Diterpenoid Isosteviol Research Articles

Self-assembly and functional activity of amphiphilic conjugates of the diterpenoid isosteviol and triphenylphosphonium cation, with focusing on biotechnological potential

Supramolecular systems based on amphiphilic triphenylphosphonium (TPP) conjugates of the diterpenoid isosteviol in which the diterpenoid skeleton and the TPP cation are linked by a polymethylene linker of varying length (n = 3, 6 or 8) have been fabricated. Elongation of this linker from 3 to 8 methylene units, allows for an 8-fold decrease in the amphiphile aggregation thresholds in aqueous solutions. These systems exhibit tunable self-assembly behavior, with the formation of both small aggregates (with a hydrodynamic diameter of ∼5–10 nm), as well as large vesicle-like structures (with a diameter of ∼50–100 nm), depending on the amphiphile concentration and length of the spacer fragment. The biotechnological potential of these amphiphiles has been demonstrated on the example of its membranotropic properties toward liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Significant capacity for integration into lipid bilayer has been revealed in these amphiphiles, which could be increased by extending the length of the polymethylene linker. Cationic liposome formulations have been prepared on the basis of these amphiphiles and DPPC by a noncovalent modification approach. Sustainability of its DH and zeta potential during longtime storage has been demonstrated. The studied systems exhibit a selective cytotoxic effect on M-HeLa cancer cell line and are a less toxic to normal Chang liver cells. The mechanism of the cytotoxic action of the liposomes is associated with the induction of apoptosis through mitochondrial pathway. The obtained formulations have successfully been applied for metronidazole encapsulation, characterized by high encapsulation efficiency and loading capacity, as well as prolonged time of drug release.

Cytotoxic Activities and QSAR Studies of Diterpenoid Isosteviol Derivatives as Anti-Esophageal Agents

The cytotoxicity of isosteviol and its twenty derivatives on three human tumor cell lines (ECA-109, MCF-7 and B16-F10) were evaluated. The results demonstrated that ECA-109 was the most sensitive cell line which was exposed to the compound (VI) with the lowest IC50 value of 1.30 ± 0.11 μM. By quantitative structure–activity relationship (QSAR) technique, the obtained cytotoxicity data were further utilized to respectively generate the statistically reliable HQSAR model (q2 = 0.828, r2 = 0.941, $$r_{{{\text{pred}}}}^{{\text{2}}}$$ = 0.849) and topomer CoMFA model (q2 = 0.608, r2 = 0.919, $$r_{{{\text{pred}}}}^{{\text{2}}}$$ = 0.747), which could provide the guidelines for the further development of novel and potent anti-esophageal agent.

Synthesis and Bioactivities of Derivatives of the Diterpenoid Isosteviol with 1,2,3,4-Tetrazole-5-Thiol Moiety

A novel 1,2,3,4-tetrazole-5-thiol-fused isosteviol derivative 3 has been synthesized and structurally characterized by IR, NMR, and HR-MS. It is more sensitive to Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis than Gram-negative bacteria E. coli O157:H7. The results of anticancer activities demonstrated that compound 3 exhibited better anticancer activities against HCT-116 cell with IC50 value of 40.98 ± 1.9 μM.

Synthesis, Structure, and Cytotoxic Activities of a Novel Lactam of the Diterpenoid Isosteviol

A novel compound lactam of 15β-hydroxymethylisosteviol ethyl ester 3 has been synthesized and structurally characterized by IR, NMR, and HR-MS. Its X-ray crystallographic analysis revealed that the nitrogen is attached to C-13 instead of C-15. The reaction mechanism was discussed, and the title compound was further evaluated against HCT-116, HGC-27, and JEKO-1 cells by the MTT assay. The results demonstrated that compound 3 exhibited better cytotoxic activities than its corresponding precursor isosteviol.

Glycosides and Glycoconjugates of the Diterpenoid Isosteviol with a 1,2,3-Triazolyl Moiety: Synthesis and Cytotoxicity Evaluation.

