Picralima Explained

Picralima is a plant genus in the family Apocynaceae, first described as a genus in 1896. It contains only one known species, Picralima nitida, native to tropical Africa (Benin, Ghana, Ivory Coast, Nigeria, Gabon, Cameroon, Cabinda, Central African Republic, Republic of Congo, Zaire, Uganda).^{[1] [2] [3] [4] [5]}

Picralima nitida, the akuamma, is a tree. The dried seeds from this plant are used in traditional medicine throughout West Africa, particularly in Ghana as well as in the Ivory Coast and Nigeria. The seeds are crushed or powdered and taken orally, and are mainly used for the treatment of malaria,^{[6] [7]} and diarrhoea, and as a painkiller.^[8] The plant produces the alkaloids pericine and akuammine, among others.^{[9] [10]}

An enterprising Ghanaian hospital started manufacturing and selling standardized 250 mg capsules of the powdered P. nitida seed, which then became a widely used palliative. This then led researchers to try to discover the active component of the seeds.

Picralima nitida seeds contain a complex mixture of alkaloids producing antipyretic and antiinflammatory effects along with analgesia in animal studies.^[11] Several of these were shown to bind to opioid receptors with weak affinity in vitro, and two compounds, akuammidine and ψ-akuammigine, were found to be μ-opioid agonists, although not particularly selective.^{[12] [13]} More recently, it has been shown that an additional constitutive analog, acuammicine, has potent activity as a kappa opioid receptor agonist.^[14]

formerly included in genus^[1]

1. Picralima elliotii (Stapf) Stapf = Hunteria umbellata (K.Schum.) Hallier f.
2. Picralima gracilis A.Chev. = Hunteria umbellata (K.Schum.) Hallier f.
3. Picralima laurifolia A.Chev. = Hunteria simii (Stapf) H.Huber
4. Picralima umbellata (K.Schum.) Stapf = Hunteria umbellata (K.Schum.) Hallier f.

Notes and References

1. http://apps.kew.org/wcsp/namedetail.do?name_id=156030 Kew World Checklist of Selected Plant Families
2. Harris, D.J. (2002). The vascular plants of the Dzanga-Sangha Reserve, Central African Republic: 1-274. National Botanic Garden (Belgium), Meise.
3. Akoègninou, A., van der Burg, W.J. & van der Maesen, L.J.G. (eds.) (2006). Flore Analytique du Bénin: 1-1034. Backhuys Publishers.
4. Sosef, M.S.M. & al. (2006). Check-list des plantes vasculaires du Gabon. Scripta Botanica Belgica 35: 1-438.
5. Figueiredo, E. & Smith, G.F. (2008). Plants of Angola. Strelitzia 22: 1-279. National Botanical Institute, Pretoria.
6. Kapadia GJ, Angerhofer CK, Ansa-Asamoah R. Akuammine: an antimalarial indolemonoterpene alkaloid of Picralima nitida seeds. Planta Medica. 1993 Dec;59(6):565-6.
7. Okunji C, Iwu M, Ito Y, Smith P. Preparative Separation of Indole Alkaloids from the Rind of Picralima nitida (Stapf) T. Durand & H. Durand by pH-Zone-Refining Countercurrent Chromatography. Journal of Liquid Chromatography & Related Technologies 2005; 28. 775-783.
8. Erharuyi O, et al. Medicinal uses, phytochemistry and pharmacology of Picralima nitida (Apocynaceae) in tropical diseases: A review. Asian Pacific Journal of Tropical Medicine 2014; 7(1): 1-8.
9. Ama-Asamoah R, et al. Picratidine, a New Indole Alkaloid from Picralima nitida Seeds. J. Nat. Prod; 1990, 53(4): 975–977.
10. Book: African Ethnobotany: Poisons and Drugs : Chemistry, Pharmacology, Toxicology . Neuwinger HD . CRC Press . 1996. 9783826100772 . 119–126.
11. Duwiejua M, Woode E, Obiri DD. Pseudo-akuammigine, an alkaloid from Picralima nitida seeds, has anti-inflammatory and analgesic actions in rats. Journal of Ethnopharmacology. 2002; (81):73-79.
12. Lewin G, Le Ménez P, Rolland Y, Renouard A, Giesen-Crouse E. Akuammine and dihydroakuammine, two indolomonoterpene alkaloids displaying affinity for opioid receptors. Journal of Natural Products. 1992 Mar;55(3):380-4.
13. Menzies JR, Paterson SJ, Duwiejua M, Corbett AD. Opioid activity of alkaloids extracted from Picralima nitida (fam. Apocynaceae). Eur J Pharmacol. 1998 May 29;350(1):101-8.
14. Simone M. Creed, Anna M. Gutridge, Malaika D. Argade, Madeline R. Hennessy, J. Brent Friesen, Guido F. Pauli, Richard M. van Rijn, and Andrew P. Riley. Isolation and Pharmacological Characterization of Six Opioidergic Picralima nitida Alkaloids. Journal of Natural Products 2021 84 (1), 71-80