by Jane Goodall
I could have sat listening for a long time as he talked of the changes he had seen in his long life. Some, he said, are good changes—he likes his cell phone. But other changes have been disastrous, such as the growth of the population, the changing weather patterns, and the gradual destruction of the forests that supply most of the medicines he needs. Many of the plants that were once common in his backyard must now be searched for, farther and farther away.
Two of our own Gombe staff are skilled in the use of medicinal plants, and Shadrack, who has spoken with them at length, tells me how some of the plants seem to have helped people with a whole variety of diseases and infections—including HIV/AIDS.
I asked Shadrack if there was proof that anyone had actually been cured of that. He said he had met several people who arrived from various regions of Tanzania looking thin and very sick, and had been told that they had AIDS. And then, following their treatment, which lasted a few weeks, they had gone off looking well and healthy. But there was no proof, he said, that they had actually become HIV negative. Still, if there is a medicinal plant that alleviates the symptoms and gives people better health and longer life expectancy, this would be wonderful.
Animal Physicians
How did traditional healers first learn about the healing properties of plants? Through trial and error? Some kind of instinct? Or perhaps, from watching animals?
About a century ago a Tanzanian medicine man, Babu Kalunde, discovered that the roots of a plant known as mulengelele to the local Watongwe people, was powerful medicine, and as a result probably saved the lives of many people in his village when there was an epidemic of a dysentery-like illness. Babu had watched a young porcupine, who had symptoms similar to the sick people, digging up a mulengelele and eating its roots. He was amazed, as he had thought that the plant was extremely poisonous. But now the situation was desperate, so Babu took a tiny dose himself. There were no ill effects, so he persuaded the sick people to try the plant—and it helped. To this day the Watongwe use mulengelele as medicine. Babu’s grandson, now a respected elder and healer himself, uses it to treat a number of different diseases.
Many dogs eat grass from time to time. I have known many dogs over the years—two of them zealously selected blade after blade, chewing them up with great gusto. Occasionally this would cause them to vomit.
There has been much speculation as to why dogs eat grass. Some believe that they just like the taste—as I love eating spinach leaves. Others think dogs do it instinctively when they feel unwell, to stimulate a vomiting response, which may help them to get rid of whatever made them feel sick. There is a school of thought that believes the grass may help to clear the intestines of parasites. Or that the dog needs more fiber in the diet: one poodle, who had regularly eaten grass for eight years, stopped once she was fed a high-fiber diet.
That animals have an instinct to cure themselves seems pretty conclusive. A recent study showed that female monarch butterflies infected with a deadly parasite lay their eggs on a particular species of milkweed that reduces the risk of the caterpillars becoming infected. They thus provide their young with medicine. Other tests show that sick domestic animals, when given a choice of foods, mineral supplements, and so on, will choose one known to be useful in treating their symptoms, perhaps detecting the medicinal properties through smell.
On a number of occasions, when one of the Gombe chimpanzees had an infected wound, we “laced” bananas with tetracycline by making a cigarette-sized hole at one end, dropping in the powder, and pressing the opening closed. We tried to follow the sick individual for four days, offering one of the bananas four times a day. What amazed me was that whereas a sick chimpanzee accepted and ate the fruit without hesitation, once he or she was better, such bananas were rejected after a cursory sniff.
It should not be surprising that chimpanzees are also able to treat some of their own illnesses. In the 1960s, during the early years of my study at Gombe, we used to check the chimpanzees’ dung to get some idea of the frequency with which they ate different foods. We found many seeds that had been swallowed along with the fruit—the plant was using the chimps to distribute its progeny. And every so often we found long, narrow leaves with stiff hairs underneath that had been swallowed whole. I pressed them (after a thorough washing!), along with the other food plants, and sent them to Bernard Verdcourt to identify at the herbarium in Nairobi. They were, he said, leaves of Aspilia pluriseta, of the daisy family.
