ArticleChemical research in toxicology2014
Natural products as topoisomerase II poisons: effects of thymoquinone on DNA cleavage mediated by human topoisomerase IIα.
Article in Chemical research in toxicology, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers.
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Who cites it
20 citing papers in PubMed, 38 citations in OpenAlex.
- Antineoplastic Effects of Thymoquinone on Pancreatic Atypical Acinar Cell Foci Treated With Azaserine.Journal of biochemical and molecular toxicology · 2025Article
- Herbal Therapies for Cancer Treatment: A Review of Phytotherapeutic Efficacy.Biologics : targets & therapy · 2024Review
- Guesstimate of thymoquinone diversity inOpen life sciences · 2023Article
- Article
- Zerumbone mediates apoptosis and induces secretion of proinflammatory cytokines in breast carcinoma cell culture.Iranian journal of basic medical sciences · 2021Article
- Review
- 1,2-Naphthoquinone as a Poison of Human Type II Topoisomerases.Chemical research in toxicology · 2021Article
- Review
- Salacia mulbarica leaf extract mediated synthesis of silver nanoparticles for antibacterial and ct-DNA damage via releasing of reactive oxygen species.IET nanobiotechnology · 2020Article
- Structural Characterization, Antimicrobial Activity, andEvidence-based complementary and alternative medicine : eCAM · 2019Article
- Synthesis, Biological Evaluation and Docking Studies of Benzoxazoles Derived from Thymoquinone.Molecules (Basel, Switzerland) · 2018Article
- Mitochondrial tyrosyl-DNA phosphodiesterase 2 and its TDP2EMBO reports · 2018Article
- Review
- Anticancer Chemodiversity of Ranunculaceae Medicinal Plants: Molecular Mechanisms and Functions.Current genomics · 2017Review
- Novel trifluoromethylated 9-amino-3,4-dihydroacridin-1(2H)-ones act as covalent poisons of human topoisomerase IIα.Bioorganic & medicinal chemistry letters · 2017Article
- Inhibition of human DNA topoisomerase IIα by two novel ellipticine derivatives.Bioorganic & medicinal chemistry letters · 2016Article
- Effects of Secondary Metabolites from the Fungus Septofusidium berolinense on DNA Cleavage Mediated by Human Topoisomerase IIα.Chemical research in toxicology · 2016Article
- Effects of Olive Metabolites on DNA Cleavage Mediated by Human Type II Topoisomerases.Biochemistry · 2015Article
- Thymoquinone: an emerging natural drug with a wide range of medical applications.Iranian journal of basic medical sciences · 2014Review
- Catalytic core of human topoisomerase IIα: insights into enzyme-DNA interactions and drug mechanism.Biochemistry · 2014Article
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Authors and funding
2 authors at 1 institution in 1 country.
Funding
Abstract
The seeds of Nigella sativa (often referred to as black seed) have long been utilized as a medicinal herb in Middle Eastern, Northern African, and Indian cultures. Historically, black seed has been used to treat a variety of illnesses associated with inflammation. More recent studies have found that it induces apoptosis and displays anticancer activity in animal and cellular models. The major bioactive compound of black seed is thymoquinone, which shares structural features with 1,4-benzoquinone and other covalent topoisomerase II poisons. Because a number of anticancer drugs target type II topoisomerases, we determined the effects of thymoquinone and a series of related quinones on human topoisomerase IIα. Thymoquinone enhanced enzyme-mediated DNA cleavage ~5-fold, which is similar to the increase seen with the anticancer drug etoposide. In order to enhance cleavage, compounds had to have at least two positions available for acylation. Furthermore, activity was decreased by the inclusion of electron-donating groups or bulky substituents. As predicted for a covalent topoisomerase II poison, the activity of thymoquinone (and related compounds) was abrogated by the addition of a reducing agent. Also, thymoquinone inhibited topoisomerase IIα activity when incubated with the enzyme prior to the addition of DNA. Cleavage complexes formed in the presence of the compound were stable for at least 8 h. Lastly, black seed extract and black seed oil both increased levels of enzyme-mediated DNA cleavage, suggesting that thymoquinone is active even in more complex herbal formulations. These findings indicate that thymoquinone can be added to the growing list of dietary and medicinal natural products with activity against human type II topoisomerases.
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