Endophytic fungi isolated from Aglaia odorata Lour. leaves

Abstract

The purpose of this research was to isolate bioactive compounds from endophytic fungi from Aglaia odorata Lour. leaves, Thai medicinal plant. Plant samples were collected from 4 provinces; Bangkok, Khonkean, Maha Sarakham and Pattani. Fungal endophytes were isolated from leaves by surface sterilization method and placed on potato dextrose agar. The total of 60 fungal isolates were obtained and tested for the production of antimicrobial compounds. By dual-culture agar diffusion assay, most of them (67 %) exhibited antimicrobial activities against the standard strains. Effect of culture media, yeast extract sucrose agar was found to be the medium of choice for used in cultivation of endophytic fungus isolates on expression of antimicrobial activities. Aopn12 and malt extract agar were chosen for the further study of bioactive compounds because the malt extract agar blocks of the isolate were active against a large number of test microorganisms. Based onmorphology, the fungus isolate Aopn12 was found as Mycelia sterilia. Based on nucleotide sequencing of ITS region, it was closely related to Oat root associated fungus OOO45 5. Isolation of mycelium ethyl acetate crude of the fungus isolate Aopn12 gave diglyceride (mixture 1), C[subscript 16-18] long chain carboxylic acid (mixture 2) and an orange solid which molecular formula may probably be C[subscript 23]H[subscript 31]NO[subscript 5] (compound 1). These structures were established on basis of spectroscopic analysis and GC analysis. Antimicrobial activities and cytotoxicity of the pure compound were tested. An orange solid (compound 1) was found to exhibit weak activity against B. subtilis with the MIC value of 500 microgram/ml, and exhibit high cytotoxic activity against SW620 (colon), BT474 (breast), KATO-3 (gastric), HEP-G2 (hepatoma) and CHAGO (lung) cell line with IC[subscript 50] 4.5, 5.4, 6, 5.4 and 3.3 microgram/ml, respectively