Determination of Senecio alkaloids by thermospray liquid chromatography/mass spectrometry.

A series of Senecio alkaloid and alkaloid N-oxide standards has been analyzed using positive and negative ion thermospray liquid chromatography/mass spectrometry (LC/MS) with an ammonium acetate-containing mobile phase. On-line separations of pyrrolizidine alkaloids from extracts of Senecio jacobaea (tansy ragwort) and Senecio vulgaris (common groundsel) were done using an ammonium hydroxide-containing mobile phase. All of the alkaloids known to be present in the extracts were detected by ammonium hydroxide thermospray LC/MS, as well as many other components which may be as-yet-unidentified alkaloids.

Pyrrolizidine alkaloids in Senecio vulgaris L. growing in Iceland.

The distribution of toxic pyrrolizidine alkaloids in the Icelandic flora has been studied for the first time. In addition to the isolation of senecionine, seneciphylline, and retrorsine from Senecio vulgaris L., the presence of riddelline was confirmed by high resolution NMR spectroscopy. The presence of this alkaloid in S. vulgaris has previously been controversial. Furthermore, senecionine oxide and seneciphylline oxide were isolated by preparative centrifugal chromatography.

The identification of pyrrolizidine alkaloid-containing plants--a study on 20 herbs of the Compositae family.

Twenty Chinese medicinal herbs of the Compositae family were investigated for the presence of pyrrolizidine alkaloid. Of these, only the Eupatorium species were shown to contain pyrrolizidine alkaloid. The amount present was found to vary with species, parts of the plant used, purchase sources and extraction methods. Possible toxicity from the use of these herbs is discussed.

Macrocyclic pyrrolizidine alkaloids from Senecio anonymus. Separation of a complex alkaloid extract using droplet counter-current chromatography.

Ten 12-membered macrocyclic pyrrolizidine alkaloids, all of them esters of the necines, retronecine or otonecine, have been isolated from Senecio anonymus. The separation, carried out by droplet counter-current chromatography, afforded senecionine [1], integerrimine [2], retrorsine [3], senkirkine [5], neosenkirkine [6], otosenine [10], hydroxysenkirkine [7], and a new alkaloid given the trivial name anonamine [9]. Traces of usaramine [4] and another new alkaloid, hydroxyneosenkirkine [8], were detected by 1H nmr. In addition, the previously unreported 3a beta-hydroxy-4-ethoxy-2,6-perhydroindoledione [11] was isolated. X-ray structures were obtained for neosenkirkine [6], hydroxysenkirkine [7], anonamine [9], and [11]. 1H-13C heteronuclear shift correlated nmr (HETCOR) provided unambiguous chemical shift assignments for 13C-nmr data. Antitumor activity was assayed using the A204-rhabdomyosarcoma cell line in soft agarose.

Identification of senecionine and senecionine N-oxide as antifertility constituents in Senecio vulgaris.

The MeOH extract of Senecio vulgaris L., administered po to rats on Days 1-10 postcoitum, significantly decreased the number of normal fetuses per pregnant rat found at autopsy on Day 16. Additional experiments showed a similar activity for its hepatotoxic constituents senecionine and senecionine N-oxide, suggesting that the latter two compounds were probably responsible for the effect seen with the extract. No antifertility effects were seen in MeOH extract-treated hamsters.

Livestock poisoning in South America by species of the Senecio plant.

The pyrrolizidine alkaloids retrorsine, senecionine, integerrimine, neosenkirkine and florosenine were isolated from different Senecio spp. common in southern Brazil, Uruguay and Paraguay. Structure elucidation of these compounds was mainly accomplished by two-dimensional FT NMR techniques. Detailed interpretations of 1H-1H and 1H-13C NMR correlation spectra are given. The alkaloids neosenkirkine, integerrimine and florosenine were found in Senecio leptolobus De Candolle, retrorsine accompanied by senecionine in Senecio selloi (Spreng.) DC and Senecio cisplatinus Cabrera. In Senecio heterotrichus DC. integerrimine is accompanied by retrorsine. Investigations on pathology and histopathology of Senecio envenomation in Brazil are summarized.

