Quantitative determination of alkaloids in multi-herbal granules: comparative analysis of uv-spectrophotometry and high-performance liquid chromatography methods

Abstract

The root of Sophora Flavescens Soland. (S.flavescens) is widely used in Mongolian traditional medicine to treat respiratory diseases and the common cold. The main active compounds are quinolizidine type alkaloids, mainly matrine, and oxymatrine. Alkaloids commonly have toxic properties. Therefore, a quantitative analysis of the alkaloid content in crude drugs is of utmost importance for quality evaluation before use in medicine. The objective of this study is to determine the suitable method to quantify alkaloid level for routine analyses in the multi-herbal medicine Norvu-7. Analyses were performed using high performance liquid chromatography and UV-spectrophotometry methods, validating the two methods in terms of linearity, precision, limit of quantification (LOQ), and limit of detection (LOD). Quantitative analyses of the biologically active alkaloids, responsible for the Norvu-7 granules’ therapeutic activity, were carried out for the first time. In the Norvu-7 granules, the total alkaloid content was determined to be 0.21±0.03% using UV-spectrophotometry, while their matrine and oxymatrine were 0.03±0.01% and 0.16±0.01%, respectively, by the HPLC method.

Both analytical methods were accurate and precise, proving that they can be used for the quantitative analysis of alkaloid content in Norvu-7 granules. However, for the determination of the active total alkaloids in the multi-herbal Norvu-7 granules, the UV-spectrophotometry method is more appropriate due to their complex chemical composition.