Common herb has flavonoids that fight flu virus
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April 28, 2009
Filed under Recent, cold & flu, flu, respiratory
CM NEWS – A commonly used Chinese herb for cold and fever contains ingredients that can fight influenza viruses, a study in China suggests.
Elsholtzia rugulosa (野拔子 ye ba zi), a common Chinese herb, is widely used in the treatment of cold and fever. A group of researchers of the Chinese Academy of Medical Sciences and Peking Union Medical College, as well as University of Macau investigated the anti-flu functions of the ingredients of this plant.
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In order to elucidate the action mechanism and the active principles from the plant against anti-influenza virus, the influenza virus neuraminidase (NA) activity assay and in vitro antiviral activity assay were established, and the isolation of the active principles was guided by NA activity.
Their study established that five active constituents were found in ye ba zi and they are all flavonoids.
What are flavonoids? Flavonoids (or bioflavonoids) are a class of plant secondary metabolites fulfilling many functions including producing yellow or red/blue pigmentation in flowers and protection from attack by microbes and insects. The widespread distribution of flavonoids, their variety and their relatively low toxicity compared to other active plant compounds (for instance alkaloids) mean that many animals, including humans, ingest significant quantities in their diet. Flavonoids have been referred to as “nature’s biological response modifiers” because of strong experimental evidence of their inherent ability to modify the body’s reaction to allergens, viruses, and carcinogens. They show anti-allergic, anti-inflammatory, anti-microbial and anti-cancer activity.
Consumers and food manufacturers have become interested in flavonoids for their medicinal properties, especially their potential role in the prevention of cancers and cardiovascular disease. The beneficial effects of fruit, vegetables, and tea or even red wine have been attributed to flavonoid compounds rather than to known nutrients and vitamins.
The five constituents are:
- apigenin
- luteolin
- apiin
- galuteolin
- luteolin 3′-glucuronyl acid methyl ester
According to the researchers, these constituents all possessed anti-influenza virus activity. Among them, apigenin and luteolin exhibited the highest activities against influenza virus (H3N2).
What is apigenin? Apigenin is described as a nonmutagenic bioflavonoid which is presented in leafy plants and vegetables (e.g., parsley, artichoke, basil, celery) and has significant chemopreventive activity against UV-radiation. Current research trials indicate that it may reduce DNA oxidative damage; inhibit the growth of human leukemia cells and induced these cells to differentiate; inhibit cancer cell signal transduction and induce apoptosis (cell death); act as an anti-inflammatory; and as an anti-spasmodic or spasmolytic.
Apigenin is also reported to be useful in fighting against antiestrogen-resistant breast cancer.
Apigenin is a bioflavone, considered to have a bioactive effect on human health as antioxidant, radical scavenger, anti-inflammatory, carbohydrate metabolism promoter, immunity system modulater.
What is luteolin? Luteolin is a flavonoid thought to play an important role in the human body as an antioxidant, a free radical scavenger, an agent in the prevention of inflammation, a promoter of carbohydrate metabolism, and an immune system modulator. These characteristics of luteolin are also believed to play an important part in the prevention of cancer. Multiple research experiments describe luteolin as a biochemical agent that can dramatically reduce inflammation.
Luteolin inhibited the excess production of TNF-alpha, which directly causes inflammation and apoptosis. Luteolin also offers hope to develop a novel type of anti-inflammatory and anti-allergic drugs.
Luteolin is most often found in leaves, but it is also seen in rinds, barks, clover blossom and ragweed pollen. It has also been isolated from Salvia tomentosa. Dietary sources include celery, green pepper, perilla and camomile tea.
[Planta Med 2008; 74: 847-851]
