Glucolipid from the ethyl acetate fraction of Acalypha wilkesiana var. lace-acalypha (Muell & Arg)
Plant recipes are classified as medicinal when the biological activities of compounds obtained from them have been scientifically established. Before now, three compounds namely, ethyl gallate, pyrogallol and D-arabino-hex-1- enitol-1, 5-anhydro-2-deoxy have been isolated from the butanol fraction of Acalypha wilkesiana var. lace-acalypha (Muell & Arg.) and their antimicrobial activities evaluated, established and documented. In this study, the ethyl acetate fraction which resulted from solvent-partitioning of the aqueous crude extract of the plant with organic solvents of increasing polarities was subjected to silica-gel column chromatography. A glucolipid, designated as H-2 [light brown oil; b.p. (391-393 0C); Rf (0.19); [n]20D (1.3989)] was isolated. The structure of H-2 has been established to be ethyl α-D-glucopyranoside by a combination of 1H NMR, 13C NMR, MS and IR spectral techniques. H-2 was remarkably bacteriostatic against B. subtilis, E. coli, K. pneumonia, Ps. aeruginosa and S. typhi. However, it recorded no activitities against S. aureus and C. albicans. H-2 and other compounds previously obtained can be used to chemotaxonomically mark this plant and hence classified as medicinal.
Keywords: Acalypha wilkesiana var. lace-acalypha; Glucolipid; Ethyl α-D-glucopyranoside; Ethyl acetate fraction