Good news for a thirsty Thursday – one of the key ingredients in beer could yield new medicines for conditions from diabetes to cancer.
University of Washington chemist Werner Kaminsky and his colleagues have a new paper this month in the journal Angewandte Chemie International Edition examining the structure of humulones. Humulones are bitter-tasting compounds derived from the resin in hops, the flowers used to flavor and stabilize beer.
“Excessive beer consumption cannot be recommended to propagate good health, but it has been demonstrated that isolated humulones and their derivatives can be prescribed with documented health benefits,” Kaminsky and his colleagues wrote.
Some researchers have found a surprising number of health benefits associated with these hoppy chemicals. A study funded by the Japanese brewery Sapporo found that humulones can help protect against certain respiratory viruses. Another Japanese study in 1995, conducted in mice, found that humulones have anti-cancer properties. Deducing the finer structure of these chemicals is important for scientists that are looking to develop humulones for pharmaceutical research.
To peer deep into the hearts of humulones, the researchers used a technique called X-ray crystallography, where a compound’s structure is divined from how it scatters X-rays, to look at humulones up close. To do this, Kaminsky enlisted the help of Seattle-based KinDex Therapeutics, which isolated humulones and derivatives from brewing beer, purified them, and converted them into salt crystals.
During the brewing process, a humulone molecule degrades from a substance with a central ring of six carbons into derivatives with five-carbon rings. These derivatives are called either cis-isohumulone or trans-humulone. Depending on how the various side groups of chemicals attached to the carbon ring are positioned, an isohumulone can take on a particular conformation, or “handedness,” which affects how it interacts with other chemicals.
Putting the wrong-“handed” molecule in a drug can sometimes lead to disastrous results. Thalidomide, used to treat morning sickness in the 1950s and 1960s, was pulled after more than 10,000 children were born with birth defects after their mothers took the drug. It was later discovered that one particular form of the drug was responsible for the birth defects.
Before humulones can come into wide use, scientists will have to be sure they know the properties of all the different forms of the molecule.
Now, thanks to this latest research, “we know which hand belongs to which molecule, we can determine which molecule goes to which bitterness taste in beer,” Kaminsky told the University of Washington news service.
Some specific forms of humulone molecules are known to affect certain illnesses, according to Kaminsky, but a slightly different chemical arrangement can render the compounds ineffective.
Now that the team has confirmed the finer chemical structure of humulones and their derivatives, “future work on their biological activities should be greatly accelerated,” the authors wrote.
SOURCE: Urban et al. “Absolute Configuration of Beer’s Bitter Compounds.” Angewandte Chemie International Edition 52: 1553-1555, 28 January 2013.
To contact the editor, e-mail: