Peel­ing back the can­cer-fight­ing po­ten­tial of On­tario-grown onions

The Woolwich Observer - - RURAL CONNECTIONS - By Jane Robin­son for AgIn­no­va­tion On­tario, a project of the Agri-Tech­nol­ogy Com­mer­cial­iza­tion Cen­tre.

THERE’S A NEW REA­SON to cry when you peel back the lay­ers on a lo­cal On­tario onion in your kitchen … tears of joy, that is.

New re­search at the Uni­ver­sity of Guelph has found a way to safely ex­tract the free-rad­i­cal fight­ing prop­er­ties of On­tario-grown onions, cre­at­ing new op­por­tu­ni­ties for On­tario farm­ers and the nu­traceu­ti­cal and food pro­duc­tion in­dus­tries.

In the not-so-dis­tant fu­ture, you could be en­joy­ing the healthy prop­er­ties of onions through sup­ple­ments, ad­di­tives and creams.

Sci­en­tist have long known that onions carry the high­est con­tent of quercetin (an an­tiox­i­dant flavonoid) of nearly 40 dif­fer­ent fruits and veg­eta­bles. Flavonoids like quercetin at­tract and neu­tral­ize free rad­i­cals – the nat­u­rally-oc­cur­ring mol­e­cules in hu­man tis­sue that can lead to can­cer­ous cells.

Suresh Neethi­ra­jan, a bio­engi­neer­ing re­searcher in the School of En­gi­neer­ing at the Uni­ver­sity of Guelph, is in the fi­nal phase of an On­tario Min­istry of Agri­cul­ture, Food and Ru­ral Af­fairs (OMAFRA) funded project ex­am­in­ing the vary­ing lev­els of quercetin in On­tario-grown onions.

“This is the first study that’s looked specif­i­cally at the 17 or 18 ma­jor va­ri­eties of onions grown in On­tario to de­ter­mine if the level of flavonoids varies among va­ri­eties,” says Neethi­ra­jan.

After ex­tract­ing flavonoids from the On­tario onion va­ri­eties us­ing a new wa­ter-based ex­trac­tion tech­nol­ogy de­vel­oped in Neethi­ra­jan’s lab, there was a clear win­ner.

“We put the onion flavonoids in di­rect con­tact with hu­man breast and colon can­cer cells, and mea­sured the rate of apop­to­sis (can­cer cell death) among the dif­fer­ent va­ri­eties. Red onions have a four-fold in­crease in the abil­ity to trig­ger can­cer cell death compared to any other va­ri­ety,” he says.

For On­tario onion grow­ers, the news gets even bet­ter.

“Onions grown in On­tario, es­pe­cially in the Hol­land Marsh, are able to re­tain more nu­tri­ents and an­tiox­i­dants,” Neethi­ra­jansays, at­tribut­ing this largely to good man­age­ment prac­tices and soil type.

With the strong de­mand for an­tiox­i­dant nu­traceu­ti­cals, Neethi­ra­jan sees po­ten­tial for a new high­value crop po­ten­tial for farm­ers and a residue-free, onion-based an­tiox­i­dant for man­u­fac­tur­ers.

“We want farm­ers to know what man­u­fac­tur­ers might be look­ing for, so they can be ready with suf­fi­cient sup­ply,” he says.

The ex­trac­tion process re­moves most of the onion smell and taste, open­ing op­tions for adding the sub­stance to drinks, bak­ery items, en­cap­su­lat­ing in a pill form, and even skin­based prod­ucts.

“Now that we have de­vel­oped a new, safer pro­to­col for ex­tract­ing flavonoids from onions, and sci­en­tif­i­cally ver­i­fied the ac­tiv­ity on breast and colon can­cer cells, the next step is to look at eco­nom­i­cal ways to pro­duce and man­u­fac­ture prod­ucts with onionex­tracted flavonoids,” he says.

And if you’re won­der­ing if you could just add more raw onion to your diet for the same health­ful ef­fect, it’s not that sim­ple.

Neethi­ra­jan says you’d need to eat a few kilo­grams of raw onion a day to re­al­ize the po­ten­tial can­cer­fight­ing ef­fects from onion flavonoids, compared to lev­els con­cen­trated through the ex­trac­tion process.


Suresh Neethi­ra­jan, a bio­engi­neer­ing re­searcher in the School of En­gi­neer­ing at the Uni­ver­sity of Guelph, sees lo­cal onions as a good source for pro­duc­ing an­tiox­i­dant nu­traceu­ti­cals.

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