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651.
Liza D. Hohenschutz E.Arthur Bell Phillip J. Jewess David P. Leworthy Robert J. Pryce Edward Arnold Jon Clardy 《Phytochemistry》1981,20(4):811-814
A new type of higher plant alkaloid, 1,6,7,8-tetrahydroxyoctahydroindolizine, designated castanospermine, has been isolated from the toxic seeds of the Australian legume Castanospermum australe. 相似文献
652.
A sensitive and rapid method for detection and quantitative determination of pyrrolizidine alkaloids is presented. It is based on stoichiometric reaction of protonated alkaloids with methyl orange, followed by a release of the latter from the complex. The color intensity of the dye is assessed visually or spectrophotometrically. The method easily detects alkaloids at a concentration of 0.5 μg/ml. The sensitivity of the quantitative assay ranges from 0.006 to 0.045 μmol/ml (from about 2 to 15μg/ml). The method proved to be especially useful during extraction, purification, and separation of minor pyrrolizidine alkaloids. 相似文献
653.
654.
A new steroidal alkaloid has been isolated from the leaves of Buxus papilosa. Its structure has been assigned as 1 on the basis of spectroscopic studies. 相似文献
655.
656.
Radio active morphine (14C- and 3H-labelled) was fed in vitro to freshly collected samples of capsules and stem latex of Papaver somniferum and it was shown that some of it was converted to radioactive N-oxide. Although metabolic activity and variation between samples of latex collected at different times were much less marked than those previously found using in vivo methods, the results do confirm that the isolated latex is a metabolically viable tissue. 相似文献
657.
658.
A mixture of (?)-nicotine-[2′-3H] and (±)-nicotine-[2′-14C] was administered to Nicotiana glauca plants for 3 days, resulting in the formation of radioactive nornicotine (49·5% incorporation) and myosmine (2·05% incorporation). Negligible activity was detected in anabasine, cotinine, or 3-acetylpyridine, the last two compounds being added as carriers to the harvested plants. The radioactive nornicotine consisted of 48% (?)-nornicotine-[2′-14C,3H] and 52% (+)-nornicotine-[2′-14C]. Thus if (+)-nornicotine is formed from (?)-nicotine the transformation must involve loss of the hydrogen from C-2′. Myosmine is presumably formed from nicotine via nornicotine. However by feeding myosmine-[2′-14C] to N. glauca it was shown that the dehydrogenation is not reversible, no activity being detected in nornicotine. Nicotinic acid (0·14% incorporation) was a metabolite of myosmine-[2′-14C]. Essentially all the activity of the nicotinic acid was located on its carboxyl group, indicating that myosmine was a direct precursor. 相似文献
659.
Aseptically propagated regenerates were cultivated in a hydroponic apparatus, a phytotron or in the field, and their growth
and littorine contents were investigated. No littorine was detected in aseptic regenerates cultured on solidified Murashige
and Skoog medium, nor was it found in leaves under the three conditions tested. In roots, it was common features to all three
conditions tested that littorine increased dramatically after transplantation from culture tubes and was a major alkaloid
up to week 4; subsequently the littorine contents varied depending on the cultivation conditions. Roots cultivated in the
field showed a marked thickening and rapid disappearance of littorine; those cultivated in the hydroponic apparatus were thin
and maintained a high level of littorine for a long time. In a plant cultivated for 16 weeks in a pot, littorine content in
the roots decreased with increasing root diameter.
Received: 1 October 1999 / Revision received: 16 March 2000 / Accepted: 24 March 2000 相似文献
660.
An enzyme system which catalyzes the O2 dependent release of 14CO2 from nicotinic acid-7-14C is present in tobacco roots. The enzyme is not present in tobacco leaves and stems. The nature of reaction catalyzed and its tissue distribution suggest that this enzyme may be involved in nicotine biosynthesis. 相似文献