Anti-SARS-CoV-2 activity of different sulfated glycans. Plots showing (A) quantitation of GFP-transduced cells in the presence of different mammalian GAGs: unfractionated heparin, UFH (black); chondroitin sulfates CS-A, CS-B (dermatan sulfate), and CS-C (purple); and marine sulfated glycans: algal BoSG and sea urchin LvSF (gray), and holothurian PpFucCS (blue), IbFucCS (red), and IbSF (green) at an examined concentration of 50 mg/l. The average for the vehicle (control) is indicated with a dotted line. The numbers between parentheses on top of each bar indicate the average value. B, curves show percentage of SARS-CoV-2 inhibition of the three holothurian sulfated glycans and unfractionated heparin in a concentration-dependent manner. Numbers in parentheses indicate the increasing times observed in the IC50 values of the curves compared with the curve of the lowest IC50 value. C, plots showing percentage cell viability of HEK293T cells when treated with holothurian sulfated glycans at the highest concentration of 50 mg/l. ns stands for nonsignificant.