Findings from the Buck Institute in California revealed that boosting the potency of the broccoli-related compound indole-3-carbinol (I3C), by ten times may promote it as a possible treatment for AMD.
Meanwhile, University of Illinois researchers have manipulated genes that manage flavonoid accumulation in broccoli. Consumption of these flavonoids has been associated with a lower risk of coronary heart disease, type II diabetes and asthma.
The findings both sought to increase the health-promoting properties of broccoli, which are already well-established.
Broccoli and related vegetables, such as kale and cabbage, belong to the Brassica family. The group’s phytochemical content has been linked to the reduction of oxidative stress and inflammation, induce detoxification enzymes, and stimulate immune system.
Identification of I3C
Using in silico, in vitro and in vivo assays, the team from the Buck’s Institute identified 2,2′-aminophenyl indole (2AI) as a molecule linked to a hydrocarbon receptor (AhR) that has been associated in maintaining good retinal health.
The researchers found that AhR itself is activated by indole-3-carbinol (I3C), which is currently being studied for cancer prevention.
By identifying the chemical composition of I3C, the team were able to conduct a search through compound databases to find those associated to I3C but would more strongly bind to AhR. The team came up with 2AI, which is ten times more potent than I3C.
“The protective action of 2AI can occur by two related mechanisms,” explained Buck faculty and lead author Dr Arvind Ramanathan.
“2AI upregulates the NRF2 pathway in retinal cells, providing a way to relieve cells of oxidative stress. It changes the lipid metabolism of retinal cells to produce unsaturated lipids. One of these unsaturated lipids (Palmitoleic acid) directly helps to protect cells from light and oxidative stress. It might do so my altering the lipid environment and fluidity of membranes,” he added.
Cross-breeding broccoli
Meanwhile the team from University of Illinois began by cross-breeding two broccoli genetic lines. Phenolic content and their ability to neutralize oxygen radicals were tested in the resulting broccoli via cellular assays.
Quantitative trait locus analysis was then used in the next stage. This genetic technique works by searching and isolating the genes responsible for phenolic creation in the progeny with most potential.
By identifying the genes involved in the build-up of these compounds, the team think that the breeding of broccoli and related Brassica vegetables like kale and cabbage with a larger composition of phenolic compounds.
“This work is a step in that direction, but is not the final answer,” said University of Illinois geneticist and study author Jack Juvik.
“We plan to take the candidate genes we identified here and use them in a breeding program to improve the health benefits of these vegetables. Meanwhile, we’ll have to make sure yield, appearance, and taste are maintained as well.”
Previous studies have implicated AhR in maintaining retinal homeostasis. It has also been shown to be activated in response to environmental stressors such as xenobiotic stimuli.
Ramanathan is also excited about the possibility of finding more potent versions of other naturally occurring molecules that show health benefits for age-related diseases.
"This method allows us to capitalise on nature's wisdom to find related molecules that can deliver therapeutic benefit." he said.
“We suspect that dietary delivery of this compound might also activate AhR in other tissue such as liver which might result in side effects that need to be investigated. That said, weak natural activators of AhR such as indole 3-carbinol (related to 2AI) seem to be safe so there is a possibility of this working, but it to be thoroughly investigated in the future.”
Source: Nature/Scientific Reports
Published online ahead of print, doi:10.1038/srep29025
“A novel AhR ligand, 2AI, protects the retina from environmental stress.”
Authors: Arvind Ramanathan et al.
Source: Molecular Breeding
Published online ahead of print, 10.1007/s11032-016-0497-4
“QTL analysis for the identification of candidate genes controlling phenolic compound accumulation in broccoli (Brassica oleracea L. var. italica).”
Authors: John Juvik et al.