Study of antiviral activity of Apogen, an extract of the microalga Spirulina platensis
Date Issued
2008
Date
2008
Author(s)
Cheng, Chun-Ting
Abstract
Rotavirus and adenovirus 41 (Ad41) are the etiological agents of acute gastroenteritis in infants and children, respiratory syncytial virus (RSV) and parainfluenza virus 3 (PIV3) are the etiological agents of lower respiratory tract infectious diseases in infants and children, and coxsackievirus A24 variant (CA24v) causes acute conjunctivitis. There are still no effective treatment for the infection of these viruses. Previously, studies have shown that enterovirus 71 induced cell apoptosis could be inhibited by commercial extracts of blue-green alga, Spirulina platensis “Apogen”, and the antiviral activity of Apogen against other viruses has also been demonstrated. In this study, we intend to understand whether the “Apogen” has antiviral activity against these viruses. Fluorescent focus reduction assay, MTT test, and hemadsorption test were used to determine the EC50 (effective concentration 50%) for rotavirus, RSV and PIV3, respectively, and the values were 0.327 mg/ml, 0.195 mg/ml and 1.17 mg/ml, respectively. The MTT test was also used to evaluate the CC50 (cytotoxicity concentration 50%), and the SI (selectivity index) was calculated. The SI values of rotavirus, RSV, and PIV3 are 55, 98, and 12.9, respectively. We also found that Apogen could not inhibit CA24v and Ad41 infection. The antiviral activities of the major protein components of Apogen, allophycocyanin and C-phycocyanin, were also evaluated and no antiviral activities were found. By the time of drug addition test, we found that Apogen could inhibit the infection of RSV and PIV3 and the replication of rotavirus in cells. The inhibition test of cell attachment and penetration provided the evidence that Apogen could inhibit RSV and PIV3 binding to cells and penetrating into cells. For PIV3, by using the hemagglutination inhibition test and hemadsorption inhibition test using HN expressed cells, we found that the activity of hemagglutinin was not influenced by Apogen. For rotavirus, by using RNA PAGE, real-time PCR, and fluorescent antibody staining, we found that the viral protein synthesis was inhibited by Apogen, but the viral RNA replication not. In conclusion, the results indicated that Apogen contains one constituent with multiple antiviral functions or two or more constituents exhibiting different antiviral activities and the substances may not be proteins. In the future, we hope to isolate the real antiviral components and further investigate the antiviral mechanisms.
Subjects
Spirulina platensis
rotavirus
respiratory syncytial virus
parainfluenza virus 3
enterovirus 71
coxsackievirus A24 variant
adenovirus 41
antiviral activity
SDGs
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