In this article, the electrochemical behavior of brucine at the multiwall carbon nanotubes (MWNTs)‐modified glassy carbon electrode (GCE) was studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). The purified MWNTs dispersed in N,N‐dimethylformamide (DMF) were characterized by transmission electron microscopy (TEM). A series of electrochemical parameters of brucine were calculated by chronoamperometry (CA) and chronocoulometry (CC). A better electrochemical response was observed at MWNTs‐modified electrode than the other film‐modified electrodes. Cyclic voltammetric curves showed an irreversible oxidative peak (E pa1  = 937 mV) and a pair of perfect well reversible peaks, ΔE p2  = 13 mV (E pa2  = 418 mV, E pc2  = 405 mV). The second redox peak current of brucine increased linearly with the square root of scan rate in the low range, so it is a diffusion‐controlled process, and the electrocatalytic process mechanism for the brucine was investigated. The SWV currents of brucine at th...

Square Wave Voltammetry Determination of Brucine at Multiwall Carbon Nanotube‐Modified Glassy Carbon Electrodes

A simple, rapid, sensitive and low-cost method using capillary electrophoresis (CE) coupled with field-amplified sample stacking (FASS) has been developed and validated for the simultaneous determination of strychnine and brucine residues in human urine. Before sample loading, a water plug (3.5 kPa, 3 s) was injected to contain sample cations and to permit FASS. Electrokinetic injection at a voltage (20 kV, 25 s) was then used to introduce cations. Separation was performed using 20 mM acetate buffer (pH 3.8) with an applied voltage of 20 kV. The calibration curves were linear over a range of 8.00–2.56 ∞ 102 ng/mL (r = 0.9995) for strychnine and 10.0–3.20 × 102 ng/mL (r = 0.9999) for brucine. Extraction recoveries in urine were greater than 79.6 and 82.8% for strychnine and brucine, respectively, with an RSD of less than 4.9%. The detection limits (signal-to-noise ratio 3) for strychnine and brucine were 2.00 and 2.50 ng/mL, respectively. A urine sample from one healthy female volunteer (26 years old, 50 kg) was pretreated and analyzed. Strychnine and brucine levels in urine could be detected 24 h after administration. On these grounds, this method was feasible for application to preliminary screening of trace levels of abused drugs for both doping control and forensic analysis. Copyright © 2009 John Wiley & Sons, Ltd.

Rapid and sensitive determination of strychnine and brucine in human urine by capillary electrophoresis with field-amplified sample stacking.

Strychnos nux vomica is an important plant source for drugs of ayurvedic and homeopathic system of medicine. In this paper a thin layer chromatographic (TLC) method has been developed for the quantitative estimation of the two major alkaloids strychnine and brucine in the plant fruit and in ayurvedic and homeopathic drugs. Chloroform–ethyl acetate–diethyl amine (0.5:8.5:1) as mobile phase gave clear separation with no interference between the bioactive markers. The R
 f
 values for strychnine and brucine were 0.55 and 0.42. The TLC method was found to be precise, rugged, robust and accurate with recovery of strychnine in the range 93.11–99.82% and brucine 96.95–99.48%. The limit of detection (LOD) and limit of quantification (LOQ) for strychnine were 1.9 and 8.25 ng and for brucine 2.2 and 9.2 ng respectively.

TLC Determination of Strychnine and Brucine of Strychnos nux vomica in Ayurveda and Homeopathy Drugs

A nonaqueous capillary electrophoresis method with photo diode-array detection was developed for the analysis of strychnine and brucine in Strychnos nux-vomica L. The separation of the two alkaloids was optimized with respect to the concentration of Tris-boric acid, the proportion of methanol and acetonitrile, and applied voltage. Baseline separation was obtained for the two analytes within 10 min using a running buffer containing 25 mM Tris-boric acid, 60% methanol and 20% acetonitrile with acetic acid adjusting pH to 4.0. In this paper, the method was used to determine the contents of strychnine and brucine in raw material and prepared Strychnos nux-vomica L.

Determination of Strychnine and Brucine in Strychnos nux-vomica L. by Nonaqueous Capillary Electrophoresis

Objective: A simple, sensitive, and specific thin layer chromatography (TLC) densitometry method has been developed for the simultaneous quantification of strychnine and brucine in the seeds of Strychnos nux-vomica . Materials and Methods: The method involved simultaneous estimation of strychnine and brucine after resolving it by high performance TLC (HPTLC) on silica gel plate with chloroform-methanol-formic acid (8.5:1.5:0.4 v/v/v) as the mobile phase. Results: The method was validated as per the ICH guidelines for precision (interday, intraday, intersystem), robustness, accuracy, limit of detection, and limit of quantitation. The relationship between the concentration of standard solutions and the peak response was linear within the concentration range of 50-1000 ng/spot for strychnine and 100-1000 ng/spot for brucine. The method precision was found to be 0.58-2.47 (% relative standard deviation [RSD]) and 0.36-2.22 (% RSD) for strychnine and brucine, respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.75% for strychnine and 100.52% for brucine, respectively. Conclusions: The HPTLC method for the simultaneous quantification of strychnine and brucine was found to be simple, precise, specific, sensitive, and accurate and can be used for routine analysis and quality control of raw material of S. nux-vomica and several unani and ayurvedic formulations containing this as an ingredient.

Simultaneous HPTLC determination of strychnine and brucine in strychnos nux-vomica seed

This paper describes the determination of strychnine and brucine in the seeds, root, stem and leaves of Strychnos species by HPLC. The analytical column used was ZY110 YNG-C18. The mobile phase was KH2PO4(0.01 mol.L-1)--MeOH(73:27), pH2.5, regulated by 10% H3PO4. Flow rate was 1.0 ml.min-1. The detection wavelength was 264 nm. The linear ranges of strychmine and brucine were 0.18-7.26 micrograms and 0.11-4.32 micrograms, respectively. The recoveries of strychnine and brucine were 98.27% and 98.04%, respectively. The analytical results showed that the contents of strychnine and brucine in samples showed great difference between different species. The contents of strychnine in the seeds of Strychnos wallichiana and S. ignatii were 5.6% and 3.9%, respectively. These results show that the two Strychnos species may be developed as the resources of strychnine.

Lian Wy

Papers

Determation of strychnine and brucine in Strychnos by HPLC