Abstract:
The purpose of this research was to isolate bioactive compounds from endophytic fungi isolated from Mitragyna speciosa Korth. Plant samples were collected from 3 provinces; Pathumthani, Ayuthaya and Surathani. Fungal endophytes were isolated from leaves by surface sterilization and placed on potato dextrose agar. Thirty-nine fungal isolates were obtained and tested for the production of antimicrobial compounds by dual culture agar diffusion technique. Fungal isolate P03 was chosen for the study of bioactive compounds because this isolate produced the compounds that were against a large number of test microorganisms. Based on morphology and nucleotide sequencing of internal transcribed spacer (ITS) regions of rDNA, isolate P03 was identified as Glomerella cingulata. Chromatographic techniques and crystallization were used to isolate bioactive compounds from sabouraud dextrose broth ethyl acetate crude, mycelium ethyl acetate crude and mycelium methanol crude. Structure elucidations of the pure compounds were investigated using physical properties and spectroscopic techniques. Mycelium ethyl acetate crude gave oil (mixture 1) and ergosterol peroxide (compound 1). Mycelium methanol crude gave ursolic acid (compound 2). Antimicrobial activities and cytotoxicity of the pure compound were tested. Ergosterol peroxide (compound 1) was found to exhibit activity against Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Candida albican ATCC 10231 with the MIC value of 15.6 (36.4), 15.6 (36.4), 15.6 (36.4), 15.6 (36.4) and 61.25 (143.1) microgram/ml (micrometre), respectively; and exhibit cytotoxic activity against HEP-G2, CHAGO, SW620, KATO-3 and BT474 with IC[subscript 50] 5.0 (11.7), 6.3 (14.7), 5.2 (12.1), 5.8 (13.6) and 8.5 (19.2) microgram/ml (micrometre), respectively. Ursolic acid (compound 2) was found to exhibit activity against Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Candida albican ATCC with the MIC value of 125 (274.1), 125 (274.1), 250 (548.2), 125 (274.1) and 125 (274.1) microgram/ml (micrometre), respectively; and exhibit cytotoxic activity against HEP-G2, CHAGO, SW620, KATO-3 and BT474 with IC[subscript 50] 5.4 (11.8), 5.6 (12.3), 0.8 (1.7), 0.5 (1.1) and 0.7 (1.5) microgram/ml (micrometre), respectively