TITLE:
Antibacterial compounds from Rutaceae with activities against Flavobacterium columnare and Streptococcus iniae
AUTHORS:
Kumudini M. Meepagala, Kevin K. Schrader, Charles L. Burandt
KEYWORDS:
Murraya koenigii; Amyris texana; Piper nigrum; Columnaris Disease; Flavobacterium columnare; Streptococcosis; Streptococcus iniae; Aquaculture
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.2 No.4,
November
5,
2013
ABSTRACT: From the ethyl acetate extract of Murraya koenegii (Rutaceae) leaves, isomahanine (1) and mahanine (2) were isolated that showed antibacterial activity towards Flavobacterium columnare and Streptococcus iniae which caused columnaris disease and streptococcosis respectively. Isomahanine was found to have the strongest activity against F. columnare (isolate ALM-00-173) and S. iniae (isolate LA94-426) based on 24-h 50% inhibition concentration (IC50) and minimum inhibition concentration (MIC). Although compound (7), a nicotinamide isolated from Amyris texana had the lowest MIC (2.8 ± 0 mg/L) of any of the test compounds against F. columnare, the 24-h IC50 of 14.8 ± 0.6 mg/L was higher than that of isomahanine and subsequently the 24-h IC50 RDC values for (7) were almost a magnitude of order higher than those obtained for isomahanine. Isomahanine also had the strongest activity against S. iniae, with a 24-h IC50 of 1.3 ± 0.1 mg/L and MIC of 3.5 ± 0 mg/L, respectively.