A practical guide for nutritional and traditional health care.
While the scientific name of the tropical fruit guava is Psidium guajava L., it has numerous common names by which it is identified at different places across the globe. The guava or Psidium guajava L. is a global plant and belongs to the myrtle family (scientific name Myrtaceae). The fruit is recognized by its common English name or its equivalent in other languages across the world. The French call the fruit goyave or goyavier, while the Spanish have named the tree guayabo or guyavo and the fruit guayaba or guyava. Similarly, the Surinamese call the fruit guave or goejaba, while in the Hawaiian Islands the fruit is known as guava or kuawa, the Dutch have named it guyaba or goeajaaba and the Portuguese call it goiaba or goaibeira. People in Malaya usually call the fruit guava or jambu batu, while in Guam it is known as abas. In addition to these names, guava is called by different names in other tropical lands like India, the Philippines and the tropical regions of Africa.
The guava is a shrub or a general shade tree that often grows naturally in the house gardens in the tropical regions. The guava trees normally grow up to a height of four meters and bears large leaves with conspicuous veins. The leaves grow in pairs and opposite each other on the slender, but firm branches. The plant also bears diminutive white hued flowers that possess several stamens maturing into smoothed or pear-shaped, yellowish fruits containing numerous seeds. The flesh of the guava fruit has a pink or yellowish hue and is very delectable as well as nutritious. What is more important is that the fruit is very rich in vitamin C content.
The guava tree is perennial with plenty of leaves and, hence, provides excellent shade, while the leaves of the plant possess some therapeutic properties. The fruits of this species may be eaten fresh when ripe or used to make beverages, ice creams and thickened to prepare jam, jelly or marmalade. In the fertile Amazon region, a guava tree may even grow up to a height of 20 meters and bear fruits that are as big in size as a tennis ball. However, the commercially cultivated types of guava trees and shrubs usually grow up to a height of 10 meters and bear fruits that are akin to lemons in size. Guava trees are distinct as they have typical slender, smooth, copper hued barks that exfoliate revealing a green colored layer below.
Although the guava fruit is not an important commodity in the commercial international trade, it grows in abundance in the tropical clime and helps to provide food for hundreds of millions of people in the tropical regions across the globe. This species has spread rapidly across the globe and naturalized in the tropical regions owing to a number of reasons. Guava is primarily propagated through its seed, though the tree can also be grown through grafting. The plant is not only able to thrive on an assortment of soils and propagates easily; it also bears fruits easily and in abundance. As the each guava fruit encloses multiple seeds, it is possible to give rise to numerous fruit-bearing trees from one fruit in a span of just four years. In the Amazon rain forests, monkeys and birds thrive merrily on ripe guava fruits and also help in the dispersion of the fruits' seeds in their droppings. As a result, one may find a unprompted growth of clusters of guava shrubs or trees all over the region.
Fresh or dried leaves, bark, fruits.
It is believed that the guava (Psidium guajava L) is likely to have been naturalized in Peru quite a few thousand years back. In fact, archeological sites in Peru have exposed that the ancient people in the region stored guava seeds along with corn, beans, squash and other plants cultivated by them. It may be mentioned here that even now the natives living in the tropical rainforests relish the guava fruit as a sweet delicacy. Since long, the leaves as well as the bark of the guava tree have been known to be used for treating various disorders and are still used in the same manner in contemporary times.
The Tikuna Indian prepares a decoction with the leaves and barks of the guava tree to treat diarrhea. In effect, several tribes inhabiting the Amazon rain forest region have been using decoctions and/ or infusions prepared with the guava leaves and barks to cure diarrhea and dysentery for ages. Even the Indians use the same preparations to treat vomiting, nausea, tender throats, stomach disorders and to cure vertigo and also to control menstrual cycles. The young leaves of the guava tree are chewed to treat bleeding gums and foul breath. It is interesting to note that if the tender guava leaves are chewed before taking intoxicating drinks, they are possibly able to alleviate hangover. Indians native to the Amazon region habitually use a decoction prepared with the leaves of guava to cure mouth sores, bleeding gums or prepare a douche with guava leaves for treating vaginal discharge as well as to tauten and tone up the vaginal walls, especially following childbirth. Similarly, a decoction prepared with the leaves and/ or barks of guava trees or a infusion prepared with the flowers of the tree is usually used to treat injuries, ulcers and aching skin. People suffering from painful eye conditions like conjunctivitis, eye injuries as well as sun strains may get relief if they apply the mashed guava flowers on the affected area.
