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How It Works
Papaya leaf extract may improve platelet counts, but more study is needed.
The papaya tree is common to many tropical regions of the world. Papaya leaves and their extracts are sold as dietary supplements to improve the immune system and increase platelet counts.
Lab studies suggest that papaya leaf extracts may inhibit a variety of bacteria and improve platelet counts. Although a study in humans also suggests it can improve platelet counts in patients with dengue fever, a meta-analysis found that evidence was lacking. More study is needed on dosing, safety, and effectiveness before papaya leaf extract can be used for this purpose.
Purported Uses
Antimicrobial
Lab studies show that papaya leaf extracts can stop the growth of a variety of bacteria.
Improve platelet count
Although papaya leaf extract may increase platelet count in patients with dengue fever, evidence is lacking. More study is needed on dosing, safety, and effectiveness before it can be used for this purpose.
Do Not Take If
You are a cancer patient or have low platelet counts: More needs to be known about dosing, safety, effectiveness, and adverse effects in humans.
You are pregnant: Animal studies have raised concerns about potential toxicities.
You have a liver impairment: Animal studies have raised concerns about potential toxicities.
Side Effects
Mild gastrointestinal disturbance
Rash
Special Point
Papaya leaf extracts should not be used in cancer patients or for low platelet count until more is known about dosing, safety, effectiveness, and adverse effects in humans.
Papaya tree is commonly found in tropical areas around the world. The fruits are consumed as food and medicine. Dried and powdered stems and leaves are prepared as medicinal teas to protect against infections and improve digestion. Papaya leaves and their extracts are also marketed as dietary supplements to enhance the immune system and improve platelet function.
In vitro, papaya leaves exhibit immunomodulatory (1), antioxidant (9), and anticancer (11)(12) effects. The leaf extracts contain antibacterial compounds that inhibit bacterial growth (4). In mice, a powdered suspension of papaya leaves increased thrombocyte count (2) and a water extract reduced alcohol-induced stomach damage (5). Hypoglycemic effects were reported with its use in a diabetic rat model (10), and the extract also appears to have low toxicity (6).
Use of papaya leaf extract to treat dengue fever and increase platelet counts has been described (3). A randomized trial also found significant increases in platelet count in patients with dengue fever (13), but a meta-analysis determined that current evidence is insufficient (14). Therefore, papaya leaf extracts should not be used to improve platelet counts until more is known about its efficacy and adverse effects in humans.
Purported Uses
Antimicrobial
Improve platelet count
Mechanism of Action
Major compounds identified in C. papaya leaf are rutin, carpaine, manghaslin, papain, and clitorin (15). Papaya leaf extract modulates the immune system by enhancing the production of Th1 cytokines such as interleukin-12, interferon-gamma, and tumor necrosis factor-alpha. Fractions with molecular weight less of than 1000 are most active in inhibiting tumor cell growth (1). Papaya leaf extract also has antioxidant effects (5) and contains antibacterial and phenolic compounds (6)(8) but the mechanism of action remains unclear.
Contraindications
Papaya leaf extracts should not be used in cancer patients or for low platelet count until more is known about dosing, safety, effectiveness, and adverse effects in humans.
Avoid in pregnant individuals and those with liver impairment, as animal studies have raised concerns about potential toxicities in these populations with long-term use (15).
Overall, C. papaya leaf consumption in juice and extract form appear to be safe for short-term use (less than 5 days) (15).
Herb-Drug Interactions
Although preclinical studies suggest potential interactions with hypoglycemics, P-glycoprotein substrates, and some antibiotics, no specific compounds or biomarkers of C. papaya leaf have been identified as contributors to these interactions (15). Clinical relevance has yet to be determined.
Herb Lab Interactions
A case report and clinical trial describe increased platelet counts with a water extract of papaya leaf in patients with dengue fever who had thrombocytopenia (3)(13).
Rahman S, Imran M, Muhammad N, et al. Antibacetial screening of leaves and stem of Carica papaya. Journal of Medicinal Plants Research. 2011; 5(20):5167-5171.
