Fluorimetric Determination Of Berberine New Method

Berberine is an active substance of traditional eastern herbal medicine. It has multiple pharmacological effects, including inhibiting acetylcholinesterase, reducing cholesterol and glucose, lowering mortality in patients with chronic congestive heart failure, as well as immunomodulatory, antimicrobial, and anti-inflammatory. Berberine exhibits very weak fluorescence emission in aqueous solution, which means that berberine cannot be detected directly in aqueous solution by normal fluorimetric method. Herein, we proposed the two fluorescence methods for determination of berberine through optimizing the micro-environment of berberine.1. Fluoresence method for detection of berberine using ionic liquid [Bmim][BF4] as micro-environment mediumIn this work, the great increase of the fluorescence intensity of berberine was observed when ionic liquid [Bmim][BF4] was added into the aqueous solution of berberine. Based on the phenomenon, a spectrofluorimetric method with high sensitivity and selectivity was developed for the determination of berberine. At optimum conditions, the linear relationship was obtained in the range of1.0×10-6-1.0×10-4g/mL with the relative coefficient of0.9924, and the detection limit was0.13μg/mL. The proposed method was successfully applied for the determination of berberine in pharmaceutical dosage preparations.2. Fluoresence method for detection of berberine using G-quadruplex as micro-environment mediumIn this work, a novel fluorescent method for berberine is presented using G-rich DNA as probe. In the presence of K+, berberine could bind G-rich DNA to form berberine-G-quadruplex complex, and the berberine-G-quadruplex complex performed the strong fluorescence emission. The fluorescence intensity of the berberine-G-quadruplex complex increased linearly with increasing berberine concentration in the range of1.0×10-8-1.0×10-5g/mL with the relative coefficient of0.9950, and the detection limit was1.2ng/mL. The turn-on fluorescent assay is simple, inexpensive, and highly sensitive. The mechanisms, which produce strong fluorescence of berberine-G-quadruplex complex, were discussed.