Several glycoconjugates of the diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) with a 1,2,3-triazolyl moiety were synthesized, and their cytotoxicity was evaluated against some human cancer and normal cell lines. Most of the synthesized compounds demonstrated weak inhibitory activities against the M-HeLa and MCF-7 human cancer cell lines. Three lead compounds, 54, 56 and 57, exhibited high selective cytotoxic activity against M-HeLa cells (IC50 = 1.7-1.9 μM) that corresponded to the activity of the anticancer drug doxorubicin (IC50 = 3.0 μM). Moreover, the lead compounds were not cytotoxic with respect to a Chang liver human normal cell line (IC50 > 100 μM), whereas doxorubicin was cytotoxic to this cell line (IC50 = 3.0 μM). It was found that cytotoxic activity of the lead compounds is due to induction of apoptosis proceeding along the mitochondrial pathway. The present findings suggest that 1,2,3-triazolyl-ring-containing glycoconjugates of isosteviol are a promising scaffold for the design of novel anticancer agents.

Synthesis and cytotoxicity of the conjugates of diterpenoid isosteviol and N-acetyl-D-glucosamine

A series of conjugates of diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) and N-acetyl-D-glucosamine was synthesised and their cytotoxicity against several human cancer cell lines (M-Hela, MCF-7, Hep G2, Panc-1, PC-3), as well as normal human cell lines (WI-38, Chang liver) was assayed. Most of the conjugates were found to be cytotoxic against the mentioned cancer cell lines in the range of IC50 values 13–89 µM. Two lead compounds 14a and 14b showed selective cytotoxicity against M-Hela (IC50 13 and 14 µM) that was two times as high as the cytotoxicity of the anti-cancer drug Tamoxifen in control (IC50 28 µM). It was found that cytotoxic activity of the lead compounds against M-Hela cells is due to induction of apoptosis.

Synthesis and anti-cancer activities of glycosides and glycoconjugates of diterpenoid isosteviol.

A series of glycosides and glycoconjugates of diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) with various monosaccharide residues were synthesized and their cytotoxicity against some human cancer and normal cell lines was assayed. Most of the synthesized compounds demonstrated moderate to significant cytotoxicity against human cancer cell lines M-HeLa and MCF-7. Three lead compounds exhibited selective cytotoxic activities against M-HeLa (IC50 = 10.0-15.1 μM) that were three times better than the cytotoxicity of the anti-cancer drug Tamoxifen (IC50 = 28.0 μM). Moreover, the lead compounds were not cytotoxic with respect to the normal human cell line Chang liver (IC50 > 100 μM), whereas Tamoxifen inhibited the viability of normal human Chang liver cells with an IC50 value of 46.0 μM. It was determined that the cytotoxicity of the lead compounds was due to induction of apoptosis proceeding along the mitochondrial pathway. The cytotoxic activity of the synthesized compounds substantially depended on the nature of the monosaccharide residue and its position, that is, whether the monosaccharide residue was attached directly to the isosteviol skeleton or was moved away from it by means of a polymethylene linker.

Synthesis and Biological Activity of Alkane-1,1-diylbis(phosphonates) of Diterpenoid Isosteviol

Isosteviol reacted with α,ω-dibromoalkanes to give 19-(ω-bromoahkyl) esters which were treated with tetraethyl methylenebis(phosphonate) to obtain bis(phosphonates) conjugated to the deterpenoid skeleton through a polymethylene spacer. The bis(phosphonates) were converted to the corresponding bis(phosphonic acids) by transformation to trimethylsilyl esters and subsequent methanolysis. One of the synthesized compounds showed a high antimicrobial activity (MIC 3.9 µg/mL) against S. aureus and a high cytotoxicity (IC50 15–18 µM) toward M-HeLa and MCF-7 human cancer cell lines.

Phosphates of the Diterpenoid Isosteviol. Synthesis and Biological Activity#

Novel phosphorylated derivatives of the diterpenoid isosteviol were synthesized and exhibited antituberculosis, antimicrobial, and anticancer activity.

