Carrageenans and the Carrageenan-Echinochrome Complex as Anti-SARS-CoV-2 Agents

DOI record: { "DOI": "10.3390/ijms26136175", "ISSN": [ "1422-0067" ], "URL": "http://dx.doi.org/10.3390/ijms26136175", "abstract": "<jats:p>The diversity of structural types of carrageenans (CRGs)—sulfated polysaccharides of red algae—determines their different biological activities. The different types of CRGs (kappa, lambda, kappa/beta-CRGs) were isolated from the red algae of the Pacific coast. Molecular docking was performed to determine potential interactions of CRGs with the receptor-binding domain (RBD) of SARS-CoV-2 and its cellular receptor—angiotensin—converting enzyme type 2 (ACE2). CRGs interacted with ACE2 and RBD via hydrogen bonding and ionic interactions. The strongest binding affinity of CRGs and ACE2 was observed for kappa-CRG. Molecular docking was confirmed by results studying the effects of CRGs against SARS-CoV-2 in vitro. The ability of CRGs, as well as the complex CRG with sea urchin echinochrome (Ech), to inhibit SARS-CoV-2 replication in Vero E6 cells was studied using cytopathic effect (CPE) inhibition and RT-PCR assays. The simultaneous treatment of cells with CRGs and the virus revealed that kappa-CRG exhibited the most significant antiviral effect among all the polysaccharides, with a selective index (SI) of 33. The kappa-CRG/Ech complex exhibited the highest virucidal effect on SARS-CoV-2 particles with an SI above 70 (more than two times higher than that of CRG and Ech) and reduced viral RNA levels by 45% (IC = 45%). Our results illustrate that CRGs and kappa-CRG/Ech complex can act as protective agents against SARS-CoV-2.</jats:p>", "alternative-id": [ "ijms26136175" ], "author": [ { "ORCID": "https://orcid.org/0000-0002-9048-6803", "affiliation": [ { "name": "G.P. Somov Institute of Epidemiology and Microbiology, Rospotrebnadzor, 690087 Vladivostok, Russia" } ], "authenticated-orcid": false, "family": "Krylova", "given": "Natalya V.", "sequence": "first" }, { "affiliation": [ { "name": "G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia" } ], "family": "Kravchenko", "given": "Anna O.", "sequence": "additional" }, { "ORCID": "https://orcid.org/0000-0003-1937-1680", "affiliation": [ { "name": "G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia" } ], "authenticated-orcid": false, "family": "Likhatskaya", "given": "Galina N.", "sequence": "additional" }, { "ORCID": "https://orcid.org/0000-0002-6723-582X", "affiliation": [ { "name": "G.P. Somov Institute of Epidemiology and Microbiology, Rospotrebnadzor, 690087 Vladivostok, Russia" } ], "authenticated-orcid": false, "family": "Iunikhina", "given": "Olga V.", "sequence": "additional" }, { "affiliation": [ { "name": "G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia" } ], "family": "Glazunov", "given": "Valery P.", "sequence": "additional" }, { "affiliation": [ { "name": "G.P. Somov Institute of Epidemiology and Microbiology, Rospotrebnadzor, 690087 Vladivostok, Russia" } ], "family": "Zaporozhets", "given": "Tatyana S.", "sequence": "additional" }, { "affiliation": [ { "name": "G.P. Somov Institute of Epidemiology and Microbiology, Rospotrebnadzor, 690087 Vladivostok, Russia" } ], "family": "Shchelkanov", "given": "Mikhail Y.", "sequence": "additional" }, { "affiliation": [ { "name": "G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of the Russian Academy of Science, 690022 Vladivostok, Russia" } ], "family": "Yermak", "given": "Irina M.", "sequence": "additional" } ], "container-title": "International Journal of Molecular Sciences", "container-title-short": "IJMS", "content-domain": { "crossmark-restriction": false, "domain": [] }, "created": { "date-parts": [ [ 2025, 6, 27 ] ], "date-time": "2025-06-27T07:33:25Z", "timestamp": 1751009605000 }, "deposited": { "date-parts": [ [ 2025, 6, 28 ] ], "date-time": "2025-06-28T04:31:11Z", "timestamp": 1751085071000 }, "funder": [ { "award": [ "122041800135-3" ], "name": "Rospotrebnadzor of the Russian Federation in the framework of the implementation of the state task" }, { "DOI": "10.13039/501100006769", "award": [ "21-74-20019-P" ], "doi-asserted-by": "crossref", "id": [ { "asserted-by": "crossref", "id": "10.13039/501100006769", "id-type": "DOI" } ], "name": "Russian Science Foundation" } ], "indexed": { "date-parts": [ [ 2025, 6, 28 ] ], "date-time": "2025-06-28T05:10:01Z", "timestamp": 1751087401944, "version": "3.41.0" }, "is-referenced-by-count": 0, "issue": "13", "issued": { "date-parts": [ [ 2025, 6, 26 ] ] }, "journal-issue": { "issue": "13", "published-online": { "date-parts": [ [ 2025, 7 ] ] } }, "language": "en", "license": [ { "URL": "https://creativecommons.org/licenses/by/4.0/", "content-version": "vor", "delay-in-days": 0, "start": { "date-parts": [ [ 2025, 6, 26 ] ], "date-time": "2025-06-26T00:00:00Z", "timestamp": 1750896000000 } } ], "link": [ { "URL": "https://www.mdpi.com/1422-0067/26/13/6175/pdf", "content-type": "unspecified", "content-version": "vor", "intended-application": "similarity-checking" } ], "member": "1968", "original-title": [], "page": "6175", "prefix": "10.3390", "published": { "date-parts": [ [ 2025, 6, 26 ] ] }, "published-online": { "date-parts": [ [ 2025, 6, 26 ] ] }, "publisher": "MDPI AG", "reference": [ { "DOI": "10.3390/md19080409", "doi-asserted-by": "crossref", "key": "ref_1", "unstructured": "Geahchan, S., Ehrlich, H., and Rahman, M.A. (2021). 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