Mechanism study of goldenseal-associated DNA damage

Abstract

Goldenseal has been used for the treatment of a wide variety of ailments including gastrointestinal disturbances, urinary tract disorders, and inflammation. The five major alkaloid constituents in goldenseal are berberine, palmatine, hydrastine, hydrastinine, and canadine. When goldenseal was evaluated by the National Toxicology Program (NTP) in the standard 2-year bioassay, goldenseal induced an increase in liver tumors in rats and mice; however, the mechanism of goldenseal-associated liver carcinogenicity remains unknown. In this study, the toxicity of the five goldenseal alkaloid constituents was characterized, and their toxic potencies were compared. As measured by the Comet assay and the expression of γ-H2A.X, berberine, followed by palmatine, appeared to be the most potent DNA damage inducer in human hepatoma HepG2 cells. Berberine and palmatine suppressed the activities of both topoisomerase (Topo) I and II. In berberine-treated cells, DNA damage was shown to be directly associated with the inhibitory effect of Topo II, but not Topo I by silencing gene of Topo I or Topo II. In addition, DNA damage was also observed when cells were treated with commercially available goldenseal extracts and the extent of DNA damage was positively correlated to the berberine content. Our findings suggest that the Topo II inhibitory effect may contribute to berberine- and goldenseal-induced genotoxicity and tumorigenicity.

Endoplasmic Reticulum Stress in Drug- and Environmental Toxicant-Induced Liver Toxicity

“…Besides drugs, herbal dietary supplements and environmental pollutants are also reported to be associated with liver damage [145][146][147][148][149]. The causes of liver damage vary, including factors such as genetic makeup, personal lifestyle, environmental factors, and pre-existing diseases.…”

The role of hepatic cytochrome P450s in the cytotoxicity of dronedarone

“…7), suggesting the parent dronedarone is more likely than its metabolites to interfere with topoisomerase IIα expression. It has been reported that some drugs and naturally occurring compounds inhibit topoisomerases II, leading to DNA damage and liver toxicity (Chen et al 2013; Poulsen et al 2014; Zhang et al 2015). In agreement with these studies, our current study highlights the role of topoisomerase IIα in drug-induced liver toxicity.…”

“…cDNAs were generated by reverse transcription of 2 μg of total RNA using a high capacity cDNA reverse transcription kit (Applied Biosystems, Foster City, CA, USA) according to the manufacturer’s instructions. Quantitative real-time PCR for topoisomerase II was performed as described previously (Chen et al 2013) to evaluate relative gene expression. Data normalization and analysis were conducted as described previously (Guo et al 2009).…”

DNA damage‐induced apoptosis and mitogen‐activated protein kinase pathway contribute to the toxicity of dronedarone in hepatic cells

“…Quantitative real-time PCR for topoisomerase IIa was performed as described previously (Chen et al, 2013) to evaluate relative gene expression. cDNAs were generated by reverse transcription of 2 mg of total RNA using high capacity cDNA reverse transcription kits (Applied Biosystems, Foster City, CA) according to the manufacturer's instruction.…”

“…The topoisomerase I enzyme assay was performed using a topoisomerase I drug screening kit (TopoGen, Buena Vista, CO) as described previously (Chen et al, 2013). Briefly, a 20 ml reaction mixture containing 10 mM Tris HCl (pH 7.9), 1 mM EDTA, 0.15 M NaCl, 0.1% BSA, 0.1 mM spermidine, 5% glycerol, 125 ng supercoiled plasmid DNA, and 2 units of purified human topoisomerase I was incubated at 378C for 30 min with or without various concentrations of dronedarone.…”