Inhibitory effect of microalgae and cyanobacteria extracts on influenza virus replication and neuraminidase activity

Abstract

BackgroundThe influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.5% of the world’s population is infected by this pathogen. This percentage can increase up to ten times during pandemics. Influenza vaccination is the most effective way to prevent disease. In addition, anti-influenza drugs are essential for prophylactic and therapeutic interventions. The oseltamivir (OST, a neuraminidase inhibitor) is the primary antiviral used in clinics during outbreaks. However, OST resistant viruses may emerge naturally or due to antiviral pressure, with a prevalence of 1–2% worldwide. Thus, the search for new anti-influenza drugs is extremely important. Currently, several groups have been developing studies describing the biotechnological potential of microalgae and cyanobacteria, including antiviral activity of their extracts. In Brazil, this potential is poorly known and explored.MethodsWith the aim of increasing the knowledge on this topic, 38 extracts from microalgae and cyanobacteria isolated from marine and freshwater biomes in Brazil were tested against: cellular toxicity; OST-sensitive and resistant influenza replications; and neuraminidase activity.ResultsFor this purpose, Madin-Darby Canine Kidney (MDCK)-infected cells were treated with 200 μg/mL of each extract. A total of 17 extracts (45%) inhibited influenza A replication, with seven of them resulting in more than 80% inhibition. Moreover, functional assays performed with viral neuraminidase revealed two extracts (from Leptolyngbya sp. and Chlorellaceae) with IC50 mean < 210 μg/mL for influenza A and B, and also OST-sensitive and resistant strains. Furthermore, MDCK cells exposed to 1 mg/mL of all the extracts showed viability higher than 80%.DiscussionOur results suggest that extracts of microalgae and cyanobacteria have promising anti-influenza properties. Further chemical investigation should be conducted to isolate the active compounds for the development of new anti-influenza drugs. The data generated contribute to the knowledge of the biotechnological potential of Brazilian biomes that are still little explored for this purpose.

Antiviral Cyanometabolites—A Review

“…In some studies, the potent antiviral activity of crude cyanobacterial extracts was documented, however, the active agents were not identified [ 132 , 133 , 134 ]. At concentrations non-toxic to MDCK cells, the extracts from several Microcystis strains inhibited the replication of influenza A virus [ 132 ].…”

Ten-Year Research Update Review: Antiviral Activities from Marine Organisms

“…Spirulina platensis (now Arthrospira platensis), a cyanobacterium able to live in both freshwater and marine water, produces a wide range of bioactive compounds with antifungal, antiprotozoal, antiviral and antibacterial activity [53][54][55]. Silva et al [16] demonstrated that ethyl acetate extract, rich in sulphated polysaccharide, of Leptolyngbya sp. is active against two Influenza viruses, A(H1N1)pdm09-WT and A(H3N2)-WT, by inhibiting the neuraminidase activity and replication.…”

“…Santoyo et al [62] also found antiviral activity of polysaccharide extracts from the Chlorophyceae Dunaliella salina. Polysaccharides-rich extract of In addition, Silva et al [16] tested crude organic extracts of the Dinophyceae Symbiodinium sp., the Raphidophyceae Chattonella sp. and Bacillariophyceae Nanofrustulum shiloi against Influenza A virus.…”

“…In addition, Silva et al [ 16 ] tested crude organic extracts of the Dinophyceae Symbiodinium sp., the Raphidophyceae Chattonella sp. and Bacillariophyceae Nanofrustulum shiloi against Influenza A virus.…”

Advances in the Biotechnological Potential of Brazilian Marine Microalgae and Cyanobacteria

“…In Brazil, the research demand for microorganisms as raw material is mostly related to bacteria, fungi and yeast. Investigations into microalgae and cyanobacteria are quite recent and address a range of interests, ranging from looking for biologically active substances to their pharmaceutical, nutraceutical and energy market applications [ 7 , 8 , 49 , 50 ]. However, a survey conducted in this work on intellectual property protection in Brazil revealed that, the use of marine cyanobacterial biomass as raw material is currently largely focused on the food market, particularly composing and, being the basis of some food supplements, according to data of the national patent registration bank in Brazil, certified by the National Institute of Industrial Property (INPI).…”