[Show abstract][Hide abstract] ABSTRACT: A bioassay-guided separation of a methanolic extract obtained from the roots of Boerhaavia diffusa L. (Nyctaginaceae) allowed us to isolate five compounds belonging to the class of rotenoids: the known boeravinone D ( 1), boeravinone E ( 2), compound 5 and two novel compounds that we have named boeravinone G ( 3) and boeravinone H ( 4). The structures of the new molecules have been determined on the basis of their HR-EI-MS, (1)H- and (13)C-NMR and 2D-NMR (HMQC, HMBC) data. All the isolated rotenoids have been evaluated for their effect on intestinal motility in vitro. Three of them (boeravinone G, boeravinone E and compound 5) exhibited spasmolytic activity. Preliminary structure-activity relationships have been established highlighting the effect of substitutions on rings B and D.
[Show abstract][Hide abstract] ABSTRACT: Investigation of the bark of Croton eluteria Bennett for biologically active compounds has led to the isolation of the new prenylbisabolane 3, whose structure was assessed by spectroscopic methods. The corresponding known enone 4 and the eudesmane sesquiterpene 2 were also obtained. Compound 3 proved active in selectively inhibiting the induction of NF-kappaB by tumor necrosis factor-alpha in T cells.
No preview · Article · Aug 2005 · Bioorganic & Medicinal Chemistry
[Show abstract][Hide abstract] ABSTRACT: Two new steroidal derivatives, named clionastatins A and B, have been isolated from the burrowing sponge Cliona nigricans. These molecules are tri-and tetrachlorinated androstane derivatives, respectively, and they represent the first polyhalogenated steroids found in a natural organism, either marine or terrestrial, and the first examples of halogenated androstanes in nature. Both clionastatins proved to be potently cytotoxic.
[Show abstract][Hide abstract] ABSTRACT: Three new diterpenoids belonging to the clerodane (2-3) and halimane (4) structural types have been isolated from the bark of Croton eluteria Bennet, commonly known as cascarilla. Their structures have been fully characterized by spectroscopic means. Cascarilla extract and its major component, cascarillin, were found to significantly increase histamine-induced gastric acid secretion in the mouse stomach. These preliminary results provide the first rationale for the use of cascarilla in bitter preparations aimed at improving digestion.
No preview · Article · Dec 2003 · Journal of Agricultural and Food Chemistry