Chemical, biological and practical aspects of brassinosteroids, a new class of plant hormones, have been reviewed with 70 references. Distribution of brassinosteroids in the plant kingdom, their microanalysis by GC/MS and HPLC methods, chemical syntheses of natural brassinosteroids and unnatural derivatives, their biological activities and physiological actions, and their practical applications in agricultural fields have been discussed. Brassinosteroids have been shown to possess the following characteristics : promotion of germination and plant growth, raising of ripening, thickening promotion, recovery from stresses under various conditions (temperature, soils, diseases, salt or pesticide injury and etc.), and effects on flowering or its differentiation. It is expected that brassinosteroids will contribute agricultural production in the near future.
The phosphorylation of alcohol with phosphorus pentoxide in the presence of water (ROH/ H2O/P2O5 phosphorylation system) was studied. To assess the influence of water on product composition, two phosphorylation methods were used : (a) ROH-H2O-P2O5 and (b) ROH-85% phosphoric acid (PA) -P2O5. Product composition was found not to depend on the reaction temperature, but on two parameters, A= (ROH+H2O) /P2O5 and B=ROH/H2O, which represent molar ratios. When alcohol was initially phosphorylated with phosphorus pentoxide in the absence of water and then in its presence, composition differed considerably from that determined by method (a). This indicates that phosphorylation is not an equilibrium reaction. The reactions of ROH/H2O/P2O5 phosphorylation system were followed by potentiometric titration (Silver nitrate method) and 31P-NMR spectroscopy after the solid phosphorus pentoxide had been dissolved. PA content was almost constant. There may thus possibly be the direct phosphorylation mechanism of alcohol with PA.
To examine the mechanism of phosphorylation of alcohol (ROH) with phosphoric acid (PA), reaction of ROH with PA under azeotropical distillation was followed by measuring the amount of distilled water and 31P-NMR spectra of the reaction mixture. The results indicated that Direct-Phosphorylation of ROH with PA occurred. Under reduced pressure without a solvent, PA conversion increased linearly with time (h) in the range of about 20 to 50% conversion. The slop (k) was expressed by the equation (1) [ln k=r-10.6×103× (1/T) -7.85×10-4×P+28.05].Activation energy of the reaction was estimated as 21kcal/mol based on the above equation. Under dehydration conditions, the pyrolysis of MAP (Monoalkyl-phosphate) occurred spontaneously. Phosphorylation with highly concentrated phosphoric acid (polyphosphoric acid) at low temperature without dehydration was studied, and ROH was found to be converted almost quantitatively to MAP without pyrolysis.
The effects of fish oils with different degrees of hardening on the biosynthesis of L-ascorbic acid were investigated using rats fed diets containing as unhardened fish oil (FO), 4 kinds of hardened fish oil (HFO), and soybean oil (SO) as the control at the 20% (wt/wt) level. Urinary excretion and concentration of L-ascorbic acid in the liver and serum were measured. The urinary excretion of L-ascorbic acid from the FO and HFO groups increased significantly regardless of the degree of hardening of the oil. In general, the liver and serum levels of acid increased in the FO and HFO groups with duration of the feeding period. From these results, it follows that the biosynthesis of L-ascorbate in rats is stimulated not only by dietary HFO but by dietary FO as well.
The qualitative characteristics of recent household fat spreads, whose production is rapidly increasing, were investigated by measuring various chemical and physical parameters of 8 brands of fat spread (vegetable oil type 7; milk fat blend type 1) and 7 brands of seasoning fat spread (cheese containing type 5; spice containing type 2). 1) From data on general and nutritional components, in fat spreads, a brand of a vegetable oil type was shown to contain 39.4% lipids, meeting the international standard of “minarine”, but most types commercially available contain 70% or more lipids. Thus, the energy of household fat spreads is 1550% less than that of household margarine. Also, all brands of fat spreads except 3 were fortified retinol at the same level as household margarine. 2) Analytical results on sterols, tocopherols and fatty acids in the fat spreads showed the vegetable oil type to be made from a high linoleic acid blend of vegetable oils only, but the spice containing type to contain animal fat, probably hardened fish oil. Also, 4 brands of fat spreads appeared to contain palm oil at low levels since trace amounts of tocotrienols were detected. Furthermore, tocopherol content in the vegetable oil type was relatively high. The content of α-tocopherol was markedly higher than that in any other type. 3) According to the curves of hardness index, oil-off values and solid fat content (SFC) for different types of fat spreads, the vegetable oil type tended to oil off with more difficulty and showed more SFC than high linoleic soft margarine, while the hardness was almost the same. A similar tendency was observed between each of the other types of fat spreads and the common soft margarine. Thus possibly household fat spread can be manufactured by directing more attention to its forming ability, since it contains more water than margarine.