Pawpaw
Scientific Name(s): Asimina triloba (L.) Dunal.
Common Name(s): Custard apple, Indiana banana, Kentucky banana, Pawpaw, Poor man's banana
Medically reviewed by Drugs.com. Last updated on Apr 22, 2024.
Clinical Overview
Use
A. triloba has traditionally been used medicinally, as well as for food and as a material in fishing nets. Although antiangiogenic, cytotoxic, antimicrobial, antioxidant, and pesticidal activities have been observed in vitro and in animal studies, published clinical trials are lacking to support its use for any indication.
Dosing
Clinical trials are lacking to provide guidance on dosing, and concerns of toxicity exist.
Contraindications
Contraindications have not been identified.
Pregnancy/Lactation
Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
None well documented.
Adverse Reactions
The crude extract of the stem bark may cause contact dermatitis.
Toxicology
Pawpaw fruit contains neurotoxins (eg, annonacin, squamocin) and has been linked to Parkinsonism in some reports; however, case studies are lacking.
Scientific Family
- Annonaceae (custard apple)
Botany
A. triloba, commonly known as pawpaw, is from the custard apple family and should not be confused with papaya (Carica papaya), which is sometimes called paw paw (see Papaya monograph).(USDA 2021, Duke 2002) A. triloba is a small, North American tree that grows approximately 3 to 12 m in height. It is common in the temperate woodlands of the eastern United States and is an orchard crop in several states.(Brannan 2015) Its large, drooping leaves give the plant a tropical appearance. The dark-brown, velvety flowers, which can bloom for up to 6 weeks, are approximately 5 cm across and grow in umbrella-like whorls similar to those of some magnolia species. The fruit is smooth-skinned and yellow to greenish-brown in color, measures approximately 8 to 15 cm in length, and can reach 0.45 kg in weight. It resembles a short, thick banana and is similar in nutrient value but has a very short shelf life, which currently limits culinary and commercial uses.(Brannan 2015) The yellow, soft, custard-like pulp is edible but sickly sweet in flavor and contains dark seeds.(Brannan 2015, Davidson 1991, Hocking 1997) A synonym of A. triloba is Anonna triloba L. (Duke 2002)
History
Pawpaw bark has been used medicinally due its alkaloid content. It has also been used as food by American Indians, and the thin, fibrous, inner bark has been used to make fishing nets.(Hocking 1997) The seeds of several Annonaceous species have emetic properties; in 1898, Eli Lilly Inc. sold an A. triloba extract for inducing emesis.(Duke 2002, Johnson 2000) Topical preparations exploit the pesticidal properties of the plant. An ointment for use in oral herpes is commercially available.(Johnson 2000, McLaughlin 2008)
Chemistry
The bark, roots, twigs, and seeds of A. triloba contain acetogenins, a group of long-chain fatty acid derivatives found in the Annonaceae plant family; compounds from this class are waxy substances that usually contain 1 to 2 tetrahydrofuran or tetrahydropyran rings and have a long aliphatic chain on one side and an aliphatic chain ending in alpha,beta-unsaturated gamma-lactone (or ketolactone) on the other side. Acetogenins are polyketide-derived molecules and are unique to the Annonaceae family. About 400 acetogenins from Asimina and other genera have been identified.(Bruneton 1999, Duke 1992, Gupta 2011, Johnson 2000, Kim 2000, Kim 2005, McLaughlin 2008, Zhao 1993)
A variety of essential oils and other extracts from the leaf of the pawpaw plant have been described, with sesquiterpenes dominating the oil composition (83%).(Derevinskaya 1983, Farag 2009)
The fruit, which contains phenolic acids and flavonoids, is a dietary source of antioxidants, although flavonoid content decreases greatly with ripening.(Brannan 2015, Harris 2009, Kobayashi 2008)
The fruit contains fatty acids ranging from C6 to C20 in length.(Wood 1999) More recently, isoquinoline alkaloids have also been isolated.(Majrashi 2019)
Uses and Pharmacology
Antiangiogenic activity
In vitro data
In a rat aortic ring bioassay, antiangiogenic activity has been noted.(Monsen 2018)
Antioxidant/Antimicrobial activity
Pawpaw, especially unripe, has an abundance of phenolic compounds with superior antioxidant activity. The antioxidant activities depend on the total phenolic content of each pawpaw tissue.(Nam 2017) Pawpaw roots may be useful as a natural source of natural antioxidants.
