ABSTRACT
A micro-assay has been developed to extract and rapidly quantify the anticancer alkaloid, camptothecin (CPT), from two leaf disks of Camptotheca acuminata Decaisne (Nyssaceae). This assay utilizes thin-layer chromatography in conjunction with fluorescence imaging to obtain reproducible measurements in the nanogram range. A large number of trees can be screened using this procedure to identify high producers of CPT in a relatively short period of time.
Subject(s)
Alkaloids/analysis , Alkaloids/isolation & purification , Antineoplastic Agents, Phytogenic/analysis , Antineoplastic Agents, Phytogenic/isolation & purification , Camptothecin/analysis , Camptothecin/isolation & purification , Plant Extracts/chemistry , Plant Leaves/chemistry , Plants, Medicinal/chemistry , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , DNA Topoisomerases, Type I/metabolism , Methylene ChlorideABSTRACT
An abscisic acid derivative was formed by reaction with pentafluorobenzyl bromide which allowed highly sensitive detection by gas-liquid chromatography with electron capture detection. In comparison to the methyl ester derivative, the pentafluorobenzyl derivative of abscisic acid was four times more sensitive to electron capture detection and was stable at room temperature in the presence of ultraviolet light. Derivatization was rapid and the molecular weight of the new compound was confirmed by gas-liquid chromatography-mass spectrometry.
Subject(s)
Plants/metabolism , Proton-Translocating ATPases/metabolism , Calcium-Transporting ATPases/metabolism , Chloroplasts/drug effects , Cryoprotective Agents/pharmacology , Electrophoresis, Polyacrylamide Gel , Freezing , Intracellular Membranes/metabolism , Plant Proteins/metabolism , Raffinose/pharmacologyABSTRACT
Differential cryoprotection is afforded to chloroplast thylakoids against freeze-induced uncoupling of cyclic photophosphorylation by equimolar concentrations of glucose, sucrose, and raffinose. This differential protective effect appears to be due to nonideal activity-concentration profiles exhibited by the sugars during freezing. When cryoprotection is analyzed as a function of the mole fraction of NaCl to which the membranes are exposed during freezing, the pattern of protection to cyclic photophosphorylation and its component reactions is not dependent upon the chemical identity of the protective solute. Cryoprotective efficiency of glucose, sucrose, and raffinose can be accounted for by proposing an activity dependent alteration in the freezing environment rather than specific solute-membrane interactions.