Broccoli is already suggested to be one of the planet's most nutritious foods. But now rsearchers believe they may be able to increase levels of glucosinolates that are suggested to have anti-cancer potential by spraying the vegetable with a plant hormone called methyl jasmonate.
Writing in the Journal of Agricultural & Food Chemistry, the research team tested five commercial types of broccoli by spraying them in the field with the hormone - finding that spraying increased levels of glucosinolates and other potentially healthful compounds, in addition to increasing levels of important breakdown metabolites such as sulforaphane by more than 150%.
Led by John Juvik from the University of Illinois, USA, the research team suggested that their findings could help industry produce even better, more healthful broccoli.
Juvik and his team tested the influence of methyl jasmonate spray treatments (250 μM) on the composition of glucosinolate compounds in the florets of five commercial broccoli types: ‘Pirate’, ‘Expo’, ‘Green Magic’, ‘Imperial’, and ‘Gypsy’.
All broccoli were grown in replicated field plantings in 2009 and 2010.
They reported that methyl jasmonate (MeJA) treatment significantly increased glucoraphanin (11%), gluconasturtiin (59%), and neoglucobrassicin (248%) concentrations and their hydrolysis products including sulforaphane (152%), phenethyl isothiocyanate (318%), N-methoxyindole-3-carbinol (313%), and neoascorbigen (232%) extracted from florets of these genotypes over two seasons.
Increased quinone reductase (QR) activity was significantly correlated with increased levels of sulforaphane, N-methoxyindole-3-carbinol, and neoascorbigen, they added.
"These results suggest that methyl jasmonate treatment can enhance QR inducing activity by increased hydrolysis of glucoraphanin into sulforaphane and the hydrolysis products of neoglucobrassicin," said the team.