Herbs and Herbal Extracts for Influenza Prevention and Treatment (Personalized Medicine for Influenza Series)

Herbs, herbal extracts, and nutrients extracted from herbs have been proved effective for the prevention and treatment of influenza. For example, flavonoids are polyphenols and commonly found in herbs. Scientists have observed that flavonoids have inhibitory effects on influenza strains including H1N1 and H3N2. Researchers have also elucidated the antiviral mechanisms of these natural products. For example, flavonoids can inhibit neuraminidase (NA), an important genetic segment in influenza. The order of the inhibition potency by some flavonoids has been discovered. Some herbs can modulate immune responses such as enhancing the production of antiviral antibodies. Some herbs have continuous effects before and after the influenza infection, and can be used for both prevention and treatment. Some herbal extracts can be potential adjuvants for the improvement of immune responses of influenza vaccines. Many of the herbs have been used for thousands of years in traditional medicines such as Chinese medicine for healing colds and fever. Scientific studies of these natural products are helpful for the development of antiviral vaccine adjuvants and drugs. The latest discoveries of herbs with effective anti-influenza activities are introduced here. The herbs or herbal extracts are explained with their backgrounds, effects and interactions, dosages, active components, scientific mechanisms, and references. For example, sometimes a low dosage may show a significant protective effect.

Excerpts:

“These findings may help explain the mechanisms of flavonoids as NA inhibitors for the influenza treatment. Such studies are also helpful for the designing of antiviral therapeutics.”

“The herbal extract may have antiviral effects. High molecular weight polyphenols in the fruit extract can inhibit influenza viruses. Treatment with the extract at concentrations … decreased … both type A and B influenza viruses.”

“Crude extraction from … has been found to be a potential adjuvant for the improvement of the immune responses of the influenza vaccine (H5N1)…”

“Flavonoids extracted from the herb have anti-influenza activities. Specifically, the herbal extract can inhibit the neuraminidase (NA) segment of influenza.”

“The herb may have anti-influenza effects. A polyphenol-rich extract from … has been found to protect mice from mortality in the A/Aichi/2/68 (H3N2) influenza infection. At the dose of …, the herbal extract showed a significant protective effect, with the protective index as high as 70.1%.”

“… may be used as potential mucosal adjuvants against influenza viruses. They may serve as immuno-modulators during influenza virus infection.”

“The antiviral activity of the herbal extract may be mediated by interaction with hemagglutinin (HA) segment of influenza at the initial stage of infection…. The derivatives had inhibitory effects for several influenza subtypes tested, including A/H1N1, A/H3N2 and B type, H2N2, and H9N2 avian influenza virus. The compounds suppressed the adsorption of the viruses by red blood cell (RBC)…. Within as early as 5 to 15 min after infection and depending on the virus strains, the growth of influenza A and B viruses could be suppressed when the cells were treated with….”

“The alkaloids of the herb inhibited the proliferation of influenza virus, at the concentration as low as ...”

“… is an active herbal component of the traditional Chinese herbal medicine recipe…”

“… Such effects suggest that … may be a safe and potent oral adjuvant for influenza HA … vaccine.”

“Exercise stress may lead to increased risk for upper respiratory tract infection…. can inhibit infectivity and replication of many viruses. The flavonoid may offset the increased susceptibility to viral infection caused by stressful exercise… Short-term supplementation of … may reduce the susceptibility to influenza (H1N1) infection…”