Most centenarians attribute their great age to some magic elixir or other. The longevity of the Italian scientist Rita Levi-Montalcini, who this week became the first Nobel Prize-winner to reach the age of 100, might be the result of a potion that is a little out of the ordinary: Professor Levi-Montalcini, it is said, puts her undiminished mental vigour down to regular doses of nerve growth factor (NGF) – the discovery that made her famous.

She was awarded the 1986 Nobel Prize for Medicine jointly with an American, Stanley Cohen, for her research into NGF: the proteins and amino-acids which enable the cells of the nervous system to grow and take on specialised tasks. Despite her age, Dr Levi-Montalcini, a neurologist and development biologist, still works every day at the European Brain Research Institute, which she founded in Rome.

During numerous celebrations this week, she claimed that her brain was more vigorous today than it was four decades ago. "If I'm not mistaken," she said, "I can say my mental capacity is greater than when I was 20 because it has been enriched by so many experiences, in the same way that my curiosity and desire to be close to those who suffer has not diminished."

According to Pietro Calissano, who collaborated with the professor on an article for Scientific American in which she announced her discovery in 1979, NGF may have played a direct role in her amazing vitality. "Every day, she takes NGF in the form of eye drops," he said, "but I can't say for sure if this is her secret. At the start, it seemed this molecule's effect was restricted to acting on the peripheral nervous system, but then it emerged that it has a very important role in the brain. Contrary to what was believed, the brain does not have a rigid structure but is in continuous movement, and NGF helps neurons – which we begin to lose between 10 and 15 years old – survive."

Italy pulled out all the stops to honour Dr Levi-Montalcini, with parties, seminars and more awards to add to her pile. Most appreciated of all was a decision by the universities ministry to award her research institute a grant of €500,000 (£448,000). She said: "The scientific director of the institute and I have spent many days wondering how to solve our financial problems." The money gives the institute a few more months' lease of life."

Dr Levi-Montalcini also praised her homeland, adding: "I say to the young, be happy that you were born in Italy because of the beauty of the human capital, both masculine and feminine, of this country ... No other country has such human capital."

Yet the country she loves did all in its power to curtail her career before it began. She was born to a cultured Jewish family in Turin in 1909, the daughter of an electrical engineer and a painter. Defying her father's wishes, she went to medical school and graduated in 1936. She immediately enrolled as a postgraduate, but in the same year Mussolini published his Manifesto for the Defence of the Race, followed in 1938 by new laws banning "inferior races" from education and forcing her out of university.

"Don't fear difficult moments," she said, "the best comes from them." But her "difficult moments" were to last nearly 10 years. She fled to Belgium to continue her studies, but the imminent invasion of the Nazis in 1940 forced her to return to Turin, where she constructed a laboratory in her bedroom. When the Allies bombed the city in 1941, she fled to the countryside and built another lab in a country cottage. Then the German invasion of Italy in 1943 sent her fleeing to Florence, where she lived incognito until the war's end, working as a nurse and doctor among the disease-ridden refugees. After the war she accepted an invitation to study in America, where in the subsequent decades her most important work was done. She only returned to Italy full time after she retired in 1977.

Dr Levi-Montalcini was made a senator for life in 2001 and from 2005 to 2007 she played a vital role in supporting the centre-left government of Romano Prodi, which had a wafer-thin Senate majority and needed every vote to stay afloat. Despite her age, Dr Levi-Montalcini never failed it, earning the wrath of the right-wing opposition in the process.