title: Cytotoxicity and DNA interaction of brucine and strychnine-Two alkaloids of semen strychni.
abstract: The cytotoxicities of the two alkaloids strychnine and brucine from the seed of Strychnos nux-vomica and their interaction with DNA were investigated. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrasolium bromide (MTT) assay was used to examine the growth inhibitory effects of these alkaloids on Vero cells after 24, 48 and 72h of incubation. The cytotoxicities of strychnine and brucine were found to be time- and concentration-dependent. Strychnine was determined to be more toxic to Vero cells than brucine. At the same time, the interactions of strychnine and brucine with DNA were investigated using neutral red (NR) dye as a probe by UV-vis spectroscopy, fluorescence spectroscopy, and an examination of the ionic strength effect, and the effects of alkaloids on DNA melting were also examined. The results indicated that a DNA-brucine mixture but not a DNA-strychnine mixture could be extracted from Vero cells after treatment with brucine and strychnine, respectively. Brucine competitively intercalated into the DNA double-helix causing fluorescence quenching of the DNA-NR system. UV absorption spectroscopy and the melting temperature (Tm) curve also provided evidence that brucine interacted with DNA through intercalation. Furthermore, the results of the ionic strength effect experiment suggested that electrostatic interactions between brucine and phosphate groups in the DNA backbone might also play an important role in the binding of brucine to DNA.
authors: The School of Public Health, Hebei Medical University, Shijiazhuang 050017, China.
authors: Fei
authors: F
authors: Liu
authors: The School of Public Health, Hebei Medical University, Shijiazhuang 050017, China.
authors: Xiaolin
authors: X
authors: Wang
authors: Institute of Viral Disease, Hebei Center for Disease Control and Prevention, Shijiazhuang 050021, China.
authors: Xu
authors: X
authors: Han
authors: The School of Public Health, Hebei Medical University, Shijiazhuang 050017, China.
authors: Xiaoxin
authors: X
authors: Tan
authors: The School of Public Health, Hebei Medical University, Shijiazhuang 050017, China. Electronic address: hbzyxyliufei@163.com.
authors: Weijun
authors: W
authors: Kang
mesh_terms: D000818:Animals; D002522:Chlorocebus aethiops; D003603:Cytotoxins / Q000378:metabolism* / Q000633:toxicity*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D009994:Osmolar Concentration; D012639:Seeds / Q000737:chemistry; D013331:Strychnine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D031461:Strychnos nux-vomica / Q000737:chemistry*; D014709:Vero Cells
chemical_list: D003603:Cytotoxins; D004365:Drugs, Chinese Herbal; C083806:brucine; D004247:DNA; D013331:Strychnine
keywords: Alkaloid; Cytotoxicity; DNA