| Due to the unique and harsh natural environment in Polar Regions, polar microorganisms endow with unique molecular mechanisms and physiological and biochemical characteristics which have been regarded as an important source for bioactive secondary metabolites with novel structures. In recent years, the polar microbes secondary metabolites researches had become popular in worldwide and numerous unique and novel compounds were isolated from polar microorganisms. Penicillium sp.S-1-16 was isolated from an Antarctic sea cucumber sample. In our previous work, we found the butyl acetate extract of Penicillium sp. S-1-16 exhibited cytotoxic activities against the tumor cell line. In order to explore bioactive secondary metabolites with novel structures, we carried out investigation of the bioactive compounds from Antarctic fungus Penicillium sp. S-1-16. The present work includes optimization of fermentation conditions, purification and structural elucidation of the secondary metabolites and bioactivities evaluation of isolated compounds.The results are as follow:1. The purpose of optimization the culture media, fermentation time and temperature of Penicillium sp. S-1-16 is to improve the yield of second metabolites, biomass, and the antitumor activity. The optimized fermentation conditions are as follow: 0.3 % yeast powder, 0.5 % peptone, 0.3 % maltose, 1 % glucose, 5 % sucrose, 15 % inoculation, initial p H7.0, 18 ℃, 180 r/min for 15 days. Comparing with the initial condition, the amount of secondary metabolites was increased to 568.75 % and cytotoxic activity against A549 cell was increased to 265 % under the optimized fermentation conditions. Furthermore, the inhition ratio against Hela cells and SGC-7901 cells was increased from 0 to 48.19% and 69.18 % respectively.2. Seventeen compounds were isolated from Antarctica fungus Penicillium sp. S-1-16 by silica gel column chromatography, ODS column chromatography, Sephadex LH-20 column chromatography, preparative thin layer chromatography and high performance liquid chromatography. The structures of these compounds were elucidated by spectroscopic methods(1D and 2D NMR, HR-ESI-MS). They were characterized as methyl 4-ureidobutanoate(1), phenochalasin B(2), penicilliumine(3), meleagrin(4), guignarderemophilane A(5), β-adenosine(6), emodin(7), chrysophanol(8), ergosterol peroxide(9), β-sitosterol(10), N-(2-hydroxypheny)-acetamide(11), chrysogine(12), 2-acetylquinazoline(13), monoheptadecanoin(14), 2,4-dioxohexahydro-1,3-diazepin(15), butyl-isobutyl-phthalate(16) and dibutyl phthalate(17). In all of them, compound 1 was a new natural product, and compound 2, compound 6 and compound 15 were firstly obtained from Penicillium genus.3. The bioactivities of these compounds were evaluated. Compound 7 exhibited strong antibacterial activities against Escherichia coli, Bacillus subtilis and Staphyloccocus aureus with MIC value of 3.125, 3.125 and 1.56 μg/m L, respectively. Compound 2 and 10 showed weak antibacterial activities against indicator bacteria. Compound 2, 4, 7, 10 and 13 could inhibit the growth of Pyricularia orygae with MIC values of 1.563, 6.25, 0.781, 6.25 and 6.25 μg/m L, respectively. Compound 2 could effectively inhibit the growth of HCT-116, K562, MCF-7 and 22RV1 tumor cells with IC50 of 0.66, 0.59, 0.13 and 2.45 μM, respectively. Compound 2 also showed weak PTP1 B inhibitory activity... |
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