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Lectins are a unique group of nonimmune carbohydrate-binding proteins or glycoproteins that exhibit specific and reversible carbohydrate-binding activity in a non-catalytic manner. Lectins have diverse sources and are classified according to their origins, such as plant lectins, animal lectins, and fish lectins. Marine organisms including fish, crustaceans, and mollusks produce a myriad of lectins, including rhamnose binding lectins (RBL), fucose-binding lectins (FTL), mannose-binding lectin, galectins, galactose binding lectins, and C-type lectins. The widely used method of extracting lectins from marine samples is a simple two-step process employing a polar salt solution and purification by column chromatography. Lectins exert several immunomodulatory functions, including pathogen recognition, inflammatory reactions, participating in various hemocyte functions (e.g., agglutination), phagocytic reactions, among others. Lectins can also control cell proliferation, protein folding, RNA splicing, and trafficking of molecules. Due to their reported biological and pharmaceutical activities, lectins have attracted the attention of scientists and industries (i.e., food, biomedical, and pharmaceutical industries). Therefore, this review aims to update current information on lectins from marine organisms, their characterization, extraction, and biofunctionalities.

Background: Sailuotong (SLT) is a standardized three-herb formulation consisting of extracts of Panax ginseng , Ginkgo biloba , and Crocus sativus for the treatment of vascular dementia (VaD). Although SLT has been shown to increase cerebral blood flow, the direct effects of SLT on vascular reactivity have not been explored. This study aims to examine the vasodilatory effects of SLT and the underlying mechanisms in rat isolated tail artery., Methods: Male (250-300 g) Wistar Kyoto (WKY) rat tail artery was isolated for isometric tension measurement. The effects of SLT on the influx of calcium through the cell membrane calcium channels were determined in Ca 2+ -free solution experiments., Results: SLT (0.1-5,000  μ g/ml) caused a concentration-dependent relaxation in rat isolated tail artery precontracted by phenylephrine. In the contraction experiments, SLT (500, 1,000, and 5,000  μ g/mL) significantly inhibited phenylephrine (0.001 to 10  μ M)- and KCl (10-80 mM)-induced contraction, in a concentration-dependent manner. In Ca 2+ -free solution, SLT (500, 1,000, and 5,000  μ g/mL) markedly suppressed Ca 2+ -induced (0.001-3 mM) vasoconstriction in a concentration-dependent manner in both phenylephrine (10  μ M) or KCl (80 mM) stimulated tail arteries. L-type calcium channel blocker nifedipine (10  μ M) inhibited PE-induced contraction. Furthermore, SLT significantly reduced phenylephrine-induced transient vasoconstriction in the rat isolated tail artery., Conclusion: SLT induces relaxation of rat isolated tail artery through endothelium-independent mechanisms. The SLT-induced vasodilatation appeared to be jointly meditated by blockages of extracellular Ca 2+ influx via receptor-gated and voltage-gated Ca 2+ channels and inhibition of the release of Ca 2+ from the sarcoplasmic reticulum., Competing Interests: As a medical research institute, NICM Health Research Institute receives research grants and donations from foundations, universities, government agencies, individuals, and industry. Sponsors and donors also provide untied funding for work to advance the vision and mission of the institute. The authors declare no conflicts of interest., (Copyright © 2020 S. Y. Yeon et al.)