In vitro data
In a study evaluating phenolic components of ripe and unripe pawpaw fruit, pawpaw extracts were more sensitive against Corynebacterium xerosis and Clostridium perfringens; in particular, the 95% ethanol extract of the ripe fruit notably inhibited C. xerosis growth, with a minimum inhibitory concentration of 1.56 mg/mL. These results showed the unripe fruit of pawpaw has abundant phenolic compounds and superior antioxidant activity, and that the 95% ethanol extract of the ripe fruit shows strong inhibitory activity against various microorganisms in vitro.(Nam 2019)
Cancer
Animal and in vitro data
Pawpaw (A. triloba) contains acetogenins that can inhibit the growth of certain cancer cells. The antiproliferative activity is higher in unripe than in ripe fruit and depends on acetogenin content.(Nam 2018) Certain acetogenins have exhibited cytotoxicity against human cancer cell lines.(He 1996, Woo 1995, Zhao 1992, Zhao 1993) A mechanism of action may be inhibition of mitochondrial nicotinamide adenine dinucleotide:ubiquinone oxidoreductase, causing a decrease in cellular adenosine triphosphate levels.(Janick 1996, Zhao 1994) Acetogenins may also inhibit hypoxia-inducible factor-1, resulting in the suppression of angiogenesis in tumors.(Coothankandaswamy 2010) Despite concerns regarding the toxicity of A. triloba extracts, limited studies have been conducted in rodents. Acetogenins may be less toxic than standard chemotherapy.(Johnson 2000)
Clinical data
No clinical data exist regarding the use of A. triloba in cancer; however, a trial has been conducted using acetogenins from an unrelated plant.(Indonesia University 2015)
Pesticidal activity
In vitro data
The pawpaw tree is usually insect resistant or disease resistant because of its acetogenin content, which deters the feeding of many organisms.(Janick 1996) In a brine shrimp larvae bioassay, pesticidal properties were demonstrated, with different plant parts having differing potencies. Small twigs yielded the most potent extract, while the leaves were the least potent. Unripe fruits, seeds, root wood and bark, and stem bark were also potent.(Ratnayake 1992) Extracts of the plant were anthelminthic in vitro.(Ferreira 2011)
Dosing
Clinical trials are lacking to provide guidance on dosing, and concerns of toxicity exist.(Levine 2015)
Pregnancy / Lactation
Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
None well documented.
Adverse Reactions
Handling of the fruit may produce a skin rash in sensitive individuals.(Duke 2002) The sensitizing potential of pawpaw was examined in guinea pigs; the crude extract of the stem bark was a weak sensitizer and elicited allergic contact dermatitis. The active compound asimicin was determined to be a weak irritant.(Smith 2014) Acetogenins may also be irritating to the eyes.(Duke 2002)
Toxicology
Pawpaw fruit contains the neurotoxins annonacin and squamocin,(Avalos 1993) and has been linked to parkinsonism in some reports(Levine 2015); however, case studies are lacking.(Gupta 2011) The total amounts of annonacin and squamocin were higher in pawpaw than in any other fruits analyzed in a study comparing the fruits and seeds of pawpaw, atemoya, and marolo.(Tran 2020)
Neurotoxicity has been reported in rodents.(McLaughlin 2008, Potts 2012) Ames tests for mutagenicity have largely been negative.(McLaughlin 2008)
Index Terms
- Anonna triloba L.
References
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This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.
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