摘要

Polyprenol (GBP) separated from Ginkgo biloba L. leaves (GBL) is an important lipid component having many bioactive effects. The five GBP derivatives, polyprenyl acetate, n-amyl polypentylene, polyprenyl-3-isoamyl benzyl ether, polyprenyl dichlorophosphite (GPD) and polyprenyl phosphate disodium salt (GPP), were synthetized from GBP homologs (C-70-C-120), isolated and purified from GBL. This study provides the new evidence of the antibacterial/antifungal activities and synergistic effect on GBP with the five GBP derivatives against five pathogenic strains (Salmonella enterica, Staphylocococus aureus, Aspergillus niger, Escherichia coli and Bacillus subtilis). As a result, GPD showed the highest activity among all the tested samples and inhibited the growth of all the strains. And the GPP and GBP mixture group had the strongest synergistic effect against S. enterica among all mixture groups against the five tested strains, and the fractional inhibitory concentration index was 0.37. The proportion of GPP and GBP was 37.41:62.59 % (wt/wt) that was determined as the optimal proportion of synergistic effect on GPP with GBP against S. enterica. It infers that the antibacterial/antifungal activities and synergistic effect on alkyl-substituted GBP derivative with GBP are decreased, while the effect of phosphate-substituted GBP derivative with GBP is increased. The author assumes that antibacterial/antifungal activity of polyprenols and their derivatives is maybe a connection between increased membrane destabilization and increased polyprenol length, and polyprenols compared with their derivatives have different arrangement to the membrane surface of microorganisms. This study provides a new scientific basis for the ethnomedical use of GBP and GBP derivatives against bacterial and fungal diseases of animals and plants.