Broccoli’s cancer protection activated by bacteria in lower gut

25-Oct-2010 - USA

bacteria in the lower gut are responsible for breaking down the major cancer fighting chemical in broccoli to release its bioactive form.

Of all the components present in crucifer vegetables, such as antioxidants and flavonoids, a molecule called glucoraphanin (GRP) is believed to play a major role explaining their anticancer properties. GRP is a precursor to the bioactive isothocyanate sulforaphane (SF). It is hydrolysed to SF by an endogenous enzyme in broccoli called myrosinase. When the broccoli is being eaten, the myrosinase gains access to the GRP and catalyses hydrolysis within the gastrointestinal tract. However, in cooked broccoli myrosinase is inactivated yet low levels of SF metabolites appear in urine following ingestion, suggesting hydrolysis has occurred.

Although evidence exists gut bacteria are responsible for GRP hydrolysis, this study is the first to report direct evidence of hydrolysis of a GRP to SF in the lower gut. The research team investigated the hydrolysis by gut bacteria and absorption across the lower intestine of GRP from broccoli in rats. Simulated digestion in vitro confirmed that GRP is not destroyed by digestive enzymes therefore reaches the lower intestine intact. Introduction of GRP directly to the lower intestine resulted in the appearance of SF and SF metabolites in the blood travelling away from the abdomen after two hours; in contrast, direct introduction of SF resulted in detection of SF and SF metabolites after only 15 minutes.

Original publication: Ren-Hau Lai, Michael Miller and Elizabeth Jeffery, Food & Function, 2010

https://www.bionity.com/en/news/124959/broccolis-cancer-protection-activated-by-bacteria-in-lower-gut.html