Immunotropic Properties of Polysaccharides Isolated From the Shoots of Alma-Ata Hawthorn (Crataegus almaatensis Pojark.) and Soft Hawthorn (Crataegus submollis Sarg.)

Background: Interest in the study of polysaccharides derived from higher plants is due to their high biological activity coupled with low toxicity. Polysaccharides and oligosaccharides extracted from the fruits and flowers of various hawthorn species (Crataegus spp.) exhibit diverse effects, including anticoagulant and hypolipidemic activities, as well as antioxidant and probiotic properties. Therefore, the study of the immunomodulatory properties of polysaccharides derived from the shoots of Alma-Ata hawthorn (Crataegus almaatensis Pojark.) and soft hawthorn (Crataegus submollis Sarg.) is of particular interest.

Aim: The work aimed to study the immunotropic effects of water-soluble polysaccharides derived from the shoots of Alma-Ata hawthorn (Crataegus almaatensis Pojark.) and soft hawthorn (Crataegus submollis Sarg.).

Methods: Water-soluble polysaccharides were derived from the shoots of Alma-Ata hawthorn and soft hawthorn by extraction followed by filtration, dialysis, and lyophilization. The water-soluble polysaccharides were injected intraperitoneally to C57BL/6 mice at a dose of 10 mg/kg; animals in the control group received 0.9% sodium chloride solution, and the comparison group received glucosaminylmuramyl dipeptide at a dose of 20 µg/kg for 10 days. The effects of the water-soluble polysaccharides on humoral and cell-mediated immune responses induced by sheep red blood cell immunization were evaluated. In in vitro experiments, water-soluble polysaccharides were added to the culture medium at a concentration of 20 µg/mL, and the production of IL-1β, TNF-α, and NO, arginase activity, cell proliferation in cultures of peritoneal macrophages, and the production of IL-2 and IFN-γ by cultures of mouse splenocytes were assessed.

Results: Course administration of water-soluble polysaccharides derived from the shoots of Alma-Ata hawthorn and soft hawthorn stimulated the humoral immune response in experimental animals and did not affect the cell-mediated immune response. Addition of the polysaccharides derived from the shoots of Alma-Ata hawthorn and soft hawthorn to the culture medium increased the production of IL-1β and TNF-α, enhanced nitric oxide synthase activity, reduced arginase induction in macrophages, and increased both spontaneous IL-2 secretion and stimulated IFN-γ production by splenocytes from C57BL/6 mice.

Conclusions: Administration of water-soluble polysaccharides derived from the shoots of Alma-Ata hawthorn and soft hawthorn resulted in an increased number of antibody-forming cells after immunization with sheep red blood cells and enhanced production of IL-1β, TNF-α, and NO by macrophages and IL-2 and IFN-γ by splenocytes from C57BL/6 mice. The studied polysaccharide samples showed no cytotoxicity against macrophages.