Asimina triloba
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 Common Pawpaw in fruit
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| Asimina triloba (Linnaeus) Michel Félix Dunal |
The Common pawpaw (Asimina triloba) is a large shrub or small tree native to North America.
[edit] Conservation status
On a global scale, the common pawpaw has a Global GRANK of G5 (Very Common).
The common pawpaw is considered a threatened species in New York, and an endangered species in New Jersey.
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.
[edit] Biochemistry
The fruits of the common pawpaw are rich in fatty acids, the major one being octanoate. They also contain cis-δ9- and cis-δ11-hexadecenoate, cis-δ9-, cis-δ11- and cis-δ13-octadecenoate.
The seeds of A. triloba 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 of A. triloba 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 of the common pawpaw 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 pesticide and anti-tumour compounds.
[edit] External links
- Natural Heritage Information Centre / Centre d'information des heritages naturelles — Asimina triloba. Ontario Ministry of Natural Resources / Ministère des richesses naturelles. Queen's Printer for Ontario, 2002. Accessed 4 May 2006.
- E.J. Kim, K.M. Suh, D.H. Kim, E.J. Jung, C.S. Seo, J.K. Son, M.H. Woo and J.L McLaughlin. Asimitrin and 4-hydroxytrilobin, new bioactive annonaceous acetogenins from the seeds of Asimina triloba possessing a bis-tetrahydrofuran ring. Journal of Natural Products. 2005 Feb; 68(2):194-7.
- J.M. Martin, S.R. Madigosky, Z.M. Gu, D. Zhou, J. Wu and J.L. McLaughlin. Chemical defense in the zebra swallowtail butterfly, Eurytides marcellus, involving annonaceous acetogenins. Journal of Natural Products. 1999 Jan; 62(1):2-4.
- G.X. Zhao, L.R. Miesbauer, D.L. Smith and J.L. McLaughlin. Asimin, asiminacin, and asiminecin: novel highly cytotoxic asimicin isomers from Asimina triloba. Journal of Medicinal Chemistry. 1994 Jun 24; 37(13):1971-6.
