Intraspecies chemical variability of the essential oil of Ledum palustre
The compositions of the essential oils of marsh tea,Ledum palustre L., from the southern regions of Tomsk, Transbaikalia and Amur province, and also from the southern part of the island of Sakhalin have been analyzed in detail. The results obtained indicate the sharply pronounced intraspecies chemical variability of this plant. In addition to the chemotype of march tea with myrcene as a macrocomponent which is widely distributed in the European part of the USSR, another three chemotypes with the macrocomponents limonene, sabinen, and p-cymene have been revealed.
Composition of essential oil of Ledum palustre.
The composition of essential oil of Ledum palustre L. was investigated. This oil was obtained by steam distillation of leaf material from plants growing in the Hortus Botanicus at Haren (Groningen). It was separated into seventeen fractions by column chromatography on silicagel and gradient elution with mixtures of petrol (bpt. < 40 degrees C) and diethylether. The investigation was made by GLC and GC-MS. In total, 80 components were identified. About 50 constituents were new, including vitispirane, perillaalcohol, perilla-aldehyde, isopinocamphone, germacrone, etc. Principal components are ledol, palustrol and myrtenal.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.