The amphipathic design in helical antimicrobial peptides.

Amphipathicity is a critical characteristic of helical antimicrobial peptides (AMPs). The hydrophilic region, primarily composed of cationic residues, plays a pivotal role in the initial binding to negatively charged components on bacterial membranes through electrostatic interactions. Subsequently, the hydrophobic region interacts with hydrophobic components, inducing membrane perturbation, ultimately leading to cell death, or inhibiting intracellular function. Due to the extensive diversity of natural and synthetic AMPs with regard to the design of amphipathicity, it is complicated to study the structure-activity relationships. Therefore, this work aims to categorize the common amphipathic design and investigate their impact on the biological properties of AMPs. Besides, the connection between current structural modification approaches and amphipathic styles was also discussed.

Pentacyclic triterpenes from the leaves of Camellia hakodae Ninh.

Nine pentacyclic triterpene derivatives including new 3-O-cis-p-coumaroyl trichadenic acid B (1) and two new ursane-type triterpene derivatives, 11α,12-[1-(methyl)-2-(4-hydroxy-3-methoxyphenyl)ethane-1,2-dioxy]-urs-12-ene-3ß-ol (2) and 11α,12-[2-(methyl)-1-(4-hydroxy-3-methoxyphenyl)ethane-1,2-dioxy]-urs-12-ene-3ß-ol (3) were isolated from the leaves of Camellia hakodae Ninh., along with six known compounds (4-9). This is the first report on pentacyclic triterpenoids from this species. New compounds 1-3 and compound 7 were tested for cytotoxic activity against four human cancer cell lines (KB; Hep-G2; Lu; MCF-7) using the MTT assay to show moderate activity.

New Reactions of Contraction of the o-Quinone Ring with the Formation of Derivatives of 2-(2-Indolyl)-cyclopenta[b]pyrrole-3,4-diones and Pyrindino[1,2-a]indoles: A Combined Experimental and Density Functional Theory Investigation.

Derivatives of 2-(2-indolyl)-cyclopenta[b]pyrrole-3,4-diones and pyrindino[1,2-a]indoles were synthesized by a new reaction of contraction of the o-quinone ring, and their structures were investigated by X-ray crystallography and nuclear magnetic resonance spectroscopy. The mechanisms of the reactions were suggested based on density functional theory calculations of the critical parts of the potential energy surfaces.

Improvement in the synthetic process of some derivatives of artemisinine containing fluor

The improvement of synthesis of 10-(trifluoroethoxy)-dihydroartemisinin was described. The improved procedure has some advantages like mild reaction conditions, good yields of products, operational simplicity and the ease of isolation and purification of the products