Several hundred years back, European merchants, explorers and missionaries visiting the Amazon Basin carried the seeds of this delicious fruit to different parts of Africa, Asia, especially India, and the tropical regions in the Pacific enabling people in the tropical regions across the globe to cultivate the species in their respective localities. As discussed earlier, ripened guava fruits are consumed fresh or used commercially in the preparation of jams, jellies, solidified jams, paste as well as juice or beverages. While the Dutch Pharmacopoeia include the guava leaves for curing diarrhea, people in Southeast Asia, Latin America and Central and West Africa also use the leaves of the tree for the same purpose. Even today, herbal medical practitioners in Peru use different parts of the guava tree to treat gastroenteritis, gastric disorders, diarrhea, intestinal worms, coughs, vomiting, vaginal discharges, menstrual pain and hemorrhages as well as edema. People in Brazil use guava as a caustic drying agent as well as a diuretic for regulating the flow of urine. People in Peru also use guava as a diuretic. Herbal medical practitioners also prescribe a decoction prepared with guava leaves as a gargle to treat aching throats, laryngitis as well as the swelling of the mouth. In addition, decoctions and/ or infusions prepared with guava leaves and/ or barks are applied externally to treat vaginal irritation, vaginal discharges and skin sores.
Interestingly enough, in the tropical regions, guava is often referred to as the poor man's apple and has long been used traditionally both as a food item as well as a therapeutic product and many of its medicinal properties have been authenticated by several researches undertaken by scientists across the world in the recent past. As has been discussed earlier, the leaves of guava are an excellent cure for diarrhea - even safe enough to be administered to ailing small children. According to the tropical herbal medicine, one or two cups of a decoction prepared with the guava leaves is considered to be the standard dosage for adults and older children for treating diarrhea and other stomach upsets. Guava leaves are generally not easily available in the markets in the United States, but one can still obtain the tea-cut or powdered leaves of the tree from a few major health food stores or wholesale dealers of botanical items. However, presently, extracts of guava leaves is a new product in the United States markets that is used in different herbal preparations meant for an assortment of purposes. The uses of this leaf extract in different herbal formulae range from medical preparations to cure diarrhea, and herbal antibiotic to regulating bowel movements as well as weight loss preparations. Laboratory tests regarding toxicity of the guava leaves and fruits on rats and mice and also restricted studies on humans have demonstrated that use of neither of these have any adverse aftereffects and are safe for use in anyone - even kids.
In all tropical regions, people use the leaves, roots, barks as well as the unripe fruits of guava to arrest gastroenteritis, dysentery and diarrhea owing to their astringent features. While the mashed guava leaves are applied externally on injuries, ulcers and painful places of the body, the young leaves of the tree are chewed to alleviate toothaches as well as cure bleeding gums. A decoction prepared with the guava leaves is widely taken to cure throat and chest problems, coughs, used as a gargle to alleviate ulcers in the mouth and aching and swollen gums, ingested to lower fevers, including malaria, as well as treat diabetes and boils. In addition, the decoction is also used as an emmenagogue (a medicine that aids in promoting menstrual discharge) and vermifuge (a medicine that expels worms or other animal parasites from the intestines) as well as to cure leucorrhea (a thick, whitish discharge from the vagina or cervical canal).
The decoction prepared with guava leaves has been found to be very effective in stopping vomiting and diarrhea in patients suffering from cholera and is also applied topically to treat skin problems. A decoction prepared with the tender shoots of the guava tree is administered as a febrifuge (a medicine that helps to dispel or reduce fever). In India, herbal medical practitioners recommend the use of an infusion prepared with the guava leaves to treat cerebral disorders, cachexia (general illness with abnormal thinness of the body normally occurring in association with cancer or any chronic infectious disease) and nephritis (inflammation of the kidneys). An extract of guava leaves is prescribed for treating epilepsy and chorea (diseases of the nervous system typified by erratic, instinctive movements, mainly of the face and extremities), while a tincture prepared with guava leaves is massaged on children's spines to alleviate spasms. On the other hand, a decoction prepared with guava leaves and the barks together is administered to women after childbirth to get rid of the placenta.
