Well-tolerated Spirulina extract inhibits influenza virus replication and reduces virus-induced mortality

[tetano]

Sci Rep. 2016 Apr 12;6:24253. doi: 10.1038/srep24253.
[h=1]Well-tolerated Spirulina extract inhibits influenza virus replication and reduces virus-induced mortality.[/h] Chen YH[SUP]1,[/SUP][SUP]2[/SUP], Chang GK[SUP]1[/SUP], Kuo SM[SUP]1[/SUP], Huang SY[SUP]1,[/SUP][SUP]2[/SUP], Hu IC[SUP]3[/SUP], Lo YL[SUP]1[/SUP], Shih SR[SUP]1,[/SUP][SUP]4,[/SUP][SUP]2,[/SUP][SUP]5[/SUP].
[h=3]Author information[/h]

[h=3]Abstract[/h] Influenza is one of the most common human respiratory diseases, and represents a serious public health concern. However, the high mutability of influenza viruses has hampered vaccine development, and resistant strains to existing anti-viral drugs have also emerged. Novel anti-influenza therapies are urgently needed, and in this study, we describe the anti-viral properties of a Spirulina (Arthrospira platensis) cold water extract. Anti-viral effects have previously been reported for extracts and specific substances derived from Spirulina, and here we show that this Spirulina cold water extract has low cellular toxicity, and is well-tolerated in animal models at one dose as high as 5,000 mg/kg, or 3,000 mg/kg/day for 14 successive days. Anti-flu efficacy studies revealed that the Spirulina extract inhibited viral plaque formation in a broad range of influenza viruses, including oseltamivir-resistant strains. Spirulina extract was found to act at an early stage of infection to reduce virus yields in cells and improve survival in influenza-infected mice, with inhibition of influenza hemagglutination identified as one of the mechanisms involved. Together, these results suggest that the cold water extract of Spirulina might serve as a safe and effective therapeutic agent to manage influenza outbreaks, and further clinical investigation may be warranted.


PMID: 27067133 [PubMed - in process] Free full text

 

[Emily]

I was relieved to see that the effective dose for humans might be much lower than the doses they used in rats. I guess they were ruling out toxicity with the high doses.

http://www.nature.com/articles/srep24253

The doses tested in rats roughly translate to a single dose of 50 g or a daily dose of 30 g for 14 days in a 60-kg human. Considering that the EC[SUB]50[/SUB] for Spirulina extract ranges from 1.0?1.3 mg/mL in vitro, and that doses of 10?50 mg/kg/day were sufficient to improve survival in flu-infected mice which is equalled to 243.3 mg/kg/day in human, it is unlikely that the high doses used in the toxicity studies would ever be applied in a clinical setting. Small scale clinical trials have shown that a daily 50-mL dose of Spirulina hot water extract enhanced interferon-γ production and natural killer (NK) cell functions in healthy male volunteers[SUP]17[/SUP], while a daily 2,000 mg dose of Spirulina significantly reduced IL-4 levels to modulate cytokine profiles in patients with allergic rhinitis[SUP]18[/SUP]. Furthermore, rhinitis patients treated with a tablet containing just 370 mg of powdered Spirulina exhibited significant improvement in symptoms[SUP]19[/SUP]. This shows that Spirulina extract may exert therapeutic effects at doses far below those tested and found to be safe in our animal toxicity studies.