The primary compound of the common hop (Humulus lupulus) is called xanthohumol (XN). More than 20 years ago, researchers found that XN suppresses cell growth in various cancer cell lines. The downside of XN is that the enzymes in the liver and the gut microbiota metabolize it into 8-prenylnaringenin (8-PN), which is said to be the most estrogenic phytoestrogen.
Phytoestrogens are plant-based compounds that are similar to female sex hormones. They help some types of tumors grow and can cause other health problems.
In the current study, researchers at Oregon State University found that the derivatives of XN also have cancer-fighting effects similar to that of XN in liver and colon cancers. But unlike XN, they don’t metabolize into phytoestrogens. These two non-estrogenic derivatives are dihydroxanthohumol (DXN) and tetrahydroxanthohumol (TXN).
When researchers orally administered the same dose of XN derivatives or XN to mice, DXN and TXN showed higher tissue concentrations in vivo than XN.
The researchers also found that DXN and TXN have a greater ability to inhibit proliferation, or halt cell growth and kill two colon and two liver cancer cell lines than XN.
In addition, XN, DXN, and TXN all induced extensive apoptosis, or programmed cell death, in all the cancer cell lines tested.
"For both of those cancers, discovering new compounds for prevention and treatment is imperative," explained study author Adrian Gombart. "In all the cell lines tested, DXN and TXN inhibited cell growth and caused cell death, as did XN. And for most cell types, DXN and TXN were slightly more potent."
The researchers used liver and colon cancer cell lines for the study because the oral intake of XN and its derivatives can result in high concentrations in the gut and liver. In the U.S., colon cancer is the third most deadly cancer, while liver cancer ranks fifth. Alarmingly, the incidence of liver cancer has tripled in the last 40 years.
The findings of the study suggested that when taken together, DXN and TXN could potentially be used as alternatives for treating colon and liver cancers in future preclinical studies, without the drawback of metabolism into a phytoestrogen.
A study published in the journal Scientific Reports found that the XN derivatives DXN and TXN can reduce weight gain and improve biomarkers of metabolic syndrome.
Metabolic syndrome is a condition characterized by having at least two of the five metabolic disorders: abdominal obesity, high blood pressure, high fasting blood sugar, high triglyceride levels, and low levels of high-density lipoprotein (HDL) or "good" cholesterol.
In this animal study, the researchers found that XN and its derivatives work by reducing the effects of high-fat diet, one of the greatest contributors to metabolic syndrome. In addition to reducing insulin resistance, they also found that XN, DXN, and TXN may improve learning and memory. This suggested that all three compounds could benefit people experiencing cognitive decline associated with metabolic syndrome.
Since hops are rarely used for culinary purposes, beer represents the main dietary source of XN. However, this is not a reason to drink more beer. Beer has empty calories, contributes to weight gain, drastically reduces blood sugar levels, and increases the risk of dehydration. The harmful effects of excessive beer intake far outweigh any health benefits.