Table 2.

Polysaccharides from natural sources reported to have antiviral activities.

Origin	Polysaccharides	Antiviral Effects	Mechanisms	References
I.Animal
Bovine and porcine tissues	Heparin	Anti-CMV, HSV, HPV, DENV, JEV, YFV, ZIKV, HIV	Inhibition of adsorption	[78,79,80]
Cartilage of animals	Chondroitin sulfate	Anti-HIV, HSV, HTLV-1, DENV	Inhibition of adsorption	[81,82,83,84]
Crustacean shell	Chitosan	Anti-bacteriophages, plant viruses, HIV, FCV-F9	Direct virucidal effect	[85,86]
Shellfish	Shellfish polysaccharide	Anti-HBV, HIV-1, IFV, HSV-1	Inhibition of adsorption	[87,88]
II.Algal and plant
Brown algae	Fucoidan	Anti-HIV, DENV, IAV, NDV, HSV	Inhibition of adsorption and transcription	[89,90,91]
	Laminarin	Anti-HIV	Inhibition of adsorption and transcription	[92]
	Alginate	Anti-HIV, HBV, IAV, TMV	Inhibition of transcription	[93,94]
Red algae	ι-carrageenan	Anti-DENV, HAV, HRV, IAV, HPV, ECMV, HSV, SFV, ASV, VV	Inhibition of adsorption, penetration, uncoating, replication and transcription	[82,92,95,96,97,98,99]
	κ-carrageenan	Anti-enterovirus, IAV, HSV, CMV, Sindbis virus, VV, HIV, DENV, TMV	Inhibition of replication and transcription	[97,100]
	λ-carrageenan	Anti-DENV, HSV, HPV, HAV, CMV, HIV, Sindbis virus, VV, BoHV-1, SuHV-1, RABV	Direct virucidal effect, inhibition of adsorption	[95,97,101,102]
	β-carrageenan	TMV	-	[103]
Green algae	Ulvan	Anti-IFV-A, JEV, NDV	Inhibition of penetration and uncoating	[104,105,106,107,108]
Diatom (microalga)	Naviculan	Anti-HIV, HSV-1, HSV-2, IFV	Inhibition of adsorption	[109]
Microalgae	Sulfated polysaccharide	Anti IAV, HIV-1, HSV-1, IFV-A, IFV-B, RSV-A, RSV-B, PIFV-2, EMCV	Inhibition of penetration and replication	[76,78,110,111,112,113]
Edible	Edible polysaccharide	Anti-DEV, HSV-1	Inhibition of adsorption, penetration and uncoating	[114,115]
Medicinal plants	Medicinal plant polysaccharide	Anti-HSV-2, PV-1, PV-2, DHAV, BoHV-1, HBV, H1N1, H3N2, HIV, rotavirus	Inhibition of adsorption and replication	[116,117]
III.Mushroom
Mushrooms	Mushroom polysaccharide	Anti-IFV-A *, PV-1, HIV-1, HBV, IHNV	Inhibition of transcription and replication	[118,119,120]
IV.Microbial
Marine bacterias	EPS	Anti-HSV-2, HSV-1	Inhibition of adsorption	[121]
Cyanobacterias	Calcium spirulan	Anti-HSV-1, HCMV, measles virus, mumps virus, IAV, HIV-1	Inhibition of adsorption and replication	[122,123]
	Nostoflan	Anti-HSV-1, HSV-2, IAV, HCMV	Inhibition of adsorption	[124,125]

* Inhibitory effect observed in vivo.