Sesquiterpene Lactones fromAnthemis melanolepis

HPLC–NMR-Based Chemical Profiling of Matricaria pubescens (Desf.) Schultz and Matricaria recutita and Their Protective Effects on UVA-Exposed Fibroblasts

The present study aimed to investigate the chemical profile and the protective activity on fibroblasts of two Matricaria species: M. pubescens, which grows wild in Algeria, and M. recutita, which is cultivated in Greece. A comparative phytochemical investigation using High-Performance Liquid Chromatography, coupled with Photodiode Array Detection and Mass Spectrometry (HPLC–PDA–MS) combined with Nuclear Magnetic Resonance (NMR), was performed for the identification of the main constituents in the flowerheads of these medicinal plants. In M. pubescens more than 25 compounds were identified and/or isolated; among them are quercetagenin-3-O-glucopyranoside, reported for the first time in Matricaria sp., and two polyamines previously reported in other Asteraceae species. In M. recutita, which is the officially recognized species in Europe, 19 constituents were identified. To minimize time analysis, the structure elucidation was based on a multi-analytical approach directly on subfractions. Two representative polar extracts from each species were characterized chemically and further screened for their protective effects on 3T3 fibroblasts. The cells were exposed to a mild toxic dose of UVA light (6 J/cm2), in the presence of different concentrations of the extracts. Both M. recutita and M. pubescens extracts were effective. The methanolic extract was the best protective agent at lower concentrations (0.1 to 10 μg/mL), and hydromethanolic was best at higher ones (100–200 μg/mL). M. recutita exhibited the most enhanced cell viability in relation to those not exposed to UV control; it ranged from of 28 to 49% higher viability, depending on the dose, leading to the conclusion that the latter seems to exhibit potent cytoprotective activity and significant regeneration activity.

A selective C-H insertion/olefination protocol for the synthesis of α-methylene-γ-butyrolactone natural products

A regio- and stereoselective one-pot C-H insertion/olefination protocol has been developed for the late stage installation of α-methylene-γ-butyrolactones into conformationally restricted cyclohexanol-derivatives. The method has been successfully applied in the total synthesis of eudesmanolide natural product frameworks, including α-cyclocostunolide.

Sesquiterpene lactones from Anthemis melanolepis and their antibacterial and cytotoxic activities. Prediction of their pharmacokinetic profile

Nine sesquiterpene lactones, anthemin A (1), 1alpha-hydroxydeacetylirinol-4alpha,5beta-epoxide (2), anthemin C (3), tatridin A (4), 1-epi-tatridin B (5), anthemin B (6), 6-deacetyl-beta-cyclopyrethrosin (7), elegalactone A (8), and 1beta,4alpha,6alpha-trihydroxyeudesm-11-en-8alpha-12-olide (9), were isolated from the aerial parts of A. melanolepis in addition to eight known flavonoids and three phenolic acids. Compounds 1, 3, and 6 are new natural products. The structures of the compounds were deduced by spectroscopic methods. The in vitro antimicrobial potential of the isolated sesquiterpene lactones against four Gram-positive and five Gram-negative bacteria and one fungus was evaluated using the microdilution method, and their in vitro cytotoxic activity was determined against a panel of human tumor cell lines. Furthermore, the pharmacokinetic profile of the sesquiterpene lactones was investigated using computational methods.

Natural sesquiterpenoids

This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. 423 references are cited.