Volume 38, Issue 1, January 2014, Pages 40–46
Open Access
Research article
Red Ginseng-containing diet helps to protect mice and ferrets from the lethal infection by highly pathogenic H5N1 influenza virus
- Open Access funded by The Korean Society of Ginseng
- Under a Creative Commons license
Abstract
The
highly pathogenic (HP) H5N1 influenza virus is endemic in many
countries and has a great potential for a pandemic in humans. The
immune-enhancing prowess of ginseng has been known for millennia. We
aimed to study whether mice and ferrets fed with Red Ginseng could be
better protected from the lethal infections of HP H5N1 influenza virus
than the infected unfed mice and ferrets. We fed mice and ferrets with
Red Ginseng prior to when they were infected with HP H5N1 influenza
virus. The mice and ferrets fed with a 60-day diet containing Red
Ginseng could be protected from lethal infections by HP H5N1 influenza
virus (survival rate of up to 45% and 40%, respectively). Interferon-α
and -γ antiviral cytokines were significantly induced in the lungs of
mice fed Red Ginseng, compared to mice fed an unsupplemented diet. These
data suggest that the diet with the immune-enhancing Red Ginseng could
help humans to overcome the infections by HP H5N1 influenza virus.
Keywords
- H5N1;
- influenza;
- interferon;
- Panax ginseng;
- pandemic
1. Introduction
Influenza viruses belong to the Orthomyxoviridae
with genomic negative-sense ribonucleic acid. They are classified as A,
B, and C by antigenic differences in their nucleocapsid (NP) and matrix
(M) proteins [1].
Influenza A viruses are circulating in aquatic birds and have been
responsible for human pandemics. Sixteen subtypes of hemagglutinin (HA)
and nine subtypes of neuraminidase (NA) of influenza A viruses have thus
far been described in aquatic birds [2] and [3].
Influenza
pandemics in humans by influenza A viruses occur three to four times
per century. During the 20th century, humans experienced three pandemics
including the Spanish pandemic by avian-like H1N1 influenza virus in
1918, the Asian pandemic by the reassorted H2N2 influenza virus in 1957,
and the Hong Kong pandemic by the reassorted H3N2 influenza virus in
1968 [4], [5], [6], [7], [8] and [9]. Among them, the Spanish pandemic was exceptional in terms of its mortality, with over 20 million human deaths [4] and [5].
In this century, a pandemic involving reassorted H1N1 influenza virus
containing the human, avian, and swine-origin genomes of influenza A
virus has occurred in 2009 [10].
Highly
pathogenic (HP) H5N1 influenza virus has the potential to become a
pandemic influenza virus in humans, because this virus continues to
infect humans and is global in its occurrence. HP H5N1 influenza virus
has successfully negotiated the species barrier from poultry to humans,
killing six of 18 infected humans in Hong Kong in 1997 [11]. Since 2003, the virus has spread to many countries including Indonesia, Pakistan, Thailand, and Vietnam [12], [13] and [14].
As of July 5, 2013, 377 of 633 infected humans have died from
infections caused by HP H5N1 influenza virus, a mortality rate of over
59%, despite the intensive care the patients received [15].
The clinical signs of human infection with HP H5N1 influenza virus include high fever, severe diarrhea, seizures, and coma [14] and [16]. Efforts have been made to develop an effective vaccine to prepare for the anticipated pandemic [17], [18] and [19].
In
seeking other forms of treatment, attention has turned to medicinal
plants, which have a history of human disease relief dating back to the
Neanderthal period [20]. Botanical gardens established to grow medical plants date back to at least the 16th century [21].
Use of herbal medications in the United States began in the early
colonial days, when women provided their family with health care. In
1974, the World Health Organization (WHO) recommended the use of herbal
medicines in developing countries, whose modern medical infrastructure
can be deficient [22].
Panax ginseng
has been used as a traditional medicine in China and Korea for over
2,000 years and has been suggested to enhance immune responses, memory,
and physical capabilities [23], [24] and [25].
Ginseng saponins (ginsenosides) are the main substances in the total
extracts of ginseng and over 30 ginsenosides have been identified in Panax ginseng [26].
The pharmacological effects of ginseng have been reported in the
central nervous, cardiovascular, endocrine, and immune systems [27].
The
present study was undertaken to investigate whether dietary treatment
with Red Ginseng could aid in the survival from lethal infections of HP
H5N1 influenza virus and the underlying mechanisms of the protection.
For these purposes, mice and ferret models were used.
2. Materials and methods
2.1. Virus and Red Ginseng
The
HP H5N1 influenza virus, A/Vietnam/1203/04 (clade 1), was kindly
provided by the WHO Collaborating Center for Influenza, the United
States Centers for Disease Control and Prevention. HP H5N1 influenza
virus was grown in 10-d-old hen eggs (Dukhee farm, Icheon, Republic of
Korea) prior to use. All viral experiments were performed in a Biosafety
Level-3 (BSL-3) facility approved by the Korean government. Red Ginseng
(Panax ginseng Meyer) extracts were provided by the Korean
Ginseng Co, Daejeon. Korean Red Ginseng (KRG) extract was prepared from
the roots of a 6-yr-old fresh Panax ginseng Meyer grown in
Korea. Red Ginseng was made by steaming fresh ginseng at 90–100°C for
3 h and then drying at 50–80°C. Red Ginseng extract was prepared from
the Red Ginseng water extract, which was extracted at 85–90°C for 8 h
using three cycles of hot water circulation. The ingredients of the Red
Ginseng (Panax ginseng Meyer) extracts included 0.71 mg/g of
Radical g (Rg)1, 0.93 mg/g of Radical e (Re), 1.21 mg/g of Radical f
(Rf), 0.78 mg/g of Radical h (Rh)1, 1.92 mg/g of Rg2(s), 1.29 mg/g of
Rg2(r), 4.62 mg/g of Radical b (Rb)1, 2.41 mg/g of Radical c (Rc),
1.83 mg/g of Rb2, 0.89 mg/g of Rd, 2.14 mg/g of Rg3(s), and 0.91 mg/g of
Rg3(r). The total content of the extracts was 19.66 mg/g.
2.2. Ethics statement
This
study was carried out in strict accordance with the recommendations in
the Guide for the Care and Use of Laboratory animals of the Korean
Veterinary Research and Quarantine Service. The protocol was approved by
the Committee on the Ethics of Animal Experiments of Chungnam National
University. All surgery was performed under Zoletil anesthesia (Virbac
Laboratories, Crros, France), and all efforts were made to minimize
suffering. Animals were fed with enough foods and water. The infected
animals were monitored twice a day.
