ABSTRACT
Objective: To study the secondary metabolites of Penicillium oxalicum, an endophytic fungus isolated from the medicinal plant Pseudostellariaheterophylla. Methods: The secondary metabolites were isolated by silica gel, Sephadex LH-20 column chromatographies, and prep-TLC methods. Their structures were elucidated by using various spectroscopic techniques including HRESIMS and NMR spectra. Results: A benzofuran compound 5,7-dihydroxy-2-methylbenzofuran-3-carboxylic acid (1), five isocoumarins including (3R,4R)-(-)-4-hydroxymellein (2), O-methylmellein (3), acremonone G (4), decarboxycitrinone (5) and decarboxyhydroxycitrinone (6), four bisabolane-type sesquiterpenoids including (7S,11S)-(+)-12-acetoxysydonic acid (7), (S)-(+)-11-dehydrosydonic acid (8), sydonic acid (9) and 1-hydroxy-boivinianin A (10), as well as two meroterpenoid-type alkaloids decaturin D (11) and decaturinC (12) were isolated. Conclusion: Compound 1 is a new benzofuran compound and named as oxafuranone A, while compounds 2-6 and 10 are characterized from P. oxalicum for the first time.
ABSTRACT
Objective: To select and identify the endophytic fungi of Rabdosia rubescens as well as study on its antitumor activity in vitro in order to obtain the high yield strains of oridonin. Methods: Using the methods of TLC and HPLC, the oridonin high yield strain was selected from 256 strains of endophytic fungi which were isolated from the previous experiments. Oridonin of fermentation broth was determined by HPLC-MS. The strain was identified by morphological characteristics and ITS sequence methods and its antitumor activity in vitro was detected by MTT assay. Results: An oridonin high yield strain M-J-5 was obtained and identified as Penicillium oxalicum, which can inhibit the activity of human breast cancer cell line MCF-7. Conclusion: a oridonin high yield strain is obtained with antitumor activity and provides scientific basis for microbial production of oridonin and the development of new anticancer drugs.
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.
ABSTRACT
The aim of this research was the analysis of the possible antagonistic effect of Penicillium oxalicum over the pathogen rice fungus A. alternata under different conditions of temperature, water activity and culture media. The macroscopic study of the dual growth revealed that according to the Index of Dominance P. oxalicum was more competitive that A. alternata at 25ºC whereas at 15ºC was this species. Microscopic analysis showed that P. oxalicum was a mycoparasite of A. alternata at all conditions tested. The antagonist penetrated into A. alternata and disintegrated its conidiophores and conidia. The results suggests that P. oxalicum may be a possible biological control agent of the rice pathogens in a future.