Chemically Engineered Sulfated Glucans from Rice Bran Exert Strong Antiviral Activity at the Stage of Viral Entry

Abstract

Attachment and entry of many viruses are mediated by their affinity for polysaccharides present on the surface of target cells. In this paper, we demonstrate that sulfated glucans isolated from rice (Oryza sativa) can be utilized as experimental drugs exerting strong antiviral activity. In particular, oleum-DMF-based extraction is described as a procedure for the generation of chemically engineered glucans from commercially available rice bran. The one-step procedure has the potential to provide a spectrum of related glucans with varying molecular masses and modifications, including sulfation. The sulfated glucans P444, P445, and P446 possess increased antiviral activity compared to a previously described glucan (S1G). P444, P445, and P446 were highly active against human cytomegalovirus (HCMV), moderately active against other members of the family Herpesviridae, while not active against unrelated viruses. Specific experimentation with HCMV-infected cells provided evidence that antiviral activity was based on inhibition of viral entry and that inhibition occurred in the absence of drug-induced cytotoxicity. These findings underline the high potential of sulfated glucans for antiviral research and drug development. In addition, the procedure described for the efficient transformation of glucan hydroxy groups to sulfate groups may be similarly beneficial for the chemical alteration of other natural products.

Differential Expression of PDGF Receptor-α in Human Placental Trophoblasts Leads to Different Entry Pathways by Human Cytomegalovirus Strains

“…As PDGFRα provides an additional CMV entry pathway into trophoblasts, specific inhibitor(s) of this pathway, in combination with potent neutralising antibodies against viral pentameric complex and gB may provide a more effective prevention of CMV infection in placental trophoblast cells, and possibly other placental cell types. In a further study, chemically engineered sulfated glucans were also shown to have high antiviral activity against CMV at the stage of viral entry into human fibroblasts 77 , and may be promising candidates for drug development and antiviral strategies.…”

Dietary Rice Bran Protects against Rotavirus Diarrhea and Promotes Th1-Type Immune Responses to Human Rotavirus Vaccine in Gnotobiotic Pigs

“…Given the RB-mediated protection against bacterial pathogens (7)(8)(9) and the stimulatory effects on both the innate and adaptive immune systems, RB represents a promising natural food product for modulating mucosal immunity and protecting against diarrhea from major enteric pathogens such as human rotavirus. The gnotobiotic (Gn) pig model of human rotavirus (HRV) infection and diarrhea has been extensively utilized to study HRV infection and vaccination (10)(11)(12)(13)(14).…”

Enzymatic Modification of Rice Bran Polysaccharides by Enzymes from Grifola Frondosa: Natural Killer Cell Cytotoxicity and Antioxidant Activity

“…For example, Wang et al. () modified the water‐soluble polysaccharide RBPSs2a, which was purified from RB, with sulfates to obtain SRBPSs2a, and the anti‐tumor activity of the polysaccharide was higher after modification (Ray et al., ). One of the most widely studied modified polysaccharides, MGN‐3, which is mainly composed of arabinoxylan from RB, was modified using carbohydrate‐hydrolyzing enzymes extracted from shiitake mushrooms (Ghoneum, ; Pérezmartínez et al., ).…”