TABLE 1.

Antiviral extracts and compounds found in gastropod and bivalve molluscs, with suggested modes of action^a

Mollusc common name and species	Antiviral extract or compound	Virus target(s)	Suggested mode of action	Reference(s)
Gastropod
Abalone Haliotis laevigata and H. rubra	Lipophilic extract from the digestive gland	HSVs	Antiviral activity occuring postentry	30
	Hemolymph plasma	HSV-1	Prevention of viral attachment and entry into cells	30
Abalone H. rufescens	Aqueous extract from canned abalone	Polyomavirus, influenza A virus, and poliovirus	Unknown	21, 22
Periwinkle Littorina littorea	Peptide extract from whole organism (littorein)	HSV-1	Unknown	34
Snail Buccinulum corneum	Kelletinin A [ribityl-pentakis (p-hydroxybenzoate)]	Human T-cell leukemia virus type 1	Inhibition of viral transcription and DNA/RNA synthesis (i.e., by inhibition of virus DNA polymerase α and reverse transcriptases)	40, 42
Veined rapa whelk Rapana venosa	Glycosylated functional unit of hemocyanin/RtH2	Respiratory syncytial virus, HSV-1 and HSV-2, and EBV	Prevention of virus attachment to cells by interaction with specific regions of HSV glycoproteins	27, 32, 39, 43, 39
Snail Helix lucorum	Hemocyanin extract	EBV	Inhibition of viral DNA replication	44
Whelk Buccinum undatum	80% SPE fraction from the acidic extract of whole organism	HSV-1	Unknown	33
Bivalves
Clam Mya arenaria	Water and ammonium sulfate extract/paolin	Amphibian virus LT-1, adenovirus type 12, HSV	Inhibition of viral infection (LT-1) at intracellular level; inhibition of tumors in hamsters by adenovirus 12	24, 26
Clam Mercenaria mercenaria	Partially purified ammonium sulfate extracts	Moloney and Friend murine leukemia viruses	Unknown	45
Clam Ruditapes philippinarum	80% SPE fraction from the acidic extract of whole organism	HSV-1	Unknown	33
Cockle Cerastoderma edule	80% SPE fraction from acidic extract of whole organism	HSV-1	Unknown	33
Mediterranean mussel Mytilus galloprovincialis	Mytilin	White spot syndrome virus	Inhibition viral transcription	29
	Defensin	HIV-1	Unknown	38
Mussel Crenomytilus grayanus	Lectin	HIV	Blocking of viral entry	37
Oyster Crassostrea virginica	Acetic acid extract/paolin 2	Poliovirus type 1	Unknown	41
Oyster C. gigas	Hemolymph plasma and peptide extracts from the whole animal	HSV-1, infectious pancreatic necrosis virus, human adenovirus, simian rotavirus	Inhibition of viral attachment to the cell surface	35, 36, 46–48
Oyster C. rhizophorae	Hemolymph plasma and peptide extracts from the whole animal	HSV-1, human adenovirus, simian rotavirus	Inhibition of viral attachment to the cell surface	46
Oyster Ostrea edulis	80% SPE fraction from the acidic extract of gills and mantle	HSV-1	Unknown	33

^aHIV-1, human immunodeficiency virus type 1; SPE, solid-phase-extraction.