Originally inherited from the Aztec in Mesoamerica, guava leaves have a long history in Guatemala as a useful, and sometimes lifesaving, tool for battling diarrhea and intestinal discomfort.  They are listed alongside 15 other plants in “Plants used in Guatemala for the treatment of gastrointestinal disorders,” published in the Journal of Ethnopharmacology, in 1993.

This paper “reports the in vitro studies [studies done in a petri dish] of the activity of 16 plant extracts against pathogenic enterobacteria (31).  The researchers start out with a list of 408 plants; they narrow the list down to 34 plants which are deemed worthy of further study.  Of these 34 plants, 16 are chosen for “confirmation” of antibacterial activity against E coli, Salmonella enteritidis, and Shigella flexneri pathogens.  Guava leaf (Psydium guajava) turns out to be one of three plants (out of the 16) that inhibits growth of all three kinds of bacteria.

For a majority of these plants, the most effective extraction agent for antibacterial activity is ethanol.  Ethanol extract, acetone extract, and n-hexane extracts of each plant are tested and compared for effectiveness.  For guava leaf, the acetone extract proved most effective for antibacterial activity.

In Guatemala, guava leaf is used for diarrhea, dysentery, stomach pain, leucorrhea (a condition of unusual vaginal discharge), and a variety skin infections.

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According to Indian folklore, “it is believed that the leaves of this plant [guava] can cure jaundice within three days” (305).  The use of guava leaves is reported to be widespread in the Mangalore district of Karnataka, in Southwest India, for the cure of jaundice.  Scientists in the area decided to verify the use of guava leaves for jaundice and other liver diseases by conducting a study on the hepatoprotective (liver protection) properties of guava leaves.

The study on the hepatoprotective effects of guava leaf extract was conducted at the Krupanidhi College of Pharmacy in Bangalore, India.  Researchers collected fresh leaves from guava trees in the Koramangala area in Bangalore.  They crushed them, and boiled the leaves in water for one hour.  They filtered out the solids, and evaporated the water, leaving a powdered guava leaf extract.  Rats were used as study subjects.

Analysis of the extract showed that it contained carbohydrates, tannins, flavanoids, saponins, steriods, protiens and amino acids.

Researchers found that the extract showed good liver protective activities; the effect produced by the higher doses of guava leaf extract (500mg/kg) was similar to that produced by Silymarin, a well-known hepatoprotective agnet.  Furthermore, the guava leaf extract prevented an increase in liver weight in rats, something Silymarin does not do.

“In conclusion,” the researchers stated, “the aqueous extract of Psidium guajava Linn. leaves [guava leaves] showed good hepatoprotective activity in CCI4 induced acute and chronic liver damage, PCM induced liver damage and TAA induced liver necrosis.  The hepatoprotective activity may be due to the antioxidant effect of the plant” (310).  In other words, guava leaves can help protect the liver.  Guava leaf tea or guava leaf extract seems to be able to help prevent damage, or help to treat damage already done.

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In the journal Nutrition and Cancer, an article on the “Action Mechanism and Signal Pathways of Psidium guajava L. Aqueous Extract in Killing Prostate Cancer LNCaP Cells” was published in 2010.  The study comes out of Taiwan, a country which makes frequent use of guava leaves for a variety of ailements.

In the article, an ”aqueous extract of Psidium guajava L budding leaves (PE) has been shown to possess anti-prostate cancer activity in a cell line model” (260).  The researchers reported that they were drawn to study guava leaves’ effect on prostate cancer cells after conducting a study which showed that guava leaves were “potent anti-glycative agents” (261); this action was ascribed to the unusual free radical scavenging and anti-oxidative capabilities of guava leaf polyphenols.  The effects of glycation can result in the formation of irreversible advanced glycation end products (AGE’s), which are associated with many progressive diseases and can also trigger cancer formation.  Since guava leaves showed strong anti-glycative properties, the scientists chose to study the leaves’ action against an abundant form of prostate cancer, LNCap: Lymph node-metastasis prostate cancer.

They performed tests both in vitro (petri dish) and in vivo (in mice).  In vitro, they found that guava leaves were cytotoxic on the cancer cells, and that the leaves ”arrested cell cycle of LNCaP cells…[guava leaves] inhibited LNCaP cell growth and proliferation by preventing the cells from entering the S phase, and…TUNEL assay also confirmed the apoptic mechanism induced by [guava leaves]” (265).

In vivo, “although no significant difference in body weight was observed among the tumor-implanted [mice], the size of the tumors in the untreated mice was much larger when compared to tumor sizes in the guava leaf-treated mice at week 6 of the study.

“Conclusively,” the authors state, “[guava leaf] is a potent anticancer agent, acting through both cytotoxic and apoptotic action mechanisms; therfore, it [can feasably be used] as a potential adjuvant anti-prostate cancer therapy, in particular, for anti-androgen-responsive PCa” (268).

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Tropical countries have been plagued with Malaria infection rates in their most vulnerable groups: young children and pregnant women. Africa has more than one million deaths per year and Nigeria has more than 75 per cent of its children under age ten infected.

Anti-malarial drugs have been used for nearly 100 years, but the parasite has developed a resistance to drugs at an alarming rate. To counter these epidemics and drug-resistant strains, Nigerian researchers have developed herbal cocktail cures from local plants.

A typical cocktail consists of Morinda lucida, Nauclea latifolia, Cymbopogon citratus, pawpaw leaves, Moringa oleifera, Mangifera indica, bitter kola, and Psidium guajava,”

said the developers, plant taxonomist at the University of Nigeria, Nsukka (UNN) and Ebonyi State University, and Professor Jonathan Okafor. Using their common names, these local ingredients are brimstone tree, leaves of ubulu inu, lemon grass, male papaya leaves, drumstick tree leaves, mango leaves and bark, bitter cola and guava.

See the full article here at the Nigerian Tribune

Hangovers and their terrible next-morning symptoms are thought to result from dehydration and low blood sugar in the body. Now, research is leading scientists to believe that chemicals formed when your liver breaks down alcohol, such as the highly toxic acetaldehyde, also contributes to your hangover.

These chemicals (known as toxins) cause trouble when they pass through the stomach to the bloodstream, which will then spread throughout your body. Toxins irritate and even damage your cells and cell membranes and your liver’s natural reactions to harmful toxins quickly run out when larger amounts of alcohol enter the system. Then acetaldehyde and other toxins build up uninhibited in the body, causing headaches and vomiting. No immediate hangover cure is on the rise, however the article states:

Herbal compounds have become increasingly popular for hangovers. These include ingredients such as milk thistle, guava leaf and ginseng, which aim to boost biochemicals that help the body to deal with toxins.

Check out the rest of the article here on The Independant’s website.