Chemical Constituents Of Penicillium Sp. MA-37a Fungus Deirved From Marine Mangrove Rhizospheres

In this dissertation, the strain Penicillium sp. MA-37(isolated from the rhizosphere of marinemangrove plant Bruguiera gymnorrhiza) was selected as aimed strain on the basis of weight offermentation extracts along with TLC and HPLC analysis. The effect of different fermentationmodes (static and dynamic) and culture media (composition, salinity and pH) on its chemicalprofiles was investigated, and the strain Penicillium sp. MA-37was fermented on MH2mediumin both static and shaking fermentation for exhaustive study of secondary metabolites. Most ofthe isolated compounds were evaluated for antimicrobial activity and brine shrimp lethality.The compounds were isolated from the fermentation extracts by repeated columnchromatography (CC) on silica gel, RP-18, and Sephadex LH-20, preparative thin layerchromatography (pTLC), preparative HPLC (pHPLC) and re-crystallization. Structures of thesecompounds were elucidated by means of spectroscopic methods including UV, IR, MS, NMRand CD, X-ray crystallography, chemical derivation as well as by comparison with authenticstandards and literature reports. As a result,22compounds were isolated and structurallydetermined from the extract of Penicillium sp. MA-37in static MH2medium, including fournovel meroterpene derivatives (MJ1, MJ2, MJ3, and MJ4) and one novel malonamic acidderivative (MJ10). When cultivated in shaking fermentation, the fungus produced ninecompounds including three new diphenyl ether derivatives (MY1, MY5, and MY7). Theproposed biosynthetic pathways of some compounds were tentatively discussed.Some of the isolated compounds were subjected to antimicrobial activity test against3bacteria and4plant pathogenic fungi, as well as the brine shrimp lethality assay. CompoundsMY5and MY8showed moderate antibacterial activity against Micrococcus luteus andEscherichia coli, with MIC value of64and16μg/mL, and256and32μg/mL, respectively.Compounds MY1, MY2, and MY4exhibited moderate brine shrimp lethal activity with LD50values of47.86,58.96,27.91μg/mL, respectively.This dissertation described on fermentation conditions, isolation and structure elucidation, andbioactivity evaluation of secondary metabolites on marine fungal strain Penicillium sp. MA-37.The chemical profiles of Penicillium sp. MA-37under different fermentation conditions weresystematically studied. These results may be helpful to the exploration and utilization of marinemicroorganisms.