To most of us, free radicals are something bad that advertisers use to convince us to buy antioxidant vitamins or expensive face creams. But to Christine Winterbourn, a professor of pathology and a world authority on free radicals, they’re a lot more complicated – and rewarding – than that.
Her work on the biology of free radicals, the focus of her career for the past 25 years, has just won her New Zealand’s highest scientific honour. At the Royal Society of New Zealand’s annual awards dinner in Wellington this week, she was awarded the Rutherford Medal “for seminal discoveries in free radical biology, promotion of rigorous standards in research and fostering excellent scientific education”. In the 20 years the medal has been awarded, she is the only woman to have received the honour.
In the 1970s, Winterbourn was one of the first scientists to show that rather than being something external that our bodies have to fight, free radicals are produced by our own cells all the time. “The message that always comes across is that free radicals are bad and antioxidants are good, but what became apparent is that our cells actually produce reactive oxidants [including free radicals], and use them as messenger molecules to control processes within the cell,” she says.
But what is a free radical? Simply put, a free radical is a molecule with an unpaired electron, which means they are unstable and want to form pairs. And this is what makes free radicals ready to react with – and sometimes damage – other molecules. When Winterbourn began studying free radicals, little was known about their role in biological systems. But free radicals are now linked to normal ageing processes as well as such diseases as cancer, coronary heart disease and arthritis. After her discovery that free radicals are something our cells produce, Winterbourn became interested in trying to determine “what our bodies do to protect against them”.
Like many of the past recipients of the Rutherford Medal – including Paul Callaghan, Peter Gluckman and Alan MacDiarmid – Winterbourn became interested in science as a child. She decided she wanted to be a scientist when she was 10, inspired by mixing concoctions with her chemistry set in her Auckland home.
After completing a PhD in biochemistry, she came to the University of Otago’s Christchurch School of Medicine in 1970. It was here she discovered that haemoglobin – the iron-rich molecule that gives blood its red colour – was releasing a type of free radical called superoxide. More than 40 years later, she’s still there, though now as director of the school’s Free Radical Research Group, a team of about 25 biochemists and cell biologists working on a range of problems related to free radicals and antioxidants.
Their work involves a lot of practical experiments, using test tubes of donated blood, centrifuges, microscopes, mass spectrometers and other high-tech machines, “the sort of things you see on programmes like CSI”. The Christchurch earthquakes damaged their building and interrupted their experiments, but her group has found temporary accommodation at the University of Canterbury and at the new premises of private biotech company Canterbury Scientific. “It’s been hugely disruptive,” says Winterbourn, “but our new hosts have been very supportive.”
One of Winterbourn’s recent areas of interest is the chemicals that white blood cells use to kill bacteria – in particular, hypochlorous acid, a chlorine bleach. “It’s quite amazing to think that what you put down the toilet to kill bacteria is also something we’re producing in our body,” she says.
The production of bleach in the body was discovered in the 1960s, but Winterbourn’s research is focused on trying to understand the biochemistry of how it is produced by white blood cells and how it kills bacteria. She’s particularly interested in the role of chlorine bleach in inflammatory diseases such as arthritis, in which white blood cells accumulate at the sites of inflammation.
“If these white blood cells produce bleach in your inflamed joint, is that somehow beneficial or contributing to the disease? And if we could inhibit bleach production, would people have a better outcome?” A better understanding of how chlorine bleach affects cells – and the degree to which it contributes to the symptoms of a disease – could be a step towards finding suitable drugs to combat inflammatory conditions. “My job is understanding the chemistry that’s going on in normal and pathological conditions, so that others can apply this information to find the right pharmacological interventions.”
As for the nutraceuticals and antioxidant face creams, Winterbourn says, “a lot of the hype you read in advertisements is an optimistic interpretation of the science”. She is an advocate of a healthy diet, but points out “the best antioxidants in the body are the proteins and enzymes we make ourselves”.
But she says interesting new evidence suggests there might be some truth to the idea that the healthiest vegetables are the ones that don’t taste very good. “New information suggests that the micronutrients inside vegetables actually act like a stress. The cell responds by boosting its antioxidant defences, so it’s better able to protect itself from the food component and also from other oxidative stresses. So the best vegetables to eat are the bitter ones like cabbages and broccoli.” You heard it from the expert. Forget the antioxidants and expensive face creams – just eat your broccoli.
RNZ National interview with Christine Winterbourn on Saturday Morning with Kim Hill:
Knitters from around the world have contributed squares to a woollen periodic table of the elements, about to be unveiled at Victoria University as part of the 2011 International Year of Chemistry. Sarah Wilcox, who curated the project on behalf of the New Zealand Institute of Chemistry, Victoria University and the Royal Society of New Zealand, thinks the project is a world first. “People have done all sorts of things with the periodic table – it’s been sewn, baked, made into furniture and computer games – but as far as we know, no one has knitted one this big before.”
Most of the squares were allocated through a website over one hectic weekend in August. “By the end of Monday they were all gone,” says Wilcox. Some knitters chose squares to match their initials or their age, but for many there was a link to their own work in science. Janis Muir, of Palmerston North, was inspired to knit carbon after working in the radio-carbon dating laboratory of the DSIR’s Institute of Nuclear Sciences in the 1960s. Mike Dickison, of Christchurch, chose calcium after being impressed by the many “beautiful and amazing forms” of this element he found in bird bones while researching for his PhD.
The knitted periodic table includes three new large and unstable elements – with atomic numbers 110, 111 and 112 – whose names have only just been approved: darmstadtium (Ds), roentgenium (Rg) and copernicium (Cn). My square? Radium and uranium were gone by the time I got to choose, but I was happy to nab element 104, Rutherfordium (Rf), named in 1997 after New Zealand’s own Ernest Rutherford. A great square to have, but I should have realised that Rf 104 would not be the easiest to knit. Whoever chose hydrogen had the right idea.