Red Onion Extracts Exhibit Anti-Cancer Properties

Onions contain one of the highest concentrations of quercetin, a flavonoid extract with anti-proliferative effects.

Ontario grown red onions could kick cancer’s butt.

In a study published in Food Research International, the investigators assessed the anti-proliferative, cytotoxic, apoptosis-inducing, and anti-migratory activities of 5 varieties of Ontario-grown onions against human adenocarcinoma (Caco-2) cells.

The investigators compared the properties of onion extracts with pure extracts of flavonoids—–quercetin, myricetin, and kaemperfol––known to exhibit anti-proliferative effects.

The results of the study showed that all the onion varieties demonstrated anti-proliferative activity similar to purified flavonoids.

But the real star was the red onion, which boasted the highest levels of quercetin and high amounts of anthocyanin. The authors noted that anthocyanin helps boost the scavenging properties of quercetin molecules.

“Anthocyanin is instrumental in providing color to fruits and vegetables,” said lead author Abdulmonem Murayyan. “So, it makes sense that the red onions, which are darkest in color, would have the most cancer-fighting power.

The study adds to recent findings that show onions are also effective at killing breast cancer cells.

“We found that onions are excellent at killing cancer cells,” Murayyan said. “Onions activate pathways that encourage cancer cells to undergo cell death. They promote an unfavorable environment for cancer cells and they disrupt communication between cancer cells, which inhibits growth.

“The next step will be to test the vegetable’s cancer-fighting powers in human trials.”

Unfortunately, current techniques for extraction use solvents that can leave a toxic residue. But the new findings piggyback a recent study regarding a novel extraction technique that eliminates the use of chemicals, to make quercetin more suitable for consumption.

“This new method that we tested to be effective only uses super-heated water in a pressurized container,” said investigator Suresh Neethirajan. “Developing a chemical-free extraction method is important because it means we can use onion’s cancer-fighting properties in nutraceuticals and in pill form.”

The authors hope that the onion extract will be added to food products or sold in pill form as a type of natural cancer treatment in the future.