The growing diversity of increasing viral diseases in human infectious pathology, which have been observed in recent decades and was associated with a limited range of effective antiviral drugs, is one of the most pressing health problems worldwide.
Type 1 herpes simplex virus (HSV-1) is a neurotropic virus that can persist in human sensory neurons for the lifetime, replicate in epithelial cells during the primary infection and after the endogenous reactivation, and cause diseases with various clinical manifestations, from labial herpes to meningitis and encephalitis [1–3]. 60 % to 95 % world population is infected with one or even several herpes viruses, according to WHO [4].
Treatment of herpetic patients is customized, depends on the clinical form of infection, the disease severity, the recurrence rate, and includes etiotropic pathogenetic and symptomatic agents [5]. Most modern medications used to treat herpes virus infections are based on modified nucleosides. Their action is usually aimed at suppressing the activity of the main virus replication enzyme, DNA polymerase. Acyclovir is the golden standard for herpes infection treatment, and such medicines as Valacyclovir and Famcyclovir are also often used. For example, Valacyclovir, a modified form of Acyclovir, is less toxic and better tolerated by patients [5]. These drugs help alleviate the disease severity and limit the frequency of the disease symptoms in most cases but cannot cure the infection [4, 6]. In this regard, the search for efficient natural compounds that suppress the virus adsorption and reproduction selectively while not causing harm to the patient’s body and combining antiviral, anti-inflammatory and immunemodulating properties, the deriving of new agents for the virus infection prevention and treatment from them is among the priorities of modern virology.
Marine aquatic organisms are of considerable potential for development of such drugs. Sulfated polysaccharides derived from seaweed, in particular, carrageenans, the sulfated galactans of red algae, have been in the focus of researchers’ attention in recent years. Carrageenans are a family of sulfated hydrocolloids, the polymer chains of which consist of galactose (G) residues and its derivatives with alternating α-1→3 — and β-1→4-bonds [7, 8]. Carrageenans are classified by the location and number of sulfate groups (S) in monosaccharide residues and the presence of 3,6-anhydrogalactose (DA) in 4-O-substituted residues. Three types of carrageenans widely used in industry, designated as Kappa- (k, DA-G4S), iota- (I, DA2S-G4S), the so-called gelling types, and lambda- (λ, D2S6S-G2S, non-gelling type), contain one, two or three sulfate groups per repeated disaccharide link, respectively [8, 9]. However, natural polysaccharides most often have a complex hybrid structure; their structural features depend on many factors: species, algae habitat, etc. [10]. The scientific literature describes in some detail the antioxidant, anti-tumour, and immunemodulating activity of carrageenans [11–15].