Synthesis and Antimicrobial and Antituberculosis Activity of the First Conjugates of the Diterpenoid Isosteviol and D-Arabinofuranose

Previously unknown conjugates of the diterpenoid isosteviol 1 and 1-O-methyl-2,3-di-O-acetyl-β-Darabinofuranoside in which the terpenoid and carbohydrate molecules were linked through polymethylene spacers of various lengths were synthesized. Isosteviol 1 and its conjugate 10 exhibited high bacteriostatic activity selectively against Staphylococcus aureus ATCC 209p. Conjugates 9–11 inhibited growth of Mycobacterium tuberculosis H37Rv at the level of the antituberculosis drug pyrazinamide. Removal of the acetyl protection from conjugate 9 increased the antituberculosis activity by eight times.

An integrative in-silico approach for therapeutic target identification in the human pathogen Corynebacterium diphtheriae.

Corynebacterium diphtheriae (Cd) is a Gram-positive human pathogen responsible for diphtheria infection and once regarded for high mortalities worldwide. The fatality gradually decreased with improved living standards and further alleviated when many immunization programs were introduced. However, numerous drug-resistant strains emerged recently that consequently decreased the efficacy of current therapeutics and vaccines, thereby obliging the scientific community to start investigating new therapeutic targets in pathogenic microorganisms. In this study, our contributions include the prediction of modelome of 13 C. diphtheriae strains, using the MHOLline workflow. A set of 463 conserved proteins were identified by combining the results of pangenomics based core-genome and core-modelome analyses. Further, using subtractive proteomics and modelomics approaches for target identification, a set of 23 proteins was selected as essential for the bacteria. Considering human as a host, eight of these proteins (glpX, nusB, rpsH, hisE, smpB, bioB, DIP1084, and DIP0983) were considered as essential and non-host homologs, and have been subjected to virtual screening using four different compound libraries (extracted from the ZINC database, plant-derived natural compounds and Di-terpenoid Iso-steviol derivatives). The proposed ligand molecules showed favorable interactions, lowered energy values and high complementarity with the predicted targets. Our proposed approach expedites the selection of C. diphtheriae putative proteins for broad-spectrum development of novel drugs and vaccines, owing to the fact that some of these targets have already been identified and validated in other organisms.

Mitochondriotropic and Cardioprotective Effects of Triphenylphosphonium-Conjugated Derivatives of the Diterpenoid Isosteviol.

Mitochondria play a crucial role in the cell fate; in particular, reducing the accumulation of calcium in the mitochondrial matrix offers cardioprotection. This affect is achieved by a mild depolarization of the mitochondrial membrane potential, which prevents the assembly and opening of the mitochondrial permeability transition pore. For this reason, mitochondria are an attractive target for pharmacological interventions that prevent ischaemia/reperfusion injury. Isosteviol is a diterpenoid created from the acid hydrolysis of Stevia rebaudiana Bertoni (fam. Asteraceae) glycosides that has shown protective effects against ischaemia/reperfusion injury, which are likely mediated through the activation of mitochondrial adenosine tri-phosphate (ATP)-sensitive potassium (mitoKATP) channels. Some triphenylphosphonium (triPP)-conjugated derivatives of isosteviol have been developed, and to evaluate the possible pharmacological benefits that result from these synthetic modifications, in this study, the mitochondriotropic properties of isosteviol and several triPP-conjugates were investigated in rat cardiac mitochondria and in the rat heart cell line H9c2. This study’s main findings highlight the ability of isosteviol to depolarize the mitochondrial membrane potential and reduce calcium uptake by the mitochondria, which are typical functions of mitochondrial potassium channel openings. Moreover, triPP-conjugated derivatives showed a similar behavior to isosteviol but at lower concentrations, indicative of their improved uptake into the mitochondrial matrix. Finally, the cardioprotective property of a selected triPP-conjugated derivative was demonstrated in an in vivo model of acute myocardial infarct.

