title: Activity of Aristolochia bracteolata against Moraxella catarrhalis.
abstract: A bioassay-guided fractionation of methanol extract of Aristolochia bracteolata whole plant was carried out in order to evaluate its antimicrobial activity and to identify the active compounds in this extract. Antibacterial and antifungal activities of methanol extract against gram-positive, gram-negative, and fungal strains were investigated by the agar disk diffusion method. Among the strains tested, Moraxella catarrhalis and sea urchin-derived Bacillus sp. showed the highest sensitivity towards the methanol extract and hence they are used as test organisms for the bioassay-guided fractionation. From this extract, aristolochic acid 1 (AA-1) has been isolated and has showed the greatest antibacterial activity against both standard strain and clinical isolates of Moraxella catarrhalis with equal minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 25 and 50 μg/mL. Modification of the AA-1 to AA-1 methyl ester completely abolished the antibacterial activity of the compound and the piperonylic acid moiety of AA-1 which suggested that the coexistence of phenanthrene ring and free carboxylic acid is essential for AA-1 antibacterial activity.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, 11111 Qasr Street, P.O. Box 1996, Sudan.
authors.forename: Malik
authors.identifier: 0000-0001-8751-4159
authors.initials: M
authors.lastname: Suliman Mohamed
authors.affiliation: Graduate School of Biomedical Sciences, School of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi 852-8521, Japan.
authors.forename: Mona
authors.identifier: 0000-0002-2319-4165
authors.initials: M
authors.lastname: Timan Idriss
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Al-Azhar University, Assuit Branch, Assuit 71524, Egypt.
authors.forename: Amgad I M
authors.initials: AI
authors.lastname: Khedr
authors.affiliation: The Medicinal and Aromatic Plants Research Institute (MAPRI), National Centre for Research, Mac Nimr Street, P.O. Box 2404, Khartoum, Sudan.
authors.forename: Haidar
authors.initials: H
authors.lastname: Abd AlGadir
authors.affiliation: Center for Industry, University and Government Cooperation, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi 852-8521, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takeshita
authors.affiliation: Kenya Research Station, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi 852-8523, Japan.
authors.forename: Mohammad Monir
authors.initials: MM
authors.lastname: Shah
authors.affiliation: Kenya Research Station, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi 852-8523, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ichinose
authors.affiliation: Graduate School of Biomedical Sciences, School of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi 852-8521, Japan; Center for Industry, University and Government Cooperation, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi 852-8521, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Maki