For many people in the tropical regions bars prepared with heavy and plentiful of guava paste and guava cheese are essential sweets. In addition to these, even guava jelly is extensively sold almost all over the world. In Hawaii, people prepare guava juice by boiling small pieces of the fruit after removing its seeds and filtering the liquid. This juice is extensively used by the Hawaiians in punch as well as ice cream sodas. Even the South Africans prepare a lucid guava juice preserving all the ascorbic acid and other characteristics of the fruit by putting it over extreme heat. To prepare the juice, the South Africans trim and mince the fruits and blend them with natural fungal enzymes that is now marketed under different brand names. Next, they keep the blend at an extremely high temperature ranging between 49° C and 54° C for about 18 long hours at a stretch. The liquid is strained to obtain the clear guava juice that is made into syrup and used on ice creams, waffles, puddings as well as in milkshakes. In the Caribbean region, nectar and guava juice comprise numerous canned and/ or bottled beverages made from fruits.
Many people also wash and trim the floral residue of the whole guava fruit and put it in syrup or just spray sugar on it before packing them in plastic pouches and freezing the delicious preparations. In effect, there are numerous procedures regarding the use of guavas in pies, puddings, ice creams, butter, cakes, chutneys, marmalades, relishes, catsup and other delicacies. Interestingly, a firm manufacturing baby food product in South Africa sells a product with guava and tapioca. In addition, an extract obtained from small and excessively ripe guavas is exploited as ascorbic acid supplement for beverages and different foodstuff.
Often guava is dehydrated to produce a powdered substance that may be employed to add essence to confectionary, ice cream as well as fruit juices. Alternately, ripened guava may also be boiled with sugar to prepare jellies or used as pectin to prepare jellies from fruits containing low pectin. In India, people find it feasible to dry and store ripened guavas when there is an abundance of the fruit during the season with the objective to prepare guava jellies during the off season. People in South Africa blend ripened guavas with cornmeal and other items to prepare food flakes for breakfast.
It may be noted here that green, but mature guavas may be used as an excellent natural resource of pectin as, compared to the ripened fruits, this provides slightly higher quantity and better quality of pectin.
Ascorbic acid: The guava fruit encloses substantial quantity of ascorbic acid. Primarily, the skin and the compact flesh contain most of the ascorbic acid, while some amount of it is also present in the middle pulp of the fruit. The amount of ascorbic acid present in these parts of the fruit range between 56 mg and 600 mg. The range of ascorbic acid in near ripened fruits may be between 350 mg and 450 mg. When different varieties of guava from the same assortment are completely ripe and soft, the ascorbic acid content in them may drop to anything between 50 mg and 100 mg. It may be noted that canning the fruit or processing it by application of heat usually wipes out approximately 50 per cent of its ascorbic acid content. In addition to ascorbic acid, the seeds of the fruit enclose 15 per cent protein, 14 per cent aromatic oil and 13 per cent starch. Carbonyl chemicals enclosed in guava are said to be responsible for the strong scent of the fruit.
Habitat and cultivation
Guava is basically indigenous to the Central American region, especially the Amazon Basin, and over the centuries, the fruit has been naturalized in many parts of the globe and is found in abundance in the tropical climes. Presently, many countries commercially cultivate guava for its various uses.
Inspired by the use of guava since long, present day researchers have undertaken several studies related to the extracts of this fruit. Several clinical studies carried out over the years have not only confirmed the benefits of guava, but also the fruit's traditional use to treat disorders such as gastroenteritis, diarrhea and other digestive problems. In fact, scientists have also created an herbal medication using the leaves of the guava tree for treating severe cases of diarrhea. The drug has been homogenized to the amount of quercetin enclosed in it. Clinical trials carried out with the medication on humans have shown that it is very useful in treating diarrhea among adults. On the other hand, researchers have also clinically examined the effectiveness of the guava juice and found it very useful for treating diarrhea among infants. A clinical study involving 62 infants suffering from rotaviral enteritis not only demonstrated that 87.1 per cent of the babies treated with guava fruit juice recuperated within three days, but also showed that compared to treatment with other medications, the disorder was cured in a much short period when guava juice was administered to them. The study wrapped up that babies suffering from infantile rotaviral enteritis had a better and faster cure when they were treated with the medication prepared with guava juice.
