Comparison on antimicrobial activity of 40 endophytic fungi strains from Ginkgo biloba and preliminary analysis on ingredients with antimicrobial activity / 中草药

ABSTRACT

Objective: To compare the antimicrobial activity of 40 endophyte strains from Ginkgo biloba and analyze the ingredients with antimicrobial activity. Methods: Endophytic fungi inhabited in leaves, stems, and fruits of Ginkgo biloba were isolated. Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus niger and Rhizopus were used as indicators to do the microbial inhibition experiment. Forty strains antimicrobial activity were investigated by using filter paper method and flat hole well diffusion method. Silica gel column chromatography, Sephadex LH-20 column chromatography, preparative HPLC, TLC, and HPLC-MS were used to isolate, purificate and identify the antimicrobial components from the broth of Penicillium oxalicum YXY009. Results: Eighteen strains produced sterile mycelia on PDA plates. Among the other strains, Penicillium spp. and Aspergillus spp. accounted for 17.5% and 15% of the total fungi. The strain with the highest antimicrobial activity was determined to be Penicillium oxalicum YXY009. The inhibiting zone diameters of the YXY009 strain reached (13.47 ± 0.46), (22.35 ± 1.32), and (23.60 ± 0.83) mm against Bacillus subtilis, Saccharomyces cerevisiae, and Rhizopus, respectively. Conclusion: An active compound POM was isolated from the fermentation broth of the strain P. oxalicum YXY009 and identified as 5-hydroxy-2-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl) oxan-2-yl] oxybenzoate for the first time.