Transformation reaction of prenylated chalcone of pinostrobin derivative and their antibacterial activity

Abstract

The transformation reaction of chalcone prenylation of pinostrobin derivatives has been done. The pinostrobin was isolated from Kaempferiapandurata rhizome which is the main component. The transformation reaction was approved by reacting monooxyprenylated chalcone (1) through zinc chloride (ZnCk) and toluene. The purification of the product was performed with chromatographic methods (radial chromatography and thin layer chromatography). Four compounds have been achieved from the transformation reaction, i.e. monocyclicprenylated chalcone (2), monocyclicprenylated pinostrobin (3), monoprenylated chalcone (4), and monoprenylated pinostrobin (5). The elucidation structures of the compounds were confirmed on the spectra of 1H NMR, 13C NMR, and mass spectrometry data. The antibacterial activity was valued using the minimum inhibitory concentration (MIC) against five bacteria, namely, Staphylococcus aureus ATCC 29737, Proteus mirabilis ATCC 21100, Bacillus subtilis ATCC 6633, Klebsiella pneumoniae ATCC 13733, and Escherichia coli O157:H7. The compound 4 showed a potential compound as antibacterial activity against Bacillus subtilis ATCC 6633 (MIC 7,8 μg/mL) and Proteus mirabilis ATCC 21100 (15,6 μg/mL) bacteria.