Kigelia africana fruit: Constituents, bioactivity, and reflection on composition disparities

• Main Authors: Ahmed Galal Osman, Zulfiqar Ali, Amar G Chittiboyina, Ikhlas A Khan
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2017-01-01
• Series: World Journal of Traditional Chinese Medicine
• Subjects: Anticryptoccocal; antileishmanial; cannabinoid receptors; Kigelia africana; opioid receptors
• Online Access: http://www.wjtcm.net/article.asp?issn=2311-8571;year=2017;volume=3;issue=4;spage=1;epage=6;aulast=Osman

Objective: Kigelia africana, a tropical tree, which has long been used in African traditional medicine. The objective of the current study has been identifying the constituents of K. africana and verifying its utilities in traditional medicine. Materials and Methods: The methanol extract of K. africana fruits was subjected to chromatographic fractionation utilizing different techniques. The methanol extract together with the isolated compounds were tested for their bioactivities in a series of cell-based assays. Results: The current work led to isolation and characterization of nine constituents including iridoid glycosides, phenylpropanoid derivatives, and a eucommiol derivative. The hexanes extract caused inhibition of the opportunistic yeast; Cryptococcus neoformans Pinh. The chloroform extract exhibited substantial antileishmanial activity of Leishmania donovani. Verminoside (1) showed weak inhibition of the CB1, CB2, and Kappa opioid receptors. Compound 4 exhibited weak inhibition of the Kappa and Mu opioid receptors. The hexanes and the chloroform extracts of K. africana exhibited inhibitory activity against the pathogenic parasite Trypanosoma brucei. The ethyl acetate extract showed the same activity. Conclusions: This is the first report on the isolation of coniferyl 4-O-β-D-glucopyranoside (7), a eucommiol derivative (crescentin IV) (6), and 6-feruloylcatalpol (4) from the genus Kigelia. It is also the first report on the separation of ajugol (2), catalpol (3), and specioside (5) from the fruits of K. africana. Revision of the 1H and 13C-NMR spectra of 6-feruloylcatalop (4) and 6-p-hydroxycinnamoylcatalpol (5, specioside) is described. Further, the results of the in vitro assays corroborate the traditional utility of this plant in medicine.