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

Abstract

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.

Integrative Literature Analysis of Holopelagic Sargassum (Sargasso) in the Western Atlantic (2011–2022): Status, Trends, and Gaps

“…It was even observed that the GC and WC were the only ones that presented healthrelated studies [45][46][47][48][49][50], which reflected how sargasso inundations were considered a public health issue in those subregions. Attitudes about sargasso as a public health issue vary, with Florida governmental officials perceiving it as a nuisance rather than a public health threat, as it is seen in the Lesser Antilles [50,51].…”

Polysaccharides and Lectins: A Natural Complementary Approach against the SARS-CoV-2 Pandemic

“…Some earlier studies of Hayashi et al [134,135] evaluating the effect of Spirulina calcium spirulan against HIV-1 and HSV-2 in mice describe significantly higher antiviral potential compared with the standard dextran sulfate via a selective inhibition of penetration mediated through a chelating mechanism of sulfate groups [136]. Interestingly, the dry powder of Arthrospira maxima dissolved in Dulbecco's modified Eagle medium (DMEM) or dimethyl sulfoxide (DMSO) solvents was reported to provide good antiviral protection against the SARS-CoV-2 infection of Vero cells at 50 TCID 50 / mL and partial protection at 100 TCID 50 /mL; in the same in vitro conditions, the dry fucoidan powder showed minor antiviral activity [137]. This could reflect an important antiviral action of Spirulina polysaccharides given that the polysaccharide yield of the algae dry weight mass reaches around 8.3% [138]; however, the exact role of these nutraceuticalderived polysaccharides in SARS-CoV-2 infections remains insufficiently studied.…”

In Vitro Antiviral Activity of Nordihydroguaiaretic Acid against SARS-CoV-2

“…In the search for new drugs, some plants have been used as an important source of molecules that could provide novel therapeutic compounds such as antivirals. Previous studies have reported compounds obtained from functional foods with antiviral activity against SARS-CoV-2, such as curcumin, quercetin, epigallocatechin gallate, thymoquinone, and sulforaphane [ 14 , 15 , 16 ]; several of these phytomolecules have a remarkable potential to act as antipathogenic agents against bacteria, fungi and viruses [ 17 , 18 , 19 ]. In this sense, therapeutic compounds with different bioactivities, such as antibacterial, antioxidant, antiapoptotic, antiparasitic, anticarcinogenic and antiviral have been isolated from the leaves of the Larrea tridentata plant (Creosote bush) [ 20 , 21 , 22 , 23 , 24 , 25 ].…”