Isolation and characterization of 24-Epibrassinolide from Brassica juncea L. and its effects on growth, Ni ion uptake, antioxidant defense of Brassica plants and in vitro cytotoxicity

Brassinosteroids (BRs) are a group of steroidal plant hormones which are essential for growth and development of plants. These hormones affect plant growth and development through a spectrum of physiological responses. Recent reports showed their stress-protective, antiviral, antitumor and antigenotoxic potential. In the present study, an attempt was made to isolate 24-Epibrassinolide from 30-days-old Brassica juncea L. plants which was characterized by ESI-MS analysis. The ESI-MS analysis of isolated Brassinolide was compared with the standard 24-Epibrassinolide, which confirmed its MS/MS fragmentation pattern. Various concentrations of the isolated brassinosteroid were given as pre-sowing treatment to the seeds of B. juncea for 8 h. The pre-treated seeds were then raised in experimental pots containing different concentrations of nickel ion. After 30 days, plants were harvested and analyzed for growth parameters, ion uptake and antioxidant defense system. It was observed that pre-treatment of isolated 24-Epibrassinolide lowered the Ni ion uptake in plants and improved growth. The amelioration of Ni toxicity was also observed by the activities of antioxidant enzymes. The in vitro cytotoxicity of natural 24-Epibrassinolide against different cancer cell lines was checked by employing sulphorhodamine bioassay and it revealed significant inhibition in the lung cancer cell line.