It may be mentioned that guava has several diverse features that add to the species' anti-diarrhea consequences and several researches have identified the prominent anti-amebic, anti-bacterial and anti-spasmodic functions of the tree as a whole. It has also been found that guava has a sedative impact on the soft muscles of the intestine, slows down the chemical progressions that are associated with diarrhea and helps the intestines re-absorb water. A number of other studies have shown that an alcoholic leaf extract contains a substance that has an effect similar to morphine and it slowed down the gastrointestinal discharge of compounds in severe cases of diarrhea. Scientists were of the opinion that the effect of the substance analogous to morphine was associated to the compound known as quercetin. Additionally, the lectin compounds enclosed in guava have demonstrated that they bind to E.coli - a familiar organism responsible for causing diarrhea. As a result, these chemicals help to thwart E.coli from sticking to the walls of the intestines. This, in turn, helps to keep away from the contagion and, hence, suffering from diarrhea.
Scientists have identified the anti-bacterial properties of guava and attribute this to the usefulness of the different parts of the tree in curing gastroenteritis, dysentery and diarrhea. In fact, the extracts from the leaves and the barks of the guava tree have demonstrated vitro toxin exploits against several bacteria. Again, during a number of studies, guava has demonstrated noteworthy anti-bacterial activities against bacteria such as Bacillus, Clostridium, E. coli, Shigella, Staphylococcus, Salmonella and Pseudomonas that are responsible for causing general diarrhea. In addition, guava has also shown anti-yeast (Candida), anti-fungal, anti-malarial as well as anti-amebic activities.
Following a study conducted with guinea pigs in 2003, researchers in Brazil confirmed the various consequences of extracts from guava leaves on the cardiovascular system that, the scientists believed, could be advantageous for curing erratic heart beat or arrhythmia. A number of earlier studies with guava had suggested that the leaf of the tree had antioxidant results that are favorable to the heart, heart protective aspects as well as enhanced myocardial (the heart muscles) performance. In addition, two human studies undertaken at random demonstrated that ingestion of the guava fruit continually for 12 weeks lowered the blood pressure by eight points on an average, resulted in a decline of blood cholesterol levels by nine per cent, lessened triglycerides by nearly eight per cent and enhanced the ‘good' HDL cholesterol or (high-density lipoproteins cholesterol) by around eight per cent.
The scientists ascribed all the above mentioned actions of guava to the rich potassium and fiber content enclosed by this tropical fruit. It may be mentioned here that the subjects of the study were required to consume one to two pounds of guava fruit every day in order to achieve these effects. Studies conducted with other animals using the extract of guava leaves demonstrated the analgesic (painkilling), tranquilizing, and central nervous system (CNS) depressant actions of the tree. In addition, these animal studies also evidenced the cough suppressant actions of the guava leaf extract. It has been recognized that the guava fruit and/ or the guava fruit juice is able to reduce the intensity of sugar in blood both in normal as well as diabetic animals and humans. In fact, majority of these studies have confirmed the multiple uses of the different parts of the guava tree in the traditional herbal medicine scheme of the tropical regions across the globe.
The chemical composition of the guava fruit comprises about nine to 12 per cent tannins along with varying proportions of flavonoids, triterpenes, saponins, essential oils, carotenoids, vitamins, lectins, fiber as well as fatty acids. While the tannin content is quite high in guava, it is interesting to note that the content of vitamin C in guava is higher than that contained in citrus fruits. Precisely speaking, 100 grams of the guava fruit encloses around 80 mg of vitamin C. In addition, guava also encloses substantial quantities of vitamin A. The fruit is also considered to be an excellent resource of a dietary fiber known as pectin. On the other hand, the leaves of the guava tree enclose high content of flavonoids, especially quercetin. It may be noted here that the majority of the remedial properties of guava are ascribed to the flavonoids contained in the fruits and leaves. The flavonoids present in guava have been identified for their anti-bacterial properties. The flavonoid quercetin enclosed in guava leaves is believed to have a major role in the leaves' anti-diarrhea actions. In addition, quercetin also helps to calm down the smooth muscles of the intestines as well as slow down the tightening of bowels. The other flavonoids and triterpenes present in the guava leaves are known to have anti-spasmodic actions or helps in alleviating spasms. The polyphenols enclosed in guava are said to be responsible for the antioxidant activities of the leaves of the tree. In addition, the guava leaves also enclose around 0.3 per cent of essential oils along with eugenol and triterpenoids that possibly adds to the overall therapeutic properties of the species.
Many people drink infusions prepared with guava leaves as a tea to treat acute diarrhea. Normally, herbal medical practitioners prescribe a normal dosage of the infusion that includes one pounded guava leaf boiled in a liter of water.