Announcement about the defense of Ruzibayeva Raykhan Matnazarovna Doctor of Philosophy (PhD) dissertation

Announcement about the defense of Ruzibayeva Raykhan Matnazarovna Doctor of Philosophy (PhD) dissertation

I. General information.

Dissertation topic, specialization code (name of the field of study for which the degree is awarded): “Alkaloids of plants Rindera oblongifolia and Lindelofia macrostyla”, 02.00.10 – Bioorganic chemistry (chemical sciences).

Dissertation topic registered number: В2023.2.PhD/К640

Supervisor: candidate of chemical sciences, Mukarramov Nuridin

Dissertation prepared institution: Institute of the Chemistry of Plant Substances named after Acad. S.Y. Yunusov. AS RUz.

Institution where Scientific Council operates, Scientific Council number: Institute of the Chemistry of Plant Substances named after Acad. S.Y. Yunusov. AS RUz., DSc. 02/30.01.2020.K/T.104.01.

Opponents: doctor of chemical sciences, Normaxamatov Nodirali Saxobataliyevich, doctor of chemical sciences, professor Matchanov Alimjan Davlatboevich.

Leading organization: National University of Uzbekistan named after M. Ulugbek.

Dissertation direction: theoretical and practical.

II. The aim of the research work is to isolate pyrrolizidine alkaloids from the aerial parts of R. oblongifolia and L. macrostyla plants, and to study of their chemical structure and biological activity.

III. The scientific novelty of the dissertation researchs:

for the first time, 12 pyrrolizidine alkaloids, 1 isoquinoline alkaloid, and 2 nesik acids have been isolated from the plant species R. oblongifolia and L. macrostyla growing in Uzbekistan, and their structures were confirmed using modern physical research methods;

two new, five known pyrrolizidine alkaloids, as well one nesik acid, were isolated from R. oblongifolia;

the structures of new pyrrolizidine alkaloids, rinderidine and oblongifolidine, along with four known alkaloids isolated from R. oblongifolia, were established using physical research methods, including IR, NMR spectroscopy, mass spectrometry and X-ray diffraction. The absolute configurations were thoroughly examined, and the chiral centers were determined;

from L. macrostyla, one new pyrrolizidine alkaloid, one new nesik acid, and two known alkaloids were isolated for the first time;

the structure of a newly identified alkaloid, N-oxide lindelofamine, isolated from L. macrostyla, was confirmed by NMR spectroscopy. Additionally, the structure of a new compound, ((E)-2-hydroxy-2-isopropyl-3-((2-methylbut-2-enoyl)oxy)-butane acid, along with two known alkaloids, was elucidated using IR, NMR spectroscopy, mass spectrometry and X-ray diffraction. The absolute configurations and chiral centers of these compounds were determined.

IV. Implementation of research results based on scientific and practical results obtained by isolation of pyrrolizidine alkaloids from plants R. oblongifolia and L. macrostyla, studying the chemical structure and biological activity of the compounds:

The alkaloids rinderidine, olongifolidine, N-oxide trachelantamine, and the chloroform fraction containing the total alkaloids from R. oblongifolia, as well as the alcohol extract, and the chloroform, ethyl acetate, n-butanol, and aqueous fractions from L. macrostyla, were utilized in fundamental research on the project “Development of Technologies for Growing Medicinal plants Listed in the Red Book and with Limited Distribution” (Certificate No. 4/1255-23, Academy of Sciences of the Republic of Uzbekistan, January 8, 2024). This research established the potential for discovering insecticidal properties among pyrrolizidine alkaloids and the total alkaloid content from these plants.

The X-ray diffraction data for the alkaloids rinderidine, oblongifolidine, lindelofine, trachelantamine N-oxide, trichodesmine, trichodesmine N-oxide,
O-methylarmepavine methyl iodide, 1-exo carboxypyrrolizidine and ((E)-2-hydroxy-

2-isopropyl-3-((2-methylbut-2-enoyl)oxy)butanoic acid have been added to the Cambridge Structural  Database (CCDC 2111256; 2111257; 2111258; 2111259; 2332411; 2332410; 2279213; 2279214 and 2279215, available at https://www.ccdc.cam.ac.uk/structures). This new data allows scientists in the field to fully characterize the structures of similar alkaloids.

Spectral data of the alkaloids rinderidine, oblongifolidine, echinatine, lindelofine, trachelantamine N-oxide, isolated from the aerial part of the plant Rindera oblongifolia, were used in foreign scientific publications included in the highly ranked Scopus database (Food Chemistry, 2024, V.445(25), P .138748, IF 8.5; Sciences, 2024, V.30(3), P.312, IF 1.4; Chemistry of Natural Compounds, 2024. V.60(5), P. 895, IF 0.8). The research results make it possible to determine the structure of natural compounds.

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