Antiviral activity of carrageenans from marine red algae

Abstract

Three carrageenan representatives of each structural type: λ- and ι –family (Gigartina acicularis), ι-family (Euchema denticulatum) and κ –family (Kappaphycus cottonii) have been tested for their in vitro antiviral activity. The carrageenans proved to be potent inhibitors of herpes human virus type 1 (HHV-1) and Poliovirus. The best results were obtained with carrageenans from Gigartina acicularis and Euchema denticulatum, which are more sulfated than those from Kappaphycus cottonii. The selective index values (CC50 /ID50 ) ranged from more than 22 to more than 545 for HHV-1 and more than 6.6 to more than 32 for Poliovirus. No citotoxic effects were observed. At 0.75 mg/ml, none of the carrageenans tested showed a virucidal activity against HHV-1 or Poliovirus. Carrageenans from Euchema denticulatum (ι- family) and Gigartina acicularis (λ- and ι –family) exerted their antiviral effect via, in part, by a lower inhibition of the virus attachment and by the interference in a subsequent stage of the virus replicative cycle. The κ-carrageenan from Kappaphycus cottonii exerted its antiviral effect mainly by a lower inhibition of the virus attachment. In cultures treated with carrageenans from Euchema denticulatum (ι-family) and Gigartina acicularis (λ- and ι –family), the HHV-1 viral DNA synthesis had a reduction of threefold and twofold with 0.75 mg/ml, respectively.