Hop leaves discarded during beer brewing contain healthful antioxidants that could fight cavities and gum disease, scientists say.
Researchers said they have also identified some of the substances that could be responsible for these healthful effects of the hop leaves.
The light green leaves are found on the pinecone-like flowers, called hops, that give beer its bitterness and aroma.
Yoshihisa Tanaka from the company Asahi Group Holdings in Japan and colleagues said that their earlier research found that antioxidant polyphenols, contained in the hop leaves (called bracts) could help fight cavities and gum disease.
Extracts from bracts stopped the bacteria responsible for these dental conditions from being able to stick to surfaces and prevented the release of some bacterial toxins.
Bracts are not used for making beer and are discarded. Thus, there is potentially a large amount of bracts that could be repurposed for dental applications, researchers said.
Tanaka's group decided to investigate what substances in these leaves might cause the healthful effects.
Using a laboratory technique called chromatography, they found three new compounds, one already-known compound that was identified for the first time in plants and 20 already-known compounds that were found for the first time in hops.
The bracts also contained substantial amounts of proanthocyanidins, which are healthful antioxidants, researchers said.
The study is published in the American Chemical Society's Journal of Agricultural and Food Chemistry.
