Secondary Metabolites And Application Studies Of Three South China Sea Coral Symbiotic Fungi

Objective（s）:This paper aims to carry out large-scale standing fermentation of three strains of South China Sea origin fungi Purpureocillium lilacinum SCSIO 41204,Aspergillus flavus SCSIO C3F31 and Penicillium reticulisporum SCSIO 75,and study secondary metabolites of fermentation products by separation and purification.Look for peptides and compounds with anti-inflammatory activity,as well as some monomeric compounds with unique structure and remarkable activity.Method（s）:In this paper,three fungi derived from the South China Sea were first subjected to large-scale standing fermentation with medium,Then,the fermentation products were extracted under reduced pressure with equal volumes of ethyl acetate,and the fermentation products were separated and purified by silica gel column chromatography,medium pressure reversed-phase column chromatography,thin layer chromatography and semi-prepared high performance liquid chromatography,and monomer compounds were obtained.Finally,the structure of the monomeric compounds isolated in this paper was identified by nuclear magnetic resonance and other spectroscopic methods and known reference data,and all compounds were screened for acetylcholinesterase inhibition,antibacterial,anti-inflammatory and antitumor activities.Result（s）:Seven previously reported compounds were isolated from secondary metabolites derived from the fungus Purpureocillium lilacinum SCSIO 41204,a coral symbiotic fungus in the Paracel Islands in the South China Sea:phenazine-1-carboxylic acid（A1）,（E）-12-hydroxyoctadec-10-enoic acid（A2）,3-benzyl-6-methyl-2,5-piperazinedione（A3）,3β,5α,9α-trihydroxy-（22E,24R）-er-gosterane-7,22-dien-6-one（A4）,AGE-1（A5）,AGE-2（A6）,volemolide（A7）;Thirty compounds（17S）-17-methylincisterol（B1）,dankasterones A（B2）,phoma pyrone B（B3）,sydowione A（B4）,sydowione B（B5）,speradines G（B6）,methyl protocatechuate（B7）,protocatechuic acid（B8）,p-Hydroxybenzaldehyde（B9）,kojic acid（B10）,4-methoxybenze neacetic acid（B11）,phomaligol A₁（B12）,speradine H（B13）,（1R,5S）-4,5-dihydroxy-1,3,5-trimethyl-2,6-dioxocyclo-hex-3-en-1-yl（S）-2-methylbutano-ate（B14）,phomapyrone C（B15）,speradine D（B16）,averufin（B17）,averufanin（B18）,penicillivinacine（B19）,1’-hydroxy versicolorin B（B21）,nidurufin（B21）,2-acetamidobenzoic acid（B22）,dibutyl Phalate（B23）,phomaligol I（B24）,phomaligadiones B（B25）,phomaligol A（B26）,oleic acid（B27）,7,9-dihy-droxy-3-（1H-indol-3-ylmethyl）-8-methoxy-2,3,11,11a-tetrahydro-6H-pyra-zino[1,2-b]isoquino-line-1,4-dione（B28）,speradines B（B29）,cyclopiamide H（B30）,including sterols,polyketones,anthraquinones,and indole alkaloids were isolated from secondary metabolites derived from the coral symbiotic epiphytic fungus Aspergillus flavus SCSIO C3F31 in Sanya,Hainan,China;Six previously including p-Hydroxybenzyl alcohol（C1）,（4-ethylphenyl）methanol（C2）,（4-methoxyphenyl）methanol（C3）,2-methylbenzene-1,3-diol（C4）,4-（4-Hydroxyphenoxy）-benze-neethanol（C5）reported compounds were isolated from secondary metabolites derived from the fungus Penicillium reticulisporum SCSIO 75,a coral symbiotic fungus in the Paracel Islands in the South China Sea.A variety of activity screens were performed on the isolated compounds,and compound B2 showed significant inhibitory activity against two prostate cancer cells.The compound B2 had an IC₅₀ value of 6.416μM for human normal prostate stromal immortalized cells（WPMY-1）,an IC₅₀ value of（5.098±1.26）μM for prostate cancer cells PC-3,and an IC₅₀ value of（3.411±1.88）μΜfor prostate cancer cell 22Rv1.Lipopoly-saccharide（LPS）was used to stimulate RAW264.7 cells to construct an in vitro cellular inflammatory response model,and NF-κB release was used as the activity index to evaluate the anti-inflammatory activity screening,and there was anti-inflammatory activity at 20μM.The compounds B6,B12,B13 and B17 displayed strong inhibitory activity against acetylcholinesterase with inhibition rates of 81.7%,84.0%,83.9%,and 80.2%,respectively;The compounds B4,B10,B11,B18,B19,B20,B21,B24,B25,B26 and B27 showed moderate inhibitory activity,and the inhibition rate was 76.9%,64.5%,71.9%,76.6%,72.4%,68.0%,55.8%,74.0%,72.0%,67.4%and 61.4%,respectively.Conclusion（s）:In this paper,a total of 42 monomeric compounds were isolated from three secondary metabolites of marine fungi of South China Sea origin Purpureocillium lilacinum SCSIO 41204,Aspergillus flavus SCSIO C3F31 and Penicillium reticulisporum SCSIO 75,and all compounds were tested for activity.One compound showed good anti-inflammatory activity,and17 compounds showed good anti-acetylcholinesterase activity.Among them,the compound B2 showed strong anti-inflammatory and prostate cancer inhibitory effects,and was a potential anti-inflammatory and anti-prostate cancer drug lead compound;The compounds B6,B12,B13 and B17 exhibit strong inhibitory effects on acetylcholinesterase and are potential agents for the treatment of Alzheimer’s disease.This study of the secondary metabolites of three fungi derived in the South China Sea further confirms that the South China Sea has rich resources,contains rich natural products with unique structure and novel activity,and is an important source of future clinical drugs and natural medicines,and further enriches marine natural products,providing a certain reference for the development of new marine drugs.