Richard Wrangham, before he became an eminent professor at Harvard, had studied chimpanzee feeding behavior at Gombe and he noticed that the chimpanzees used their tongues and lips to roll Aspilia leaves into a sort of cylinder, with the plant hairs on the outside. Instead of chewing them, they would then swallow them whole. When he heard that the local villagers used this plant as medicine as well, we were all excited.
Since then Dr. Mike Huffman has made detailed studies of the use of Aspilia by chimpanzees, lowland gorillas, and bonobos. At first it was suspected that the leaves contained some kind of chemical, but in fact it is the physical characteristics of the leaves that are significant—as they pass through the stomach and intestines, the stiff hairs flush out the nematodes and tapeworms that tend to multiply during the rainy season.
Many animals medicate themselves with plants. This chimpanzee is eating Aspilia pluriseta to help flush out nematodes and tapeworms from the gut that flourish during the rainy season. (CREDIT: MICHAEL A. HUFFMAN)
Some hundred miles south of Gombe is the Mahale Mountains National Park, site of an intensive chimpanzee study carried out by the Japanese since 1966. There the chimpanzees make use of the extraordinarily bitter pith of Vernonia amygdalina, also of the daisy family. This plant, found in most African countries, is used by people as a treatment for, among other things, malaria, internal parasites, and lack of appetite. It is also used by chimpanzees infested in the rainy season with the nodule worm Oesophagostomum stephanostomum. Mike told me of two cases when chimpanzees who were clearly sick—they had lost weight, were lethargic, and were known to have a nematode infestation—had spent time chewing Vernonia pith. Between twenty and twenty-four hours afterward, both showed definite signs of recovery.
Subsequent research in the lab has shown that Vernonia pith is indeed effective against certain microorganisms that infect both chimpanzees and humans. The scientists also isolated two chemical compounds from the pith that actually suppressed egg-laying activity in a common parasitic worm. How chimpanzees know they should take these medicinal plants is still a mystery. Mike suspects the chimps—and many other animals—are actually using even more plant species as medicines.
And not only as medicines: in Calcutta, S. Sengupta and other naturalists observed that a pair of house sparrows lined their nests with neem leaves at hatching time. It seems they somehow know that the leaves act as a pesticide. To make sure that it had not been an accidental choice, the nest lining was removed—again the birds selected neem leaves as a replacement.
The Neem Tree—“Nature’s Drugstore”
The neem (Azadirachta indica) is an evergreen of the mahogany family that can reach heights of around one hundred feet. It originated in the Indian subcontinent, where it is common in backyards—and it continues to grow in suitable wild habitats as well. For more than 4,500 years Indians have known that all parts of the neem tree have medicinal value—extracts from leaves, bark, flowers, seeds, and roots have been and are being used to treat an incredible number of different medical conditions. The Indians’ appreciation of its virtues is reflected in its many names: “nature’s drugstore,” “panacea for all disease,” “tree of forty cures,” “village pharmacy,” “heal all”—and in one area, “the sacred tree.”
It has been especially valued for its properties as a pesticide, and various preparations are used to protect crops in the fields. Oil from its seed protects stored crops for around twenty months. Neem “cakes” dug into the earth promote good growth, repelling insect pests and plant diseases
, storing nitrogen, and encouraging the proliferation of earthworms to aerate the soil.
In 1959, during a terrible plague of locusts in Sudan, German entomologist Heinrich Schmutterer noticed that whereas the voracious insects consumed just about everything that grew, leaving leafless trees and bare fields, the neem trees were still green once they had moved on. The locusts would land on the foliage—but then fly off. They were repelled. It was this that caught the attention of Western scientists, although it would be another thirty years or so before the huge potential benefits of the neem tree—for agriculture and medicine—were more widely appreciated.
This tree was brought to Africa by the Indians and now grows in many parts of the continent. The word we use for it in Tanzania is arabaini, which in Kiswahili means “forty” and refers to the fact that it has at least forty different uses, including the treatment of malaria.
