Antibacterial activity of furoquinolone alkaloids against potato soft rot bacterium, erwinia carotovora from ruta chalepensis leaves

Abstract EN

Soft rot bacterium ; Erwinia carotovora is one of the most severe post-harvest diseases of potatoes worldwide.

This bacterium affects tubers during storage, transit and marketing.

The aqueous ethanolic extract (80 %) of Ruta chalepensis leaves (Rutaceae) showed antibacterial activity against Erwinia carotovora (MIC = 625 µg / ml).

Bioassay-guided isolation of this aqueous extract by using a combination of different chromatographic methods (TLC and column chromatography) yielded two furoquinolone alkaloids for the first time from this plant.

Their structures were characterized as 2, (hydroxy isopropyl)– 6, hydroxy –9, methyl-dihydrofuro [2, 3]–quinol-4-one (I) and 3, (hydroxy methyl)-6, methoxy-2, 2, 9-trimethyl-dihydrofuro [2, 3] quinol-4-one (II) by 1H, 13C NMR and MS spectral data.

The isolated alkaloids I and II showed antibacterial activity against Erwinia carotovora with MIC at 20 and 35 µg / ml respectively.