For Patients & Caregivers
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.
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.
For Healthcare Professionals
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.
Mechanism of Action
Papaya leaf extract modulates the immune system by enhancing the production of Th1 type cytokines, such as interleukin (IL-12), interferon (IFN-gamma) and tumor necrosis factor (TNF-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.