Search for novel cosmeuceutical agents from the Actinobacteria Micromonospora sp.

In the frame of MICROSMETICS project, 614 extracts from 110 actinobacteria strains were evaluated for their anti-ageing activity. Anti-oxidant, skin-protecting and skin-whitening bioactivities were analyzed and 12 actinobacteria strains were selected. Different cell-based analyses have been performed to evaluate their anti-ageing activity. The extracts were screened for tyrosinase inhibition effect (skin whitening) in mouse melanocytes (B16F10 cell line), as well as for their capacity to activate proteostasis and autophagy system in normal human skin fibroblasts, ensuring anti-ageing mechanisms [1]. One of the most active strains, Micromonospora sp. CA-129255 has been selected for large-scale cultivation, fractionation, dereplication and identification of bioactive compounds.

Biomass was first extracted with Hexane, followed by EtOAc and EtOH/H₂O. Preliminary biological evaluation of the EtOH/H₂O extract showed statistically significant increasing of cathepsin activity (56% at 1 µg/ml) of human fibroblast exposed to the extract while the EtOAc extract showed inhibitory effects against tyrosinase activity on melanocyte cells (66% at 300 µg/ml). The dereplication of the extract was performed using UHPLC-HRMS and the isolation of secondary metabolites was realized using classical chromatographic methods. In order to elucidate the structure of all isolated compounds, the full set of spectroscopic (1 & 2D NMR) and spectrometric data (HRMS/MS) were recorded. A series of indole derivatives, including the chlorinated compound N-acetyl-6-chloro-L-tryptophan as well as a series of thymidine and guanosine derivatives were isolated from the EtOH/H₂O extract. All the isolates are currently under investigation for their anti-ageing properties in order to standardize the extract on specific biomarkers that can be used for cosmeceutical industry.

This work has been financially supported by EU under the frame of MICROSMETICS project (FP7-PEOPLE-IAPP 2013, Grant agreement: 612276).

[1] Georgousaki K et al. Planta Medica 2015; 81 – PM_234