Anastasiya I. Govdi

Rapid access to new bioconjugates of betulonic acid via click chemistry.

Plant-derived pentacyclic triterpenoids of lupane and oleanane families provide a versatile structural platform for the discovery of new biologically active compounds. A number of semisynthetic derivatives of these molecules, possess high medical efficiency including antiviral (HIV-1), anticancer and immunomodulating activity. Even small structural changes in these triterpenoid derivatives were reported to lead to significant changes in their activity, making a convincing case for a systematic study of structure-activity relationships in this class of compounds. Our earlier work opened synthetic access to alkynes derived from the betulonic scaffold and enabled the development of a new family of biohybrids using Click Chemistry (CC). The computer-aided prediction of several types of biological activity were performed with program PASS (Prediction Activity Spectra of Substances. Experimental studies based on mouse models verified the SAR predictions obtained by the PASS program. The observed correlation between the anti-inflammatory and antioxidant activity indicates substantial contribution of the latter in the mechanism of anti-inflammatory effect of the triazole derivatives of betulonic acid.

Efficient synthesis of the first betulonic acid-acetylene hybrids and their hepatoprotective and anti-inflammatory activity.

The Sonogashira reaction can be applied for the preparation of acetylenic derivatives of betulonic acid where the triterpenoid moiety can serve as either the halo- or the acetylenic component. This reaction opened access to the first derivatives of betulonic acid containing either the arylethynyl (C[triple bond]C-Ar(Het) or the ethynyl (C[triple bond]CH) moieties. From the fundamental perspective, this work illustrates the possibility of selective Pd-catalyzed cross-coupling at terminal acetylenes in the presence of a terminal alkene. Hepatoprotective and anti-inflammatory properties of selected acetylenic derivatives of betulonic acid were investigated using the CCl4-induced hepatitis and carrageenan-induced edema models, respectively.

Synthesis of new betulinic acid–peptide conjugates and in vivo and in silico studies of the influence of peptide moieties on the triterpenoid core activity

The modification of betulinic acid derivatives bearing an ethynyl group at the C-3 position by different azidopeptides using Cu(I)-catalyzed alkyne-azide cycloaddition has been described. All obtained compounds were tested for their anti-inflammatory activity using a histamine-induced paw edema model. Betulinic acid–peptide conjugates containing histidine, alanine, tryptophan and isoleucine amino acid fragments were found to exhibit high anti-inflammatory activity, comparable to that of indomethacin. It has been shown by molecular docking that the obtained conjugates are incorporated into the binding site of the protein Keap1 Kelch-domain by their amino acid residues and form more non-covalent bonds, but have lower affinity than the initial triterpenoid core. It has been suggested that peptide moieties can modify the activity of the initial triterpenoid scaffold due to the change in the conformational and thermodynamic characteristics, which have influence on the binding of the compound to its molecular target.

Acetylenic derivatives of betulonic acid amide as a new type of compounds possessing spasmolytic activity

Efficient and versatile synthetic procedures towards novel derivatives of betulonic acid via Mannich reaction, Sonogashira cross-coupling, and copper(i)-catalyzed 1,3-dipolar cyclo-additions were developed. Introduction of secondary amines (Mannich reaction) into betulonic acid amides led to derivatives possessing marked spasmolytic activity, which is not characteristic of the triterpene fragment.

The synthesis and anti-inflammatory activity of propargylamino derivatives of naphthoquinonlevopimaric acid

Naphthoquinonlevopimaric acid was modified with propargylamino residues and anti-inflammatory activities of the synthesized Mannich bases was studied.