Brucine

Int J Biol Macromol. 2015 Jun;77:92-8.

Cytotoxicity and DNA interaction of brucine and strychnine-Two alkaloids of semen strychni.[Pubmed: 25796448]

METHODS AND RESULTS:
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.
CONCLUSIONS:
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.

J Chromatogr A. 2014 Jul 25;1352:1-7.

Ionic liquid-based electromembrane extraction and its comparison with traditional organic solvent based electromembrane extraction for the determination of strychnine and brucine in human urine.[Pubmed: 24925450]

METHODS AND RESULTS:
An ionic liquid-based electromembrane extraction (IL-EME) method was presented, and its performance was compared with 2-ethylnitrobenzene (ENB) based EME for the determination of strychnine and Brucine in human urine. For the two methods, the fundamental extraction parameters such as supported liquid membrane, voltage, extraction time, pH values of sample solution and acceptor solution, temperature and salting-out effect were separately optimized. IL-EME provided 96- and 122-fold enrichment factors for strychnine and Brucine, respectively, which were better than those obtained in EME (83- and 86-fold, respectively). The calibration curves were linear over the ranges of 20-720 μg L(-1) for strychnine and 20-640 μg L(-1) for Brucine with the correlation coefficients higher than 0.9950. The repeatability of EME and IL-EME were evaluated by five parallel experiments giving the relative standard deviations of 5.12-6.98%.
CONCLUSIONS:
As the results indicated, compared with ENB based EME, the proposed IL-EME is more reliable and could provide better extraction performance for the determination of strychnine and Brucine in human urine.

Toxicol Lett. 2013 Oct 24;222(2):91-101.

Brucine, an alkaloid from seeds of Strychnos nux-vomica Linn., represses hepatocellular carcinoma cell migration and metastasis: the role of hypoxia inducible factor 1 pathway.[Pubmed: 23933019]

Brucine is an alkaloid derived from the seeds of Strychnos nux-vomica Linn. which have long been used as a traditional medicine for the treatment of hepatocellular carcinoma (HCC) in China. HCC prognosis can be greatly influenced by metastasis. There has thus far been little research into Brucine as a source of anti-metastasis activity against HCC.
METHODS AND RESULTS:
In this study, we revealed that Brucine dramatically repressed HepG2 and SMMC-7721 HCC cell migration with few cytotoxic effects. Hypoxia inducible factor 1 (HIF-1) is a key transcription factor mediating cell migration and invasion. Brucine suppressed HIF-1-dependent luciferase activity in HepG2 cells. The transcriptions of four known HIF-1 target genes involved in HCC metastasis, i.e., fibronectin, matrix metallopeptidase 2, lysyl oxidase, and cathepsin D, were also attenuated after Brucine treatment. Experiments in vivo showed that an intraperitoneal injection of 5 and 15 mg/kg of Brucine resulted in dose-dependent decreases in the lung metastasis of H22 ascitic hepatoma cells. Moreover, a dosage of Brucine at 15 mg/kg exhibited very low toxic effects to tumor-bearing mice. Consistently, Brucine downregulated expression levels of HIF-1 responsive genes in vivo.
CONCLUSIONS:
Our current study demonstrated the capacity of Brucine in suppressing HCC cell migration in vitro and lung metastasis in vivo. The inhibition of the HIF-1 pathway is implicated in the anti-metastasis activity of Brucine.

Zhongguo Fei Ai Za Zhi. 2014 Jun 20;17(6):444-50.

Brucine inhibits the proliferation of human lung cancer cell line PC-9 
via arresting cell cycle

[Pubmed: 24949683]

It has been proven that Cyclin D1 and Cyclin E are the important positive regulators of cell cycle, they are closely related to the tumor proliferation. The aim of this study is to explore the relationship between Brucine and the proliferation in human lung cancer cell line PC-9, and the effect of it on the expression of Cyclin D1 and Cyclin E.
METHODS AND RESULTS:
: PC-9 cells were divided to 4 groups: the normal control group, the DMSO control group (2‰), the 150 μM Brucine group, and the 300 μM Brucine group. The proliferation rate of PC-9 cells was determined by The CellTiter-Glo Luminescent Cell Viability Assay and Colony Formation assay. The change of cell cycle was detected by Flow cytome try. Expressions of cell cycle regulators Cyclin D1, Cyclin E mRNA were determined by qRT-PCR. Protein expression of cell cycle regulators Cyclin D1, Cyclin E were determined by Western blot. Compared with the control, Brucine remarkably inhibited the proliferation of PC-9 cells in a dose- and time-dependent manner (P<0.01); Flow cytome try showed that Brucine blocked the cell cycle of PC-9 cells at G0/G1, and the differences were statistically significant (P<0.01); qRT-PCR showed that the expression of Cyclin D1, Cyclin E mRNA were down-regulated; Western blot showed that the protein expression of Cyclin D1, Cyclin E were down-regulated.
CONCLUSIONS:
Brucine can inhibit the proliferation of human lung cancer cell line PC-9 mainly by blocking the cell cycle at G0/G1 via down-regulating the expression of Cyclin D1, Cyclin E.

Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2014 Jun;22(3):681-6.

Inducing-apoptosis effect of brucine on human monocytic leukemia cell line THP-1 and its mechanism[Pubmed: 24989276]

This study was aimed to investigate the inducing-apoptosis effect of Brucine on human monocytic leukemia cell line THP-1 cells and its possible mechanism.
METHODS AND RESULTS:
The inhibition effect of Brucine on growth of THP-1 cells was measured by CCK-8 method. Morphological changes of THP-1 cells treated with Brucine was detected by acridine orange/ethidium bromide (AO/EB)double staining. Annexin-V/PI double labeling method was used to assay the apoptosis rate of THP-1 cells. The effect of Brucine on THP-1 cell cycle distribution was detected by PI single staining. RT-PCR was used to detect the expression of BCL-2 and BAX. The results showed that the Brucine could inhibit the THP-1 cell growth in concentration and time-dependent manners at the range of 50 to 400 μg/ml. The cells stained with AO/EB revealed that the Brucine induced the nuclear chromatin condensation. After the THP-1 cells were treated with Brucine of 400μg/ml for 48 hours, most nucleic were stained as orange-red, and condensed, displaying the late apoptotic cell morphology. Annexin-V/PI detection showed that Brucine could induce apoptosis of THP-1 cells in a concentration-dependent manner. Compared with the control group, more cells in Brucine-treated group were arrested at G0/G1 phase in a concentration-dependent manner. RT-PCR detection revealed that the expression of BCL-2 was down-regulated strikingly and BAX was up-regulated.
CONCLUSIONS:
It is concluded that Brucine can efficiently inhibit cell growth and block THP-1 cells in G0/G1 phase. The mechanism of THP-1 cell apoptosis induced by Brucine may be related to the inhibition of BCL-2 and activation of BAX.