title: Antibacterial steroid alkaloids from the stem bark of Holarrhena pubescens.
abstract: Holarrhena pubescens (syn. H. antidysenterica) (L.) WALL. stem bark was tested for antibacterial efficacy against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa using the microdilution broth method as well as the disc diffusion method. The crude methanolic extract was active against all tested bacteria. Further chemical fractionation indicated that the antibacterial activity was mainly associated with the alkaloids. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for the crude extract, the total alkaloids and the neutral fraction using microdilution broth method. The results were compared with reference antibiotics. The total alkaloids showed remarkable activity against S. aureus (MIC = 95 microg/ml).
authors.affiliation: Institute of Pharmacognosy, University of Graz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Chakraborty
authors.forename: A H
authors.initials: AH
authors.lastname: Brantner
mesh_terms: D000470:Alkaloids / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D000432:Methanol / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D017551:Microdialysis; D010936:Plant Extracts / Q000494:pharmacology*; D012995:Solubility; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000470:Alkaloids; D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D000432:Methanol