Guaianolides and phenolic constituents from Crepis dioscoridis L., growing wild in Greece

Fifteen compounds were isolated from the aerial parts of Crepis dioscoridis L., growing wild in Greece. These compounds comprise one new and nine known guaianolides, two flavonoids, two phenolic acids and one simple phenolic derivative. The structures of the isolated compounds were established by means of NMR [1H-1H COSY, 1H-13C HSQC, HMBC, NOESY, ROESY] and MS spectral analyses. The main sesquiterpene lactones were by order of their abundance integrifolin 3β-d-glucopyranoside, crepiside C and 8-epi-grosheimin. These results are in agreement with previously studied Crepis sp.; this evidence could be of chemotaxonomic significance for the genus, since the predominance of costus type sesquiterpene lactones is a characteristic feature of the Crepis genus. It is noteworthy that some of them were also found in the genera Lapsana L. and Ixeris L., all belonging to the section Lactuceae of the sub-tribe Crepidinae. © 2013 Phytochemical Society of Europe

Computational Analysis of LOX1 Inhibition Identifies Descriptors Responsible for Binding Selectivity

Lipoxygenases are a family of cytosolic, peripheral membrane enzymes, which catalyze the hydroperoxidation of polyunsaturated fatty acids and are implicated in the pathogenesis of major human diseases. Over the years, a substantial number of scientific reports have introduced inhibitors active against one or another subtype of the enzyme, but the selectivity issue has proved to be a major challenge for drug design. In the present work, we assembled a dataset of 317 structurally diverse molecules hitherto reported as active against 15S-LOX1, 12S-LOX1, and 15S-LOX2 and identified, using supervised machine learning, a set of structural descriptors responsible for the binding selectivity toward the enzyme 15S-LOX1. We subsequently incorporated these descriptors in the training of QSAR models for LOX1 activity and selectivity. The best performing classifiers are two stacked models that include an ensemble of support vector machine, random forest, and k-nearest neighbor algorithms. These models not only can predict LOX1 activity/inactivity but also can discriminate with high accuracy between molecules that exhibit selective activity toward either one of the isozymes 15S-LOX1 and 12S-LOX1

Iridoids from Scutellaria albida ssp. albida

Three iridoid glycosides, 6′-O-E-p-coumaroylgardoside (1), 6′-O-p-E-coumaroyl-8-epi-loganic acid (2) and scutelloside (3) were isolated from the aerial parts of Scutellaria albida subsp. albida, in addition to an anomeric mixture in equilibrium of one iridoid aglycone (4, 4a), nine iridoid glycosides (5-13), four known phenylethanoid glycosides (14-17), and six known phenolic derivatives (18-23). © 2007 Elsevier Ltd. All rights reserved