Diminution of free radical induced DNA damage by extracts/fractions from bark of Schleichera oleosa (Lour.) Oken

Abstract

The present study was undertaken to investigate the effect of extracts of Schleichera oleosa (Sapindaceae) for its cytotoxic and hydroxyl radical-scavenging activities. The bark of the tree was used to prepare extracts with different solvents (i.e., hexane, chloroform, ethyl acetate, methanol, and water). The extracts were initially assessed for their in vitro cytotoxicity potential in the sulforhodamine B dye assay against cell lines, such as 502713 (colon), SW-620 (colon), HCT-15 (colon), A-549 (lung), HEP-2 (liver), SK-NS-H (central nervous system), and IMR-32 (neuroblastoma). It was observed that the water extract was effective against all the three colon cancer cell lines, while only methanol and water extracts were effective against A-549 (lung) and HEP-2 (liver), respectively. As DNA damage is one of the hallmarks of cell death, so the extracts were assessed for their ability to scavenge hydroxyl radicals, in the deoxyribose degradation assay (site- and nonsite specific) as well as their protective effect against the hydroxyl radical–induced DNA damage in the plasmid nicking assay, using pBR322. It was observed that all the extracts, except chloroform and hexane, exhibited relatively greater antioxidant activity in the nonsite-specific than in the site-specific assay. Similarly, the extracts were also found to be effective in inhibiting the hydroxyl radical–induced unwinding of supercoiled DNA, which further confirmed the hydroxyl radical–scavenging ability of the extracts in the deoxyribose degradation method.

Keywords::

• Schleichera oleosa
• deoxyribose
• reactive oxygen species
• plasmid DNA
• human cancer cell lines

Acknowledgements

The authors are thankful to Guru Nanak Dev University, Amritsar (Punjab), for providing necessary laboratory facilities for the work.

Declaration of interest

Financial assistance provided by University Grants Commission (UGC), New Delhi, India is also duly acknowledged. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.