New Diterpenes from Cultures of the Fungus Engleromyces goetzii and Their CETP Inhibitory Activity

Thiomethylphenyl benzenesulfonamides as potential cholesteryl ester transfer protein inhibitors: Synthesis, molecular modeling and biological evaluation

Background:

The number of lipid disorders cases has risen dramatically around the world as a result of poor dietary habits, hereditary risk factors, or other diseases or medicines. Cholesteryl ester transfer protein (CETP) is a 476 amino acid lipophilic glycoprotein that helps transport cholesteryl esters and phospholipids from proatherogenic LDL and VLDL to atheroprotective HDL. CETP inhibition increases HDL cholesterol, lowers LDL cholesterol and triglycerides, rendering it a promising therapy option for hyperlipidemia and its comorbidities.

Methods:

In this research, fourteen benzenesulfonamides 7a-7g and 8a-8g were synthesized and identified using 1H-NMR, 13C-NMR, IR and MS. The in vitro biological evaluation of 7a-7g and 8a-8g revealed CETP inhibitory activities ranging from 15.6 to 100% at 10 μM concentration.

Results:

Four aromatic rings compounds bearing either m-CH3 (8c) or p-Cl (8g) were the most potent compounds with 100% CETP inhibition, while the most active compound was 7c bearing three aromatic rings and m-CH3 with an IC50 of 0.12 μM. LibDock displayed that benzeneulfonamides can form hydrophobic interactions with the side chains of Leu129, Cys13, Ala202, Val198, Leu217 and Ile215 and participate in п-п stacking with Phe441, Phe197 and Arg201 in the binding pocket of CETP.

Conclusion:

Pharmacophore mapping showed significant matching with the pharmacophoric features of Hypo4/8 and shape-complemented Hypo4/8 of CETP inhibitors for potent compounds.

Diterpenoids from Blumea balsamifera and Their Anti-Inflammatory Activities

Six new diterpenoids, blusamiferoids A–F (1–6), including four pimarane-type diterpenoids, one rosane-type diterpenoid (3), and one rearranged abietane-type diterpenoid (6), were isolated from the dry aerial parts of Blumea balsamifera. Their structures were characterized by spectroscopic and computational methods. In particular, the structures of 1 and 4 were confirmed by X-ray crystallography. Compounds 5 and 6 were found to dose-dependently inhibit the production of TNF-α, IL-6, and nitrite oxide, and compound 5 also downregulated NF-κB phosphorylation in lipopolysaccharide (LPS)-induced RAW 264.7 cells.

Synthesis of ent-Cleistanthane Diterpenoid Spruceanol: Construction of an Aromatic C Ring via Lewis Acid-Controlled Regioselective Diels-Alder Cycloaddition

The first synthesis of ent-cleistanthane-type diterpenoid spruceanol with significant anticancer activity is described. A chiral pool approach was employed with a linear sequence of 13 steps beginning from readily available and inexpensive andrographolide. The approach features the construction of an aromatic ring with hydroxyl and methyl groups at C-12 and C-13 of the target compound, respectively, via Lewis acid-controlled regioselective Diels-Alder cycloaddition and the regioselective removal of the primary hydroxyl group of the Diels-Alder adduct.

Antiproliferative and Enzyme Docking Analysis of Engleromycin from Engleromyces goetzei

Engleromyces goetzei P. Henn. (E. goetzei) has been widely used as a traditional herb for many years in Kenya due to its diverse biological effects. Although engleromycin was first isolated from E. goetzei in 1980, its pharmacological activity is still unknown. In this study, engleromycin from E. goetzei was identified by spectroscopic analyses, and subsequently examined for its antiproliferative activity using human cancer cell lines of SGC-7901, HT-29, HeLa and A549. As a result, it was revealed that engleromycin strongly inhibited the growth of SGC-7901, HT-29, HeLa and A549 cells with IC₅₀ values at 26.77 ± 1.69 µM, 7.73 ± 0.18 µM, 7.00 ± 0.12 µM and 3.14 ± 0.03 µM, respectively. The results of topoisomerase II (Top II) inhibition assay in vitro implied that engleromycin might be a Top II inhibitor. Further insights into the potential mechanism of antiproliferative activity displayed that engleromycin could dock into the binding pockets of Top II, like the clinical inhibitor doxorubicin, and then inhibit the biological activity of Top II. Taken together, our findings suggest that engleromycin has an anticancer potential, and may serve as a leading compound for the development of antitumor agents.

ent-Rosane diterpenoids from Euphorbia milii showing an Epstein–Barr virus lytic replication assay

Thirteen new ent-rosane diterpenoids were bioassay-guided isolated from the aerial parts of Euphorbia milii evaluating by Epstein–Barr virus lytic replication assay.

Enantioselective desymmetrization of cyclohexadienones via an intramolecular Rauhut-Currier reaction of allenoates

The Rauhut–Currier (RC) reaction represents an efficient method for the construction of carbon–carbon bond in organic synthesis. However, the RC reactions involving allenoate substrates are very rare, and in particular, asymmetric intramolecular RC reaction of allenoates is yet to be discovered. Here, we show that the intramolecular RC reaction proceeds smoothly in the presence of 1 mol% β-ICD, and bicyclic lactones are obtained in high yields and with excellent enantiomeric excesses. With the employment of γ-substituted allenoates as racemic precursors, a novel dynamic kinetic resolution of allenes via RC reaction is observed, which allows for facile synthesis of highly enantiomerically enriched allenes.

The Rauhut-Currier reaction is a powerful method to form carbon-carbon bonds. Here, the authors report an enantioselective intramolecular variant between alkenes and allenoates, giving access to highly functionalised bicyclic lactones in excellent enantiomeric excess.