Essential oils from guava leaves have shown strong anti-cancer activity in vitro (Manosroi et al.
Members of the genus Psidium, the guavas, are typical Myrtoideae, with tough dark leaves that are opposite, simple, elliptic to ovate, and 5-15 centimeters long.
Mites like Pronematus pruni and Tydeus munsteri are known to parasitize Apple Guava (P. guabaya) and perhaps other species.
Guavas are often considered superfruits, being rich in vitamins A and C, omega-3 and omega-6 polyunsaturated fatty acids, and especially high levels of dietary fiber.
Guavas may be eaten raw or used in jams, jellies, juices, preserves, and sauces (Herbst 2001).
Guava is in the Myrtaceae or myrtle family, a taxon of dicotyledon plants that includes such well-known representatives as myrtle, cloves, feijoa, allspice, and eucalyptus.
The name guava particularly is associated with the commercially important common or apple guava, Psidium guajava, which is grown for its sweet, juicy fruit.
Members of the genera Accara and Feijoa (= Acca, pineapple guava) were formerly included in this genus as well.
From preliminary medical research in laboratory settings, extracts from guava leaves or bark are implicated in possible therapeutic mechanisms against cancer, bacterial infections, inflammation, and pain (Chen et al.
Guava wood is used for meat smoking in Hawaii and may be used to barbecue.
Red guavas can be used as the base of salted products such as sauces, constituting a substitute for tomatoes, especially for those sensitive to the latter's acidity.
The guava fruit is edible, round to pear-shaped, from 3 to 10 centimeters (cm) in diameter (up to 12 cm in some selected cultivars).
Common guava has generally a more diverse and dense nutrient content, including extraordinary richness of vitamin C (228 mg per 100 g) (ND 2008b).
The same anti-diarrheal substances useful in folk medicine may also cause constipation when large amounts of guava fruits are consumed.
On the other hand, several species have become very rare and at least one species, Jamaican guava (P. dumetorum), is considered to have recently gone extinct.
Guava leaves or bark have been used traditionally to treat diabetes (Mukhtar et al.
P. cattleianum) is another well-known species, with two notable varieties: the red-fruited strawberry guava, and the yellow-fruited lemon guava.
In Asia, fresh raw guava is often dipped in preserved prune powder or salt, and a tea is made from guava fruits and leaves.
The spread of introduced guavas owes much to this fact, as animals will eat the fruit and disperse the seeds in their droppings.
Mature trees of most guava species are fairly cold-hardy and can survive as low as 5°C for short periods of time, but younger plants will not survive.
Apple guava (P. guajava) and its cultivars are those most commonly traded internationally.
Guavas are cultivated in many tropical and subtropical countries for their edible fruit.
Guavas contain both major classes of antioxidant pigments—carotenoids and polyphenols—giving them relatively high dietary antioxidant value among plant foods (Mahattanatawee et al.
Guavas are also of interest to home growers in temperate areas, being one of the very few tropical fruits that can be grown to fruiting size in pots indoors.