Brassins

Sculier, J. P., Coune, A., Brassine, C., Laduron, C., Atassi, G., Ruysschaert, J. M., and Fruhling, H. (1986). Intravenous infusion of high doses of liposomes containing NSC 251635, a water-insoluble cytostatic agent. A pilot study with pharmacokinetic data, J. Clin. Oncol., 4, 789-797. 

Sculier JP, Coune A, Meunier F, Brassine C, Laduron C, Hollaerl C, Collete N, Heymans C, Klastersky J (1988) Eur J Cancer Clin Oncol 24 527... 

Mitchell, J.W., Mandava, N.B., Worley, J.F., Plimmer, J.R., Smith, M.V. (1970). Brassins a new family of plant hormones from rape pollen. Nature (London) 225,1065-1066. 

Among the compounds that have been isolated from the brassins were a new group of glucosyl esters of fatty acids, the structures of which were established by spectral methods (254, 255) as well as by chemical and biochemical synthesis (256, 257, 258). Although these esters were much less active than brassinolide in the bean second internode bioassay, their presence may be essential for seed germination since the enzymatic synthesis of these esters was correlated to germination (257, 258). 

Mitchell s search for biological activity in pollen led in 1970 to the first published report on the biologically active fraction, termed brassins, from an ethyl ether extract of pollen of the rape plant (Brassica napus L.) (7). ... 

The partially purified biologically active extract from rape pollen will be referred to as "brassins" in this Chapter. The extract was partially purified via a thin layer silica gel chromatographic procedure. Biologically active fractions were detected and monitored via the "bean 2nd internode bioassay" (6). Fractions from the... 

Further studies of pollen extracts of a number of different plant types for brassins-like activity showed that some induced the same type activity whereas others did not, and some were inactive (8, 9). Because rape pollen was a rich source of brassin-like activity, and because it could be relatively easily obtained, it was chosen for further detailed chemical and biological studies. 

Prior to his retirement from the USDA in 1974, Mitchell sought increased support to establish field trials to evaluate the effects of brassins for enhancing yields of several crop plants. Because the purification, isolation, and identification of the active component(s) were proving to be so very difficult, Mitchell also sought additional support for a concerted research effort in these area. The ARS administration considered both aspects to be of importance and plans for a multi-disciplined, multilocation project were made. 

Purification, Isolation, and Identification of Active Component(s) of Brassins As indicated, the brassins complex was found to contain glucosyl esters of fatty acids (17) which were thought to be the active brassins constituents. Starting with this information, glucosyl esters from rape pollen were purified and esters of these types were synthesized (18, 19, 20). However, neither the esters purified from pollen nor those synthesized proved to have brassins-like biological activity in the bean 2nd internode test. It was therefore concluded that components other than glucosyl esters, most likely present in very small amounts, were responsible for the biological activity of brassins. 

Because of the apparent low concentration of the active component(s) in the brassins complex, it was necessary to plan for the extraction of a large quantity of rape pollen. Honeybee-collected rape pollen was available from Canada since pollen is used in specialty-type natural food products, for example baked goods. Arrangements were made (not without some difficulty) to obtain a large lot (over 1/4 ton ) of rape pollen from Canada for a pilot plant-scale extraction at ERRC. Earlier work by Mandava et al. (16) was the basis for the pilot plant extraction procedure that was developed and used (21). Contributors to the project, in addition to M. Kozempel and N. Mandava, were H. Kenney of ERRC J.F. Worley, D. Matthees, J.D. Warthen, Jr., M. Jacobson and G.L. Steffens of BARC and M.D. Grove, NRRC. 

Figure 1. Flow diagram for the isolation of brassins from rape pollen. (Reproduced from reference 21. Copyright 1978 American Chemical Society.)...

A second column chromatography clean-up step similar to the first was then conducted on the active material from the first column. Sixty g batches of the active residue were applied and the column successively eluted with increasing concentrations of methanol in chloroform. Bioassay monitoring showed that essentially all the activity was eluted from the column when the methanol concentration reached 10-20%. The second chromatography step reduced the 450 g of active material to ca. 200 g of active brassins per 181 kg pollen (ca. 252 g active brassins per 227 kg pollen, equivalent) ... 

Figure 3. Responses of bean internode segments in the bean 2nd internode assay to increases in concentration (left to right) of the active component of brassins nearing final purification. (Reproduced with permission from reference 22. Copyright 1981 Butterworth-Heinemann.)...

Field experiments at seven locations in the U. S. were established to determine if increased seed yields could be obtained by treating soybean with brassins prior to... 

Summary of 1974-1975 Field Experiments. From these rather large and detailed soybean and barley field studies, it was apparent that biological activity of brassins was not transferred into economic yield increases via the technique used to treat the seed in these experiments. 

Intact Plant Studies with Brassins - BARC. Because yields were not increased in the 1974-75 field studies by the brassins treatment procedure used, application techniques... 

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