Artemisinin can inhibit the calmodulin-mediated activation of phosphodiesterase in comparison with Cyclosporin A.

Artemisinin and Cyclosporin A were examined for their ability to inhibit the calmodulin-mediated activation of phosphodiesterase, which is based on the hydrolysis of cAMP to AMP by phosphodiesterase in the presence or absence of inhibitors, followed by quantitative analysis using spectrophotometer method. Anti-calmodulin activity of these agents was investigated by spectrofluorometry. Our results indicates that Artemisinin and Cyclosporin A induced some conformational changes on calmodulin and increased the fluorescence emission, but Artemisinin increased fluorescence emission of calmodulin in higher amounts compared with the Cyclosporin A. Kinetic analysis of the Artemisinin-calmodulin and Cyclosporine A-calmodulin interaction showed that these agents competitively inhibited the activation of phosphodiesterase without affecting Vmax. Artemisinin increased Km value in higher amounts compared with the Cyclosporin A. Ki values of Artemisinin and Cyclosporin A were determined as 10 microM and 35 microM, respectively. The DeltaG (H2O), the best parameter for the estimation of macromolecule stability, was determined for calmodulin in the absence and presence of Artemisinin and Cyclosporin A. However, the degree of decrease in DeltaG (H2O) value was as follows: Artemisinin>Cyclosporin A, which means Artemisinin induced more instability in the calmodulin structure.In conclusion, our findings showed a good correlation between the ability of both Artemisinin and Cyclosporin A to block the activation of phosphodiesterase and their ability to bind to the activator and that Artemisinin is a more potent inhibitor of phosphodiesterase compared with Cyclosporin A.

Three new acylated triterpene saponins from Acanthophyllum squarrosum.

Three new triterpenoid saponins, 1-3, were isolated from the roots of Acanthophyllum squarrosum. Their structures were established mainly by 2D NMR techniques as 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucuronopyranosyl-gypsogenin-28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->4)-3-O-acetyl-alpha-L-rhamnopyranosyl-(1-->2)-3,4-di-O-acetyl-beta-D-fucopyranoside (1), 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucuronopyranosyl-gypsogenin-28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[5-O-acetyl-alpha-L-arabinofuranosyl-(1-->3)]-4-O-acetyl-beta-D-fucopyranoside (2), and 3-O-beta-D-glucopyranosyl-quillaic acid-28-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (3).

Two new biologically active triterpene saponins from Acanthophyllum squarrosum.

Two novel triterpenoid saponins (1 and 2) have been isolated from the roots of Acanthophyllum squarrosum. The structures were established mainly by a combination of 2D NMR techniques as 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-be ta-D-glucuronopyranosylgypsogenin-28-O-beta-D-xylopyranosyl-(1-->3 )-b eta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L- rhamnopyranosyl-(1-->3)]-beta-D-fucopyranoside (1) and 3-O-beta-D-glucopyranosylgypsogenin-28-O-alpha-L-rhamnopyranosyl-( 1-- >2)-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->6 )]- beta-D-glucopyranoside (2). Compound 1 showed a moderate concentration-dependent immunomodulatory effect in an in vitro lymphocyte proliferation assay.

Structure and antibacterial activity ofp6 new labdane diterpenoid from Salvia leriaefolia.

Phytochemical investigation of the choloroform extract of Salvia leriaefolia afforded 8(17),12E,14-labdatrien-6,19-olide (1), and its structure was determined by a combination of spectral methods. Compound 1 was found to possess antibacterial activity against Staphylococcus aureus.

Squarroside A, a biologically active triterpene saponin from Acanthophyllum squarrosum.

A new bioactive saponin has been isolated from the roots of Acanthophyllum squarrosum. Based on spectroscopic data, especially direct and long-range heteronuclear 2D NMR analysis, and on chemical transformations, the structure of this new compound was elucidated as 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta- D-glucuronopyranosyl gypsogenin 28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L- rhamnopyranosyl-(1-->2)-[alpha-L-arabinofuranosyl-(1-->3)]-beta-D-4-O- acetylfucopyranoside for which we proposed the name squarroside A. This molecule showed a concentration dependent immunomodulatory effect in the in vitro lymphocyte transformation test.

Sesquiterpene Glycosides from Calendula persica.

The polar fractions of the extract of the aerial parts of CALENDULA PERSICA afforded eight sesquiterpene glycosides, five derived from viridiflorol, two of beta-eudesmol, and one of 4alpha-hydroxygermacra-1(10) E,5E-diene. In addition to fucopyranosides, also chinovopyranosides were present. The structures were elucidated by high field NMR techniques.

Neue Guajanolide aus Centaurea imperialis.

The aerial parts of CENTAUREA IMPERIALIS afforded three new guaianolides, 3-desoxysolstitialin A and two derivatives of centaurepensin.