1.Synthesis of fluorescent-labeled aeruginosin derivatives for high-throughput fluorescence correlation spectroscopy assays.
Hoshina Y1, Yamada Y, Tanaka H, Doi T, Takahashi T. Bioorg Med Chem Lett. 2007 May 15;17(10):2904-7. Epub 2007 Feb 22.
The design and solid-phase synthesis of effective fluorescent-labeled aeruginosin derivatives and their application to the fluorescence correlation spectroscopy (FCS)-based competitive binding assay of an aeruginosin library are described. The phenolic hydroxyl group on the (R)-3-(4-hydroxyphenyl)lactic acid (d-Hpla) residue was observed to be suitable for connecting Rhodamine green derivative with minimum loss of biological activity. In addition, the FCS-based binding assay of the library using fluorescent-labeled chemical probes was also achieved.
2.Use of non-melanocytic HEK293 cells stably expressing human tyrosinase for the screening of anti-melanogenic agents.
Kim M1, An SM, Koh JS, Jang DI, Boo YC. J Cosmet Sci. 2011 Sep-Oct;62(5):515-23.
Tyrosinase (TYR) from mushrooms has been inappropriately used in the screening assay for hypopigmenting agents even though its biochemical properties are different from those of human TYR. Cell-free extracts of human epidermal melanocyes (HEMs) could be another choice for the assay, but HEMs grow too slowly to get a sufficient amount of cell-free extracts. In the present study, human embryonic kidney (HEK) 293 cells were transfected with a human TYR construct to establish a cell line that grows rapidly and expresses human TYR constitutively. Cell-free extracts of the established cell line, HEK293-TYR, were tentatively used in the screening assays for 11 phenylpropanoids that have chemical structures similar to that of L-tyrosine, the substrate of TYR. Of the 11 compounds, the strongest inhibition of TYR activity was shown by p-coumaric acid (IC50, 3 μM), followed by 3-(4-hydroxyphenyl)propionic acid (50 μM) and 3-(4-hydroxyphenyl)lactic acid (70 μM).
3.Production of beta-(4-hydroxyphenyl)ethanol and beta-(4-hydroxyphenyl)lactic acid by Candida species.
Narayanan TK, Rao GR. Can J Microbiol. 1976 Mar;22(3):384-9.
Two crystalline compounds were isolated from the culture filtrates of Candida species grown in synthetic medium supplemented with L-tyrosine as the sole source of nitrogen. These compounds were characterized as beta-(4-hydroxyphenyl)ethanol (HOPEA) and beta-(4-hydroxyphenyl)lactic acid (HOPLA). The production of these compounds in five species (both pathogenic and non-pathogenic) was compared and marked differences were revealed. Experiments using L-[14C]tyrosine indicated that both HOPEA and HOPLA are synthesized from L-tyrosine.
4.Identification of antioxidants produced by Lactobacillus plantarum.
Suzuki Y1, Kosaka M, Shindo K, Kawasumi T, Kimoto-Nira H, Suzuki C. Biosci Biotechnol Biochem. 2013;77(6):1299-302. Epub 2013 Jun 7.
We identified two compounds that demonstrated 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity from cultures of Lactobacillus plantarum. Spectroscopic analyses proved these compounds to be L-3-(4-hydroxyphenyl) lactic acid (HPLA) and L-indole-3-lactic acid (ILA). The respective EC50 values for HPLA and ILA were 36.6 ± 4.3 mM and 13.4 ± 1.0 mM.
