Scientists turn bitter around

From one sense to another - taste. As children, and indeed adults, how many of us have been forced to swallow bitter-tasting medicines ? But there could be a solution for present and future generations, and a natural one at that.

A biotechnology company in the US claims that its recently patented family of blockers, from natural compounds, could not only help pharmaceutical companies make bitter-tasting medicines more palatable, they could also help food manufacturers reduce the amounts of sugar, salt and fat they add to processed foods - frequently used to mask bitter tastes.

Biotech company Linguagen last month received patent protection for the family of blockers it has discovered, and it claims that there is already interest from food and drug companies, according to a report in the UK science journal New Scientist​ this week.

"A major food ingredient company is testing them, and a major pharmaceutical company,"​ said chief operating officer Shawn Marcell.

Linguagen was founded by Robert Margolskee of the Mount Sinai School of Medicine in New York, who discovered the particular cascade of reactions that leads to bitterness perception. When taste receptor cells in the mouth detect bitter compounds such as naringin, found in grapefruit, caffeine and the painkiller ibuprofen, they release a protein called gustducin. This triggers a series of reactions that finally results in a nerve impulse being sent to the brain saying "bitter".

Researchers at Linguagen tested a wide range of compounds from chemical libraries to see if any could block gustducin release. They mixed the compounds one by one with a dye and the relevant components found in the mouth. When the dye turned blue, it signalled that gustducin had been produced. If it did not turn blue, the researchers assumed that the compound was blocking gustducin production.

The team confirmed that the potential blockers did prevent bitterness being perceived when lab mice could not distinguish a bitter solution doped with the blocker from plain water.

The scientists report that the compounds that blocked bitterness are nucleotides, the family of molecules that includes the building blocks for DNA and RNA. All of them are naturally occurring and already found in various foods - which means the compounds will not require approval from the US Food and Drug Administration when small amounts are added to food and drugs.

"We don't know exactly how it works,"​ admitted Gravina. But the researchers believe that by bonding to the mouth's bitter taste receptors in place of the bitter compounds, they inhibit the release of gustducin.

If Linguagen's blockers are proven safe and effective, reports the New Scientist, they could go a long way to making food healthier. Bitter blockers would avoid the need to mask unpleasant flavours in processed foods and could also make bitter-tasting, healthy foods such as broccoli and soya more palatable.

As well as working to develop more potent blockers to work in extremely bitter medicines, such as HIV drugs, Linguagen also hopes to tackle entirely different messengers and reaction pathways to produce artificial sweeteners and salt substitutes.