Capillary supercritical fluid chromatography of pyrrolizidine alkaloids.

The application of capillary supercritical fluid chromatography (SFC) for the separation of pyrrolizidine alkaloids (PAs) is examined. Most of these compounds are powerful toxins. Because they are present in at least 3% of all flowering plants, they are responsible for serious losses of livestock and human disease. Capillary SFC, with its high separation efficiency, is shown to be an excellent method for the chromatographic analysis of complex PA mixtures. Complete separation of the PAs of the retronecine and otonecine family has been achieved by pressure-programmed capillary SFC. The operating conditions are mild enough to prevent thermal decomposition of the alkaloids during analysis.

Large scale extraction of pyrrolizidine alkaloids from tansy ragwort (Senecio jacobaea).

A new technique of large-scale pyrrolizidine alkaloid (PA) extraction was developed in response to toxicity studies on food animals. Results of toxicity experiments on cattle vary from those on rodents (2); therefore, dose/response studies need to be germaine to the appropriate species. This new technique for extraction utilizes protonation of the ring nitrogen and partition of solvent to preferentially extract the alkaloid. The primary equipment used in the system we developed includes a large stainless-steel extraction/separation tank, holding tanks, and a 100-liter vacuum distillation system. From 23 kg of plant material of Senecio jacobaea , our system was able to produce 8-10 g of alkaloid per run, compared to the 3 g which we achieved using other extraction methods (2,4). Additional advantages of our system include a lower labor cost and the ability to recycle the organic solvent.

Toxicity of threadleaf groundsel (Senecio douglasii var longilobus) to cattle.

Threadleaf groundsel (Senecio douglasii var longilobus), a common plant on much of the rangeland of southwestern United States, was experimentally fed to 55 cattle by gastric gavage, mixed in alfalfa hay, or pelleted in feed. Since the pyrrolizidine alkaloid (PA) content of threadleaf groundsel fluctuates greatly, dosage was determined by the plant PA content. Animals that died survived up to 506 days. Whether they were acutely or chronically affected they had typical signs of seneciosis. Major gross and histopathologic changes are reported. The estimated minimum lethal plant dose by gavage was sufficient plant to provide 13 mg of PA/kg of calf body weight/day for 15 days or a total of approximately 200 mg of PA/kg in a 15-day period. Cattle that consumed up to 600 mg of PA/kg total in 20- to 100-day periods in hay or pellets were unaffected or minimally affected. These findings emphasize the importance of the time-dose relationship in PA toxicosis in cattle and indicate that there is a threshold level of PA that must be exceeded for the toxicosis to develop.

Senecio lautus toxicity in cattle.

Mortalities and a poor growth syndrome in cattle in the Hunter River valley of New South Wales were associated with pyrrolizidine alkaloid toxicity caused by Senecio lautus (common fireweed). A clinical problem of poor growth rate on a large property, where S. lautus was very common, was associated with consistent evidence of some degree of hepatic pyrrolizidine alkaloid lesions in young growing cattle and cows. S lautus subsp maritimus from this property caused the death of 2 experimentally fed calves within 77 days and depressed growth rate in a third calf. Pyrrolizidine alkaloidosis was evident histopathologically in the liver, biliary tree and gall bladder and other organs, especially kidney, of these calves. Histopathology of liver biopsy samples was the most sensitive monitoring technique of those used to indicate exposure to pyrrolizidine alkaloids in this investigation.

Identification of pyrrolizidine alkaloids (Senecio longilobus).

Pyrrolizidine alkaloids derived from Senecio longilobus have been rapidly isolated and identified. The potential of isolating individual pyrrolizidine alkaloids utilizing high pressure liquid chromatography is discussed. The utilization of a single 10 mu CN column to isolate closely related pyrrolizidine alkaloids suggests a marked improvement in pyrrolizidine alkaloid chemistry.