GUAVA
ITS MEDICAL IMPLICATIONS

Scientific Name(s): Psidium guajava L. Family: Myrtaceae

Common Name(s): Guava (in English), guayabo (in Spanish), goiabeira (Brazil), red guava , guyava , kuawa 1 , 2 , 3
Uses of Guava

Scientific investigations on the medicinal properties of guava leaf products date back to the 1940s. Most scientific evidence examines the clinical efficacy of guava in treating GI disorders. Other investigations examined antiamebic, antibiotic, antidiarrheic, antihyperglycemic, antimutagenic, antispasmodic, and sedative effects, as well as anticough and narcotic-like activities of the plant species. A randomized double-blind study of 122 subjects documented P. guajava leaf extract to be as effective as tetracycline in treating acute infectious diarrhea.
Guava Dosing

One trial used the P. guajava extract QG-5 , which is standardized to contain quercetin 1 mg per 500 mg capsule. Patients with infectious gastroenteritis received 1 capsule of QG-5 orally every 8 hours for 3 days. Guava is commercially available in capsules, liquids, powders, and tablets.
Contraindications

Hypersensitivity to any of the ingredients in guava.
Pregnancy/Lactation

Avoid use during pregnancy and lactation because of lack of clinical data.
Guava Interactions

None well documented.
Guava Adverse Reactions

Besides constipation, no serious adverse reactions have been reported in patients taking QG-5 .
Toxicology

In vitro genotoxicity and mutagenicity tests on P. guajava in human peripheral blood lymphocytes found no disturbances in cell division.
Botany

P. guajava is a member of the Myrtaceae family, which contains at least 133 genera and more than 3,800 species. P. guajava is a large evergreen shrub or small tree that grows up to 15 m in height. It is native to and widely distributed in Mexico and Central America. Today, the plant is cultivated from the west coast of Africa to the Pacific region, including India and China, with varieties originally introduced over the past 300 years from the United States. The guava berry, also known as guava, is an important tropical fruit that is mostly consumed fresh. The berry contains several small seeds and consists of a fleshy pericarp and seed cavity with pulp. 2 , 4 , 5
History

P. guajava has a rich ethnomedicinal history. Different parts of the plant are used in various indigenous systems of medicine, primarily for the treatment of GI ailments. 6 , 7

The therapeutic properties of the leaves have been described in detail by historical Mexican herbal sources dating back 500 years. 5
Chemistry

Most phytochemical analyses investigated the properties of guava leaf products, revealing more than 20 isolated compounds, including alkaloids, anthocyanins, carotenoids, essential oils, fatty acids, lectins, phenols, saponins, tannins, triterpenes, and vitamin C (80 mg per 100 g of guava). 6 , 8 , 9 , 10 , 11 , 12 , 13

The essential oil contains alpha pinene, caryophyllene, cineol, D-limonene, eugenol, and myrcene. The major constituents of the volatile acids include (E)-cinnamic acid and (Z)-3-hexenoic acid. Carbohydrate esters have been isolated from the fruit. 8 , 11

The main active constituent in the plant is quercetin. Spasmolytic and antidiarrheal effects are associated with its quercetin-derived flavonoid glycosides, which support use of this ancient leaf remedy in treating GI disorders. 5

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