Study On The Secondary Metabolites From Aquilaria Sinensis And The Microbialtransformation Of Its Endophytic Fungi

The volatile oils of endophytic fungus A14 (Aspergillus sp.) from Aquilaria sinensis were extracted by solvent method and their antimicrobial activities against 3 pathogens were tested by agar disc diffusion method. The results indicated that the volatile oils of A14 exhibited weak antimicrobial activities against S. aureus、MRSA as well as C. albicans.14 ingredients were identified from the volatile oil of A14 by GC-MS analysis, and mellein was the main component, which accounted for 93.41% of the peak area.Seventeen compounds were isolated from the ethanol extract of the stem of Aquilaria sinensis by column chromatography, and their structures were elucidated by physicochemical and spectral data (UV, IR, MS, 1D NMR, and 2D NMR) as:aquilarin A (1), aquilarin B (2), 23,24-dihydrocucurbitacin-F (3),phorbol 13-acetate (4), apigenin-7,4’-dimethylethers (5), 5-hydroxyl-7,3’,4’-trimethoxyflavone (6),7,4’-dimethyl-luteolin (7), genkwanin (8), 4’,5-dihydroxy-3’,7-dimethoxyflavone (9), akuranetin (10),4-(3’-(hydroxymethyl) oxiran-2’-yl)-2,6-dimethoxyphenol (11), coniferaldehyde (12), balanophonin (13), evofolin B (14), (+)-lariciresinol (15),(3β,5α,8α,22E,24R)-5,8-epidioxyergosta-6,22-dien-3-ol (16) andβ-Sitosterol (17). Among them, compound 1 and 2 were new compounds.The cytotoxic activities of all the compounds were measured by MTT method. Compound 3 exhibited cytotoxic activities against SMMC-7721, SGC-7901 and K562 cell lines. Compound 4 and 13 exhibited cytotoxic activities against SGC-7901 cell lines. Compound 15 exhibited cytotoxic activities against SMMC-7721 and SGC-7901 cell lines. The antimicrobial activities of all the compounds were measured using paper disco diffusion method. Compound 3 exhibited anti-microbial activities against Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus.In addition, eight strains were chosen from the forty-two endophytic fungi isolated from A. sinensis, and their microbialtransformations of the A. sinensis plant were investigated in this thesis by both TLC and HPLC methods. Acremonium were proved by the result to transform the 4-(3’-(hydroxymethyl) oxiran-2’-yl)-2,6-dimethoxyphenol produced by A. sinensis. and this transformation is stable in the four Acremonium sp. strains in the test. This research tells that the microbialtransformation of endophytic fungi plays a special role in the A. sinensis plant, and may also be important in the formation of Chinese eaglewood, which is worthy of further study.