Bioactive polyphenols in Ximenia americana and the traditional use among Malian healers.
BACKGROUND
Ximenia americana is a medicinal bushy, spiny shrub or small tree used in Mali in West Africa for treatment of various diseases, most common are infectious and inflammatory ailments.


OBJECTIVE
(1) To perform an ethnopharmacological survey on the traditional use of Ximenia americana among healers in Mali. (2) To isolate and identify chemical constituents from the ethanol extract of Ximenia americana leaves and to study their radical scavenging and enzyme inhibitory effects.


METHODS
In five different districts in Mali, 38 healers were interviewed about their medicinal use of Ximenia americana. An aqueous ethanol extract of the leaves of this tree was prepared and further fractionated with liquid-liquid extraction, VersaFlash and Sephadex LH-20 column chromatography, and preparative HPLC. Isolated compounds were identified by 1D and 2D NMR spectroscopy. Extracts, subfractions and isolated compounds were investigated as DPPH radical scavengers and as inhibitors of xanthine oxidase and 15-lipoxygenase.


RESULTS
Major areas of use by Malian healers were against throat infection, amenorrhea and as tonic. Fractionation of the ethanol extract led to the isolation and identification of the cyanogenic glycoside sambunigrin (1), which is previously known from the plant. Additionally, gallic acid (2) and the gallotannins β-glucogalline (3) and 1,6-digalloyl-β-glucopyranose (4) were found. The following flavonoids were isolated: quercetin (5), quercitrin (quercetin-3-O-α-rhamnopyranoside) (6), avicularin (quercetin-3-O-α-arabinofuranoside) (7), quercetin-3-O-β-xylopyranoside (8), quercetin-3-O-(6″-galloyl)-β-glucopyranoside (9) and kaempferol-3-O-(6″-galloyl)-β-glucopyranoside (10). The flavonoids were active both as enzyme inhibitors and DPPH radical scavengers.


CONCLUSIONS
Sambunigrin (1) was the main compound in the EtOAc soluble fraction of the alcoholic extract of Ximenia americana leaves. Gallic acid (2), gallotannins (3-4) and flavonoids (5-10) were identified for the first time in the genus Ximenia. The identified compounds may give a rationale for the traditional use of Ximenia americana in Mali. Healers interviewed reported the use against throat infections, amenorrhea, as tonic, for wound healing and against pain.
Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Oslo, Norway.
Nhat Hao Tran
NH
Le
Karl Egil
KE
Malterud
Drissa
D
Diallo
Berit Smestad
BS
Paulsen
Cecilie Sogn
CS
Nergård
Helle
H
Wangensteen
D000568:Amenorrhea / Q000188:drug therapy; D020834:Ethnopharmacology; D005260:Female; D006801:Humans; D007239:Infections / Q000188:drug therapy; D008297:Male; D008302:Mali; D016488:Medicine, African Traditional; D031656:Olacaceae / Q000737:chemistry*; D010146:Pain / Q000188:drug therapy; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D018515:Plant Leaves; D059808:Polyphenols / Q000494:pharmacology / Q000627:therapeutic use*; D014945:Wound Healing / Q000187:drug effects
D010936:Plant Extracts; D059808:Polyphenols