THE fruit goes by several names: soursop, custard apple, graviola, and guyabano. In the science world, it is called "Annona muricata." It became sort of a celebrity among health aficionados when an e-mail was circulated around the world claiming that it is "a miraculous natural cancer cell killer 10,000 times stronger than chemotherapy."
"What's more, unlike chemotherapy, the compound extracted from the graviola tree selectively hunts down and kills only cancer cells," the e-mail said. "It does not harm healthy cells!" In addition, it "effectively targets and kills malignant cells in 12 types of cancer, including colon, breast, prostate, lung and pancreatic cancer."
According to the e-mail, a research has been conducted and showed that the extracts from guyabano can "attack cancer safely and effectively with an all-natural therapy that does not cause extreme nausea, weight loss and hair loss."
It also "protects your immune system and avoids deadly infections; feels stronger and healthier throughout the course of the treatment; and boosts your energy and improves your outlook on life."
"When you have strong and obviously exaggerated claims like this," commented Dr. Rafael R. Castillo, a physician who writes a weekly column for a national daily and editor-in-chief of "Health and Lifestyle" magazine, "you tend to doubt and we should ask for published scientific evidence."
So, Dr. Castillo asked one of his magazine staff to do an extensive research on the subject. One of those literature found was a claim that guyabano extracts are 10,000 times potent than Adriamycin, a drug used in chemotherapy treatments.
"No published clinical trials on human are available," Dr. Castillo noted. Some websites just provide testimonials from individuals relating anecdotes about their cancer sickness, how they opted not to follow their doctor's recommendation to undergo surgery or chemotherapy and just take guyabano products.
These patients believe that the guyabano fruit cured them from their cancer, which was already late-stage or Stage 4 in some cases. "Whether they really had cancer or not, we're not sure, because no documentation of their cancer is presented," Dr. Castillo wrote in his column.
In fairness to the several networking companies marketing these medicinal guyabano extracts, "there's a modicum of basis for their claims, but what is unacceptable is their exaggeration of the fruit's health benefits as if it's already tried and tested," Dr. Castillo pointed out.
However, he noted that there were some studies done on guyabano. The Catholic University of South Korea and Purdue University in Indiana, United States, found out that guyabano tree extracts had acted in a way that prevented it from harming normal cells, while successfully targeting the dangerous ones, unlike chemotherapy, which destroys all cells that multiply. The findings of the Catholic University of South Korea were published in the "Journal of Natural Products."
"But, it has to be emphasized that all of these trials were conducted in the laboratory only using nonliving models, or what is called as in vitro experiments," Dr. Castillo noted. "Absolutely, (there's no) no research in humans, so far (has been conducted)."
But there's one truth that needs no research: guyabano is one of the healthiest fruits known to man. The flesh of the fruit, consists of a white edible pulp, is high in carbohydrates (particularly fructose) and considerable amounts of Vitamin C, Vitamin B1, Vitamin B2, potassium and dietary fiber. Guyabano is low in cholesterol, saturated fat and sodium.
Not only is guyabano a good health food, it also tastes delicious.
Aside from being eaten raw, the guyabano fruit is processed into candies, tarts, shakes, ice cream, and sherbets and other beverages. An assortment of punch and cocktail drinks can be made by mixing the nectar with wine rum or cola drinks or "buko" (fresh coconut) juice and ice.
In Indonesia, immature guyabano are cooked as vegetables or used in soup in Indonesia. In the northeastern part of Brazil, they are either roasted or fried.
Research done by the author showed the fruit, seeds, and leaves have a number of herbal medicinal uses in countries where the plant is common.
The sap of the young leaves may be applied directly on pimples to induce suppuration. The sap is also considered parasitical.
An alcoholic extract of the leaves, when distilled with steam, yields a small amount of essential oil. The portion of alcoholic extract which is soluble in water contains a large amount of potassium chloride together with dextrose tannins, amorphous products, and a small amount of an alkaloid substance which could not be crystallized. The leaves and roots also cure colic and convulsions.
To reduce fever, a decoction of leaves can be taken internally. It has the same effect as when leaves are added to bathing water. In the Caribbean, it is believed that laying the leaves of the guyabano on a bed below a sleeping person with a fever will break the fever by the next morning.
The crushed fresh leaves are also applied on skin eruptions for faster healing. A poultice of young guyabano leaves is applied on the skin to alleviate rheumatism and other skin infections like eczema. Applied during the healing of wounds, this can result in less or no skin scars.
The decoction can also be used as a wet compress on swollen feet and other inflammations. Poultice of mashed leaves and sap of young leaves are used for eczema and skin eruptions.
The guyabano leaves are believed to have tranquilizing and sedative properties. In the Netherlands Antilles, the leaves are placed inside pillows or placed on top of the mattress to induce a good night's sleep. Boiling the leaves and drinking may help induce sleep.
Guyabano are also good in checking insect pests. Pulverizing the guyabano seeds and mixing it with soap and water can be used as an effective spray against caterpillars, armyworms and leafhoppers on plants. The petroleum ether and chloroform extracts of guyabano are toxic to black carpet beetle larvae. The seed oil kills head lice.
The bark of the guyabano tree has been used in tanning. The bark fiber is strong but, since fruiting trees are not expendable, is resorted to only in necessity. Bark, as well as seeds and roots, has been used as fish poison.
The wood is pale, aromatic, soft, light in weight and not durable. It has been used for ox yokes because it does not cause hair loss on the neck. In Brazil, analyses of the wood show cellulose content of 65 to 76%, high enough to be a potential source of paper pulp.
Here are some words of warning: A study conducted in the Caribbean has suggested a connection between consumption of guyabano and atypical forms of Parkinson's disease due to the very high concentration of annonacin (which is described as "1,000 times more toxic to neurons than MPP+, the toxic chemical associated with synthetic heroin"). On the other hand, the seeds contain 45 percent of yellow non-drying oil which is an irritant poison, causing severe eye inflammation.
"Guyabano seeds are toxic, and care must be taken to assure that all are removed before the pulp is processed," reminds "Underexploited Tropical Plants with Promising Economic Value," published by the US National Academy of Sciences.