Antiviral activity of microalgae extracts against Mayaro virus

Chlorella spp., Spirulina spp., and fucoidan dry powders, are commercialized as food supplements and are considered safe for human consumption. Their broad-spectrum antiviral properties have been studied, however, their effect against SARS-CoV-2 remains unknown. We investigated the potential antiviral activity of three algae powders: Chlorella vulgaris, Arthrospira maxima (Spirulina) and fucoidan purified from marine brown algae Sargassum spp. against SARS-CoV-2 infection in vitro. Vero cells were incubated with 70 μg/ml of each algae powder and either 50 or 100 TCID50/ml of SARS-CoV-2, in two types of experiments (pretreatment and simultaneous) and comparing two kinds of solvents (DMEM and DMSO). Chlorella vulgaris powder, inhibited SARS-CoV-2 infection in all assays; viral RNA was significantly reduced in supernatants at 24, 48, 72, and 96 h post-infection, the highest difference in viral load (8000-fold) was observed after 96 h. Arthrospira maxima powder inhibited SARS-CoV-2 infection using 50 TCID50/ml for both experimental schemes, but protection percent was lower when viral inoculum was increase to 100 TCID50/ml; viral RNA decreased 48 h after infection, reaching a 250-fold difference at 72 h. Fucoidan powder partially inhibited SARS-CoV-2 infection since no CPE was observed in 62.5% of trated cultures in DMEM, but the antiviral activity was increased to 100% of protection when DMSO was used as solvent. All the algae samples showed high antiviral activity against SARS-CoV-2 with a SI above of 18. These results suggest that all three algae samples are potential therapeutic candidates for the treatment of COVID-19.

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“…Magdalena et al . 44 reported for C. vulgaris and A. maxima against Mayaro virus (MAYV) SI of 51.16 and 25.5 respectively 28 , 45 .…”

Section: Discussionmentioning

confidence: 99%

In vitro inhibition of SARS-CoV-2 Infection by dry algae powders

Garcia-Ruiz¹,

Villalobos-Sánchez²,

Alam-Escamilla³

et al. 2022

Sci Rep

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“…Microalgae are attractive and, even more, are considered crucial as natural sources of bioactive metabolites for developing innovative health compounds [ 12 , 17 , 18 ]. Indeed, it has been estimated that 9% of natural-sourced biomedical molecules are isolated from algal biomass, and many of them cannot be obtained via synthetic pathways [ 19 , 22 ].…”

Section: Discussionmentioning

confidence: 99%

“…The latter, perfectly in line with fluorimetric results, further suggested that an efficient stoichiometry of photosynthetic pigment was maintained in both cultures [ 42 ]; for comparative data on N. oleoabundans , see [ 9 , 10 , 26 ]. In addition to results on biomass yield and the whole physiological status of algae samples, the choice of the harvesting time was further supported by the notion that secondary metabolites, which can exert bioactive properties also as antivirals, are usually produced in larger amounts at the stationary phase of growth when cell duplication is reduced, and the products of the primary metabolism are channeled as substrates for the secondary metabolism [ 22 , 43 ]. In accordance, [ 22 ] found that the best antiviral effect against Mayaro Fever (due to the arbovirus MAYV) was obtained using extracts from A. platensis at the stationary phase.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to results on biomass yield and the whole physiological status of algae samples, the choice of the harvesting time was further supported by the notion that secondary metabolites, which can exert bioactive properties also as antivirals, are usually produced in larger amounts at the stationary phase of growth when cell duplication is reduced, and the products of the primary metabolism are channeled as substrates for the secondary metabolism [ 22 , 43 ]. In accordance, [ 22 ] found that the best antiviral effect against Mayaro Fever (due to the arbovirus MAYV) was obtained using extracts from A. platensis at the stationary phase. In those extracts, terpenoids, flavonoids, fatty acids and carotenoids were detected, essentially compounds with antiviral/antioxidant effects [ 19 , 22 , 44 ].…”

Section: Discussionmentioning

confidence: 99%

“…Focusing on the health sector, microalgae are a source of various bioactive compounds, like pigments, vitamins, polyunsaturated fatty acids, phenolics, polysaccharides, or proteins, which have been studied for their antibacterial, antiviral, anti-inflammatory, antioxidant, anticancer and other pharmacological activities [ 12 , 17 , 18 ]. As concerns microalgae with antiviral properties, promising results come from the cyanobacteria Spirulina platensis (also referred to Arthrospira platensis ) and Nostoc ellipsosporum , and from the Chlorophyta Dunaliella primolecta or Chlorella vulgaris and C. pyrenoidosa [ 19 , 20 , 21 , 22 ]; little of the literature information is available on other microalgae [ 19 , 23 , 24 ]. As an example, according to Scopus ® , around 200 documents with “microalgae” and “antiviral” as keywords were published from 1985 up to 2022; narrowing the search to “Spirulina” or “ Nostoc ” or “ Chlorella ” or “ Dunaliella ” and “antiviral” documents were, respectively, 126, 55, 48 and 19; papers referring to other microalgae were usually below 10 (searched genera: Scenedesmus , Chlamydomonas , Neochloris , Tetraselmis , Amphora ).…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Neochloris oleoabundans under Different Cultivation Modes and First Results on Bioactivity of Its Extracts against HCoV-229E Virus

Baldisserotto

Gentili

Rizzo

et al. 2022

Plants

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Microalgae are proposed in several biotechnological fields because of their ability to produce biomass enriched in high-value compounds according to cultivation conditions. Regarding the health sector, an emerging area focuses on natural products exploitable against viruses. This work deals with the characterization of the green microalga Neochloris oleoabundans cultivated under autotrophic and mixotrophic conditions as a source of whole aqueous extracts, tested as antivirals against HCoV-229E (Coronaviridae family). Glucose was employed for mixotrophic cultures. Growth and maximum quantum yield of photosystem II were monitored for both cultivations. Algae extracts for antiviral tests were prepared using cultures harvested at the early stationary phase of growth. Biochemical and morphological analyses of algae indicated a different content of the most important classes of bioactive compounds with antiviral properties (lipids, exo-polysaccharides, and total phenolics, proteins and pigments). To clarify which phase of HCoV-229E infection on MRC-5 fibroblast cells was affected by N. oleoabundans extracts, four conditions were tested. Extracts gave excellent results, mainly against the first steps of virus infection. Notwithstanding the biochemical profile of algae/extracts deserves further investigation, the antiviral effect may have been mainly promoted by the combination of proteins/pigments/phenolics for the extract derived from autotrophic cultures and of proteins/acidic exo-polysaccharides/lipids in the case of mixotrophic ones.

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