Picralima

{{Short description|Genus of flowering plants}}

{{Speciesbox

| image = Picralima Nitida - 03.jpg

| image_caption =

| display_parents = 3

| genus = Picralima

| parent_authority = Pierre

| species = nitida

| authority = (Stapf) T.Durand & H.Durand

| synonyms_ref =

| synonyms =

• Tabernaemontana nitida Stapf
• Picralima klaineana Pierre
• Picralima macrocarpa A.Chev.

}}

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).[http://apps.kew.org/wcsp/namedetail.do?name_id=156030 Kew World Checklist of Selected Plant Families]Harris, D.J. (2002). The vascular plants of the Dzanga-Sangha Reserve, Central African Republic: 1-274. National Botanic Garden (Belgium), Meise.Akoègninou, A., van der Burg, W.J. & van der Maesen, L.J.G. (eds.) (2006). Flore Analytique du Bénin: 1-1034. Backhuys Publishers.Sosef, M.S.M. & al. (2006). Check-list des plantes vasculaires du Gabon. Scripta Botanica Belgica 35: 1-438.Figueiredo, E. & Smith, G.F. (2008). Plants of Angola. Strelitzia 22: 1-279. National Botanical Institute, Pretoria.

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,Kapadia GJ, Angerhofer CK, Ansa-Asamoah R. Akuammine: an antimalarial indolemonoterpene alkaloid of Picralima nitida seeds. Planta Medica. 1993 Dec;59(6):565-6.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. {{doi|10.1081/JLC-200048915}} and diarrhoea, and as a painkiller.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. {{doi|10.1016/S1995-7645(13)60182-0}} The plant produces the alkaloids pericine and akuammine, among others.Ama-Asamoah R, et al. Picratidine, a New Indole Alkaloid from Picralima nitida Seeds. J. Nat. Prod; 1990, 53(4): 975–977. {{doi|10.1021/np50070a032}}{{Cite book | title = African Ethnobotany: Poisons and Drugs : Chemistry, Pharmacology, Toxicology | vauthors = Neuwinger HD | publisher = CRC Press | date = 1996| isbn = 9783826100772 | pages = 119–126}}

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.{{citation needed|date=April 2017}} 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.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. 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.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.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. {{doi|10.1016/s0014-2999(98)00232-5}} {{PMID|9683021}} More recently, it has been shown that an additional constitutive analog, acuammicine, has potent activity as a kappa opioid receptor agonist.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 {{doi|10.1021/acs.jnatprod.0c01036}}

;formerly included in genus

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.