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Akuammine, an indole alkaloid also known as vincamajoridine,〔Janot MM, Le Men J, Aghoramuthry K, Robinson R. The identity of vincamajoridine and akuammine. ''Experientia''. 1955;11(9):343.〕 is the most abundant active alkaloid found in the seeds from the tree ''Picralima nitida'', commonly known as Akuamma. 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.〕 and diarrhoea, and as a painkiller. An enterprising Ghanaian hospital started manufacturing standardised 250 mg capsules of the powdered ''P. nitida'' seed, and sold them around the country where they became widely accepted as a safe and effective pain relief product. This then led researchers to try to discover the active component of the seeds. ''P. nitida'' seeds contain a mixture of alkaloids producing antipyretic and antiinflammatory effects along with analgesia.〔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.〕〔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.〕 Several of these were shown to bind to opioid receptors ''in vitro'', and two compounds, akuammidine and ψ-akuammigine, were found to be potent μ-opioid agonists, although not particularly selective. Surprisingly the main alkaloid from the seeds, akuammine, was found to be an opioid antagonist when tested ''in vitro'' and canceled out the effects of the active agonist components.〔Menzies JRW, Paterson SJ, Duwiejua M, Corbett AD. Opioid activity of alkaloids extracted from ''Picralima nitida'' (fam. Apocynaceae). ''European Journal of Pharmacology''. 1998 May 29;350(1):101-8.〕 This finding contradicts the belief by some pharmacological scientists that there are no naturally occurring opioid antagonists. Given the confirmed activity of the whole seed extract in humans, this makes it likely that akuammine is in fact being metabolised once inside the body to form a metabolite acting as an opioid receptor agonist. Akuammine is the main alkaloid found in the seeds, comprising 0.56% of the dried powder, indicating that the 250 mg "Picap Capsules" sold commercially should contain approximately 1.4 mg of akuammine, plus 0.085 mg akuammidine and 0.015 mg ψ-akuammigine. Akuammine is structurally related to both yohimbine and mitragynine, both of which are alkaloid plant products with uses in medicine. == References == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Akuammine」の詳細全文を読む スポンサード リンク
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