Killer Plants

by Gabrielle DeMarco on December 7, 2011

The human immune system is a marvelous machine. Bacteria enter the body (perhaps through those nasty, chalky mints at the local diner that you simply could not resist diving in to). Above is a gross image of the mints’ effects as you see salmonella bacteria attacking human tissue. To fight the invasion, our white blood cells immediately get to work to attack the bacteria. If you are lucky, the bacteria are neutralized by the immune system and you can peel yourself off the bathroom floor and move on with your life, hopefully avoiding future contact with publicly shared jars of candy.

Scientists are discovering that plants also have a type of immune system that attacks bacteria and fungi. Instead of white blood cells, plants produce an abundance of things called flavonoids. And some very ingenious scientists here at Rensselaer are starting to ask the question, “If it works for plants, might it also work for humans?”

Why bother checking if flavonoids stop the spread of bacteria in humans? The answer is simple: society is running out of ways to kill bacteria. New methods to stop bacteria are becoming essential as the old methods – antibiotics like Z-pak, penicillin, amoxicillin, and the like – become less and less effective.

Despite being very simple organisms, bacteria have developed some exceptionally smart survival systems. As they and their brethren have been bombarded by decades by pills and sticky medicines, they have slowly adapted to survive the barrage. One of these adaptations actually allows bacteria to pump toxic compounds like antibiotics out of their systems before the drugs can leave lasting damage. And so, the antibiotics go in and the bacteria spit them right back out. To combat this, doctors need entirely new molecules to throw at the bacteria. When faced with a new molecule, the bacteria simply will not have the systems in place to combat it and they will be killed.

Of course there are a lot of different chemicals and compounds out there besides antibiotics that will kill bacteria on contact. But, drinking pool chlorine or injecting battery acid is not something I look forward to. I am guessing you are with me on at least this point. So, new drugs to combat bacteria also need to be safe for the very sensitive human system.

Flavonoids have long been praised for their health benefits (eat your kale), but little is understood about their antimicrobial effects. Mattheos Koffas who works in the Center for Biotechnology and Interdisciplinary Studies and a team of researchers at the State University of Buffalo and in the pharmaceutical industry are looking at how effective flavonoids might be in combating bacteria in the human system. The scientists recently published a paper in the journal PLoS One that shared some very promising results on the future uses of flavonoids in medicine.

What they found was that naturally occurring flavonoids in plants had strong antibacterial and antifungal properties. They were also safe to human cells. Koffas and the team then took the research an important step forward by designing non-natural flavonoids in the lab. These new molecules took all the best aspects of the natural flavonoids and essentially turned up the volume.

What they found was that these chemically-synthesized non-natural flavonoids were even more potent against bacteria and fungi. They also appeared safe for human use.

The research provides an important path forward for a new class of antimicrobial agents – flavonoids. Koffas plans to continue to study the potential of these new molecules.