Explore The Metabolites From A Marine-derived Fungus YS7-10-4

The seas and the oceans always have harsh environmental conditions. Such as,high salinity, low-luminance, low temperature, high pressure, oligotrophic, etc. Inorder to adapt to the harsh environment, marine-derived fungi produced differentmetabolic and defence systems. Therefore, we can often find many secondarymetabolites, with various novel and specific chemical structures, from marine-derivedfungi. The metabolites from marine-derived fungi have various biological activitiesincluding antibacterial, antitumor and antiviral activity, which have attractedconsiderable attention in chemical and pharmaceutical communities. This article hasstudies on the metabolites from a marine-derived fungus YS7-10-4, which is a brownfungus and was separated from yangsha mountain, Ningbo, Zhejiang. Threecompounds were isolated and structure elucidated: YS A (1), haematocin (2), and YSB (3). Among them, compound2is a known compound, compounds1and3are newcompounds. Comparing the structure of the3compounds, we find that these3compounds are come from the same diketopiperazine (DKP) biosynthesis pathway.They all come from two L-Phe’s cyclic condensation. Compound2is centralsymmetry, and one double bond of each benzene is hydrolyzed and then acetylesterificated, respectively. Compared with compound2, the only difference ofcompounds1and2is that one of the two hydroxyls of compound1is not acetylesterificated. Similarly, Compared with compounds1and2, compound3still has acomplete benzene ring. The antibacterial activities test found that the threecompounds’ minimal inhibitory concentration (MIC) to Methicillin-resistantStaphylococcus aureus (MRSA), Staphylococcus aureus (SA), Bacillus subtilis (BS),Enterococcus faecalis (Ef), Pseudomonas aeruginosa (PA) and Escherichia coli(E.coli) are all above100μg/mL. So, there are barely no antimicrobial activities. Inaddition to this, we have established an efficient method for preparative separation ofthese3compounds through a combination of high speed counter-currentchromatography (HSCCC) and high performance liquid chromatography (HPLC). Firstly, we used HSCCC to gradiently separate compunds1+2part and3part. Then,we used semi-preparing HPLC to further separate the1+2part. Eventually, wesucceeded in high-efficient preparation of compounds1,2, and3, and their puritiesare all above95%. This part of work not only lay the foundation for high-efficientpreparation of compounds1,2, and3, but also can be used for high-efficientpreparation of other marine natural products. Thus, it can be seen that HSCCC hasextensive application prospect in the separation and purification of marine naturalproducts.