Abstract
The present communication represents the first attempt to subject
Abutilon pannosum
Forst. f. Schlecht. and
A. figarianum
Webb (Malvaceae) to bioactivity-directed fractionation in order to detect their bioactivities and the profile of the secondary metabolites associated with these activities. Dried flowers were extracted separately by petroleum ether, chloroform and 80% methanol. The extracts were tested against two gram positive and three gram negative human pathogenic bacteria. The chloroform extracts of
A. figarianum
and
A. pannosum
exhibited inhibitory activity against
Bacillus subtillus
of 18mm and 16mm, at a concentration of 1mg/ml, respectively. Meanwhile, higher concentration (5mg/ml) of the methanolic extract of both
A. figarianum
and
A. pannosum
exhibited significant inhibitory activity against
Bacillus subtillus
(80%, 76%),
Escherichia coli
(52%, 60%),
Pseudomonas aeruginosa
(70%, 80%),
Staphylococcus aureus
(70%, 60%) and
Proteus vulgaris
(80%, 70%), respectively. The aqueous residue of the methanolic extract was further partitioned with ethyl acetate and
n
-butanol. The ethyl acetate fractions of both plants possessed a prominent antioxidant activity (80% inhibition) at a concentration of 1mg/ml using DPPH (1,1-diphenyl-2-picrylhydrazyle) as a free radical source. The chemical structures of the compounds present in the bioactive extracts and their respective fractions were elucidated by tandem mass spectrometry (HPLC-MS/MS-ESI) leading to the identification of 18 compounds: 13 flavonols, 3 flavones, 1 flavanons and 2 anthocyanins derivatives. A number of reports of the antioxidant and antimicrobial activities of other
Abutilon
species have already been published [1,2].
References:
[1] Porchezhian, E., and Ansari, S.H. (2005) Phytomedicine 12:62–64.
[2] Matlawska, I. and Sikorska, M. (2005) Acta Pol. Pharm. Drug Res. 62:135–139.