“Try one,” my son, Grub, urges me, handing me a small green leaf from the neem tree in our garden in Dar es Salaam. I know how it tastes, but I bruise the little leaf with my teeth anyway. At once my face contorts—it is incredibly bitter. I reject the rest, and watch with amazement as Grub, who has already chewed up five of these leaves, swallows a couple more. He has a headache and thinks it could be heralding a bout of malaria—he has been forgetting to chew his daily couple of leaves and is now making up for it.
I have a Tanzanian friend, Christopher Liundi, who grew up in Dar es Salaam. His mother had forced him to drink an infusion of neem leaves once a week. “It was so bitter I could hardly get it down without vomiting,” he told me. But it was worth it—Chris has never had malaria, a miracle for someone living in an area so teeming with malarial mosquitoes.
My mother and I both got very sick with malaria when we first got to Gombe. Side by side we lay in our shared ex-army tent, too weak to go into town to seek treatment. We eventually recovered, though I think my mother, whose temperature rose to 105 degrees Fahrenheit for five days running, nearly died.
The Roots of Quinine
Indeed, malaria is a common and often deadly disease throughout the tropics, especially for small children and people newly arrived in a malaria area. But it was not the neem but the cinchona tree (Cinchona spp.), a member of the coffee family, that would provide a cure. Without that discovery, the history of colonial settlements in Asia, Africa, and the Americas might have been very different.
There are over forty species of cinchona, all found in the tropical Andes—in Colombia, Ecuador, Peru, and Bolivia. It is the bark of this tree that is so important—it contains many chemical compounds known as alkaloids, one of which is quinine. I knew about quinine from an early age, as I had an aunt and uncle living in India, and my father was stationed in the Far East during World War II. They all told me about the quinine tablets they had to take each day to protect against malaria. It was because of the small amount of quinine found in tonic water that “gin and tonic” became the drink of choice for expats and others living in the tropics. And I cannot resist adding here that when there was a bad outbreak of avian malaria in Calcutta, the naturalist Sengupta’s little sparrows actually exchanged the neem-leaf lining of their nests for the leaves of the paradise flower tree (Caesalpinia pulcherrima), which is rich in quinine. They also ate the leaves.
In the sixteenth century, Spanish settlers in South America discovered that local indigenous people had, for hundreds of years, been using powdered cinchona bark as a treatment for fevers, and it seems that Jesuit priests first introduced the wonder bark to Spain. By 1630 regular shipments were being sent from Peru to Spain, from whence it was traded to other European countries. Word spread and the demand grew. By the early 1800s cinchona bark was seen as essential for the health of all those administering the European colonies in tropical areas around the world.
As all this bark came from trees growing in the wild, it soon became impossible to meet the constantly increasing need for the bark, and prices soared. Finally, in 1820, two French chemists were able to extract, from the bark, an alkaloid that had antimalarial properties; they named it “quinine.” But even though quinine soon became commercially available, demand for the complete, natural cinchona bark continued, and in the mid-1850s, Peru and Bolivia tried to retain their monopoly on the export of cinchona seeds and seedlings.
The British promptly sent that intrepid explorer of the Amazon Richard Spruce to find another supply that they could grow in their overseas colonies. He was able to get some seeds and plants of a cinchona, C. succirubra, from Ecuador. They grew readily, and cinchona soon became the most widely planted species in British colonial India, Sri Lanka, Jamaica, and East Africa.
At about the time Spruce was searching for seeds in Ecuador, one Charles Ledger bought seeds of a species of Cinchona from an aboriginal trader in Bolivia. He tried to sell them to the British, but as Spruce’s collection had just arrived, no one was interested. Ledger therefore sold his seeds to the Dutch, and this led to their extremely successful Cinchona plantations in Java.
