VEGETABLE PURGATIVES CONTAINING ANTHRACENE DERIVATIVES
In Part I of this series of papers1 reference was made to a preliminary test on an extract of Senna pod which was found to contain only about 5 per cent. of its theoretical activity. Biological and chemical tests have since been carried out on a number of galenical preparations of senna pod and the results have confirmed that only a small proportion of the activity of the pod is present in these concentrated preparations. The ultimate aim of the work described in this paper has been to devise a method of preparing an extract representing the full activity of the pod from which it was made, and as a result, it has been possible to set out the principles underlying efficient extraction and concentration processes.
The distribution of anthraquinone glycosides in Cassia senna L.
Abstract The distribution of rhein-type and aloe-emodin type anthraquinone glycosides in developing Cassia senna L. plants has been studied. The seeds contain no anthraquinones but shortly after germination chrysophanol, then aloe-emodin and finally rhein are formed in the young plant. In the presence of adequate light, glycosylation follows and significant quantities of glycosides appear in the young leaves. These are probably translocated to the flowers and ovaries since large concentrations of glycosides accumulate there. During fruit development the amount of aloe-emodin glycoside in the pericarp falls when the seeds become separable from the pericarp and the amount of rhein glycoside falls markedly when the seeds mature and become viable. It is suggested that in this plant anthraquinone production is intimately associated with fruit and seed development.
Two new organic reference materials for delta13C and delta15N measurements and a new value for the delta13C of NBS 22 oil.
Analytical grade L-glutamic acid is chemically stable and has a C/N mole ratio of 5, which is close to that of many of natural biological materials, such as blood and animal tissue. Two L-glutamic acid reference materials with substantially different 13C and 15N abundances have been prepared for use as organic reference materials for C and N isotopic measurements. USGS40 is analytical grade L-glutamic acid and has a delta13C value of -26.24 per thousand relative to VPDB and a delta15N value of -4.52 per thousand relative to N2 in air. USGS41 was prepared by dissolving analytical grade L-glutamic acid with L-glutamic acid enriched in 13C and 15N. USGS41 has a delta13C value of +37.76 per thousand and a delta15N value of +47.57 per thousand. The delta13C and delta15N values of both materials were measured against the international reference materials NBS 19 calcium carbonate (delta13C=+1.95 per thousand ), L-SVEC lithium carbonate (delta13C=-46.48 per thousand ), IAEA-N-1 ammonium sulfate (delta15N=0.43 per thousand ), and USGS32 potassium nitrate (delta15N=180 per thousand ) by on-line combustion continuous-flow and off-line dual-inlet isotope-ratio mass spectrometry. Both USGS40 and USGS41 are isotopically homogeneous; reproducibility of delta13C is better than 0.13 per thousand, and that of delta15N is better than 0.13 per thousand in 100-microg amounts. These two isotopic reference materials can be used for (i) calibrating local laboratory reference materials, and (ii) quantifying drift with time, mass-dependent fractionations, and isotope-ratio-scale contraction in the isotopic analysis of various biological materials. Isotopic results presented in this paper yield a delta13C value for NBS 22 oil of -29.91 per thousand, in contrast to the commonly accepted value of -29.78 per thousand for which off-line blank corrections probably have not been quantified satisfactorily.