First Total Syntheses of Oresbiusins A and B, Their Antipodes, and Racemates: Configuration Revision and Anti-HIV Activity

In Vitro and In Silico Studies of Soluble Epoxide Hydrolase Inhibitors from the Roots of Lycopus lucidus

Soluble epoxide hydrolase (sEH) is an enzyme that is considered a potential therapeutic target in human cardiovascular disease. Triterpenes (1–4) and phenylpropanoids (5–10) were isolated from Lycopus lucidus to obtain sEH inhibitors through various chromatographic purificationtechniques. The isolated compounds were evaluated for their inhibitory activity against sEH, and methyl rosmarinate (7), martynoside (8), dimethyl lithospermate (9) and 9″ methyl lithospermate (10) showed remarkable inhibitory activity, with the IC₅₀ values ranging from 10.6 ± 3.2 to 35.7 ± 2.1 µM. Kinetic analysis of these compounds revealed that 7, 9 and 10 were competitive inhibitors bound to the active site, and 8 was the preferred mixed type inhibitor for allosteric sites. Additionally, molecular modeling has identified interacting catalytic residues and bindings between sEH and inhibitors. The results suggest that these compounds are potential candidates that can be used for further development in the prevention and treatment for cardiovascular risk.

Synthesis of the natural product descurainolide and cyclic peptides from lignin-derived aromatics

Alternative sources of potential feedstock chemicals are of increasing importance as the availability of oil decreases. The biopolymer lignin is viewed as a source of useful mono-aromatic compounds as exemplified by the industrial scale production of vanillin from this biomass. Alternative lignin-derived aromatics are available in pure form but to date examples of the use of these types of compounds are rare. Here we address this issue by reporting the conversion of an aromatic keto-alcohol to the anti- and syn-isomers of Descurainolide A. The key step involves a rhodium-catalyzed allylic substitution reaction. Enantio-enriched allylic alcohols were generated via an isothiourea-catalyzed kinetic resolution enabling access to both the (2R,3R) and (2S,3S) enantiomers of anti-Descurainolide A. In addition we show that the lignin-derived keto-alcohols can be converted into unnatural amino acid derivatives of tyrosine. Finally, these amino acids were incorporated into cyclic peptide scaffolds through the use of both chemical and an enzyme-mediated macrocylisation.

The First Total Synthesis of (±)-Methyl Salvianolate A Using a Convergent Strategy

Herein, a convergent, practicable and first total synthesis of the natural product, (±)-methyl salvianolate A, is reported. The key features of the approach are the use of a Horner–Wadsworth–Emmons reaction and the protection of multiple hydroxyls using silyl protecting groups. The employment of the readily removable silyl protecting groups allows the synthesis of (±)-methyl salvianolate A and its derivatives on a reasonably large scale.

Salviachinensines A-F, Antiproliferative Phenolic Derivatives from the Chinese Medicinal Plant Salvia chinensis

Six new phenolic acid derivatives, salviachinensines A-F (1-6), together with 14 known compounds (7-20) were isolated from the Chinese medicinal plant Salvia chinensis. The structures of salviachinensines A-F (1-6) were elucidated by NMR spectroscopy, bioinspired chemical synthesis, ECD analysis, and quantum chemical calculation methods. Compounds 2 and 3 are a pair of cis- trans isomers, and compounds 5 and 6 a pair of epimers. The solvent-induced isomerization of compounds 5 and 6 and the hypothetical biogenetic pathway of compounds 1-6, as well as the antiproliferative property and the ability of 1 to induce apoptosis and arrest cell cycle progression of MOLM-13 cells, were also investigated.