It is hard to overemphasize the major role that quinine, our gift from the Cinchona tree, has played in world history. Only when colonialists had access to this drug did West Africa cease to be known as “The White Man’s Grave.” It was when supplies from plantations in Java were cut off during World War II that the United States established its own plantations in Costa Rica. But before these trees could mature and provide a new source of quinine, hundreds of thousands of US troops died in Africa and the South Pacific due to lack of the drug. Indeed, it is said that there were more deaths from malaria than from all the bullets and bombs combined.
Quinine is still used in treating some forms of malaria that have become resistant to the latest drugs, though usually as a last resort, because it can have some unpleasant side effects. I know about these from personal experience. I was in Dar es Salaam, suffering from one of my frequent bouts of the disease, and was persuaded to seek help from the physician attached to the American embassy at the time. He took a blood test and, staring at the multitude of parasites wiggling about under his microscope, concluded that my death was imminent. Afterward he told me that the only other person he had seen with as high a count had indeed died. Panicking, he gave me a double dose of quinine. It cured the malaria, but I became almost stone deaf and had blurred vision for several days.
The Miracle Drug of Folk Medicine
Another plant whose incredible power to heal was confirmed by Western medicine is the Madagascar periwinkle (Catharanthus roseus), a member of the dogbane family, a common little plant in southeast Madagascar. Because of its pretty flowers, this periwinkle got its early fame as an ornamental bedding plant—and by the eighteenth century it had proliferated in many gardens and botanical gardens throughout much of Europe. Soon it had escaped to colonize suitable areas in the country as well as vacant lots. Gradually it adapted to the different climates in which it now lives, becoming a garden annual in temperate zones and a perennial shrublet in the tropics. We have rosy periwinkles in our garden in Dar es Salaam.
But this plant is a lot more than an attractive garden flower. In its native Madagascar, traditional healers always used it as a remedy for a number of diseases. And as it traveled farther and farther around the world, more and more people began talking about its healing properties—although it can be toxic if used improperly. It is a widely used drug of folk medicine, prescribed by herbalists in southern Africa, India, Australia, the Caribbean, and the Philippines—for constipation, toothache, malaria, and diabetes. It was this last claim that attracted the attention of Western medicine.
In 1952 Dr. Robert Noble, of Toronto University, received a package of twenty-five leaves from his brother, Clark, in Jamaica. He had been told that an infusion of the leaves was used to treat diabetic patients when insulin was not available. Robert Noble and his team ran tests and found that while there was no evidence that the plant could help diabetics, it contained alkaloids that could arrest the growth of blood cancers.
Six years
later, Noble, now joined by Dr. Charles Beer, and their team, isolated and purified a potent alkaloid extract—vinblastine—and suggested it be tested as a treatment for childhood leukemia. The results were very promising, but it took twelve tons or more of dried periwinkles for one ounce of vincristine sulfate, and there were bad side effects, including hair loss. Clearly further research was necessary, but the team persevered, and today the extract from the rosy periwinkle, in combination with other alkaloids, is the main weapon against childhood leukemia. Many have recovered completely—and all because of a little Madagascan plant.
Stopping Biopiracy—The Theft of Indigenous Plants and Wisdom
When I was thirteen years old, my uncle Eric, who was a surgeon, told us about a new anesthetic—curare—that was derived from a liana (Chondrodendron tomentosum). It grew in the rain forests of South America, where it was used to poison the arrows and darts of indigenous tribes of the western Amazon. At his hospital they were calling it “jungle juice.” Interestingly, the extracts from this plant, though highly lethal when injected or rubbed onto a wound, are harmless when taken orally—which explains why poisoned prey can be eaten with no ill effects.
In 1804 the medical potential of curare was first suggested by British naturalist and explorer Charles Waterton, and in 1942 it made its debut as a “wonder drug” that would relax muscles during anesthesia. Soon after, my uncle began to use it. But it was not until years later that I began to think about the indigenous people who had discovered the power of the vine that could kill. How had they been affected by Western interest in this plant?