**2. Results**

CRGs were isolated by aqueous extraction from the non-fruited form of red algae *Chondrus armatus* (Gigartinaceae), *Tichocarpus crinitus* (Tichocarpaceae), and *Ahnfeltiopsis flabelliformis* (Phyllophoraceae), harvested along the Russian coast of the Japanese Sea and separated using 4% KCl into the KCl-insoluble and KCl-soluble fractions. The structures of polysaccharides were studied by 13C-NMR and FT-IR-spectroscopy. The obtained spectra have been compared with the spectra of polysaccharides, which we had isolated earlier, from the above-mentioned species of algae [20–22]. The identity of the spectra indicates that the KCl-insoluble fraction form of *C. armatus*, *T. crinitus*, *A. flabelliformis*, were κ-, κ/β-, and ι/κ-types, respectively, and a KCl-soluble fraction from was *C. armatus*–λ-CRG.

The structures of disaccharide repeating units of the carrageenans and the sulfate content, as well as the average molecular weights of all the samples investigated, are summarized in Table 1. CRGs differ from each other in number and position of sulfated groups, and in the presence (κ, κ/β and ι/κ) or absence (λ) of 3,6-anhydrogalactose units (DA). The degree of sulfation decreased in the following row: λ > ι/κ > κ > κ/β.


**Table 1.** The structures of disaccharides repeating units of carrageenans from algae of Gigartinaceae and Phyllophoraceae families.
