Tom Phillips in Rio de Janeiro
guardian.co.uk, Monday 27 April 2009 13.05 BST
The boat ploughs north along this vast, rust-tinted river. Ahead, a white haze of torrential rain and a task as immense as the Amazon rainforest itself: discovering a new treatment for cancer somewhere in the depths of the greatest tropical rainforest on earth.
Onboard three men prepare themselves for their mission into the jungle: Drauzio Varella, a gangly 65-year-old oncologist, broadcaster and best-selling author who is also Brazil's most famous doctor; Mateus Paciencia, 33, a fresh-faced botanist from São Paulo; and Osmar Ferreira Barbosa, 45, a former chainsaw operator turned mateiro or forest guide, armed with a machete and a life-time's knowledge of the rainforest.
"From an amoeba to an elephant… every living thing is a factory of substances, and plants aren't different," enthused Paciencia, as the boat edged ever closer to his group's scientific base, a small wooden shack on the banks of the Cuieiras river, around four hours' boat journey from Manaus, the capital of Brazil's Amazonas state.
"A plant or tree is a small medicine factory. All we need to do is try and find the application for these substances."
The boat is a floating laboratory belonging to São Paulo's Paulista University (Unip) and is on the frontline of a quest for the medicines of the future and part of an innovative drive to save the Brazilian rainforest by providing economic alternatives to those who once destroyed the forest.
The project is the brainchild of Drauzio Varella, a São Paulo-born oncologist who has dedicated much of his career to cancer patients, among them his younger brother, Fernando, a smoker who died of lung cancer in 1991, aged 45.
Today, spurred on by an obsession with the Amazon and nearly 40 years as an oncologist, Varella leads monthly expeditions up the Cuieiras river in search of natural medicines that he believes could change the future of his profession and eventually bring new hope to cancer victims around the world.
"[As a child] I didn't even know that [the Amazon] existed," Varella told the Observer during his latest mission to the group's base on the Cuieiras river. "I'd heard the children's stories, about the Indians with two feathers in their hair. But you didn't even talk about the Amazon back then. It was such a distant thing."
That changed in October 1992, during a trip to the Amazon with Robert Gallo, the US biomedical researcher credited with co-discovering the HIV virus. One afternoon, while visiting the rivers around Manaus, Gallo inquired if anyone was looking for new medicines in the plants and trees of the Amazon.
"You can see the biodiversity here ," recalled Varella. "And Gallo said to me: 'Who is studying this? [Who is] looking for activity in these species?' And I didn't know what to tell him. This idea stayed in my head."
In 1995 the idea became a reality with the first trip. Since then Varella's team has gathered more than 2,000 extracts from plants and trees in the rainforest. This year sees a step change in activity following a partnership with São Paulo's Sírio-Libanês Hospital, one of Brazil's leading research institutes. The team will explore a new area further up the Rio Negro towards the border with Colombia, and within two years they aim to have set up a third base.
After being plucked from the rainforest the samples are taken to Manaus, where they are dried and transformed into a powder before being shipped to São Paulo for testing. Over 70 extracts have demonstrated some impact on tumour cells while over 50 have shown results against bacterial infections.
"The advantage of these natural products is their unpredictability," said Varella. While molecular design techniques used by laboratories would remain crucial, natural products could suggest paths "we didn't even imagine existed," he said, citing Taxol, a drug which originated from the bark of the North American yew tree and is now widely used to treat ovarian and breast cancer. "You open the door to the unknown."
Paciencia believes medical research could also hold the key to slowing rainforest destruction. Environmentalists claim that almost 20% of the Brazilian Amazon has disappeared, mostly since the 1960s.
"Instead of replacing the forest with cattle we are studying a cure for cancer and for infectious diseases," said the botanist, sporting a goatie beard and a tattoo of Bob Marley on his bicep. "You don't need to chop a single tree down to obtain these resources. You cut a little piece of the plant… [and] next year it will have grown back. I can't see anything more environmentally correct than a project like this."
The group's guide is a case in point. Born in the remote Amazon town of Canutama, a notorious hotspot for illegal deforestation, Barbosa used to work for the loggers as a chain-saw operator. Now the father of three is employed to guide Varella's team through the labyrinthine jungle.
Currently the project focuses on two types of forest environment – the submerged forests or "igapós" and the "terra firme", or dry land. During each visit the team collects samples from families of plants that have shown positive results in the group's São Paulo laboratory, as well as new species.
"We don't know yet if the plants we are going to collect today have [these qualities]. But this group of plants has shown pretty positive results," explained Paciencia, picking his way towards an area of thick rainforest where his team has demarcated three different sectors in which specific trees and plants are monitored. Further on, the group's guide, Barbosa, shimmied up a towering tree and clipped off half a dozen branches. The branches crashed down through the rainforest canopy before settling on the damp earth and being separated into specially marked sacks.
Few doubt that the Amazon rainforest conceals an abundance of medical secrets. But, according to Varella, government bureaucracy is as dense as the forest itself, prompted by a deep fear of bio-piracy. It means foreign scientists or pharmaceutical companies find it hard to join the hunt for natural medicines in the Brazilian Amazon.
"If it is difficult for us, then imagine for people from overseas," says Varella, whose project is one of a tiny number that has official permission from the Brazilian environmental agency, Ibama. "They have no chance."
"Ten to fifteen years is the average time between finding the plant, [identifying its exact use] and patenting it into a drug [so] it is a long-term investment. It is commercially very uninteresting and it will create political problems for the business, so why do it?"
As a pair of toucans peer down at the expedition, their bright yellow beaks poking out from a green mesh of leaves, Pacienca reflects:"The Amazon has something like 20% of all the biodiversity in the world. Just in terms of plants with flowers, there are around 22 or 23 thousand."
"It is impossible to imagine that… not one of them will have an active substance for some disease."
The rainforest, he says, is "an infinite sea of possibilities".