PROTECTIVE ANTI-ULCER EFFECTS OF WATER EXTRACT OF LICHEN PARMELIAVAGANS IN RATS DURING EXPERIMENTAL ULCEROGENESIS MODELING

Abstract: the gastroprotective activity of water extract of lichen Parmelia vagans was studied on 3 experimental models of ulcer formation: ethanol, stress and pilorus ligation. It is known that usninic acid and other symbiotic metabolites of lichens have expressed anti-inflammatory properties, which have been proven in various experimental models of pathology: models of adjuvant arthritis, burn disease, atopic dermatitis, etc. Peptic ulcer disease is also accompanied by a significant inflammatory process, so it has been suggested that the biologically active substances of lichens can have an anti-ulcer effect, largely preventing the development and speeding up the healing of ulcers.

It was shown that the aqueous extract of the studied lichen increases the resistance of the gastric mucosa to various ulcerogenic factors of both local and central origin. The ethanol model of ulceration and pilorus ligation mainly involves peripheral mechanisms of ulcerogenesis caused by a violation of adequate blood flow, changes in acidic secretion of the stomach and direct vasoconstriction associated with ethanol exposure. The stress model of ulceration involves the Central mechanisms of ulcerogenesis, primarily associated with the activation of the hypothalamic-pituitary-adrenal and sympatho-adrenal systems, which ultimately leads to hyperproduction of the main stress hormones-cortisol, epinephrine and norepinephrine. The latter, in turn, have a powerful vasoconstrictor effect, which leads to the development of persistent tissue ischemia and microcirculatory disorders.

The value of the protective anti-ulcer effect on all three experimental models of ulceration was statistically significant and amounted to 77.4% for the ethanol model, 83.3% for the stress model, and 81% for the pylorus ligation.

Keywords: antiulcer activity, Parmelia vagans, homeostasis of the gastric mucosa

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