Study of Micromonospora sp. from the mesophotic zone of the Gulf of Thailand aimed at discovery of anti-aging natural products

Marine actinobacteria have attracted the attention of the scientific community in recent years, as a novel source of a wide variety of bioactive natural compounds. In continuation of our work towards the investigation of this microbial group within the TASCMAR project framework, a strain identified as Micromonospora sp. (XLm-22-s1) was chosen for further study and bio-guided isolation of its secondary metabolites. After cultivation in both solid and liquid conditions, the extraction of the cultures was conducted using ethyl acetate and methanol. Four extracts (two ethyl-acetate and two methanolic extracts of solid and liquid cultures, respectively) were enzymatically evaluated via bioassays for their anti-elastase, anti-tyrosinase and anti-proteasome activities. The ethyl acetate extract of the solid culture demonstrated 57.51% proteasome inhibitory effect. The profiling and fractionation of the extracts were performed using various chromatographic methods (preparative TLC, semi-prep HPLC, CC). From the analysis of the obtained spectroscopic data (1D and 2D NMR, LC-HRMS), seventeen compounds were identified, of which six belonged to the diketopiperazine group, three were characterized as indolocarbazole derivatives, three were alkaloids, one was identified as a quinone, a single compound belonged to amino acids, and lastly, a nucleobase and a nucleoside were also identified. While sixteen of the aforesaid compounds are well described in the literature, one represents a novel natural product. All compounds were further evaluated for their anti-aging activity. In conclusion, the isolate of Micromonospora sp. has proved to be an important source of bioactive secondary metabolites. The Authors declare that there is no conflict of interest.

 

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Artikel online veröffentlicht:
12. Dezember 2022