The Common pawpaw (Asimina triloba) is a species of pawpaw, native to eastern North America, from southernmost Ontario and New York west to eastern Nebraska, and south to northern Florida and eastern Texas.
The flowers are produced in early spring at the same time as or slightly before the new leaves appear, each flower dark red, 2-5 cm diameter, with three sepals and six petals; they have a fetid smell.
In Canada, it is only found in portions of southern Ontario, where it has a National NRANK of N3 (Vulnerable) and a Provincial SRANK of S3 (Vulnerable). The Ontario Ministry of Natural Resources has given A. triloba a general status of "Sensitive", and its populations are monitored.
The seeds have been shown to contain the chemicals asimitrin (an adjacent ring-hydroxylated bis-tetrahydrofuran acetogenin) and 4-hydroxytrilobin (an adjacent bis-THF ring with two flanking hydroxyl groups and an α,β-unsaturated γ-lactone with a 4-hydroxyl group). These chemicals seem to have selective cytotoxicity against prostate adenocarcinoma (PC-3) and colon adenocarcinoma (HT-29) cell lines, thus may become a useful chemotherapeutic chemical for these types of cancer.
The leaves also contain toxic annonaceous acetogenins, making them impalatable to most insects. The one notable exception is the zebra swallowtail butterfly (Eurytides marcellus), whose larvae feed on the leaves. This confers protection from predation throughout the butterfly's life, as trace amounts of acetogenins remain present, making them impalatable to birds and other predators.
The bark contains other acetogenins, including asimin, asiminacin and asiminecin, which have been shown to be potent inhibitors of mitochondrial NADH:ubiquinone oxidoreductase, making A. triloba a promising source of pesticide and anti-tumour compounds.
Biological screening of Annonaceous Brazilian medicinal plants using Artemia salina (brine shrimp test). (Short Communication).
Mar 01, 2003; Summary Eighteen different extracts from five Annona species collected in Minas Gerais state, Brazil, were submitted to the brine...