiatica for the first time. The results of the anti tobacco mosaic virus activity test showed that compound 8 had a significantly higher inhibitory rate on the protective effect of TMV infected tobacco leaves than Ningnanmycin; Compounds 1, 4, 9-13 showed no significant difference in protective effects against Xinye tobacco compared to Ningnan mycin, indicating that these compounds can induce tobacco to acquire plant systemic resistance against viruses. The inhibitory rate of compound 13 on the therapeutic effect of tobacco infection TMV is higher than that of Ningnanmycin; The inhibition rate of compound 9 showed no significant difference compared to Ningnanmycin. There was no significant difference in the in vitro inactivation effect of compounds 8 and 9 on TMV compared to the inhibition rate of Ningnanmycin, indicating that these two compounds can directly act on the virus to exert anti TMV effects.
In summary, the chemical components of Senecio grandiflorus have a significant inhibitory effect on TMV, with alkaloids, terpenes, and some flavonoids showing strong anti TMV activity. It is worth further exploring whether these components are the main antiviral active ingredients. This study enriches the scope of Senecio grandiflorus chemical components and biological activities, and provides a scientific basis for the green prevention and control of tobacco mosaic disease in the future.