''Picralima'' is a plant genus in the family

Apocynaceae Apocynaceae (from ''Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison Members of the ...

, first described as a genus in 1896. It contains only one known species, ''Picralima nitida'', native to tropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

(

Benin Benin ( , ; french: Bénin , ff, Benen), officially the Republic of Benin (french: République du Bénin), and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, Burkina Faso to the north ...

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, Cabinda,

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).Kew World Checklist of Selected Plant Families
/ref> ''Picralima nitida'', the akuamma, is a tree. The dried seeds from this plant are used in traditional medicine throughout

West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Maurit ...

, particularly in

as well as in the

and

. The seeds are crushed or powdered and taken orally, and are mainly used for the treatment of

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

, and

diarrhoea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...

, and as a painkiller. The plant produces the

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

pericine Pericine is one of a number of indole alkaloids found in the tree ''Picralima nitida'', commonly known as akuamma. As with some other alkaloids from this plant such as akuammine, pericine has been shown to bind to mu opioid receptors ''in vitro'' ...

and

akuammine Akuammine (vincamajoridine) is an indole alkaloid. It is the most abundant alkaloid found in the seeds from the tree ''Picralima nitida'', commonly known as akuamma, comprising 0.56% of the dried powder. It has also been isolated from ''Vinca ma ...

, among others. 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 An antipyretic (, from ''anti-'' 'against' and ' 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which r ...

and

antiinflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as o ...

effects along with

analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals ...

in animal studies. 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. 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 ;formerly included in genus # ''Picralima elliotii'' (Stapf) Stapf = '' Hunteria umbellata'' (K.Schum.) Hallier f. # ''Picralima gracilis'' A.Chev. = '' Hunteria umbellata'' (K.Schum.) Hallier f. # ''Picralima laurifolia'' A.Chev. = '' Hunteria simii'' (Stapf) H.Huber # ''Picralima umbellata'' (K.Schum.) Stapf = '' Hunteria umbellata'' (K.Schum.) Hallier f.

References

External links

* * {{Taxonbar, from1=Q9059428, from2=Q12065824 Flora of Africa Monotypic Apocynaceae genera Rauvolfioideae