Antiplasmodial activity of triterpenes isolated from the methanolic leaf extract of Combretum racemosum P. Beauv.
J Ethnopharmacol
; 247: 112203, 2020 Jan 30.
Article
em En
| MEDLINE
| ID: mdl-31472271
ABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE Combretum racemosum showed activity in previous ethnopharmacological investigations of some Combretum species used in malaria treatment in parts of West Africa. AIM OF THE STUDY This study aimed at confirming the antimalarial potential of this plant by an activity-guided isolation of its active principles. MATERIALS AND METHODS:
A crude methanolic leaf extract of Combretum racemosum and fractions thereof obtained by partition with chloroform and n-butanol were investigated for antiplasmodial activity against chloroquine-sensitive (D10) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Repeated chromatographic separations were conducted on the chloroform fraction to isolate bioactive compounds for further tests on antiplasmodial activity. The characterization of the isolated substances was performed by applying NMR- and MS-techniques (ESI-MS, HR-ESIMS, 1D and 2D NMR).RESULTS:
The chloroform fraction (D10 IC50â¯=â¯33.8⯱â¯1.5⯵g/mL and W2 IC50â¯=â¯27.8⯱â¯2.9⯵g/mL) exhibited better antiplasmodial activity than the n-butanol fraction (D10 IC50â¯=â¯78.1⯱â¯7.3⯵g/mL and W2 IC50â¯=â¯78⯱â¯15⯵g/mL) as well as the methanolic raw extract (D10 IC50â¯=â¯64.2⯱â¯2.7⯵g/mL and W2 IC50â¯=â¯65.8⯱â¯14.9⯵g/mL). Thus, the focus of the phytochemical investigation was laid on the chloroform fraction, which led to the identification of four ursane-type (19α-hydroxyasiatic acid (1), 6ß,23-dihydroxytormentic acid (4), madecassic acid (8), nigaichigoside F1 (10)) and four oleanane-type (arjungenin (2), combregenin (5), terminolic acid (7), arjunglucoside I (11)) triterpenes, as well as abscisic acid (9). Compounds 1 and 2, 4 and 5, 7 and 8 as well as 10 and 11 were isolated as isomeric mixtures in fractions CR-A, CR-C, CR-E and CR-H, respectively. All isolated compounds and mixtures exhibited moderate to low activity, with madecassic acid being most active (D10 IC50â¯=â¯28⯱â¯12⯵g/mL and W2 IC50â¯=â¯17.2⯱â¯4.3⯵g/mL).CONCLUSION:
This paper reports for the first time antiplasmodial principles from C. racemosum and thereby gives reason to the traditional use of the plant.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plasmodium falciparum
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Triterpenos
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Extratos Vegetais
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Combretum
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Antimaláricos
Limite:
Animals
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Humans
País/Região como assunto:
Africa
Idioma:
En
Revista:
J Ethnopharmacol
Ano de publicação:
2020
Tipo de documento:
Article