Application of Bromocresol Green for Spectrophotometric Determination of Alkaloid Content Using the Example of Ruta graveolens

Studies were carried out to select conditions for the spectrophotometric determination of total alkaloid content using bromocresol green (BCG): buffer pH, formation time of the BCG-alkaloid ion pair, and stability time of the BCG-alkaloid ion pair. It is shown that the method is applicable for tropane, isoquinoline, indole, and pyridine alkaloids. The method was used for rapid assessment of alkaloid content in the biomass of Ruta graveolens L. regenerated plants and in the pharmaceutical preparation Ruta graveolens herb. Using a minimum volume of dry plant material (20 mg), it was determined that the content of alkaloids in regenerated plants was 10.55 mg/g dry weight, which is 1.62 times less than in pharmaceutical drug samples. Using reverse-phase HPLC, 16 compounds of varying intensity were identified in purified alkaloid fractions, six of which were common to regenerating plants and to the pharmaceutical preparation.