Synthesis and antituberculous activity of glycoconjugates of glucosamine, glucuronic acid and trehalose with diterpenoid isosteviol

Synthesis and antituberculous activity of glycoconjugates of glucosamine, glucuronic acid and trehalose with diterpenoid isosteviol

Synthesis and antituberculosis activity of the first macrocyclic glycoterpenoids comprising glucosamine and diterpenoid isosteviol

The first macrocyclic glycoterpenoids comprising glucosamine and diterpenoid isosteviol moieties were synthesized and evaluated for inhibition activity against Mycobacterium tuberculosis H37Rv.

Synthesis and anticancer evaluation of complex unsaturated isosteviol-derived triazole conjugates.

For the last two decades, diterpenoid isosteviol and its derivatives have gained significant attention for novel chemical transformation in the drug discovery field. An efficient way towards the synthesis of structurally diverse isosteviol derivatives was described here employing unsaturated functionalities as attractive templates for further transformation such as epoxidation. These structurally diverse compounds exhibited promising cytotoxic activities on different types of cancer cell lines, leading to drug discovery derived from natural products for the treatment of cancer. In this work, novel isosteviol derivatives with Michael acceptors were synthesized to expand the diversity and complexity of a class of isosteviol-derived triazole conjugates to facilitate the development of potential antitumor agents.

Synthesis of macrocycles on the basis of diterpenoid isosteviol and trehalose

Macrocyclic glycoterpenoids containing trehalose and isosteviol fragments have been synthesized. Selective screening has revealed compounds exhibiting antitubercular activity against H37RV, M. Avium and M. Terrae at a level comparable to the known antitubercular drugs isoniazid, ofloxacin, and pyrazinamide.

Development of synthetic approaches to macrocyclic glycoterpenoids on the basis of glucuronic acid and diterpenoid isosteviol

An approach has been developed to the synthesis of macrocyclic glycoterpenoids containing diterpenoid isosteviol and glucuronic acid fragments. Selective screening revealed compounds exhibiting antitubercular activity against H37RV, M. Avium, and M. Terrae strains at a level comparable to the known antitubercular drugs isoniazid, ofloxacin, and pyrazinamide. The compound possessing the highest antitubercular activity is non-cytotoxic toward human erythrocytes.

Synthesis of the First Macrocyclic Glycoterpenoid Based on Trehalose and the Diterpenoid Isosteviol

A macrocyclic glycoterpenoid containing the diterpenoid dihydroisosteviol (16-hydroxy-ent-beyeran-19- oic acid) and α,α′-trehalose linked by an ester spacer was synthesized.

Synthesis of a Macrocyclic Conjugate of the Diterpenoid Isosteviol and Glucuronic Acid

A macrocyclic conjugate of the natural diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) and glucuronic acid was synthesized for the first time. The conjugate contained two molecules of dihydroisosteviol β-D-glucuronoside joined by 1,8-octanedicarboxylate and 1,8-octanedicarbazoyl spacers.

Triphenylphosphonium Cations of the Diterpenoid Isosteviol: Synthesis and Antimitotic Activity in a Sea Urchin Embryo Model.

A series of novel triphenylphosphonium (TPP) cations of the diterpenoid isosteviol (1, 16-oxo-ent-beyeran-19-oic acid) have been synthesized and evaluated in an in vivo phenotypic sea urchin embryo assay for antimitotic activity. The TPP moiety was applied as a carrier to provide selective accumulation of a connected compound into mitochondria. When applied to fertilized eggs, the targeted isosteviol TPP conjugates induced mitotic arrest with the formation of aberrant multipolar mitotic spindles, whereas both isosteviol and the methyltriphenylphosphonium cation were inactive. The structure-activity relationship study revealed the essential role of the TPP group for the realization of the isosteviol effect, while the chemical structure and the length of the linker only slightly influenced the antimitotic potency. The results obtained using the sea urchin embryo model suggested that TPP conjugates of isosteviol induced mitotic spindle defects and mitotic arrest presumably by affecting mitochondrial DNA. Since targeting mitochondria is considered as an encouraging strategy for cancer therapy, TPP-isosteviol conjugates may represent promising candidates for further design as anticancer agents.