Ralitsa Istatkova

Antimicrobial and immunological activity of ethanol extracts and fractions from Isopyrum thalictroides

The antimicrobial and immunological properties of ethanol extracts, non-alkaloid, tertiary alkaloid and quaternary alkaloid fractions, obtained from roots and aerial parts of Isopyrum thalictroides were examined. The non-alkaloid fraction from aerial parts inhibited the growth of seven test microorganisms and was the most effective suppressor of classical pathway (CP) complement activity in normal human serum (NHS) and guinea pig serum (GPS). The alkaloid fractions, containing quaternary alkaloids expressed suppressive effect on mitogen-induced splenocyte proliferation. The in vitro antibody response against sheep red blood cells (anti-SRBC) was inhibited by ethanol extracts and quaternary alkaloid fraction. The intraperitoneal (i.p.) application of ethanol extract and tertiary alkaloid fraction from aerial parts showed that they possess in vivo effect on alternative pathway (AP) complement activity, anti-SRBC response and delayed type hypersensitivity (DTH).

Alkaloids from Mongolian species Hypecoum lactiflorum Kar. et Kir. Pazij.

A new secoberbine alkaloid (–)-N-methylcorydalisol was isolated from the aerial parts of Hypecoum lactiflorum Kar. et Kir. Pazij. (Papaveraceae) of Mongolian origin and was characterised. The known alkaloids of protopine and protoberberine type protopine, allocryptopine, (–)-N-methylcanadine and (–)-N-methylstylopine were also isolated. (–)-N-methylstylopine is a new alkaloid for the genus, while (–)-N-methylcanadine is new for the species. All structures were established by physical and spectral analysis.

Alkaloids from Papaver nudicaule L.

A new promorphinane alkaloid (−)-8,14-dihydroflavinantine was isolated from the aerial parts of Papaver nudicaule L. (Papaveraceae) growing in Mongolia. Six known isoquinoline alkaloids (+)-amuronine, pseudoprotopine, allocryptopine, (−)-dihydroamuronine, (−)-amurensinine N-oxide A and (−)-amurensinine N-oxide B were isolated, too. Pseudoprotopine has been found for the first time in a plant of the family Papaveraceae. (−)-dihydroamuronine, (−)-amurensinine N-oxide A and (−)-amurensinine N-oxide B are new for the genus Papaver. All structures were established using spectral and physical data.

A new 8,14-dihydropromorphinane alkaloid from Papaver nudicaule L.

A racem. 8,14-dihydroamurine is a new promorphinane alkaloid isolated from the aerial parts of Papaver nudicaule L. (Papaveraceae) of Mongolian origin. The known promorphinane and isopavine alkaloids (+)-amurine, (−)-amurensinine, (−)-O-methylthalisopavine, (−)-flavinantine and (−)-amurensine were also described. All structures were established by physical and spectral analysis. Flavinantine has been found for the first time in the species.

Chemical and antiviral study on alkaloids from Papaver pseudocanescens M. Pop.

The phytochemical investigation of the aerial parts of Papaver pseudocanescens M. Pop. of Mongolian origin resulted in the isolation and structural elucidation of 8 alkaloids of the isoquinoline and promorphinane type. 8,14-Dihydroamurine, 8,14-dihydroflavinantine, and flavinantine are promorphinanes. Alborine, mecambridine, and mecambridine methohydroxide are retroprotoberberines. Amurensinine is an isopavine alkaloid and O-methylarmepavine is a benzylisoquinoline alkaloid. O-Methylarmepavine is a new alkaloid for the genus Papaver. Promorphinane-type alkaloids have been found for the first time in the species. All structures were established by physical and spectral analysis. As a first attempt to describe some of the biological activities of these alkaloids, the antiviral effect was tested against the in vitro replication of several viruses which belong to different taxonomic groups and represent significant human pathogens. Based on the results, the conclusion could be drawn that particular alkaloids from P. pseudocanescens possess selective antiviral effects against the replication of poliovirus 1 and human rhinovirus 14, two viruses from the Enterovirus genus of the Picornaviridae family.

Phytochemical Study and Antiinflammatory Properties of Lobelia laxiflora L

Abstract Three new piperidine alkaloids were isolated from stems, leaves and flowers of Lobelia laxiflora L. (Campanulaceae). The structures of racem. cis-8,10-diethyl-3,4-dehydrolobelidiol (1), racem. trans-8-ethyl-10-phenyl-3,4-dehydrolobelidiol (2) and racem. cis-8-ethyl-10-phenyl-3, 4-dehydrolobelidiol (3) were established by spectral analyses. The residues obtained from the ethanol extracts from stems (S), leaves (L), and flowers (F) were applied in carrageenan (Car)-and cobra venom (CV)-induced acute inflammation in mice. A suppression of paw edema formation at a dose of 100 mg kg-1 was established. In this study the antiinflammatory potential of Lobelia I. was regarded in connection with the complement system. The sequential activation and assembly into functional units of complement components can proceed via two different pathways, named classical (CP) and alternative (AP). The ability of the residues, nonalkaloid fractions, alkaloid fractions and the three alkaloids at a concentration from 0.125 to 1.0 mg ml-1 to inhibit complement activation and thus to prevent inflammatory process was estimated in vitro in human serum via both pathways. All of them inhibited complement activity with a predominant action on CP.

Alkaloids from Isopyrum thalictroides L.

Two new aporphine-benzylisoquinoline alkaloids thaliphine and isothaliphine with a new type of ether bridge were isolated from the roots and rhyzomes of Isopyrum thalictroides L. (Ranunculaceae). Their structures were established by physical and spectral analysis. The known alkaloid N-methylglaucine was isolated for the first time from a plant of the family Ranunculaceae.