13,14-dihydrocoptisine--the genuine alkaloid from Chelidonium majus.

The genuine major benzylisoquinoline alkaloid occurring in the traditional medicinal plant greater celandine (Chelidonium majus L.) is 13,14-dihydrocoptisine and not - as described previously - coptisine. Structure of 13,14-dihydrocoptisine was elucidated. The discrepancy between the alkaloid pattern of the living plants and that of detached and dried leaves is due to the rapid and prompt conversion of 13,14-dihydrocoptisine to coptisine in the course of tissue injuries. Indeed, apart from the major alkaloid, some minor alkaloids might also be converted; this however is not in the centre of focus of this paper. This conversion is initiated by the change of pH. In vivo 13,14-dihydrocoptisine is localized in the acidic vacuoles, where it is stable. In contrast, in the neutral milieu, which results when vacuoles are destroyed in the course of tissue injuries, the genuine alkaloid is oxidized to yield coptisine. Accordingly, when alkaloids from C.majus should be analyzed, any postmortal conversion of 13,14-dihydrocoptisine has to be prevented.

Effects of oregano on performance and immunmodulating factors in weaned piglets.

Many health effects can be attributed to the Mediterranean herb oregano (Origanum vulgare L.) and several studies demonstrated the improving effect on performance, changes in blood count, antibacterial, antifungal and immunmodulating abilities. The majority of these investigations were carried out with processed essential oil, while whole plant material was only used in a few studies. Thus, the aim of the present experiment was to test the effect of increasing proportions of dried oregano in piglet feed on health and performance, with a special focus on immune modulation. A total of 80 male castrated weaned piglets (body weight [BW] 7.9 kg ± 1.0 kg) were used in a feeding experiment lasting 5 weeks. They were assigned to 4 experimental groups: a control diet, and three diets with an oregano supplementation at 2 g, 4 g and 8 g per kg feed, respectively, corresponding to 23.5 mg, 46.9 mg and 93.9 mg carvacrol/kg DM. After 3 weeks, half of each group was challenged with 5 µg lipopolysaccharides (LPS) per kg BW. Blood samples were collected 2 h after LPS stimulation and analysed for T-cell phenotypes, granulocyte activity, clinical-chemistry as well as white and red blood count. The results indicate no effects of oregano on performance. In contrast, oregano altered the lymphocyte proportion and the ratio of CD4(+) and CD8(+) T-cells as well as the triglyceride concentration in the serum of non-stimulated and in LPS-stimulated piglets. In conclusion, whole plant supplementation of oregano to piglet feed altered immune-related parameters, but did not modulate the acute inflammatory response induced by LPS stimulation.

Stress enhances the synthesis of secondary plant products: the impact of stress-related over-reduction on the accumulation of natural products.

Spice and medicinal plants grown under water deficiency conditions reveal much higher concentrations of relevant natural products compared with identical plants of the same species cultivated with an ample water supply. For the first time, experimental data related to this well-known phenomenon have been collected and a putative mechanistic concept considering general plant physiological and biochemical aspects is presented. Water shortage induces drought stress-related metabolic responses and, due to stomatal closure, the uptake of CO2 decreases significantly. As a result, the consumption of reduction equivalents (NADPH + H(+)) for CO2 fixation via the Calvin cycle declines considerably, generating a large oxidative stress and an oversupply of reduction equivalents. As a consequence, metabolic processes are shifted towards biosynthetic activities that consume reduction equivalents. Accordingly, the synthesis of reduced compounds, such as isoprenoids, phenols or alkaloids, is enhanced.

The glucosinolate-myrosinase system in nasturtium (Tropaeolum majus L.): variability of biochemical parameters and screening for clones feasible for pharmaceutical utilization.

Leaves of Tropaeolum majus L. contain high amounts of the glucosinolate glucotropaeolin. They are used in traditional medicine to treat infections of the urinary tract. When Tropaeolum leaves are consumed, glucotropaeolin is hydrolyzed to yield mustard oils, which are absorbed in the intestine and excreted in the urine, exhibiting their antimicrobial activity. For a corresponding phytopharmacon, a sufficiently high glucotropaeolin concentration is required and any degradation of glucosinolates while drying must be minimized, i.e. the post mortal cleavage by myrosinases, which are activated by ascorbic acid. In extensive screenings, the dominant parameters determining the glucotropaeolin content in the dried leaves were quantified. It turned out that the glucotropaeolin concentration in the dried leaves represented the most suitable screening parameter. The screening of several hundred Tropaeolum plants resulted in the selection of eight high-yield varieties, from which in vitro plants had been generated and propagated as a source for large field trials.