Thymoquinone causes multiple effects, including cell death, on dividing plant cells

Area of Science:

• Plant Biology
• Molecular Biology
• Toxicology

Background:

• Thymoquinone (TQ), a key compound in Nigella sativa oil, exhibits known antioxidant and anti-inflammatory effects in animal cells.
• TQ also demonstrates anti-proliferative and apoptosis-inducing properties in human skin cancer cells.

Purpose of the Study:

• To investigate the effects of Thymoquinone on dividing plant cells.
• To examine the influence of TQ on the expression of Bcl2-associated athanogene-like (BAG-like) genes involved in cell death.

Main Methods:

• Wheat seed germination assays were conducted using varying concentrations of TQ.
• Glycine max (soybean) root tips and onion hairy root tips were treated with TQ.
• Evans blue staining, light microscopy, and transmission electron microscopy were employed to assess cell viability and morphology.
• Gene expression analysis was performed on Glycine max root tip cells.

Main Results:

• TQ inhibited wheat seed germination in a dose-dependent manner.
• TQ induced moderate to severe cell death in Glycine max root meristems.
• Anti-mitotic activity, nuclear membrane disruption, and nuclear fragmentation were observed in onion root tips.
• Ultrastructural changes in TQ-treated plant cells included plasma membrane shrinkage and nuclear condensation.
• Expression of a BAG-like gene was upregulated in response to TQ treatment in soybean root cells.

Conclusions:

• Thymoquinone exerts multiple cytotoxic effects on dividing plant cells, including inhibition of germination and induction of cell death.
• Plant systems provide a valuable model for studying the mechanisms of TQ-induced cell death in eukaryotic cells.
• TQ influences the expression of BAG-like genes, suggesting a role in plant cell death pathways.