Pharmacognostic specification and quantitative analysis of strychnine and brucine in Strychnos nux-vomica seeds

Abstract

Strychnos nux-vomica Linn. or Sa-leang-jai is a medicinal and poisonous plant. S. nux-vomica seeds have been used in traditional Thai medicine for a long time. This study aimed to develop quality specification and the quantitative analysis of strychnine and brucine in S. nux-vomica seeds. The crude drug samples from 15 sources throughout Thailand were collected to assess the macroscopic and microscopic evaluation. The details were illustrated by drawing of whole plant, powder and cross section characteristics. The physico-chemical properties of S. nux-vomica seeds were established in average contents of water , loss on drying, total ash, acid insoluble ash, ethanol and water extractive matters as 8.08 ± 0.60, 8.80 ± 0.25, 1.20 ± 0.03, 0.15 ± 0.02, 3.90 ± 0.33 and 13.12 ± 0.77 % by weight respectively. Thin layer chromatographic fingerprint using silica gel 60 GF254 as stationary phase and toluene: ethyl acetate: diethylamine (7: 2: 1) as mobile phase showed the phytochemical compounds under UV wavelength of 254 and 365 nm and the alkaloids by Dragendorff’s developing reagent. The quantitative analysis of strychnine and brucine were performed by TLC image analysis using Image J software and TLC densitometry using CAMAG TLC scanner and winCATS. The contents of strychnine and brucine in S. nux-vomica seeds were found to be 1.09 ± 0.56, 0.48 ± 0.30 and 1.03 ± 0.51, 0.46 ± 0.28 g/100g by both methods respectively. These methods were validated in term of specificity, linearity, accuracy, precision, limit of detection, limit of quantitation and robustness. The toxic potential on DNA damage of strychnine, brucine and ethanolic extract of S. nux-vomica seeds were assessed in vitro. All treated samples exhibited human lymphocyte DNA damage. Strychnine was more toxic than brucine and the extract respectively. This study provided the quality specification, standardization and safety used of S. nux-vomica seeds in Thailand.