ABSTRACT
Objective: To isolate and purify endophytic fungus from Glycyrrhiza uralensis, and screen the specific strain with better antibacterial and antioxidant activity (DPPH• radical scavenging, total reducing power, determination of hydroxyl radical scavenging) and anti-alpha-glucosidase activity. Methods: The endophytic fungi were isolated and purified from G. uralensis by tissue cutting. N-butanol, ethyl acetate and ethanol were used to extract the fermentation liquid and mycelium. Antibacterial activity was detected by filter paper. Three methods were used to characterize antioxidant activity. A total of 36 endophytic fungi were isolated from G. uralensis by PNPG method. Results: A total of seven genera were isolated from 108 samples by concentrated fermentation liquid extraction. Trichoderma. sp was the dominant species. The experimental results showed that 43.52% of the samples had different degrees of antibacterial effect, of which 8.33% performed well; The extracts showed different levels of antioxidant activity, of which 4.63% to 10.12% showed better performance in the three methods. 99.07% of the samples had different levels of anti-α-glucosidase activity, of which 5.56% of the samples performed well. Conclusion: The strains isolated from G. uralensis have good antibacterial activity, antioxidant activity, and anti-alpha-glucosidase activity, which further study is needed.
ABSTRACT
Objectives: To isolate endophytic fungi from the roots and stems of Narcissus tazetta var. chinensis, and to determine their antimicrobial and antitumor activities. Medthods: After isolating the endophytic fungi, the antimicrobial activity from the isolated endophytic fungi was detected using filter paper method with Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae as indicator microorganisms. And the antitumor activity on HepG2 was detected by MTT assay. Results: A total of 18 strains of the endophytic fungi were isolated. The ethyl acetate extracts of the fermentation broth had the significant antibiotic activity on almost all the indicator microorganisms, and had the apparent antitumor activity on HepG2. Among these, the antibiotic activity of strains SX-R202 and SX-S102 against E. coli and P. aeruginosa were the highest, with the inhibiting zone diameters of 18 and 20 mm, respectively, at the concentration of 10 mg/mL. And at the extracts concentration of 1 mg/mL, the inhibitory rates (IR) of strains SX-R201, SX-R202, SX-R203, and SX-R204 on HepG2 were (86.0 ± 1.1)%, (89.8 ± 1.3)%, (62.9 ± 0.9)%, and (90.6 ± 1.0)%. With the identification by morphology and molecular biology, strain SX-R201 was determined to belong to the genus Fusarium sp., and SX-R202 and SX-R203 to Penicillium sp., SX-R204 and SX-S102 to Aspergillus sp., respectively. Conclusion: The results indicate that the endophytic fungi of N. tazetta var. chinensis are potential antimicrobial and antitumor resource, which deserves further studies.
ABSTRACT
Objective: To isolate and purify endophytic fungi from the roots and stems of Narcissus tazetta var. chinensis, and to analyze the composition and diversity of endophytic fungi. Medthods: Endophytic fungi were isolated from the bulb and root of N. tazetta var. chinensis by surface sterilization and streaking on plate. Then, the isolates were identified based on morphological characteristics and internal transcribed spacer-rDNA (ITS-rDNA) sequences analysis. Besides, Shannon-Wiener biodiversity (H) and evenness (E) were selected as two key indexes, and the composition and diversity of endophytic fungi were analyzed. Results: Eighteen strains of endophytic fungi were isolated, in which 16 strains were obtained from the root (88.89%), the other two strains were obtained from the bulb (11.11%). ITS-rDNA fragments from 14 samples were respectively amplified by PCR method with their genomic DNA as templates. The sequencing results showed that most of these DNA fragments were about 500 bp. In addition, according to sequence analysis and comparison with the data in GenBank by BLAST, four strains with the similarity of 95% to 99% were classified as Penicillium, three strains were classified as Aspergillus with the similarity of 99% to 100%, three strains were classified as Rhinocladiella with the similarity of 99%, and the other four strains were classified as Trichoderma, Alternaria, Gibberella, and Fusarium, respectively, with the similarities about 99%. Therefore, it was concluded that Penicillium was the dominant endophytic fungi genus in N. tazetta var. chinensis under our experimental conditions. The phylogenic tree showed that these 14 endophytic fungi were clustered into two main branches, by which factors H and E were determined as 1.778 and 0.9137, respectively. Conclusion: The composition of endophytic fungi community has a certain diversity and difference.