I am looking for clear-cut protocols for the quantification of tyrosinase inhibition of plant extracts or isolated compounds from plant sources. What are the differences if crude extracts were used instead of pure, isolated compounds? Sensitivity and specificity? I downloaded some papers and now looking for expert opinion on this matter.
I am an MSc student at the University of Pretoria, Department of Plant Science. We do some in vitro inhibition studies on tyrosinase using the colorimetric assay. The assay monitors the appearance of the colour change from clear to brown (melanin formation) in the presence and absence of different concentrations of potential inhibitors.
Have a look at the articles:
"The tyrosinase inhibition assay performed :Tyrosinase activity of Greyia flanaganii (Bolus) constituents" Phytomedicine, 18(11) 2011,1006–1012
M.B. Mapunya, A.A. Hussein, B. Rodriguez, N. Lall
"Glabrene and Isoliquiritigenin as Tyrosinase Inhibitors from
Licorice Roots" J. Agric. Food Chem. 2003, 51, 1201−1207
OHAD NERYA, JACOB VAYA, RAMADAN MUSA, SARIT IZRAEL, RUTH BEN-ARIE AND SNAIT TAMIR
There is a slight difference between testing crude extracts and pure compounds.
For the crude extracts it is important to make a colour control when reading the plate on the ELISA reader. This is to remove any interference from the colour of the extract which may influence the colour which is formed during the conversion of L-tyrosine or L-DOPA to melanin and ultimately your results when calculating percentage inhibition.
For pure compounds we generally test at slightly lower concentrations as they show better activity. A general problem with pure compounds though is precipitation when mixed with the assay buffer.
I am an MSc student at the University of Pretoria, Department of Plant Science. We do some in vitro inhibition studies on tyrosinase using the colorimetric assay. The assay monitors the appearance of the colour change from clear to brown (melanin formation) in the presence and absence of different concentrations of potential inhibitors.
Have a look at the articles:
"The tyrosinase inhibition assay performed :Tyrosinase activity of Greyia flanaganii (Bolus) constituents" Phytomedicine, 18(11) 2011,1006–1012
M.B. Mapunya, A.A. Hussein, B. Rodriguez, N. Lall
"Glabrene and Isoliquiritigenin as Tyrosinase Inhibitors from
Licorice Roots" J. Agric. Food Chem. 2003, 51, 1201−1207
OHAD NERYA, JACOB VAYA, RAMADAN MUSA, SARIT IZRAEL, RUTH BEN-ARIE AND SNAIT TAMIR
There is a slight difference between testing crude extracts and pure compounds.
For the crude extracts it is important to make a colour control when reading the plate on the ELISA reader. This is to remove any interference from the colour of the extract which may influence the colour which is formed during the conversion of L-tyrosine or L-DOPA to melanin and ultimately your results when calculating percentage inhibition.
For pure compounds we generally test at slightly lower concentrations as they show better activity. A general problem with pure compounds though is precipitation when mixed with the assay buffer.
Hi, there!
If you have solubility trouble, add a small proportion of DMSO (less than 10%)
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